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Jeong GJ, Khan F, Tabassum N, Kim YM. Motility of Acinetobacter baumannii: regulatory systems and controlling strategies. Appl Microbiol Biotechnol 2024; 108:3. [PMID: 38159120 DOI: 10.1007/s00253-023-12975-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 01/03/2024]
Abstract
Acinetobacter baumannii is a Gram-negative opportunistic zoonotic pathogenic bacterium that causes nosocomial infections ranging from minor to life-threatening. The clinical importance of this zoonotic pathogen is rapidly increasing due to the development of multiple resistance mechanisms and the synthesis of numerous virulence factors. Although no flagellum-mediated motility exists, it may move through twitching or surface-associated motility. Twitching motility is a coordinated multicellular movement caused by the extension, attachment, and retraction of type IV pili, which are involved in surface adherence and biofilm formation. Surface-associated motility is a kind of movement that does not need appendages and is most likely driven by the release of extra polymeric molecules. This kind of motility is linked to the production of 1,3-diaminopropane, lipooligosaccharide formation, natural competence, and efflux pump proteins. Since A. baumannii's virulence qualities are directly tied to motility, it is possible that its motility may be used as a specialized preventative or therapeutic measure. The current review detailed the signaling mechanism and involvement of various proteins in controlling A. baumannii motility. As a result, we have thoroughly addressed the role of natural and synthetic compounds that impede A. baumannii motility, as well as the underlying action mechanisms. Understanding the regulatory mechanisms behind A. baumannii's motility features will aid in the development of therapeutic drugs to control its infection. KEY POINTS: • Acinetobacter baumannii exhibits multiple resistance mechanisms. • A. baumannii can move owing to twitching and surface-associated motility. • Natural and synthetic compounds can attenuate A. baumannii motility.
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Affiliation(s)
- Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Fazlurrahman Khan
- Institute of Fisheries Sciences, Pukyong National University, Busan, 48513, Republic of Korea.
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea.
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea.
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Young-Mog Kim
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea.
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea.
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea.
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O'Hara MT, Shimozono TM, Dye KJ, Harris D, Yang Z. Surface hydrophilicity promotes bacterial twitching motility. mSphere 2024:e0039024. [PMID: 39194233 DOI: 10.1128/msphere.00390-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 06/24/2024] [Indexed: 08/29/2024] Open
Abstract
Twitching motility is a form of bacterial surface translocation powered by the type IV pilus (T4P). It is frequently analyzed by interstitial colony expansion between agar and the polystyrene surfaces of petri dishes. In such assays, the twitching motility of Acinetobacter nosocomialis was observed with MacConkey but not Luria-Bertani (LB) agar media. One difference between these two media is the presence of bile salts as a selective agent in MacConkey but not in LB. Here, we demonstrate that the addition of bile salts to LB allowed A. nosocomialis to display twitching. Similarly, bile salts enhanced the twitching of Acinetobacter baumannii and Pseudomonas aeruginosa in LB. These observations suggest that there is a common mechanism, whereby bile salts enhance bacterial twitching and promote interstitial colony expansion. Bile salts disrupt lipid membranes and apply envelope stress as detergents. Surprisingly, their stimulatory effect on twitching appears not to be related to a bacterial physiological response to stressors. Rather, it is due to their ability to alter the physicochemical properties of a twitching surface. We observed that while other detergents promoted twitching like bile salts, stresses applied by antibiotics, including the outer membrane-targeting polymyxin B, did not enhance twitching motility. More importantly, bacteria displayed increased twitching on hydrophilic surfaces such as those of glass and tissue culture-treated polystyrene plastics, and bile salts no longer stimulated twitching on these surfaces. Together, our results show that altering the hydrophilicity of a twitching surface significantly impacts T4P functionality. IMPORTANCE The bacterial type IV pilus (T4P) is a critical virulence factor for many medically important pathogens, some of which are prioritized by the World Health Organization for their high levels of antibiotic resistance. The T4P is known to propel bacterial twitching motility, the analysis of which provides a convenient assay for T4P functionality. Here, we show that bile salts and other detergents augment the twitching of multiple bacterial pathogens. We identified the underlying mechanism as the alteration of surface hydrophilicity by detergents. Consequently, hydrophilic surfaces like those of glass or plasma-treated polystyrene promote bacterial twitching, bypassing the requirement for detergents. The implication is that surface properties, such as those of tissues and medical implants, significantly impact the functionality of bacterial T4P as a virulence determinant. This offers valuable insights for developing countermeasures against the colonization and infection by bacterial pathogens of critical importance to human health on a global scale.
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Affiliation(s)
- Megan T O'Hara
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Tori M Shimozono
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Keane J Dye
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - David Harris
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Zhaomin Yang
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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Son SM, Ahn E, Ahn S, Cho S, Ryu S. Prevalence of antibiotic-resistant Acinetobacter spp. on soil and crops collected from agricultural fields in South Korea. Food Sci Biotechnol 2024; 33:1931-1937. [PMID: 38752113 PMCID: PMC11091005 DOI: 10.1007/s10068-023-01496-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/14/2023] [Accepted: 11/27/2023] [Indexed: 05/18/2024] Open
Abstract
The emergence of antibiotic resistance in Acinetobacter spp. is a rising public health concern worldwide. The objective of this study was to investigate the prevalence of antibiotic-resistance genes and the virulence of Acinetobacter spp. isolated from soil and crops obtained from agricultural fields in South Korea. Eight Acinetobacter spp. isolates carried various antibiotic resistance genes, such as emrAB (100%), cat/craA (100%), and aadA gene (87.5%). Minimum inhibitory concentration (MIC) analysis revealed that strains harboring antibiotic resistance genes exhibited high resistance to the respective antibiotics, such as colistin, chloramphenicol, and streptomycin. Interestingly, most of these isolates had high capability of biofilm formation and swarming motility, along with faster growth rates. Taken together, our study demonstrated that antibiotic-resistant Acinetobacter isolated from agricultural settings in South Korea not only frequently carries antibiotic resistance genes but also has virulence-related traits. Supplementary Information The online version contains supplementary material available at 10.1007/s10068-023-01496-7.
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Affiliation(s)
- Su Min Son
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
- Center for Food and Bioconvergence, Seoul National University, Seoul, 08826 Republic of Korea
| | - Eunbyeol Ahn
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
| | - Sojin Ahn
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, 08826 Republic of Korea
- eGnome Inc., Seoul, 05836 Republic of Korea
| | - Seoae Cho
- eGnome Inc., Seoul, 05836 Republic of Korea
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Republic of Korea
- Center for Food and Bioconvergence, Seoul National University, Seoul, 08826 Republic of Korea
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Narancic J, Gavric D, Kostanjsek R, Knezevic P. First Characterization of Acinetobacter baumannii-Specific Filamentous Phages. Viruses 2024; 16:857. [PMID: 38932150 PMCID: PMC11209303 DOI: 10.3390/v16060857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/17/2024] [Accepted: 05/23/2024] [Indexed: 06/28/2024] Open
Abstract
Filamentous bacteriophages belonging to the order Tubulavirales, family Inoviridae, significantly affect the properties of Gram-negative bacteria, but filamentous phages of many important pathogens have not been described so far. The aim of this study was to examine A. baumannii filamentous phages for the first time and to determine their effect on bacterial virulence. The filamentous phages were detected in 15.3% of A. baumannii strains as individual prophages in the genome or as tandem repeats, and a slightly higher percentage was detected in the culture collection (23.8%). The phylogenetic analyses revealed 12 new genera within the Inoviridae family. Bacteriophages that were selected and isolated showed structural and genomic characteristics of the family and were unable to form plaques. Upon host infection, these phages did not significantly affect bacterial twitching motility and capsule production but significantly affected growth kinetics, reduced biofilm formation, and increased antibiotic sensitivity. One of the possible mechanisms of reduced resistance to antibiotics is the observed decreased expression of efflux pumps after infection with filamentous phages.
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Affiliation(s)
- Jelena Narancic
- PK Lab., Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia; (J.N.); (D.G.)
| | - Damir Gavric
- PK Lab., Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia; (J.N.); (D.G.)
| | - Rok Kostanjsek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jaminkarjeva 101, SI-1000 Ljubljana, Slovenia;
| | - Petar Knezevic
- PK Lab., Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia; (J.N.); (D.G.)
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Vijayakumar S, Swetha RG, Bakthavatchalam YD, Vasudevan K, Abirami Shankar B, Kirubananthan A, Walia K, Ramaiah S, Biswas I, Veeraraghavan B, Anbarasu A. Genomic investigation unveils colistin resistance mechanism in carbapenem-resistant Acinetobacter baumannii clinical isolates. Microbiol Spectr 2024; 12:e0251123. [PMID: 38214512 PMCID: PMC10846133 DOI: 10.1128/spectrum.02511-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
Colistin resistance in Acinetobacter baumannii is mediated by multiple mechanisms. Recently, mutations within pmrABC two-component system and overexpression of eptA gene due to upstream insertion of ISAba1 have been shown to play a major role. Thus, the aim of our study is to characterize colistin resistance mechanisms among the clinical isolates of A. baumannii in India. A total of 207 clinical isolates of A. baumannii collected from 2016 to 2019 were included in this study. Mutations within lipid A biosynthesis and pmrABC genes were characterized by whole-genome shotgun sequencing. Twenty-eight complete genomes were further characterized by hybrid assembly approach to study insertional inactivation of lpx genes and the association of ISAba1-eptA. Several single point mutations (SNPs), like M12I in pmrA, A138T and A444V in pmrB, and E117K in lpxD, were identified. We are the first to report two novel SNPs (T7I and V383I) in the pmrC gene. Among the five colistin-resistant A. baumannii isolates where complete genome was available, the analysis showed that three of the five isolates had ISAba1 insertion upstream of eptA. No mcr genes were identified among the isolates. We mapped the SNPs on the respective protein structures to understand the effect on the protein activity. We found that majority of the SNPs had little effect on the putative protein function; however, some SNPs might destabilize the local structure. Our study highlights the diversity of colistin resistance mechanisms occurring in A. baumannii, and ISAba1-driven eptA overexpression is responsible for colistin resistance among the Indian isolates.IMPORTANCEAcinetobacter baumannii is a Gram-negative, emerging and opportunistic bacterial pathogen that is often associated with a wide range of nosocomial infections. The treatment of these infections is hindered by increase in the occurrence of A. baumannii strains that are resistant to most of the existing antibiotics. The current drug of choice to treat the infection caused by A. baumannii is colistin, but unfortunately, the bacteria started to show resistance to the last-resort antibiotic. The loss of lipopolysaccharides and mutations in lipid A biosynthesis genes are the main reasons for the colistin resistance. The present study characterized 207 A. baumannii clinical isolates and constructed complete genomes of 28 isolates to recognize the mechanisms of colistin resistance. We showed the mutations in the colistin-resistant variants within genes essential for lipid A biosynthesis and that cause these isolates to lose the ability to produce lipopolysaccharides.
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Affiliation(s)
- Saranya Vijayakumar
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Rayapadi G. Swetha
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | | | - Karthick Vasudevan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
- Department of Biotechnology, School of Applied Sciences, REVA University, Bangalore, India
| | - Baby Abirami Shankar
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | | | - Kamini Walia
- Division of Epidemiology and Communicable Diseases, Indian Council for Medical Research, New Delhi, India
| | - Sudha Ramaiah
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Indranil Biswas
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas, USA
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Anand Anbarasu
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
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Chukamnerd A, Saipetch N, Singkhamanan K, Ingviya N, Assanangkornchai N, Surachat K, Chusri S. Association of biofilm formation, antimicrobial resistance, clinical characteristics, and clinical outcomes among Acinetobacter baumannii isolates from patients with ventilator-associated pneumonia. THE CLINICAL RESPIRATORY JOURNAL 2024; 18:e13732. [PMID: 38286744 PMCID: PMC10784708 DOI: 10.1111/crj.13732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 09/05/2023] [Accepted: 12/27/2023] [Indexed: 01/31/2024]
Abstract
INTRODUCTION Biofilm formation is an important virulence factor of Acinetobacter baumannii. Here, we examined the biofilm formation of archived A. baumannii causing ventilator-associated pneumonia (VAP). METHODS Eighteen and twenty isolates of A. baumannii causing bacteremic pneumonia and non-bacteremic pneumonia were included, respectively. Antimicrobial susceptibility testing was performed by broth microdilution method, while biofilm formation was evaluated by microtiter dish biofilm formation assay. RESULTS All 38 isolates were still susceptible to colistin and tigecycline, whereas almost all isolates were non-susceptible (intermediate to resistant) to several antimicrobial agents, especially ceftriaxone and cefotaxime. Approximately, 44% of bacteremic isolates and 50% of non-bacteremic isolates were classified as carbapenem-resistant A. baumannii (CRAB). Biofilm formation was detected in 42% of the studied isolates. Bacteremia among the patients infected with biofilm-producing isolates was significantly higher than in those infected with non-biofilm-producing isolates. The antimicrobial susceptibilities of A. baumannii with biofilm formation were lower than those without biofilm formation, but the differences did not have statistical significance. The patients infected with non-biofilm-producing isolates had good clinical and non-clinical outcomes than those infected with biofilm-producing isolates. The survival rate of patients diagnosed with VAP due to biofilm-producing A. baumannii was lower than in those patients diagnosed with VAP due to non-biofilm-producing isolates. CONCLUSION Biofilm formation of A. baumannii causing VAP was associated with antimicrobial resistance and bacteremia as well as unfavorable clinical outcomes.
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Affiliation(s)
- Arnon Chukamnerd
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of MedicinePrince of Songkla UniversityHat YaiThailand
| | - Niwat Saipetch
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of MedicinePrince of Songkla UniversityHat YaiThailand
| | - Kamonnut Singkhamanan
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of MedicinePrince of Songkla UniversityHat YaiThailand
| | - Natnicha Ingviya
- Department of Pathology, Faculty of MedicinePrince of Songkla UniversityHat YaiThailand
| | - Nawaporn Assanangkornchai
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of MedicinePrince of Songkla UniversityHat YaiThailand
| | - Komwit Surachat
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of MedicinePrince of Songkla UniversityHat YaiThailand
- Translational Medicine Research Center, Faculty of MedicinePrince of Songkla UniversityHat YaiThailand
| | - Sarunyou Chusri
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of MedicinePrince of Songkla UniversityHat YaiThailand
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Ahmad I, Nadeem A, Mushtaq F, Zlatkov N, Shahzad M, Zavialov AV, Wai SN, Uhlin BE. Csu pili dependent biofilm formation and virulence of Acinetobacter baumannii. NPJ Biofilms Microbiomes 2023; 9:101. [PMID: 38097635 PMCID: PMC10721868 DOI: 10.1038/s41522-023-00465-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 11/23/2023] [Indexed: 12/17/2023] Open
Abstract
Acinetobacter baumannii has emerged as one of the most common extensive drug-resistant nosocomial bacterial pathogens. Not only can the bacteria survive in hospital settings for long periods, but they are also able to resist adverse conditions. However, underlying regulatory mechanisms that allow A. baumannii to cope with these conditions and mediate its virulence are poorly understood. Here, we show that bi-stable expression of the Csu pili, along with the production of poly-N-acetyl glucosamine, regulates the formation of Mountain-like biofilm-patches on glass surfaces to protect bacteria from the bactericidal effect of colistin. Csu pilus assembly is found to be an essential component of mature biofilms formed on glass surfaces and of pellicles. By using several microscopic techniques, we show that clinical isolates of A. baumannii carrying abundant Csu pili mediate adherence to epithelial cells. In addition, Csu pili suppressed surface-associated motility but enhanced colonization of bacteria into the lungs, spleen, and liver in a mouse model of systemic infection. The screening of c-di-GMP metabolizing protein mutants of A. baumannii 17978 for the capability to adhere to epithelial cells led us to identify GGDEF/EAL protein AIS_2337, here denoted PdeB, as a major regulator of Csu pili-mediated virulence and biofilm formation. Moreover, PdeB was found to be involved in the type IV pili-regulated robustness of surface-associated motility. Our findings suggest that the Csu pilus is not only a functional component of mature A. baumannii biofilms but also a major virulence factor promoting the initiation of disease progression by mediating bacterial adherence to epithelial cells.
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Affiliation(s)
- Irfan Ahmad
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, SE-90187, Umeå, Sweden.
- Institute of Biomedical and Allied Health Sciences, University of Health Sciences, Lahore, Pakistan.
| | - Aftab Nadeem
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, SE-90187, Umeå, Sweden
| | - Fizza Mushtaq
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, SE-90187, Umeå, Sweden
- Institute of Biomedical and Allied Health Sciences, University of Health Sciences, Lahore, Pakistan
| | - Nikola Zlatkov
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, SE-90187, Umeå, Sweden
| | - Muhammad Shahzad
- Department of Pharmacology, University of Health Sciences, Lahore, Pakistan
| | - Anton V Zavialov
- Department of Biochemistry, University of Turku, Tykistökatu 6A, 20520, Turku, Finland
| | - Sun Nyunt Wai
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, SE-90187, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-90187, Umeå, Sweden
| | - Bernt Eric Uhlin
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, SE-90187, Umeå, Sweden
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Mihalov P, Hodosy J, Koščálová A, Čaprnda M, Kachlíková M, Jurenka J, Bendžala M, Sabaka P. Antimicrobial Therapy as a Risk Factor of Multidrug-Resistant Acinetobacter Infection in COVID-19 Patients Admitted to the Intensive Care Unit. THE CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY = JOURNAL CANADIEN DES MALADIES INFECTIEUSES ET DE LA MICROBIOLOGIE MEDICALE 2023; 2023:4951273. [PMID: 37745269 PMCID: PMC10513818 DOI: 10.1155/2023/4951273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 07/10/2023] [Accepted: 09/01/2023] [Indexed: 09/26/2023]
Abstract
Background Multidrug-resistant Acinetobacter (MDR-Ab) is one of the most important pathogens causing superinfections in COVID-19 patients hospitalised in the intensive care unit (ICU). The occurrence of MDR-Ab superinfection significantly impairs the prognosis of patients in the ICU. Overuse of antibiotics in COVID-19 patients might contribute to the risk of developing MDR-Ab infection. Objective The objective was to assess the role of prior antibiotic exposure as an independent predictor of MDR-Ab infection in COVID-19 patients admitted to the ICU. Methods We conducted a retrospective cohort study in 90 patients admitted to the ICU of the Department of Infectology and Geographical Medicine, University Hospital in Bratislava, for respiratory failure due to COVID-19 between 1 September 2021 and 31 January 2022 (delta variant predominance). Patients underwent regular microbial screening. Superinfection was defined as infection occurring ≥48 h after admission. We assessed the role of prior antibiotic exposure and other factors as independent predictors of MDR-Ab isolation. Results Fifty-eight male and 32 female patients were included in the analysis. Multidrug-resistant bacteria were cultured in 43 patients (47.8%), and MDR-Ab was isolated in 37 patients. Thirty-three (36.7%) patients had superinfection caused by MDR-Ab. Fifty-four (60%) patients were exposed to antibiotics prior to MDR-Ab isolation; of those, 35 (64.8%) patients received ceftriaxone. Prior exposure to ceftriaxone (odds ratio (OR) 4.1; 95% confidence interval (CI) 1.4-11.9; P < 0.05), tocilizumab therapy (OR 4.7; 95% CI 1.3-15.0; P < 0.05), and ICU length of stay exceeding 11 days (OR 3.7; 95% CI 1.3-10.3; P < 0.05) were independent predictors of MDR-Ab infection. Conclusions Prior exposure to ceftriaxone increases the risk of MDR-Ab infection in COVID-19 patients admitted to the ICU. Our findings suggest that antibiotic use in COVID-19 patients admitted to the ICU should be restricted to patients with documented bacterial superinfection.
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Affiliation(s)
- P. Mihalov
- Department of Infectology and Geographical Medicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - J. Hodosy
- Emergency Department, University Hospital in Bratislava, Bratislava, Slovakia
- Institute of Molecular Biomedicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - A. Koščálová
- Department of Infectology and Geographical Medicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - M. Čaprnda
- 1st Department of Internal Medicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - M. Kachlíková
- Department of Infectology and Geographical Medicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - J. Jurenka
- Department of Infectology and Geographical Medicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - M. Bendžala
- Department of Infectology and Geographical Medicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
| | - P. Sabaka
- Department of Infectology and Geographical Medicine, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovakia
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Morgado SM, Fonseca ÉL, Freitas FS, Bighi NS, Oliveira PPC, Monteiro PM, Lima LS, Santos BP, Sousa MAR, Assumpção AO, Mascarenhas LA, Vicente ACP. Outbreak of high-risk XDR CRAB of international clone 2 (IC2) in Rio Janeiro, Brazil. J Glob Antimicrob Resist 2023; 34:91-98. [PMID: 37419183 DOI: 10.1016/j.jgar.2023.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/13/2023] [Accepted: 06/24/2023] [Indexed: 07/09/2023] Open
Abstract
OBJECTIVES Among the high-risk clones of Acinetobacter baumannii, called international clones (ICs), IC2 represents the main lineage causing outbreaks worldwide. Despite the successful global spread of IC2, the occurrence of IC2 is rarely reported in Latin America. Here, we aimed to evaluate the susceptibility and genetic relatedness of isolates from a nosocomial outbreak in Rio de Janeiro/Brazil (2022) and perform genomic epidemiology analyses of the available genomes of A. baumannii. METHODS Sixteen strains of A. baumannii were subjected to antimicrobial susceptibility tests and genome sequencing. These genomes were compared phylogenetically with other IC2 genomes from the NCBI database, and virulence and antibiotic resistance genes were searched. RESULTS The 16 strains represented carbapenem-resistant A. baumannii (CRAB) with an extensively drug-resistant profile. In silico analysis established the relationship between the Brazilian CRAB genomes and IC2/ST2 genomes in the world. The Brazilian strains belonged to three sub-lineages, associated with genomes from countries in Europe, North America, and Asia. These sub-lineages presented three distinct capsules, KL7, KL9, and KL56. The Brazilian strains were characterised by the co-presence of blaOXA-23 and blaOXA-66, in addition to the genes APH(6), APH(3"), ANT(3"), AAC(6'), armA, and the efflux pumps adeABC and adeIJK. A large set of virulence genes was also identified: adeFGH/efflux pump; the siderophores barAB, basABCDFGHIJ, and bauBCDEF; lpxABCDLM/capsule; tssABCDEFGIKLM/T6SS; and pgaABCD/biofilm. CONCLUSION Widespread extensively drug-resistant CRAB IC2/ST2 is currently causing outbreaks in clinical settings in southeastern Brazil. This is due to at least three sub-lineages characterised by an enormous apparatus of virulence and resistance to antibiotics, both intrinsic and mobile.
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Affiliation(s)
- Sérgio M Morgado
- Laboratory of Molecular Genetics of Microorganisms, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
| | - Érica L Fonseca
- Laboratory of Molecular Genetics of Microorganisms, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Fernanda S Freitas
- Laboratory of Molecular Genetics of Microorganisms, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Nathalia S Bighi
- Laboratory of Molecular Genetics of Microorganisms, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Priscila P C Oliveira
- Hospital Infection Control Committee, São Francisco na Providência de Deus Hospital, Rio de Janeiro, Brazil
| | - Priscilla M Monteiro
- Hospital Infection Control Committee, São Francisco na Providência de Deus Hospital, Rio de Janeiro, Brazil
| | - Lorena S Lima
- Hospital Infection Control Committee, São Francisco na Providência de Deus Hospital, Rio de Janeiro, Brazil
| | - Bianca P Santos
- Hospital Infection Control Committee, São Francisco na Providência de Deus Hospital, Rio de Janeiro, Brazil
| | - Maria A R Sousa
- Hospital Infection Control Committee, São Francisco na Providência de Deus Hospital, Rio de Janeiro, Brazil
| | - Adriana O Assumpção
- Hospital Infection Control Committee, São Francisco na Providência de Deus Hospital, Rio de Janeiro, Brazil
| | - Luiz A Mascarenhas
- Hospital Infection Control Committee, São Francisco na Providência de Deus Hospital, Rio de Janeiro, Brazil
| | - Ana Carolina P Vicente
- Laboratory of Molecular Genetics of Microorganisms, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
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10
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Vo N, Sidner BS, Yu Y, Piepenbrink KH. Type IV Pilus-Mediated Inhibition of Acinetobacter baumannii Biofilm Formation by Phenothiazine Compounds. Microbiol Spectr 2023; 11:e0102323. [PMID: 37341603 PMCID: PMC10433872 DOI: 10.1128/spectrum.01023-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/26/2023] [Indexed: 06/22/2023] Open
Abstract
Infections by pathogenic Acinetobacter species represent a significant burden on the health care system, despite their relative rarity, due to the difficulty of treating infections through oral antibiotics. Multidrug resistance is commonly observed in clinical Acinetobacter infections and multiple molecular mechanisms have been identified for this resistance, including multidrug efflux pumps, carbapenemase enzymes, and the formation of bacterial biofilm in persistent infections. Phenothiazine compounds have been identified as a potential inhibitor of type IV pilus production in multiple Gram-negative bacterial species. Here, we report the ability of two phenothiazines to inhibit type IV pilus-dependent surface (twitching) motility and biofilm formation in multiple Acinetobacter species. Biofilm formation was inhibited in both static and continuous flow models at micromolar concentrations without significant cytotoxicity, suggesting that type IV pilus biogenesis was the primary molecular target for these compounds. These results suggest that phenothiazines may be useful lead compounds for the development of biofilm dispersal agents against Gram-negative bacterial infections. IMPORTANCE Acinetobacter infections are a growing burden on health care systems worldwide due to increasing antimicrobial resistance through multiple mechanisms. Biofilm formation is an established mechanism of antimicrobial resistance, and its inhibition has the potential to potentiate the use of existing drugs against pathogenic Acinetobacter. Additionally, as discussed in the manuscript, anti-biofilm activity by phenothiazines has the potential to help to explain their known activity against other bacteria, including Staphylococcus aureus and Mycobacterium tuberculosis.
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Affiliation(s)
- Nam Vo
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Benjamin S. Sidner
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Yafan Yu
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Kurt H. Piepenbrink
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Nebraska Food for Health Center, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
- Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
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Fursova NK, Fursov MV, Astashkin EI, Fursova AD, Novikova TS, Kislichkina AA, Sizova AA, Fedyukina GN, Savin IA, Ershova ON. Multidrug-Resistant and Extensively Drug-Resistant Acinetobacter baumannii Causing Nosocomial Meningitis in the Neurological Intensive Care Unit. Microorganisms 2023; 11:2020. [PMID: 37630581 PMCID: PMC10458171 DOI: 10.3390/microorganisms11082020] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/31/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
Acinetobacter baumannii is one of the significant healthcare-associated meningitis agents characterized by multidrug resistance and a high mortality risk. Thirty-seven A. baumannii strains were isolated from thirty-seven patients of Moscow neuro-ICU with meningitis in 2013-2020. The death rate was 37.8%. Strain susceptibility to antimicrobials was determined on the Vitek-2 instrument. Whole-genome sequencing was conducted using Illumina technology; the sequence types (ST), capsular types (KL), lipooligosaccharide outer core locus (OCL), antimicrobial resistance genes, and virulence genes were identified. The prevalent ST was ST2, belonging to the international clone IC2, and rarer, ST1, ST19, ST45, ST78, ST106, and ST400, with prevalence of KL9 and OCL1. Twenty-nine strains belonged to multidrug-resistant (MDR) and eight extensively drug-resistant (XDR) categories. Genes conferring resistance to beta-lactams (blaPER, blaGES, blaADC, blaCARB, blaCTX-M, blaTEM, and blaOXA-types), aminoglycosides (aac, aad, ant, aph, and arm), tetracyclines (tet), macrolides (msr and mph), phenicols (cml, cat, and flo), sulfonamides (dfr and sul), rifampin (arr), and antiseptics (qac) were identified. Virulence genes of nine groups (Adherence, Biofilm formation, Enzymes, Immune evasion, Iron uptake, Regulation, Serum resistance, Stress adaptation, and Antiphagocytosis) were detected. The study highlights the heterogeneity in genetic clones, antimicrobial resistance, and virulence genes variability among the agents of A. baumannii meningitis, with the prevalence of the dominant international clone IC2.
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Affiliation(s)
- Nadezhda K. Fursova
- Department of Molecular Microbiology, State Research Center for Applied Microbiology and Biotechnology, Territory “Kvartal A”, 142279 Obolensk, Russia; (E.I.A.); (A.D.F.); (T.S.N.)
| | - Mikhail V. Fursov
- Department of Training and Improvement of Specialists, State Research Center for Applied Microbiology and Biotechnology, Territory “Kvartal A”, 142279 Obolensk, Russia;
| | - Evgeny I. Astashkin
- Department of Molecular Microbiology, State Research Center for Applied Microbiology and Biotechnology, Territory “Kvartal A”, 142279 Obolensk, Russia; (E.I.A.); (A.D.F.); (T.S.N.)
| | - Anastasiia D. Fursova
- Department of Molecular Microbiology, State Research Center for Applied Microbiology and Biotechnology, Territory “Kvartal A”, 142279 Obolensk, Russia; (E.I.A.); (A.D.F.); (T.S.N.)
| | - Tatiana S. Novikova
- Department of Molecular Microbiology, State Research Center for Applied Microbiology and Biotechnology, Territory “Kvartal A”, 142279 Obolensk, Russia; (E.I.A.); (A.D.F.); (T.S.N.)
| | - Angelina A. Kislichkina
- Department of Culture Collection, State Research Center for Applied Microbiology and Biotechnology, Territory “Kvartal A”, 142279 Obolensk, Russia; (A.A.K.); (A.A.S.)
| | - Angelika A. Sizova
- Department of Culture Collection, State Research Center for Applied Microbiology and Biotechnology, Territory “Kvartal A”, 142279 Obolensk, Russia; (A.A.K.); (A.A.S.)
| | - Galina N. Fedyukina
- Department of Immunochemistry of Pathogenic Microorganisms, State Research Center for Applied Microbiology and Biotechnology, Territory “Kvartal A”, 142279 Obolensk, Russia;
| | - Ivan A. Savin
- Department of Clinical Epidemiology, National Medical Research Center of Neurosurgery Named after Academician N.N. Burdenko, 125047 Moscow, Russia; (I.A.S.); (O.N.E.)
| | - Olga N. Ershova
- Department of Clinical Epidemiology, National Medical Research Center of Neurosurgery Named after Academician N.N. Burdenko, 125047 Moscow, Russia; (I.A.S.); (O.N.E.)
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12
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Solanki V, Tiwari M, Tiwari V. Investigation of Peptidoglycan-Associated Lipoprotein of Acinetobacter baumannii and Its Interaction with Fibronectin To Find Its Therapeutic Potential. Infect Immun 2023; 91:e0002323. [PMID: 37017535 PMCID: PMC10187120 DOI: 10.1128/iai.00023-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/07/2023] [Indexed: 04/06/2023] Open
Abstract
Acinetobacter baumannii causes hospital-acquired infections and is responsible for high mortality and morbidity. The interaction of this bacterium with the host is critical in bacterial pathogenesis and infection. Here, we report the interaction of peptidoglycan-associated lipoprotein (PAL) of A. baumannii with host fibronectin (FN) to find its therapeutic potential. The proteome of A. baumannii was explored in the host-pathogen interaction database to filter out the PAL of the bacterial outer membrane that interacts with the host's FN protein. This interaction was confirmed experimentally using purified recombinant PAL and pure FN protein. To investigate the pleiotropic role of PAL protein, different biochemical assays using wild-type PAL and PAL mutants were performed. The result showed that PAL mediates bacterial pathogenesis, adherence, and invasion in host pulmonary epithelial cells and has a role in the biofilm formation, bacterial motility, and membrane integrity of bacteria. All of the results suggest that PAL's interaction with FN plays a vital role in host-cell interaction. In addition, the PAL protein also interacts with Toll-like receptor 2 and MARCO receptor, which suggests the role of PAL protein in innate immune responses. We have also investigated the therapeutic potential of this protein for vaccine and therapeutic design. Using reverse vaccinology, PAL's potential epitopes were filtered out that exhibit binding potential with host major histocompatibility complex class I (MHC-I), MHC-II, and B cells, suggesting that PAL protein is a potential vaccine target. The immune simulation showed that PAL protein could elevate innate and adaptive immune response with the generation of memory cells and would have subsequent potential to eliminate bacterial infection. Therefore, the present study highlights the interaction ability of a novel host-pathogen interacting partner (PAL-FN) and uncovers its therapeutic potential to combat infection caused by A. baumannii.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
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13
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Ng HK, Puah SM, Teh CSJ, Idris N, Chua KH. Characterisation of pellicle-forming ability in clinical carbapenem-resistant Acinetobacter baumannii. PeerJ 2023; 11:e15304. [PMID: 37214089 PMCID: PMC10194081 DOI: 10.7717/peerj.15304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 04/06/2023] [Indexed: 05/24/2023] Open
Abstract
Background Acinetobacter baumannii was reported to have resistance towards carbapenems and the ability to form an air-liquid biofilm (pellicle) which contributes to their virulence. The GacSA two-component system has been previously shown to play a role in pellicle formation. Therefore, this study aims to detect the presence of gacA and gacS genes in carbapenem-resistant Acinetobacter baumannii (CRAB) isolates recovered from patients in intensive care units and to investigate their pellicle forming ability. Methods The gacS and gacA genes were screened in 96 clinical CRAB isolates using PCR assay. Pellicle formation assay was performed in Mueller Hinton medium and Luria Bertani medium using borosilicate glass tubes and polypropylene plastic tubes. The biomass of the pellicle was quantitated using the crystal violet staining assay. The selected isolates were further assessed for their motility using semi-solid agar and monitored in real-time using real-time cell analyser (RTCA). Results All 96 clinical CRAB isolates carried the gacS and gacA genes, however, only four isolates (AB21, AB34, AB69 and AB97) displayed the ability of pellicle-formation phenotypically. These four pellicle-forming isolates produced robust pellicles in Mueller Hinton medium with better performance in borosilicate glass tubes in which biomass with OD570 ranging from 1.984 ± 0.383 to 2.272 ± 0.376 was recorded. The decrease in cell index starting from 13 hours obtained from the impedance-based RTCA showed that pellicle-forming isolates had entered the growth stage of pellicle development. Conclusion These four pellicle-forming clinical CRAB isolates could be potentially more virulent, therefore further investigation is warranted to provide insights into their pathogenic mechanisms.
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Affiliation(s)
- Heng Kang Ng
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Suat Moi Puah
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Cindy Shuan Ju Teh
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Nuryana Idris
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Kek Heng Chua
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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Rajapaksha DC, Edirisinghe SL, Nikapitiya C, Whang I, De Zoysa M. The Antimicrobial Peptide Octopromycin Suppresses Biofilm Formation and Quorum Sensing in Acinetobacter baumannii. Antibiotics (Basel) 2023; 12:antibiotics12030623. [PMID: 36978490 PMCID: PMC10044867 DOI: 10.3390/antibiotics12030623] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/03/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Acinetobacter baumannii is an opportunistic bacterial pathogen that causes severe infections in immunocompromised individuals. A. baumannii forms biofilm and produces extracellular matrix, which supports bacteria to survive under harsh conditions and be resistant to antibacterial treatments. In the present study, we investigated the biofilm and quorum-sensing inhibitory effects of antimicrobial peptide, octopromycin in A. baumannii. Field emission-scanning electron microscopy results clearly showed significantly reduced biofilm mass and caused a collapse in biofilm architecture at the minimum inhibitory concentration (50 µg/mL) and minimum bactericidal concentration (200 µg/mL) of octopromycin. Antibiotic-resistant persister cells of A. baumannii were successfully killed by octopromycin treatment, and it inhibited violacein production in Chromobacterium violaceum in a concentration-dependent manner. Octopromycin also inhibited alginate production, surface movements (swarming and swimming), and twitching motility of A. baumannnii, confirming its anti-quorum-sensing activity. Multiple metabolic pathways, two-component regulation systems, quorum-sensing, and antibiotic synthesis-related pathways in A. baumannii biofilms were strongly affected by octopromycin treatment. The collective findings indicate that the antibacterial peptide octopromycin may control A. baumannii biofilms through multi-target interactions. Octopromycin could be a desirable therapeutic option for the prevention and control of A. baumannii infections.
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Affiliation(s)
- Dinusha Chathurangi Rajapaksha
- College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Shan Lakmal Edirisinghe
- College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Chamilani Nikapitiya
- College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Ilson Whang
- National Marine Biodiversity Institute of Korea (MABIK), 75, Jangsan-ro 101 beon-gil, Janghang-eup, Seochun-gun 33662, Chungchungnam-do, Republic of Korea
| | - Mahanama De Zoysa
- College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungnam National University, Daejeon 34134, Republic of Korea
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Santajit S, Bhoopong P, Kong-Ngoen T, Tunyong W, Horpet D, Paehoh-ele W, Zahedeng T, Pumirat P, Sookrung N, Hinthong W, Indrawattana N. Phenotypic and Genotypic Investigation of Carbapenem-Resistant Acinetobacter baumannii in Maharaj Nakhon Si Thammarat Hospital, Thailand. Antibiotics (Basel) 2023; 12:antibiotics12030580. [PMID: 36978447 PMCID: PMC10044629 DOI: 10.3390/antibiotics12030580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
(1) Background: Acinetobacter baumannii is well known as a causative agent of severe hospital-acquired infections, especially in intensive care units. The present study characterised the genetic traits of biofilm-forming carbapenem-resistant A. baumannii (CRAB) clinical isolates. Additionally, this study determined the prevalence of biofilm-producing A. baumannii isolates from a tertiary care hospital and investigated the association of biofilms with the distribution of biofilm-related and antibiotic resistance-associated genotypes. (2) Methods: The 995 non-duplicate A. baumannii isolates were identified, and their susceptibilities to different antibiotics were determined using the disk diffusion method. Using the modified microtiter plate assay, the CRAB isolates were investigated for their biofilm formation ability. Hemolysin and protease activities were determined. CRABs were subjected to polymerase chain reaction (PCR) assays targeting blaVIM, blaNDM, blaIMP, blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, csuE and pgaB genes. Individual CRAB isolates were identified for their DNA fingerprint by repetitive element sequence-based (REP)-PCR. (3) Results: Among all A. baumannii isolates, 172 CRABs were identified. The major antibiotic resistance gene among the CRAB isolates was blaOXA-51-like (100%). Ninety-nine isolates (57.56%) were biofilm producers. The most prevalent biofilm gene was pgaB (79.65%), followed by csuE (76.74%). Evidence of virulence phenotypes revealed that all CRAB exhibited proteolytic activity; however, only four isolates (2.33%) were positive for the hemolytic-producing phenotype. REP-PCR showed that 172 CRAB isolates can be divided into 36-DNA fingerprint patterns. (4) Conclusions: The predominance of biofilm-producing CRAB isolates identified in this study is concerning. The characterisation of risk factors could aid in controlling the continual selection and spreading of the A. baumannii phenotype in hospitals, thereby improving patient care quality.
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Affiliation(s)
- Sirijan Santajit
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Research Center in Tropical Pathobiology, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Phuangthip Bhoopong
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Thida Kong-Ngoen
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Witawat Tunyong
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Dararat Horpet
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Wanfudhla Paehoh-ele
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Tasneem Zahedeng
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Pornpan Pumirat
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Nitat Sookrung
- Siriraj Center of Research Excellence in Allergy and Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Biomedical Research Incubator Unit, Department of Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Woranich Hinthong
- Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok 10210, Thailand
| | - Nitaya Indrawattana
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Correspondence: ; Tel.: +66-2-354-9100 (ext. 1598)
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Garza-Ramos U, Rodríguez-Medina N, Córdova-Fletes C, Rubio-Mendoza D, Alonso-Hernández CJ, López-Jácome LE, Morfín-Otero R, Rodríguez-Noriega E, Rojas-Larios F, Vázquez-Larios MDR, Ponce-de-Leon A, Choy-Chang EV, Franco-Cendejas R, Martinez-Guerra BA, Morales-de-La-Peña CT, Mena-Ramírez JP, López-Gutiérrez E, García-Romo R, Ballesteros-Silva B, Valadez-Quiroz A, Avilés-Benítez LK, Feliciano-Guzmán JM, Pérez-Vicelis T, Velázquez-Acosta MDC, Padilla-Ibarra C, López-Moreno LI, Corte-Rojas RE, Couoh-May CA, Quevedo-Ramos MA, López-García M, Chio-Ortiz G, Gil-Veloz M, Molina-Chavarria A, Mora-Domínguez JP, Romero-Romero D, May-Tec FJ, Garza-González E. Whole genome analysis of Gram-negative bacteria using the EPISEQ CS application and other bioinformatic platforms. J Glob Antimicrob Resist 2023; 33:61-71. [PMID: 36878463 DOI: 10.1016/j.jgar.2023.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/23/2023] [Accepted: 02/26/2023] [Indexed: 03/07/2023] Open
Abstract
OBJECTIVES To determine genomic characteristics and molecular epidemiology of carbapenem non-susceptible Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa from medical centres of Mexico using whole genome sequencing data analysed with the EPISEQⓇ CS application and other bioinformatic platforms. METHODS Clinical isolates collected from 28 centres in Mexico included carbapenem-non-susceptible K. pneumoniae (n = 22), E. coli (n = 24), A. baumannii (n = 16), and P. aeruginosa (n = 13). Isolates were subjected to whole genome sequencing using the Illumina (MiSeq) platform. FASTQ files were uploaded to the EPISEQⓇ CS application for analysis. Additionally, the tools Kleborate v2.0.4 and Pathogenwatch were used as comparators for Klebsiella genomes, and the bacterial whole genome sequence typing database was used for E. coli and A. baumannii. RESULTS For K. pneumoniae, both bioinformatic approaches detected multiple genes encoding aminoglycoside, quinolone, and phenicol resistance, and the presence of blaNDM-1 explained carbapenem non-susceptibility in 18 strains and blaKPC-3 in four strains. Regarding E. coli, both EPISEQⓇ CS and bacterial whole genome sequence typing database analyses detected multiple virulence and resistance genes: 20 of 24 (83.3%) strains carried blaNDM, 3 of 24 (12.4%) carried blaOXA-232, and 1 carried blaOXA-181. Genes that confer resistance to aminoglycosides, tetracyclines, sulfonamides, phenicols, trimethoprim, and macrolides were also detected by both platforms. Regarding A. baumannii, the most frequent carbapenemase-encoding gene detected by both platforms was blaOXA-72, followed by blaOXA-66. Both approaches detected similar genes for aminoglycosides, carbapenems, tetracyclines, phenicols, and sulfonamides. Regarding P. aeruginosa, blaVIM, blaIMP, and blaGES were the more frequently detected. Multiple virulence genes were detected in all strains. CONCLUSION Compared to the other available platforms, EPISEQⓇ CS enabled a comprehensive resistance and virulence analysis, providing a reliable method for bacterial strain typing and characterization of the virulome and resistome.
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Affiliation(s)
| | | | | | - Daira Rubio-Mendoza
- Facultad de Medicina, Universidad Autónoma de Nuevo León, Nuevo León, Mexico
| | | | | | - Rao Morfín-Otero
- Hospital Civil de Guadalajara Fray Antonio Alcalde, Universidad de Guadalajara, Jalisco, Mexico
| | | | | | | | - Alfredo Ponce-de-Leon
- Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de Mexico, Mexico
| | | | | | | | | | - Juan Pablo Mena-Ramírez
- Hospital General de Zona No. 21, IMSS. Centro Universitario de los Altos, Universidad de Guadalajara. Jalisco, Mexico
| | | | | | | | | | | | | | - Talia Pérez-Vicelis
- Hospital Regional de alta especialidad Bicentenario de la independencia, Estado de México, Mexico
| | | | | | | | | | | | | | | | | | - Mariana Gil-Veloz
- Hospital Regional de Alta Especialidad del Bajío, Guanajuato, Mexico
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Novović K, Kuzmanović Nedeljković S, Poledica M, Nikolić G, Grujić B, Jovčić B, Kojić M, Filipić B. Virulence potential of multidrug-resistant Acinetobacter baumannii isolates from COVID-19 patients on mechanical ventilation: The first report from Serbia. Front Microbiol 2023; 14:1094184. [PMID: 36825087 PMCID: PMC9941878 DOI: 10.3389/fmicb.2023.1094184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/13/2023] [Indexed: 02/10/2023] Open
Abstract
Since the WHO declared the COVID-19 pandemic in March 2020, the disease has spread rapidly leading to overload of the health system and many of the patients infected with SARS-CoV-2 needed to be admitted to the intensive care unit (ICU). Around 10% of patients with the severe manifestation of COVID-19 need noninvasive or invasive mechanical ventilation, which represent a risk factor for Acinetobacter baumannii superinfection. The 64 A. baumannii isolates were recovered from COVID-19 patients admitted to ICU at General Hospital "Dr Laza K. Lazarević" Šabac, Serbia, during the period from December 2020 to February 2021. All patients required mechanical ventilation and mortality rate was 100%. The goal of this study was to evaluate antibiotic resistance profiles and virulence potential of A. baumannii isolates recovered from patients with severe form of COVID-19 who had a need for mechanical ventilation. All tested A. baumannii isolates (n = 64) were sensitive to colistin, while resistant to meropenem, imipenem, gentamicin, tobramycin, and levofloxacin according to the broth microdilution method and MDR phenotype was confirmed. In all tested isolates, representatives of international clone 2 (IC2) classified by multiplex PCR for clonal lineage identification, bla AmpC, bla OXA-51, and bla OXA-23 genes were present, as well as ISAba1 insertion sequence upstream of bla OXA-23. Clonal distribution of one dominant strain was found, but individual strains showed phenotypic differences in the level of antibiotic resistance, biofilm formation, and binding to mucin and motility. According to PFGE, four isolates were sequenced and antibiotic resistance genes as well as virulence factors genes were analyzed in these genomes. The results of this study represent the first report on virulence potential of MDR A. baumannii from hospital in Serbia.
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Affiliation(s)
- Katarina Novović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | | | | | - Gordana Nikolić
- General Hospital “Dr Laza K. Lazarević” Šabac, Šabac, Serbia
| | - Bojana Grujić
- General Hospital “Dr Laza K. Lazarević” Šabac, Šabac, Serbia
| | - Branko Jovčić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia,Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Milan Kojić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Brankica Filipić
- Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia,*Correspondence: Brankica Filipić,
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Kumkar SN, Kamble EE, Chavan NS, Dhotre DP, Pardesi KR. Diversity of resistant determinants, virulence factors, and mobile genetic elements in Acinetobacter baumannii from India: A comprehensive in silico genome analysis. Front Cell Infect Microbiol 2022; 12:997897. [PMID: 36519127 PMCID: PMC9742364 DOI: 10.3389/fcimb.2022.997897] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 11/07/2022] [Indexed: 11/29/2022] Open
Abstract
Introduction The frequency of infections associated with multidrug resistant A. baumannii has risen substantially in India. The use of next-generation sequencing (NGS) techniques combined with comparative genomics has great potential for tracking, monitoring, and ultimately controlling the spread of this troublesome pathogen. Here, we investigated the whole genome sequences of 47 A. baumannii from India. Methods In brief, A. baumannii genomes were analyzed for the presence of antibiotic resistance genes (ARGs), virulence factors genes (VFGs), and mobile genetic elements (MGEs) using various in silico tools. The AbaR-type resistance islands (AbaRIs) were detected by examining the genetic environment of the chromosomal comM gene. Multilocus sequence types were determined using the Pasteur scheme. The eBURST and whole genome SNPs-based phylogenetic analysis were performed to analyze genetic diversity between A. baumannii genomes. Results and discussion A larger number of A. baumannii isolates belonging to the ST2 genotype was observed. The SNPs-based phylogenetic analysis showed a diversity between compared genomes. The predicted resistome showed the presence of intrinsic and acquired ARGs. The presence of plasmids, insertion sequences, and resistance islands carrying putative ARGs conferring resistance to antibiotics, quaternary ammonium compounds, and heavy metals was predicted in 43 (91%) genomes. The presence of putative VFGs related to adherence, biofilm formation and iron uptake was observed in the study. Overall, the comprehensive genome analysis in this study provides an essential insight into the resistome, virulome and mobilome of A. baumannii isolates from India.
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Affiliation(s)
- Shital N. Kumkar
- Department of Microbiology, Savitribai Phule Pune University, Pune, Maharashtra State, India
| | - Ekta E. Kamble
- Department of Microbiology, Savitribai Phule Pune University, Pune, Maharashtra State, India
| | - Nikeeta S. Chavan
- National Centre for Cell Science, Savitribai Phule Pune University Pune, Maharashtra State, India
| | - Dhiraj P. Dhotre
- National Centre for Cell Science, Savitribai Phule Pune University Pune, Maharashtra State, India,*Correspondence: Dhiraj P. Dhotre, ; Karishma R. Pardesi,
| | - Karishma R. Pardesi
- Department of Microbiology, Savitribai Phule Pune University, Pune, Maharashtra State, India,*Correspondence: Dhiraj P. Dhotre, ; Karishma R. Pardesi,
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19
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Choudhary M, Shrivastava R, Vashistt J. Acinetobacter baumannii Biofilm Formation: Association with Antimicrobial Resistance and Prolonged Survival under Desiccation. Curr Microbiol 2022; 79:361. [PMID: 36253556 DOI: 10.1007/s00284-022-03071-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/29/2022] [Indexed: 11/30/2022]
Abstract
Biofilm-forming multidrug-resistant Acinetobacter baumannii has emerged as a global pathogen. This study investigated the impact of biofilm formation by A. baumannii on antimicrobial resistance and prolonged survival under desiccation, which is essential for effective infection control of A. baumannii in hospital settings. Seventy-eight clinical isolates of A. baumannii were identified, and antibiotic susceptibility profiles were assessed. All the isolates were investigated for their biofilm-forming abilities at 24 and 48 h. The biofilm inhibitory concentrations of antibiotics were evaluated for selected biofilm-forming isolates to determine the influence of biofilm on antibiotic tolerance. The impact of biofilm formation on desiccation tolerance was also evaluated for up to 48 days. The results revealed that out of 78 A. baumannii clinical isolates, 83% were MDR and 17% non-MDR. Overall, 79% of isolates formed high biofilm after 24 h. The extent of biofilm formation gets significantly increased after 48 h, and 87% of isolates formed high biofilm. It was observed that eradicating mature biofilm requires up to a thousandfold higher concentration of antibiotics than MICs, and biofilm-forming isolates can survive for a prolonged period under desiccation. In conclusion, our findings revealed that both MDR and non-MDR isolates of A. baumannii could form biofilms on abiotic surfaces. A. baumannii biofilms contribute to endurance in the presence of antimicrobials and desiccation conditions, which are significant trouble for hospital patient care management. The present findings may offer insights for developing preventive measures to tackle biofilm-associated A. baumannii infection.
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Affiliation(s)
- Monika Choudhary
- Department of Biotechnology & Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh, 173234, India
| | - Rahul Shrivastava
- Department of Biotechnology & Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh, 173234, India
| | - Jitendraa Vashistt
- Department of Biotechnology & Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh, 173234, India.
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20
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Elshaer SL, Shaldam MA, Shaaban MI. Ketoprofen, Piroxicam and Indomethacin Suppressed Quorum Sensing and Virulence Factors in Acinetobacter baumannii. J Appl Microbiol 2022; 133:2182-2197. [PMID: 35503000 DOI: 10.1111/jam.15609] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/23/2022] [Accepted: 04/28/2022] [Indexed: 12/01/2022]
Abstract
AIM Quorum sensing (QS) inhibition is a promising strategy to suppress bacterial virulence, and control infection caused by Gram-negative and Gram-positive bacteria. This study explores the quorum sensing inhibiting activity of the non-steroidal anti-inflammatory drugs (NSAIDs) in Acinetobacter baumannii. METHODS AND RESULTS Ketoprofen, piroxicam, and indomethacin revealed QS inhibition via elimination of violacein production of the reporter strain Chromobacterium violaceum ATCC 12472 without affecting bacterial growth. The minimal inhibitory concentration (MIC) of ketoprofen, piroxicam, and indomethacin was determined against A. baumannii strains ATCC 17978, ATCC 19606, A1, A11, and A27 by the microbroth dilution method. The MICs of ketoprofen against tested isolates were 3.12-6.25 mg mL-1 , piroxicam MICs were 1.25-2.5 mg mL-1 , and indomethacin MICs were 3.12-12.5 mg mL-1 . Those compounds significantly inhibited QS-associated virulence factors such as biofilm formation, and surface motility, as well as, significantly increased bacterial tolerance to oxidative stress without affecting bacterial growth. On the molecular level, the three compounds significantly inhibited the transcription of QS regulatory genes abaI/abaR, and biofilm regulated genes cusD, and pgaB. Molecular docking analysis revealed potent binding affinity of the three compounds with AbaI via hydrogen and/or hydrophobic bonds. CONCLUSION These results indicate that NSAIDs, ketoprofen, piroxicam, and indomethacin, could be potential inhibitors of the QS and could suppress the QS-related virulence factors of A. baumannii. SIGNIFICANCE AND IMPACT Ketoprofen, piroxicam, and indomethacin could provide promising implications and strategies for combating the virulence, and pathogenesis of A. baumannii.
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Affiliation(s)
- Soha Lotfy Elshaer
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, 35516, Egypt
| | - Moataz A Shaldam
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kafrelsheikh University, Kafr El Sheikh 33516, Egypt
| | - Mona I Shaaban
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, 35516, Egypt
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21
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Rakovitsky N, Lellouche J, Ben David D, Frenk S, Elmalih P, Weber G, Kon H, Schwartz D, Wolfhart L, Temkin E, Carmeli Y. Increased Capsule Thickness and Hypermotility Are Traits of Carbapenem-Resistant Acinetobacter baumannii ST3 Strains Causing Fulminant Infection. Open Forum Infect Dis 2021; 8:ofab386. [PMID: 34514017 PMCID: PMC8423469 DOI: 10.1093/ofid/ofab386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/18/2021] [Indexed: 12/13/2022] Open
Abstract
Background Acinetobacter baumannii is a successful nosocomial pathogen, causing severe, life-threatening infections in hospitalized patients, including pneumonia and bloodstream infections. The spread of carbapenem-resistant Acinetobacter baumannii (CRAB) strains is a major health threat worldwide. The successful spread of CRAB is mostly due to its highly plastic genome. Although some virulence factors associated with CRAB have been uncovered, many mechanisms contributing to its success are not fully understood. Methods Here we describe strains of CRAB that were isolated from fulminant cases in 2 hospitals in Israel. These isolates show a rare hypermucoid (HM) phenotype and were investigated using phenotypic assays, comparative genomics, and an in vivo Galleria mellonella model. Results The 3 isolates belonged to the ST3 international clonal type and were closely related to each other, as shown by Fourier-transform infrared spectroscopy and phylogenetic analyses. These isolates possessed thickened capsules and a dense filamentous extracellular polysaccharides matrix as shown by transmission electron microscopy (TEM), and overexpressed the capsule polysaccharide synthesis pathway-related wzc gene. Conclusions The HM isolates possessed a unique combination of virulence genes involved in iron metabolism, protein secretion, adherence, and membrane glycosylation. HM strains were more virulent than control strains in 2 G. mellonella infection models. In conclusion, our findings demonstrated several virulence factors, all present in 3 CRAB isolates with rare hypermucoid phenotypes.
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Affiliation(s)
- Nadya Rakovitsky
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel
| | - Jonathan Lellouche
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel
| | - Debby Ben David
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Sammy Frenk
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel
| | - Polet Elmalih
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel
| | - Gabriel Weber
- The B. Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.,Infectious Disease and Infection Control Unit, Carmel Medical Center, Haifa, Israel
| | - Hadas Kon
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel
| | - David Schwartz
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel
| | - Liat Wolfhart
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel
| | - Elizabeth Temkin
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel
| | - Yehuda Carmeli
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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22
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Rangel K, Chagas TPG, De-Simone SG. Acinetobacter baumannii Infections in Times of COVID-19 Pandemic. Pathogens 2021; 10:pathogens10081006. [PMID: 34451470 PMCID: PMC8399974 DOI: 10.3390/pathogens10081006] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 12/15/2022] Open
Abstract
The COVID-19 pandemic has generated an overuse of antimicrobials in critically ill patients. Acinetobacter baumannii frequently causes nosocomial infections, particularly in intensive care units (ICUs), where the incidence has increased over time. Since the WHO declared the COVID-19 pandemic on 12 March 2020, the disease has spread rapidly, and many of the patients infected with SARS-CoV-2 needed to be admitted to the ICU. Bacterial co-pathogens are commonly identified in viral respiratory infections and are important causes of morbidity and mortality. However, we cannot neglect the increased incidence of antimicrobial resistance, which may be attributed to the excess use of antimicrobial agents during the COVID-19 pandemic. Patients with COVID-19 could be vulnerable to other infections owing to multiple comorbidities with severe COVID-19, prolonged hospitalization, and SARS-CoV-2-associated immune dysfunction. These patients have acquired secondary bacterial infections or superinfections, mainly bacteremia and urinary tract infections. This review will summarize the prevalence of A. baumannii coinfection and secondary infection in patients with COVID-19.
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Affiliation(s)
- Karyne Rangel
- FIOCRUZ, Center for Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation in Neglected Population Diseases (INCT-IDPN), Rio de Janeiro 21040-900, Brazil
- Correspondence: (K.R.); (S.G.D.-S.); Tel.: +55-213865-8240 (K.R. & S.G.D.-S.)
| | | | - Salvatore Giovanni De-Simone
- FIOCRUZ, Center for Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation in Neglected Population Diseases (INCT-IDPN), Rio de Janeiro 21040-900, Brazil
- Department of Molecular and Cellular Biology, Biology Institute, Federal Fluminense University, Niterói 24220-008, Brazil
- Correspondence: (K.R.); (S.G.D.-S.); Tel.: +55-213865-8240 (K.R. & S.G.D.-S.)
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23
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Could the analgesic drugs, paracetamol and indomethacin, function as quorum sensing inhibitors? Microb Pathog 2021; 158:105097. [PMID: 34284088 DOI: 10.1016/j.micpath.2021.105097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/05/2020] [Accepted: 07/15/2021] [Indexed: 11/22/2022]
Abstract
The current failure of antimicrobials in treating life-threatening diseases, the high rate of multidrug resistant pathogens and the slow progress in the development of new antibiotics directed scientists to develop antivirulence drugs that targets quorum sensing (QS). In many microbes, QS acts as a communication system which control pathogenicity of microbes. Analgesics can be beneficial in controlling virulence traits of microbes and hence they may augment the efficacy of antimicrobials. In this study, two analgesics were screened for the inhibition of QS in Chromobacterium violaceum CV026 and their effects on virulence production in Pseudomonas aeruginosa PAO1 strain and clinical isolates of Acinetobacter baumannii were evaluated. The traits investigated were biofilm formation, pyocyanin and rhamnolipid production, twitching, swarming or surface associated motilities, production of protease, phospholipase and gelatinase enzymes and sensitivity to oxidative stress. Relative expression of abaI gene was calculated by performing qRT-PCR. Docking analysis of paracetamol as QSI (quorum sensing inhibitor) of AbaI and AbaR proteins was performed. Paracetamol inhibited QS in CV026, but indomethacin devoids anti-QS activity. Paracetamol inhibited virulence factors of PAO1. It strongly inhibited biofilm formation, and swarming by 66.4% and 57.1%, respectively. While, it moderately to slightly inhibited rhamnolipid, pyocyanin, gelatinase, resistance to oxidative stress, protease and twitching motility by 33.3%, 33.1% 17.5%, 9.1%, 8.7% and 7.7%, respectively. For A. baumannii, paracetamol strongly inhibited biofilm by 39.7-93% and phospholipase enzyme by 8.7-100%, reduced twitching and surface motility by 6.7-82.5% and 7.7-29.4%, respectively, And slightly reduced sensitivity to oxidative stress by 3.3-36.4%. Paracetamol at sub-MIC suppressed the expression of abaI gene by 32% in A. baumannii. Docking studies suggested that paracetamol can bind to AbaR and AbaI proteins and bind more to AbaR, hence it may act by inhibiting AHL signal reception. As a conclusion, paracetamol, beside its analgesic activity, has anti-QS activity and could be used in the eradication of P. aeruginosa and A. baumannii infections in combination with antibiotics.
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24
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Pimentel C, Le C, Tuttobene MR, Subils T, Papp-Wallace KM, Bonomo RA, Tolmasky ME, Ramirez MS. Interaction of Acinetobacter baumannii with Human Serum Albumin: Does the Host Determine the Outcome? Antibiotics (Basel) 2021; 10:antibiotics10070833. [PMID: 34356754 PMCID: PMC8300715 DOI: 10.3390/antibiotics10070833] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/06/2021] [Accepted: 07/06/2021] [Indexed: 01/16/2023] Open
Abstract
Acinetobacter baumannii has become a serious threat to human health due to its extreme antibiotic resistance, environmental persistence, and capacity to survive within the host. Two A. baumannii strains, A118 and AB5075, commonly used as model systems, and three carbapenem-resistant strains, which are becoming ever more dangerous due to the multiple drugs they can resist, were exposed to 3.5% human serum albumin (HSA) and human serum (HS) to evaluate their response with respect to antimicrobial resistance, biofilm formation, and quorum sensing, all features responsible for increasing survival and persistence in the environment and human body. Expression levels of antibiotic resistance genes were modified differently when examined in different strains. The cmlA gene was upregulated or downregulated in conditions of exposure to 3.5% HSA or HS depending on the strain. Expression levels of pbp1 and pbp3 tended to be increased by the presence of HSA and HS, but the effect was not seen in all strains. A. baumannii A118 growing in the presence of HS did not experience increased expression of these genes. Aminoglycoside-modifying enzymes were also expressed at higher or lower levels in the presence of HSA or HS. Still, the response was not uniform; in some cases, expression was enhanced, and in other cases, it was tapered. While A. baumannii AB5075 became more susceptible to rifampicin in the presence of 3.5% HSA or HS, strain A118 did not show any changes. Expression of arr2, a gene involved in resistance to rifampicin present in A. baumannii AMA16, was expressed at higher levels when HS was present in the culture medium. HSA and HS reduced biofilm formation and production of N-Acyl Homoserine Lactone, a compound intimately associated with quorum sensing. In conclusion, HSA, the main component of HS, stimulates a variety of adaptative responses in infecting A. baumannii strains.
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Affiliation(s)
- Camila Pimentel
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.E.T.)
| | - Casin Le
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.E.T.)
| | - Marisel R. Tuttobene
- Área Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario 2000, Argentina;
| | - Tomas Subils
- Instituto de Procesos Biotecnológicos y Químicos de Rosario (IPROBYQ, CONICET-UNR), Rosario S2002LRK, Argentina;
| | - Krisztina M. Papp-Wallace
- Research Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; (K.M.P.-W.); (R.A.B.)
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
| | - Robert A. Bonomo
- Research Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA; (K.M.P.-W.); (R.A.B.)
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.E.T.)
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831-3599, USA; (C.P.); (C.L.); (M.E.T.)
- Correspondence: ; Tel.: +1-657-278-4562
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25
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Grier JT, Arivett BA, Ramírez MS, Chosed RJ, Bigner JA, Ohneck EJ, Metz ML, Wood CR, Arce S, Tartaro A, Relich RF, Actis LA, Fiester SE. Two Acinetobacter baumannii Isolates Obtained From a Fatal Necrotizing Fasciitis Infection Display Distinct Genomic and Phenotypic Characteristics in Comparison to Type Strains. Front Cell Infect Microbiol 2021; 11:635673. [PMID: 33912474 PMCID: PMC8072282 DOI: 10.3389/fcimb.2021.635673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/11/2021] [Indexed: 11/23/2022] Open
Abstract
Acinetobacter baumannii has been recognized as a critical pathogen that causes severe infections worldwide not only because of the emergence of extensively drug-resistant (XDR) derivatives, but also because of its ability to persist in medical environments and colonize compromised patients. While there are numerous reports describing the mechanisms by which this pathogen acquires resistance genes, little is known regarding A. baumannii’s virulence functions associated with rare manifestations of infection such as necrotizing fasciitis, making the determination and implementation of alternative therapeutic targets problematic. To address this knowledge gap, this report describes the analysis of the NFAb-1 and NFAb-2 XDR isolates, which were obtained at two time points during a fatal case of necrotizing fasciitis, at the genomic and functional levels. The comparative genomic analysis of these isolates with the ATCC 19606T and ATCC 17978 strains showed that the NFAb-1 and NFAb-2 isolates are genetically different from each other as well as different from the ATCC 19606T and ATCC 17978 clinical isolates. These genomic differences could be reflected in phenotypic differences observed in these NFAb isolates. Biofilm, cell viability and flow cytometry assays indicate that all tested strains caused significant decreases in A549 human alveolar epithelial cell viability with ATCC 17978, NFAb-1 and NFAb-2 producing significantly less biofilm and significantly more hemolysis and capacity for intracellular invasion than ATCC 19606T. NFAb-1 and NFAb-2 also demonstrated negligible surface motility but significant twitching motility compared to ATCC 19606T and ATCC 17978, likely due to the presence of pili exceeding 2 µm in length, which are significantly longer and different from those previously described in the ATCC 19606T and ATCC 17978 strains. Interestingly, infection with cells of the NFAb-1 isolate, which were obtained from a premortem blood sample, lead to significantly higher mortality rates than NFAb-2 bacteria, which were obtained from postmortem tissue samples, when tested using the Galleria mellonella in vivo infection model. These observations suggest potential changes in the virulence phenotype of the A. baumannii necrotizing fasciitis isolates over the course of infection by mechanisms and cell processes that remain to be identified.
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Affiliation(s)
- Jennifer T Grier
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, SC, United States
| | - Brock A Arivett
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, United States
| | - Maria S Ramírez
- Department of Biological Science, California State University Fullerton, Fullerton, CA, United States
| | - Renee J Chosed
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, SC, United States
| | - Jessica A Bigner
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, SC, United States
| | - Emily J Ohneck
- Department of Microbiology, Miami University, Oxford, OH, United States
| | - Maeva L Metz
- Department of Microbiology, Miami University, Oxford, OH, United States
| | - Cecily R Wood
- Department of Microbiology, Miami University, Oxford, OH, United States
| | - Sergio Arce
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, SC, United States.,Cancer Institute, Prisma Health, Greenville, SC, United States
| | - Andrea Tartaro
- Computer Science Department, Furman University, Greenville, SC, United States
| | - Ryan F Relich
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Luis A Actis
- Department of Microbiology, Miami University, Oxford, OH, United States
| | - Steven E Fiester
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, SC, United States.,Department of Pathology, Prisma Health, Greenville, SC, United States
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26
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Martinez J, Razo-Gutierrez C, Le C, Courville R, Pimentel C, Liu C, Fung SE, Tuttobene MR, Phan K, Vila AJ, Shahrestani P, Jimenez V, Tolmasky ME, Becka SA, Papp-Wallace KM, Bonomo RA, Soler-Bistue A, Sieira R, Ramirez MS. Cerebrospinal fluid (CSF) augments metabolism and virulence expression factors in Acinetobacter baumannii. Sci Rep 2021; 11:4737. [PMID: 33637791 PMCID: PMC7910304 DOI: 10.1038/s41598-021-81714-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/06/2021] [Indexed: 12/14/2022] Open
Abstract
In a recent report by the Centers for Disease Control and Prevention (CDC), multidrug resistant (MDR) Acinetobacter baumannii is a pathogen described as an "urgent threat." Infection with this bacterium manifests as different diseases such as community and nosocomial pneumonia, bloodstream infections, endocarditis, infections of the urinary tract, wound infections, burn infections, skin and soft tissue infections, and meningitis. In particular, nosocomial meningitis, an unwelcome complication of neurosurgery caused by extensively-drug resistant (XDR) A. baumannii, is extremely challenging to manage. Therefore, understanding how A. baumannii adapts to different host environments, such as cerebrospinal fluid (CSF) that may trigger changes in expression of virulence factors that are associated with the successful establishment and progress of this infection is necessary. The present in-vitro work describes, the genetic changes that occur during A. baumannii infiltration into CSF and displays A. baumannii's expansive versatility to persist in a nutrient limited environment while enhancing several virulence factors to survive and persist. While a hypervirulent A. baumannii strain did not show changes in its transcriptome when incubated in the presence of CSF, a low-virulence isolate showed significant differences in gene expression and phenotypic traits. Exposure to 4% CSF caused increased expression of virulence factors such as fimbriae, pilins, and iron chelators, and other virulence determinants that was confirmed in various model systems. Furthermore, although CSF's presence did not enhance bacterial growth, an increase of expression of genes encoding transcription, translation, and the ATP synthesis machinery was observed. This work also explores A. baumannii's response to an essential component, human serum albumin (HSA), within CSF to trigger the differential expression of genes associated with its pathoadaptibility in this environment.
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Affiliation(s)
- Jasmine Martinez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Chelsea Razo-Gutierrez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Casin Le
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Robert Courville
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Camila Pimentel
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Christine Liu
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Sammie E Fung
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Marisel R Tuttobene
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Kimberly Phan
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Alejandro J Vila
- Instituto de Biología Molecular Y Celular de Rosario (IBR, CONICET-UNR), Rosario, Argentina
- Área Biofísica, Facultad de Ciencias Bioquímicas Y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Parvin Shahrestani
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Veronica Jimenez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Marcelo E Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Scott A Becka
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
| | - Krisztina M Papp-Wallace
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
| | - Robert A Bonomo
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
| | - Alfonso Soler-Bistue
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín-Consejo Nacional de Investigaciones Científicas Y Técnicas, San Martín, Buenos Aires, Argentina
| | - Rodrigo Sieira
- Fundación Instituto Leloir - IIBBA CONICET, Buenos Aires, Argentina
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA.
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El Khatib LS, Yacoub MA, Bdour SM, Shehabi AA. Phagoburst Response Level of Neutrophils to Septic and Non-Septic Acinetobacter baumannii Isolates. Open Microbiol J 2021. [DOI: 10.2174/1874285802115010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
Acinetobacter baumannii is an opportunistic pathogen causing community-acquired and nosocomial infections. Dissemination of infection to blood causes septicemia associated with serious morbidity and mortality of patients. Neutrophils are essential for the control of A. baumannii infections by different mechanisms, including oxidative burst.
Aims:
This study was conducted as an attempt to determine the effect of septicemic and non-septicemic A. baumannii isolates on the phagoburst response of neutrophils.
Methods:
Neutrophils were isolated from an immunocompetent individual; chronic myeloid leukemia (CML) and lung solid tumor (ST) patients. The phagoburst response of these neutrophils to various strains of A. baumannii isolated from septic and non-septic patients was investigated by flow cytometer.
Results:
The presence of this pathogen lowered the phagoburst response in the different types of neutrophils compared to their response to the opsonized Escherichia coli. The phagoburst response of the neutrophils from the immunocompetent individual was significantly higher than that of neutrophils from the immunodeficient patients when stimulated by the septicemic or nonsepticemic A. baumannii isolates. The isolate type (septicemic or non-septicemic) had no significant effect on the neutrophil phagoburst response of the immunocompetent individual and a significant effect on the phagoburst response of neutrophils from the immunodeficient patients. The phagoburst response of the neutrophils from the immunodeficient patients stimulated by septicemic A. baumannii isolates was significantly lower than that when neutrophils stimulated by the nonsepticemic isolates. Also, there was a significant difference in the phagoburst response of neutrophils from the CML and ST patients when stimulated by the septicemic and non-septicemic isolates. This observation might be due to the combined effect of virulent A. baumannii isolates and the chemotherapy regime the patient was undertaking.
Conclusion:
The results suggest that both the isolate type and the source of neutrophils have a significant effect on the neutrophil phagoburst response. The potential virulence of the septicemic A. baumannii isolates and dissemination to blood may be dependent on the host’s immune status and the neutrophils phagoburst response.
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Mea HJ, Yong PVC, Wong EH. An overview of Acinetobacter baumannii pathogenesis: Motility, adherence and biofilm formation. Microbiol Res 2021; 247:126722. [PMID: 33618061 DOI: 10.1016/j.micres.2021.126722] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022]
Abstract
The Gram-negative opportunistic pathogen Acinetobacter baumannii has gain notoriety in recent decades, primarily due to its propensity to cause nosocomial infections in critically ill patients. Its global spread, multi-drug resistance features and plethora of virulence factors make it a serious threat to public health worldwide. Though much effort has been expended in uncovering its successes, it continues to confound researchers due to its highly adaptive nature, mutating to meet the needs of a given environment. Its persistence in the clinical setting allows it to be in close proximity to a potential host, where contact can be made facilitating infection and colonization. In this article, we aim to provide a current overview of the bacterial virulence factors, specifically focusing on factors involved in the initial stages of infection, highlighting the role of adaptation facilitated by two-component systems and biofilm formation. Finally, the study of host-pathogen interactions using available animal models, their suitability, notable findings and some perspectives moving forward are also discussed.
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Affiliation(s)
- Hing Jian Mea
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Phelim Voon Chen Yong
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Eng Hwa Wong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia.
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Sogasu D, Girija ASS, Gunasekaran S, Priyadharsini JV. Molecular characterization and epitope-based vaccine predictions for ompA gene associated with biofilm formation in multidrug-resistant strains of A.baumannii. In Silico Pharmacol 2021; 9:15. [PMID: 33520594 PMCID: PMC7829033 DOI: 10.1007/s40203-020-00074-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/26/2020] [Indexed: 11/28/2022] Open
Abstract
The present study was conducted to molecularly characterize the biofilm associated ompA gene from the drug resistant strains of A. baumannii and its immuno-dominant vaccine epitope predictions through immuno-informatic approach. ompA was amplified by PCR from the genomic DNA and was sequenced. Using the ORF, ompA protein sequence was retrieved and was subjected for IEDB T cell and B cell epitope analysis for the selection of the epitope peptides. Selected peptides were evaluated using appropriate servers and tools to assess the propensity for its antigenicity, solubility, physico-chemical property, toxigenicity and class-I immunogenicity. MHC class I and II restriction of HLA alleles was also performed. 48% (n = 24) of the strains possessed ompA gene. Protein structure was successfully retrieved with the selection of two epitopes viz., E1- FDGVNRGTRGTSEEGTLGNA and E2-KLSEYPNATARIEGHTDNTGPRKL. Final docking with TLR-2, showed E2 as the best epitope candidate predicted with the highest number of hydrogen bonds.
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Affiliation(s)
- Deepthi Sogasu
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences [SIMATS], Saveetha University, P.H.Road, Chennai, Tamilnadu, 600077 India
| | - A S Smiline Girija
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences [SIMATS], Saveetha University, P.H.Road, Chennai, Tamilnadu, 600077 India
| | - Shoba Gunasekaran
- Department of Biotechnology, Dwaraka Doss Goverdhan Doss Vaishnav College, Arumbakkam, Chennai, 60010 India
| | - J Vijayashree Priyadharsini
- DRC, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences [SIMATS], Saveetha University, P.H.Road, Chennai, Tamilnadu 600077 India
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Boone RL, Whitehead B, Avery TM, Lu J, Francis JD, Guevara MA, Moore RE, Chambers SA, Doster RS, Manning SD, Townsend SD, Dent L, Marshall D, Gaddy JA, Damo SM. Analysis of virulence phenotypes and antibiotic resistance in clinical strains of Acinetobacter baumannii isolated in Nashville, Tennessee. BMC Microbiol 2021; 21:21. [PMID: 33422000 PMCID: PMC7796680 DOI: 10.1186/s12866-020-02082-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 12/27/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Acinetobacter baumannii is a gram-negative bacterium which causes opportunistic infections in immunocompromised hosts. Genome plasticity has given rise to a wide range of strain variation with respect to antimicrobial resistance profiles and expression of virulence factors which lead to altered phenotypes associated with pathogenesis. The purpose of this study was to analyze clinical strains of A. baumannii for phenotypic variation that might correlate with virulence phenotypes, antimicrobial resistance patterns, or strain isolation source. We hypothesized that individual strain virulence phenotypes might be associated with anatomical site of isolation or alterations in susceptibility to antimicrobial interventions. METHODOLOGY A cohort of 17 clinical isolates of A. baumannii isolated from diverse anatomical sites were evaluated to ascertain phenotypic patterns including biofilm formation, hemolysis, motility, and antimicrobial resistance. Antibiotic susceptibility/resistance to ampicillin-sulbactam, amikacin, ceftriaxone, ceftazidime, cefotaxime, ciprofloxacin, cefepime, gentamicin, levofloxacin, meropenem, piperacillin, trimethoprim-sulfamethoxazole, ticarcillin- K clavulanate, tetracyclin, and tobramycin was determined. RESULTS Antibiotic resistance was prevalent in many strains including resistance to ampicillin-sulbactam, amikacin, ceftriaxone, ceftazidime, cefotaxime, ciprofloxacin, cefepime, gentamicin, levofloxacin, meropenem, piperacillin, trimethoprim-sulfamethoxazole, ticarcillin- K clavulanate, tetracyclin, and tobramycin. All strains tested induced hemolysis on agar plate detection assays. Wound-isolated strains of A. baumannii exhibited higher motility than strains isolated from blood, urine or Foley catheter, or sputum/bronchial wash. A. baumannii strains isolated from patient blood samples formed significantly more biofilm than isolates from wounds, sputum or bronchial wash samples. An inverse relationship between motility and biofilm formation was observed in the cohort of 17 clinical isolates of A. baumannii tested in this study. Motility was also inversely correlated with induction of hemolysis. An inverse correlation was observed between hemolysis and resistance to ticarcillin-k clavulanate, meropenem, and piperacillin. An inverse correlation was also observed between motility and resistance to ampicillin-sulbactam, ceftriaxone, ceftoxamine, ceftazidime, ciprofloxacin, or levofloxacin. CONCLUSIONS Strain dependent variations in biofilm and motility are associated with anatomical site of isolation. Biofilm and hemolysis production both have an inverse association with motility in the cohort of strains utilized in this study, and motility and hemolysis were inversely correlated with resistance to numerous antibiotics.
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Affiliation(s)
- Ranashia L Boone
- Department of Life and Physical Sciences, Fisk University, Talley-Brady Hall, 1000 17th Ave. N, Nashville, TN, 37208, USA
| | - Briana Whitehead
- Department of Life and Physical Sciences, Fisk University, Talley-Brady Hall, 1000 17th Ave. N, Nashville, TN, 37208, USA
| | - Tyra M Avery
- Department of Life and Physical Sciences, Fisk University, Talley-Brady Hall, 1000 17th Ave. N, Nashville, TN, 37208, USA
| | - Jacky Lu
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jamisha D Francis
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Miriam A Guevara
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Rebecca E Moore
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | | | - Ryan S Doster
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, A2200 Medical Center North, 1161 21st Avenue South, Nashville, TN, 37232, USA
| | - Shannon D Manning
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | | | - Leon Dent
- Department of Pathology, Anatomy, and Physiology, Meharry Medical College, Nashville, TN, USA
- Trauma Services, Phoebe Putney Memorial Hospital, Albany, GA, USA
| | - Dana Marshall
- Department of Pathology, Anatomy, and Physiology, Meharry Medical College, Nashville, TN, USA
| | - Jennifer A Gaddy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, A2200 Medical Center North, 1161 21st Avenue South, Nashville, TN, 37232, USA.
- Department of Veterans Affairs, Tennessee Valley Healthcare Systems, Nashville, TN, USA.
| | - Steven M Damo
- Department of Life and Physical Sciences, Fisk University, Talley-Brady Hall, 1000 17th Ave. N, Nashville, TN, 37208, USA.
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA.
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Clinical Biofilm Ring Test ® Reveals the Potential Role of β-Lactams in the Induction of Biofilm Formation by P. aeruginosa in Cystic Fibrosis Patients. Pathogens 2020; 9:pathogens9121065. [PMID: 33352641 PMCID: PMC7766936 DOI: 10.3390/pathogens9121065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/03/2022] Open
Abstract
Biofilms are characterized by high tolerance to antimicrobials. However, conventional antibiograms are performed on planktonic microorganisms. Through the clinical Biofilm Ring Test® (cBRT), initially aimed to measure the adhesion propensity of bacteria, we discerned a variable distribution of biofilm-producer strains among P. aeruginosa samples isolated from expectorations of cystic fibrosis (CF) patients. Despite a majority of spontaneous adherent isolates, few strains remained planktonic after 5 h of incubation. Their analysis by an adapted protocol of the cBRT revealed an induction of the biofilm early formation by sub-inhibitory doses of β-lactams. Microscopic observations of bacterial cultures stained with Syto 9/Propidium Iodide (PI) confirmed the ability of antimicrobials to increase either the bacterial biomass or the biovolume occupied by induced sessile cells. Finally, the cBRT and its derivatives enabled to highlight in a few hours the potential inducer property of antibiotics on bacterial adhesion. This phenomenon should be considered carefully in the context of CF since patients are constantly under fluctuating antimicrobial treatments. To conclude, assays derived from the Biofilm Ring Test® (BRT) device, not only define efficient doses preventing biofilm formation, but could be useful for the antimicrobial selection in CF, to avoid inducer molecules of the early biofilm initiation.
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Leus IV, Adamiak J, Trinh AN, Smith RD, Smith L, Richardson S, Ernst RK, Zgurskaya HI. Inactivation of AdeABC and AdeIJK efflux pumps elicits specific nonoverlapping transcriptional and phenotypic responses in Acinetobacter baumannii. Mol Microbiol 2020; 114:1049-1065. [PMID: 32858760 DOI: 10.1111/mmi.14594] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/17/2020] [Indexed: 12/24/2022]
Abstract
Multidrug resistant (MDR) strains of Acinetobacter baumannii present a serious clinical challenge. The development of antibiotic resistance in this species is enabled by efflux pumps of the Resistance-Nodulation-Division (RND) superfamily of proteins creating an efficient permeability barrier for antibiotics. At least three RND pumps, AdeABC, AdeIJK, and AdeFGH are encoded in the A. baumannii genome and are reported to contribute to antibiotic resistance in clinical isolates. In this study, we analyzed the contributions of AdeABC and AdeIJK in antibiotic resistance and growth physiology of the two MDR strains, AYE and AB5075. We found that not only the two pumps have nonoverlapping substrate specificities, their inactivation leads to specific nonoverlapping changes in gene expression as determined by RNA sequencing and confirmed by gene knockouts and growth phenotypes. Our results suggest that inactivation of AdeIJK elicits broader changes in the abundances of mRNAs and this response is modified in the absence of AdeB. In contrast, inactivation of AdeB leads to a focused cellular response, which is not sensitive to the activity of AdeIJK. We identified additional efflux pumps and transcriptional regulators that contribute to MDR phenotype of clinical A. baumannii isolates.
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Affiliation(s)
- Inga V Leus
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Justyna Adamiak
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Anhthu N Trinh
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Richard D Smith
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD, USA
| | - Lauren Smith
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Sophie Richardson
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD, USA
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
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Proteomic and Systematic Functional Profiling Unveils Citral Targeting Antibiotic Resistance, Antioxidant Defense, and Biofilm-Associated Two-Component Systems of Acinetobacter baumannii To Encumber Biofilm and Virulence Traits. mSystems 2020; 5:5/6/e00986-20. [PMID: 33203690 PMCID: PMC7677002 DOI: 10.1128/msystems.00986-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a nosocomial-infection-causing bacterium and also possesses multidrug resistance to a wide range of conventional antibiotics. The biofilm-forming ability of A. baumannii plays a major role in its resistance and persistence. There is an alarming need for novel treatment strategies to control A. baumannii biofilm-associated issues. The present study demonstrated the strong antibiofilm and antivirulence efficacy of citral against A. baumannii. In addition, proteomic analysis revealed the multitarget potential of citral against A. baumannii. Furthermore, citral treatment enhances the susceptibility of A. baumannii to the host innate immune system and reactive oxygen species (ROS). Cytotoxicity analysis revealed the nonfatal effect of citral on human PBMCs. Therefore, citral could be the safest therapeutic compound and can be taken for further clinical evaluation for the treatment of biofilm-associated infections by A. baumannii. Acinetobacter baumannii has been reported as a multidrug-resistant bacterium due to biofilms and antimicrobial resistance mechanisms. Hence, novel therapeutic strategies are necessary to overcome A. baumannii infections. This study revealed that citral at 200 μg/ml attenuated A. baumannii biofilms by up to 90% without affecting viability. Furthermore, microscopic analyses and in vitro assays confirmed the antibiofilm efficacy of citral. The global effect of citral on A. baumannii was evaluated by proteomic, transcriptional, and in silico approaches. Two-dimensional (2D) gel electrophoresis and matrix-assisted laser desorption ionization–time of flight/time of flight (MALDI-TOF/TOF) analyses were used to assess the effect of citral on the A. baumannii cellular proteome. Quantitative real-time PCR (qPCR) analysis was done to validate the proteomic data and identify the differentially expressed A. baumannii genes. Protein-protein interactions, gene enrichment, and comparative gene network analyses were performed to explore the interactions and functional attributes of differentially expressed proteins of A. baumannii. Global omics-based analyses revealed that citral targeted various mechanisms such as biofilm formation, antibiotic resistance, antioxidant defense, iron acquisition, and type II and type IV secretion systems. The results of antioxidant analyses and antibiotic sensitivity, blood survival, lipase, and hemolysis assays validated the proteomic results. Cytotoxicity analysis showed a nontoxic effect of citral on peripheral blood mononuclear cells (PBMCs). Overall, the current study unveiled that citral has multitarget efficacy to inhibit the biofilm formation and virulence of A. baumannii. IMPORTANCEAcinetobacter baumannii is a nosocomial-infection-causing bacterium and also possesses multidrug resistance to a wide range of conventional antibiotics. The biofilm-forming ability of A. baumannii plays a major role in its resistance and persistence. There is an alarming need for novel treatment strategies to control A. baumannii biofilm-associated issues. The present study demonstrated the strong antibiofilm and antivirulence efficacy of citral against A. baumannii. In addition, proteomic analysis revealed the multitarget potential of citral against A. baumannii. Furthermore, citral treatment enhances the susceptibility of A. baumannii to the host innate immune system and reactive oxygen species (ROS). Cytotoxicity analysis revealed the nonfatal effect of citral on human PBMCs. Therefore, citral could be the safest therapeutic compound and can be taken for further clinical evaluation for the treatment of biofilm-associated infections by A. baumannii.
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Mayer C, Muras A, Parga A, Romero M, Rumbo-Feal S, Poza M, Ramos-Vivas J, Otero A. Quorum Sensing as a Target for Controlling Surface Associated Motility and Biofilm Formation in Acinetobacter baumannii ATCC ® 17978 TM. Front Microbiol 2020; 11:565548. [PMID: 33101239 PMCID: PMC7554515 DOI: 10.3389/fmicb.2020.565548] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/10/2020] [Indexed: 12/14/2022] Open
Abstract
The important nosocomial pathogen Acinetobacter baumannii presents a quorum sensing (QS) system (abaI/abaR) mediated by acyl-homoserine-lactones (AHLs) and several quorum quenching (QQ) enzymes. However, the roles of this complex network in the control of the expression of important virulence-related phenotypes such as surface-associated motility and biofilm formation is not clear. Therefore, the effect of the mutation of the AHL synthase AbaI, and the exogenous addition of the QQ enzyme Aii20J on surface-associated motility and biofilm formation by A. baumannii ATCC® 17978TM was studied in detail. The effect of the enzyme on biofilm formation by several multidrug-resistant A. baumannii clinical isolates differing in their motility pattern was also tested. We provide evidence that a functional QS system is required for surface-associated motility and robust biofilm formation in A. baumannii ATCC® 17978TM. Important differences were found with the well-studied strain A. nosocomialis M2 regarding the relevance of the QS system depending on environmental conditions The in vitro biofilm-formation capacity of A. baumannii clinical strains was highly variable and was not related to the antibiotic resistance or surface-associated motility profiles. A high variability was also found in the sensitivity of the clinical strains to the action of the QQ enzyme, revealing important differences in virulence regulation between A. baumannii isolates and confirming that studies restricted to a single strain are not representative for the development of novel antimicrobial strategies. Extracellular DNA emerges as a key component of the extracellular matrix in A. baumannii biofilms since the combined action of the QQ enzyme Aii20J and DNase reduced biofilm formation in all tested strains. Results demonstrate that QQ strategies in combination with other enzymatic treatments such as DNase could represent an alternative approach for the prevention of A. baumannii colonization and survival on surfaces and the prevention and treatment of infections caused by this pathogen.
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Affiliation(s)
- Celia Mayer
- Departamento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía, Edificio CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Andrea Muras
- Departamento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía, Edificio CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Ana Parga
- Departamento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía, Edificio CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Manuel Romero
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Soraya Rumbo-Feal
- Microbioloxía, Instituto de Investigación Biomédica da Coruña, Centro de Investigacións Científicas Avanzadas da Coruña, Universidade da Coruña, A Coruña, Spain
| | - Margarita Poza
- Microbioloxía, Instituto de Investigación Biomédica da Coruña, Centro de Investigacións Científicas Avanzadas da Coruña, Universidade da Coruña, A Coruña, Spain
| | - José Ramos-Vivas
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla-Instituto de Investigación Valdecilla, Santander, Spain
| | - Ana Otero
- Departamento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía, Edificio CIBUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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Özkul C, Hazırolan G. Oxacillinase Gene Distribution, Antibiotic Resistance, and Their Correlation with Biofilm Formation in Acinetobacter baumannii Bloodstream Isolates. Microb Drug Resist 2020; 27:637-646. [PMID: 32991256 DOI: 10.1089/mdr.2020.0130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Objectives: The limitations of treatment options in bloodstream infections caused by multidrug-resistant Acinetobacter baumannii (MDRAB) have been related to high morbidity and mortality. The aim of our present study was to determine antimicrobial susceptibility profiles, molecular resistance patterns, and biofilm properties of A. baumannii isolated from bloodstream infections. Materials and Methods: In the present study, a total of 44 A. baumannii bloodstream isolates were included. Antimicrobial susceptibility profiles and biofilm formation ability were assessed. The distribution of class D carbapenemases, ISAba1, ISAba1/blaOXA-23, blaNDM-1, mcr-1, and ompA was investigated by polymerase chain reaction (PCR). Arbitrarily primed-PCR (AP-PCR) was performed to evaluate clonal relationships. Results: A total of 32 isolates were MDRAB, whereas 6 isolates were also resistant to colistin without mcr-1 positivity. All isolates were harboring blaOXA-51 gene, whereas blaOXA-23 positivity was 63.6%. Fifty percent of the isolates had ISAba1. ISAba1 upstream of blaOXA-23 was determined in 18 isolates. None of the isolates were positive for blaNDM-1 gene. Majority of the strains were strong biofilm producers (86.8%). A total of 56.8% of the isolates were positive for ompA gene with no direct association with strong biofilm formation. However, blaOXA-51 + 23 genotype and trimethoprim-sulfamethoxazole resistance showed a significant relationship with biofilm formation. AP-PCR analysis revealed six distinct clusters of A. baumannii. Conclusions: Herein, majority of the A. baumannii blood isolates were characterized as blaOXA-51+OXA-23 carbapenemase genotype and were strong biofilm formers. None of the isolates were positive for blaNDM-1, which was promising. Resistant isolates were tended to form strong biofilms. Our results highlight the emergence of oxacillinase-producing MDRAB isolated from bloodstream with high biofilm formation ability.
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Affiliation(s)
- Ceren Özkul
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy and Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Gülşen Hazırolan
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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36
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Li J, Yu T, Luo Y, Peng JY, Li YJ, Tao XY, Hu YM, Wang HC, Zou MX. Characterization of carbapenem-resistant hypervirulent Acinetobacter baumannii strains isolated from hospitalized patients in the mid-south region of China. BMC Microbiol 2020; 20:281. [PMID: 32928115 PMCID: PMC7489012 DOI: 10.1186/s12866-020-01957-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/24/2020] [Indexed: 01/10/2023] Open
Abstract
Background Acinetobacter baumannii has traditionally been considered an opportunistic pathogen with low virulence. In this study, we characterized the carbapenem-resistant hypervirulent A. baumannii (CR-hvAB) stains isolated from our hospital in mid-south region of China. Results Blood samples collected between January 2017 and May 2019 were used for virulence experiments and biofilm assays of individual carbapenem-resistant A. baumannii (CR-AB) strains, performed using a Galleria mellonella infection model and crystal violet staining method, respectively. CR-AB isolates that induced high mortality in the G. mellonella infection model were subjected to genotyping, susceptibility testing, and clinical data analysis, and the genetic characterization of these isolates was performed by whole-genome sequencing (WGS). Among the 109 CR-AB clinical strains, the survival rate of G. mellonella larvae infected with 7 (6.4%) CR-AB isolates (number of strains with mortality of 0, 10 and 20% was 4, 1, and 2, respectively), was significantly lower than that of A. baumannii ATCC 19606 (100.0%) and the remaining CR-AB isolates (> 80.0%). Consistent with these results, patients infected with these seven isolates had an average 7-day mortality rate of 42.9%, suggesting that the isolates were CR-hvAB. These seven isolates belonged to four sequence types (STs): ST457, ST195, ST369, and ST2088 (a new ST), and mainly ST457 (n = 4). The results of the biofilm study showed that eight strains had powerful biofilm ability (strong [n = 1] and moderate [n = 7] biofilm producers) including these seven CR-hvAB isolates. Conclusions CR-hvAB isolates that induced a high mortality rate were cloned in our hospital, most of which belonged to ST457; thus, monitoring of these strains, particularly ST457, should be strengthened in the future. Meanwhile, A. baumannii, which was isolated from blood specimens and found to powerful biofilm-forming ability, is a probable hvAB isolate.
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Affiliation(s)
- Jun Li
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Ting Yu
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yi Luo
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Jing-Yi Peng
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yu-Jia Li
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Xiao-Yan Tao
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yong-Mei Hu
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Hai-Chen Wang
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Ming-Xiang Zou
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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Abirami G, Durgadevi R, Velmurugan P, Ravi AV. Gene expressing analysis indicates the role of Pyrogallol as a novel antibiofilm and antivirulence agent against Acinetobacter baumannii. Arch Microbiol 2020; 203:251-260. [PMID: 32918098 DOI: 10.1007/s00203-020-02026-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/14/2020] [Accepted: 09/02/2020] [Indexed: 11/28/2022]
Abstract
Acinetobacter baumannii has emerged worldwide as a leading cause of hospital-acquired infections. Although A. baumannii was initially regarded to as a low-grade pathogen, evidence has been accumulated suggesting that A. baumannii infections are associated with increased mortality in critically ill patients. Here, we describe the efficacy of pyrogallol, a polyphenolic organic compound found in the galls and barks of various trees, which shows anti-biofilm and anti-virulence potential against A. baumannii. Pyrogallol shows concentration-based biofilm inhibition, as evidenced through light and confocal laser scanning microscopic analysis. The other virulence factors are protease, swarming motility, and extracellular polymeric substances that are also inhibited by pyrogallol. Through real-time PCR, it was found that pyrogallol downregulates expression of the biofilm and virulence-related ompA, bap, csuA/B, katE, pgaA, and pgaC genes. Furthermore, pyrogallol moderately inhibited the mature biofilms of A. baumannii in a concentration-dependent manner (5, 10, and 20 µg/ml). The present study reports that the anti-biofilm and anti-virulence potential of pyrogallol disrupts the biofilm formation, adherence of cells, and cell-to-cell signaling mechanism of A. baumannii. Thus, pyrogallol is a promising therapeutic agent for A. baumannii-related infections.
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Affiliation(s)
- Gurusamy Abirami
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamilnadu, 630003, India
| | - Ravindran Durgadevi
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamilnadu, 630003, India
| | - Palanivel Velmurugan
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamilnadu, 630003, India
| | - Arumugam Veera Ravi
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamilnadu, 630003, India.
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Lindarto WW, Wasito EB, Debora K. Effect of Glucose Induction on Biofilm Density in Clinical Isolate Acinetobacter baumannii Patients in Intensive Care Unit of Dr. Soetomo Hospital, Surabaya. FOLIA MEDICA INDONESIANA 2020. [DOI: 10.20473/fmi.v56i2.21230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study aimed to analyze the effect of glucose induction on the clinical isolate biofilm density of Acinetobacter baumannii. Thirteen clinical isolates of A. baumannii non biofilm forming were collected from non-DM patients who were treated at the ICU of Dr. Soetomo Hospital, Surabaya, was treated with the addition of 0.08% glucose, 0.15% glucose, 0.2% glucose, and 0.4% glucose in TSB growth media, followed by biofilm density examination with Tissue Culture Plate Method (TCPM) using 96 wells flatbottomed polyesterene tissue culture plate and read by autoreader ELISA with a wavelength of 630 nm (OD630). Biofilm density obtained was analyzed using ANOVA statistical analysis. The results of OD630 showed that the biofilm density increased significantly at the addition of 0.2% and 0.4% glucose. There was a significant increase in biofilm density at the addition of 0.2% and 0.4% glucose so that the management of blood sugar levels in ICU patients was needed before and when medical devices were installed.
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Mutation of the Carboxy-Terminal Processing Protease in Acinetobacter baumannii Affects Motility, Leads to Loss of Membrane Integrity, and Reduces Virulence. Pathogens 2020; 9:pathogens9050322. [PMID: 32357487 PMCID: PMC7281292 DOI: 10.3390/pathogens9050322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/13/2020] [Accepted: 04/24/2020] [Indexed: 01/17/2023] Open
Abstract
Motility plays an essential role in the host–parasite relationship of pathogenic bacteria, and is often associated with virulence. While many pathogenic bacteria use flagella for locomotion, Acinetobacter baumannii strains do not have flagella, but have other features that aid in their motility. To study the genes involved in motility, transposon mutagenesis was performed to construct A. baumannii mutant strains. Mutant strain MR14 was found to have reduced motility, compared to wild-type ATCC 17978. NCBI BLAST analysis revealed that the Tn10 transposon in the MR14 genome is integrated into the gene that encodes for carboxy-terminal processing protease (Ctp). Additionally, MR14 exhibits a mucoidy, sticky phenotype as the result of increased extracellular DNA (eDNA) caused by bacterial autolysis. Transmission and scanning electron microscopy revealed cytoplasmic content leaving the cell and multiple cell membrane depressions, respectively. MR14 showed higher sensitivity to environmental stressors. Mutation of the ctp gene reduced invasion and adhesion of A. baumannii to airway epithelial cells, potentially due to increased hydrophobicity. In the zebrafish model of infection, MR14 increased the survival rate by 40% compared to the wild-type. Taken together, the ctp gene in A. baumannii has a pivotal role in maintaining membrane integrity, adaptation to environmental stress, and controlling virulence.
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40
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Seleem NM, Abd El Latif HK, Shaldam MA, El-Ganiny A. Drugs with new lease of life as quorum sensing inhibitors: for combating MDR Acinetobacter baumannii infections. Eur J Clin Microbiol Infect Dis 2020; 39:1687-1702. [PMID: 32328851 PMCID: PMC7180647 DOI: 10.1007/s10096-020-03882-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/27/2020] [Indexed: 12/21/2022]
Abstract
The emergence of multidrug-resistant (MDR) strains is a major health problem worldwide. There is an urgent need for novel strategies to combat bacterial infections caused by MDR strains like Pseudomonas aeruginosa and Acinetobacter baumannii. Quorum sensing (QS) is a critical communication system in bacterial community controlling survival and virulence. The awareness of the importance of QS in bacterial infections has stimulated research to identify QS inhibitors (QSIs) to defeat microbes. In this study, four FDA-approved drugs (besides azithromycin as positive QSI) were tested for potential QS inhibition against clinical A. baumannii isolates and P. aeruginosa (PAO1) standard strain. The inhibitory effect of these drugs on virulence factors of both microbes has been investigated. The studied virulence factors include biofilm formation, twitching and swarming motilities, proteolytic enzyme production, and resistance to oxidative stress. The four tested drugs (erythromycin, levamisole, chloroquine, and propranolol) inhibited QS in Chromobacterium violaceum by 84, 72, 55.1, and 37.3%, respectively. They also significantly inhibited virulence factors in both PAO1 and A. baumannii at sub-inhibitory concentrations. These findings were confirmed by qRT-PCR and mice mortality test, where tested drugs highly repressed the expression of abaI gene and showed significantly improved mice survival rates. In addition, molecular docking studies against AbaI and AbaR proteins of QS system in A. baumannii revealed the potential inhibition of QS by tested drugs. Beside their known activities, the tested drugs could be given new life as QSIs to combat A. baumannii nosocomial infections (alone or in combination with antimicrobials).
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Affiliation(s)
- Noura M Seleem
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Hemat K Abd El Latif
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Moataz A Shaldam
- Department of Medicinal Chemistry, Faculty of Pharmacy, Kafr-elsheikh University, Kafr El Sheikh, 33516, Egypt
| | - Amira El-Ganiny
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt.
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Loraine J, Heinz E, Soontarach R, Blackwell GA, Stabler RA, Voravuthikunchai SP, Srimanote P, Kiratisin P, Thomson NR, Taylor PW. Genomic and Phenotypic Analyses of Acinetobacter baumannii Isolates From Three Tertiary Care Hospitals in Thailand. Front Microbiol 2020; 11:548. [PMID: 32328045 PMCID: PMC7153491 DOI: 10.3389/fmicb.2020.00548] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/13/2020] [Indexed: 12/24/2022] Open
Abstract
Antibiotic resistant strains of Acinetobacter baumannii are responsible for a large and increasing burden of nosocomial infections in Thailand and other countries of Southeast Asia. New approaches to their control and treatment are urgently needed and an attractive strategy is to remove the bacterial polysaccharide capsule, and thus the protection from the host's immune system. To examine phylogenetic relationships, distribution of capsule chemotypes, acquired antibiotic resistance determinants, susceptibility to complement and other traits associated with systemic infection, we sequenced 191 isolates from three tertiary referral hospitals in Thailand and used phenotypic assays to characterize key aspects of infectivity. Several distinct lineages were circulating in three hospitals and the majority belonged to global clonal group 2 (GC2). Very high levels of resistance to carbapenems and other front-line antibiotics were found, as were a number of widespread plasmid replicons. A high diversity of capsule genotypes was encountered, with only three of these (KL6, KL10, and KL47) showing more than 10% frequency. Almost 90% of GC2 isolates belonged to the most common capsule genotypes and were fully resistant to the bactericidal action of human serum complement, most likely protected by their polysaccharide capsule, which represents a key determinant of virulence for systemic infection. Our study further highlights the importance to develop therapeutic strategies to remove the polysaccharide capsule from extensively drug-resistant A. baumanii during the course of systemic infection.
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Affiliation(s)
- Jessica Loraine
- School of Pharmacy, University College London, London, United Kingdom
| | - Eva Heinz
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom.,Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom
| | | | - Grace A Blackwell
- Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom.,European Bioinformatics Institute, European Molecular Biology Laboratory, Hinxton, Cambridge, United Kingdom
| | - Richard A Stabler
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Potjanee Srimanote
- Faculty of Allied Health Sciences, Thammasat University, Pathumtanee, Thailand
| | | | - Nicholas R Thomson
- Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom.,London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Peter W Taylor
- School of Pharmacy, University College London, London, United Kingdom
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Ayoub Moubareck C, Hammoudi Halat D. Insights into Acinetobacter baumannii: A Review of Microbiological, Virulence, and Resistance Traits in a Threatening Nosocomial Pathogen. Antibiotics (Basel) 2020; 9:antibiotics9030119. [PMID: 32178356 PMCID: PMC7148516 DOI: 10.3390/antibiotics9030119] [Citation(s) in RCA: 201] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/01/2020] [Accepted: 03/02/2020] [Indexed: 12/12/2022] Open
Abstract
Being a multidrug-resistant and an invasive pathogen, Acinetobacter baumannii is one of the major causes of nosocomial infections in the current healthcare system. It has been recognized as an agent of pneumonia, septicemia, meningitis, urinary tract and wound infections, and is associated with high mortality. Pathogenesis in A. baumannii infections is an outcome of multiple virulence factors, including porins, capsules, and cell wall lipopolysaccharide, enzymes, biofilm production, motility, and iron-acquisition systems, among others. Such virulence factors help the organism to resist stressful environmental conditions and enable development of severe infections. Parallel to increased prevalence of infections caused by A. baumannii, challenging and diverse resistance mechanisms in this pathogen are well recognized, with major classes of antibiotics becoming minimally effective. Through a wide array of antibiotic-hydrolyzing enzymes, efflux pump changes, impermeability, and antibiotic target mutations, A. baumannii models a unique ability to maintain a multidrug-resistant phenotype, further complicating treatment. Understanding mechanisms behind diseases, virulence, and resistance acquisition are central to infectious disease knowledge about A. baumannii. The aims of this review are to highlight infections and disease-producing factors in A. baumannii and to touch base on mechanisms of resistance to various antibiotic classes.
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Affiliation(s)
- Carole Ayoub Moubareck
- College of Natural and Health Sciences, Zayed University, Dubai P.O. Box 144534, UAE
- Correspondence: ; Tel.: +971-4-402-1745
| | - Dalal Hammoudi Halat
- Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Beirut, Bekaa Campuses 1103, Lebanon;
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Antimicrobial and antibiofilm activities of Clostridium butyricum supernatant against Acinetobacter baumannii. Arch Microbiol 2020; 202:1059-1068. [PMID: 32020245 DOI: 10.1007/s00203-020-01823-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 01/15/2020] [Accepted: 01/28/2020] [Indexed: 01/03/2023]
Abstract
Acinetobacter baumannii is the major nosocomial pathogen that causes serious infections such as ventilator-associated pneumonia and bacteremia due to its biofilms. Hence, this study investigated the antimicrobial and antibiofilm potentials of cell-free supernatants (CFS) obtained from Clostridium butyricum, as probiotic, against A. baumannii. Our results demonstrated that C. butyricum CFS inhibited A. baumannii cell growth in planktonic culture. Also, C. butyricum CFS not only inhibited the biofilm development and dispersed mature biofilms, but also suppressed the metabolic activity of biofilm cells, showing antibiofilm activity. The biofilm components reduced by C. butyricum CFS were observed via confocal laser scanning microscopy. In addition, C. butyricum CFS exhibited antivirulence effect by inhibiting the motility of A. baumannii. Furthermore, C. butyricum CFS significantly downregulated the expression of efflux pump-related genes including adeA, adeB and adeC in A. baumannii. Our data demonstrate that C. butyricum CFS showed antimicrobial and antibiofilm effects on A. baumannii. These effects are closely associated with suppression of motility and efflux pump-related genes in A. baumannii. The findings suggest that C. butyricum CFS can be used as a new therapeutic alternative against biofilm-associated infection caused by multidrug-resistant A. baumannii.
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Araújo Lima AV, da Silva SM, do Nascimento Júnior JAA, Correia MDS, Luz AC, Leal-Balbino TC, da Silva MV, Lima JLDC, Maciel MAV, Napoleão TH, Oliveira MBMD, Paiva PMG. Occurrence and Diversity of Intra- and Interhospital Drug-Resistant and Biofilm-Forming Acinetobacter baumannii and Pseudomonas aeruginosa. Microb Drug Resist 2020; 26:802-814. [PMID: 31916896 DOI: 10.1089/mdr.2019.0214] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Acinetobacter baumannii and Pseudomonas aeruginosa are the most relevant Gram-negative bacteria associated with hospital and opportunistic infections. This study aimed to evaluate the dynamics of drug-resistant A. baumannii and P. aeruginosa and biofilm formers from two public hospitals in northeastern Brazil. One hundred isolates (35 from A. baumannii and 65 from P. aeruginosa) were identified using the automated Vitek®2 Compact method (bioMérieux) and confirmed using the MALDI-TOF (MS) mass spectrometry technique. Molecular experiments were performed by polymerase chain reaction (PCR) to detect the frequency of blaKPC, blaIMP, blaVIM, and blaSHV genes. The biofilm formation potential was evaluated using crystal violet in Luria Bertani Miller and trypticase soy broth culture media under the following conditions: at standard concentration, one quarter (25%) of the standard concentration and supplemented with 1% glucose. In addition, the genetic diversity of the isolates was verified by the ERIC-PCR technique. Isolates presented distinct resistance profiles with a high level of beta-lactam resistance. The highest index of genes detected was blaKPC (60%), followed by blaSHV (39%), blaVIM (8%), and blaIMP (1%). All the isolates were sensitive to the polymyxins tested and formed biofilms at different intensities. Twelve clones of A. baumannii and eight of P. aeruginosa were identified, of which few were indicative of intra- and interhospital dissemination. This study reveals the dispersion dynamics of these isolates in the hospital environment. The results demonstrate the importance of monitoring programs to combat the spread of these pathogens.
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Affiliation(s)
- Ana Vitoria Araújo Lima
- Departamento de Bioquímica, Centro de Biociências/Universidade Federal de Pernambuco, Recife, Brazil
| | - Sivoneide Maria da Silva
- Departamento de Bioquímica, Centro de Biociências/Universidade Federal de Pernambuco, Recife, Brazil
| | | | | | - Ana Carolina Luz
- Departamento de Microbiologia, FIOCRUZ Aggeu Magalhães, Recife, Brazil
| | | | - Márcia Vanusa da Silva
- Departamento de Bioquímica, Centro de Biociências/Universidade Federal de Pernambuco, Recife, Brazil
| | | | | | - Thiago Henrique Napoleão
- Departamento de Bioquímica, Centro de Biociências/Universidade Federal de Pernambuco, Recife, Brazil
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Shin B, Park C, Park W. Stress responses linked to antimicrobial resistance in Acinetobacter species. Appl Microbiol Biotechnol 2020; 104:1423-1435. [DOI: 10.1007/s00253-019-10317-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 12/09/2019] [Accepted: 12/13/2019] [Indexed: 11/25/2022]
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46
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Human pleural fluid triggers global changes in the transcriptional landscape of Acinetobacter baumannii as an adaptive response to stress. Sci Rep 2019; 9:17251. [PMID: 31754169 PMCID: PMC6872806 DOI: 10.1038/s41598-019-53847-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 11/06/2019] [Indexed: 12/16/2022] Open
Abstract
Acinetobacter baumannii is a feared, drug-resistant pathogen, characterized by its ability to resist extreme environmental and nutrient-deprived conditions. Previously, we showed that human serum albumin (HSA) can increase foreign DNA acquisition specifically and alter the expression of genes associated with pathogenicity. Moreover, in a recent genome-wide transcriptomic study, we observed that pleural fluid (PF), an HSA-containing fluid, increases DNA acquisition, can modulate cytotoxicity, and control immune responses by eliciting changes in the A. baumannii metabolic profile. In the present work, using more stringent criteria and focusing on the analysis of genes related to pathogenicity and response to stress, we analyzed our previous RNA-seq data and performed phenotypic assays to further explore the impact of PF on A. baumannii's microbial behavior and the strategies used to overcome environmental stress. We observed that PF triggered differential expression of genes associated with motility, efflux pumps, antimicrobial resistance, biofilm formation, two-component systems (TCSs), capsule synthesis, osmotic stress, and DNA-damage response, among other categories. Phenotypic assays of A. baumannii A118 and two other clinical A. baumannii strains, revealed differences in their responses to PF in motility, biofilm formation, antibiotic susceptibility, osmotic stress, and outer membrane vesicle (OMV) production, suggesting that these changes are strain specific. We conclude that A. baumannii's pathoadaptive responses is induced by HSA-containing fluids and must be part of this bacterium armamentarium to persist in hostile environments.
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Aliramezani A, Soleimani M, Fard RMN, Nojoomi F. Virulence determinants and biofilm formation of Acinetobacter baumannii isolated from hospitalized patients. Germs 2019; 9:148-153. [PMID: 31646145 DOI: 10.18683/germs.2019.1171] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/19/2019] [Accepted: 08/28/2019] [Indexed: 11/08/2022]
Abstract
Introduction Acinetobacter baumannii are nosocomial bacteria that are responsible for outbreaks and severe infections in hospitalized patients globally. The major target of this study was the characterization of virulence determinants and biofilm formation of A. baumannii isolates from hospitalized patients. Methods In total, 100 A. baumannii were collected from three hospitals in Tehran, Iran, 2017-2018. The isolates were assessed using phenotypic and genotypic methods and then screened for virulence factor encoding genes such as plcN and lasB using conventional polymerase chain reaction. Furthermore, bacterial biofilm formation, motility and hemolytic and proteolytic activities were assessed. Results Of 100 A. baumannii isolates, 20 isolates included plcN and four isolates included lasB using PCR assay. Overall, 21 isolates were negative for biofilm formation while 45, 20 and 14 of the total isolates were reported as weak, moderate and strong biofilm producers, respectively. All isolates were positive for bap genes using PCR. Moreover, 35 isolates were motile on Luria-Bertani media, 47 isolates were α-hemolytic on Brucella blood agar media and all isolates displayed proteolytic activity. Conclusions Healthcare-associated infections with A. baumannii are a major concern, importantly due to their potency to acquire virulence factor genes. Therefore, shedding light in the discovery of new antimicrobial and/or therapeutic agents against virulent A. baumannii strains seem to be necessary.
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Affiliation(s)
- Amir Aliramezani
- PhD, Department of Microbiology, Faculty of Medicine, AJA University of Medical Sciences, Tehran, PO Box: 14117-18541, Iran, Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Soleimani
- PhD, Department of Microbiology, Faculty of Medicine, AJA University of Medical Sciences, Tehran, PO Box: 14117-18541, Iran
| | - Ramin Mazaheri Nezhad Fard
- PhD, Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, PO Box: 14716-13151, Iran, Food Microbiology Research Centre, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farshad Nojoomi
- PhD, Department of Microbiology, Faculty of Medicine, AJA University of Medical Sciences, Tehran, PO Box: 14117-18541, Iran
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Liu J, Xiao X, Cen C, Yuan H, Yang M. Rare purulent pericarditis caused by carbapenem-resistant Acinetobacter baumannii: A case report. Medicine (Baltimore) 2019; 98:e17034. [PMID: 31567940 PMCID: PMC6756694 DOI: 10.1097/md.0000000000017034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Pericardial infection caused by Acinetobacter baumannii is rare, particularly that of carbapenem-resistant A baumannii (CRAB). CASE PRESENTATION We describe a rare case of purulent pericarditis due to CRAB in a 76-year-old man with acute myocardial infarction and acute kidney injury. The man was admitted to the intensive care unit for a catheter-related bloodstream infection. Pericardial effusion was detected via the bedside X-ray and ultrasound, and pericardiocentesis was performed. Cultures of the pericardial fluid, catheter tip, and blood independently revealed the presence of CRAB. These findings confirmed a diagnosis of purulent pericarditis. CONCLUSIONS Clinicians should be reminded that CRAB infection can lead to purulent pericarditis, particularly in patients with congestive heart failure or renal insufficiency.
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Affiliation(s)
| | | | | | - Hong Yuan
- Center of Clinical Pharmacology, Third Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
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49
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Dolzani L, Milan A, Scocchi M, Lagatolla C, Bressan R, Benincasa M. Sub-MIC effects of a proline-rich antibacterial peptide on clinical isolates of Acinetobacter baumannii. J Med Microbiol 2019; 68:1253-1265. [PMID: 31215857 DOI: 10.1099/jmm.0.001028] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION Acinetobacter baumannii is one of the most important nosocomial pathogens, mainly due to its ability to accumulate antibiotic-resistances and to persist in the hospital environment - characteristics related to biofilm production. It is well-known that A. baumannii is inhibited by the proline-rich peptide Bac7(1-35), but its putative effects at sub-MICs were never considered. AIMS We examined the sub-MIC effect of Bac7(1-35) on the growth rate, resistance induction and some A. baumannii features linked to virulence. METHODOLOGY Growth kinetics in the presence of sub-MICs of Bac7(1-35) were evaluated spectrophotometrically. Peptide uptake was quantified by cytometric analysis. The ability of Bac7(1-35) to interfere with biofilm production was investigated by the crystal violet method and confocal microscopy. Bacterial motility was observed at the interphase between a layer of a semi-solid medium and the polystyrene bottom of a Petri dish. The induction of resistance was evaluated after serial passages with sub-MICs of the peptide. RESULTS Although the MIC of Bac7(1-35) was between 2-4 µM for all tested strains, its effect on the growth rate at sub-MICs was strain-dependent and correlated with the amount of peptide internalized by each strain. Sub-MICs of Bac7(1-35) induced a strongly strain-dependent effect on biofilm formation and reduced motility in almost all strains, but interestingly the peptide did not induce resistance. CONCLUSION Bac7(1-35) is internalized into A. baumannii and is able to inhibit biofilm formation and bacterial motility, without inducing resistance. This study stresses the importance of considering possible effects that antimicrobials could have at sub-MICs, mimicking a common condition during antibiotic treatment.
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Affiliation(s)
- Lucilla Dolzani
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Annalisa Milan
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Marco Scocchi
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | | | - Raffaela Bressan
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Monica Benincasa
- Department of Life Sciences, University of Trieste, Trieste, Italy
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Biofilm Formation in Acinetobacter Baumannii: Genotype-Phenotype Correlation. Molecules 2019; 24:molecules24101849. [PMID: 31091746 PMCID: PMC6572253 DOI: 10.3390/molecules24101849] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/11/2019] [Accepted: 05/13/2019] [Indexed: 02/01/2023] Open
Abstract
Strains of Acinetobacter baumannii are commensal and opportunistic pathogens that have emerged as problematic hospital pathogens due to its biofilm formation ability and multiple antibiotic resistances. The biofilm-associated pathogens usually exhibit dramatically decreased susceptibility to antibiotics. This study was aimed to investigate the correlation of biofilm-forming ability, antibiotic resistance and biofilm-related genes of 154 A. baumannii isolates which were collected from a teaching hospital in Taiwan. Biofilm-forming ability of the isolates was evaluated by crystal violet staining and observed by scanning electron microscopy. Antibiotic susceptibility was determined by disc diffusion method and minimum inhibitory concentration; the biofilm-related genes were screened by polymerase chain reaction. Results showed that among the 154 tested isolates, 15.6% of the clinical isolates were weak biofilm producers, while 32.5% and 45.4% of them possessed moderate and strong biofilm formation ability, respectively. The experimental results revealed that the multiple drug resistant isolates usually provided a higher biofilm formation. The prevalence of biofilm related genes including bap, blaPER-1, csuE and ompA among the isolated strains was 79.2%, 38.3%, 91.6%, and 68.8%, respectively. The results indicated that the antibiotic resistance, the formation of biofilm and the related genes were significantly correlated. The results of this study can effectively help to understand the antibiotic resistant mechanism and provides the valuable information to the screening, identification, diagnosis, treatment and control of clinical antibiotic-resistant pathogens.
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