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Li Y, Cui Y, Song K, Shen L, Xiao L, Jin J, Zhao Y, Yan Y, Zhao S, Yao W, Wang S, Du Z, Yang R, Yi B, Song Y. TagP, a PAAR-domain containing protein, plays roles in the fitness and virulence of Acinetobacter baumannii. Front Cell Infect Microbiol 2024; 14:1379106. [PMID: 39193505 PMCID: PMC11348943 DOI: 10.3389/fcimb.2024.1379106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 07/03/2024] [Indexed: 08/29/2024] Open
Abstract
Background Type VI secretion system (T6SS) is widely present in Gram-negative bacteria and directly mediates antagonistic prokaryote interactions. PAAR (proline-alanine-alanine-arginine repeats) proteins have been proven essential for T6SS-mediated secretion and target cell killing. Although PAAR proteins are commonly found in A. baumannii, their biological functions are not fully disclosed yet. In this study, we investigated the functions of a PAAR protein termed TagP (T6SS-associated-gene PAAR), encoded by the gene ACX60_RS09070 outside the core T6SS locus of A. baumannii strain ATCC 17978. Methods In this study, tagP null and complement A. baumannii ATCC 17978 strains were constructed. The influence of TagP on T6SS function was investigated through Hcp detection and bacterial competition assay; the influence on environmental fitness was studied through in vitro growth, biofilm formation assay, surface motility assay, survivability in various simulated environmental conditions; the influence on pathogenicity was explored through cell adhesion and invasion assays, intramacrophage survival assay, serum survival assay, and G. melonella Killing assays. Quantitative transcriptomic and proteomic analyses were utilized to observe the global impact of TagP on bacterial status. Results Compared with the wildtype strain, the tagP null mutant was impaired in several tested phenotypes such as surface motility, biofilm formation, tolerance to adverse environments, adherence to eukaryotic cells, endurance to serum complement killing, and virulence to Galleria melonella. Notably, although RNA-Seq and proteomics analysis revealed that many genes were significantly down-regulated in the tagP null mutant compared to the wildtype strain, there is no significant difference in their antagonistic abilities. We also found that Histone-like nucleoid structuring protein (H-NS) was significantly upregulated in the tagP null mutant at both mRNA and protein levels. Conclusions This study enriches our understanding of the biofunction of PAAR proteins in A. baumannii. The results indicates that TagP involved in a unique modulation of fitness and virulence control in A. baumannii, it is more than a classic PAAR protein involved in T6SS, while how TagP play roles in the fitness and virulence of A. baumannii needs further investigation to clarify.
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Affiliation(s)
- Yanbing Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yiming Cui
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Kai Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Leiming Shen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Liting Xiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Junyan Jin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yanting Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yanfeng Yan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Shengyuan Zhao
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wenwu Yao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Shihua Wang
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zongmin Du
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Bin Yi
- Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yajun Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
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Jha NK, Gopu V, Sivasankar C, Singh SR, Devi PB, Murali A, Shetty PH. In vitro and in silico assessment of anti-biofilm and anti-quorum sensing properties of 2,4-Di-tert butylphenol against Acinetobacter baumannii. J Med Microbiol 2024; 73. [PMID: 38506718 DOI: 10.1099/jmm.0.001813] [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] [Indexed: 03/21/2024] Open
Abstract
Introduction. Acinetobacter baumannii is a nosocomial pathogen with a high potential to cause food-borne infections. It is designated as a critical pathogen by the World Health Organization due to its multi-drug resistance and mortalities reported. Biofilm governs major virulence factors, which promotes drug resistance in A. baumannii. Thus, a compound with minimum selection pressure on the pathogen can be helpful to breach biofilm-related virulence.Hypothesis/Gap Statement. To identify anti-biofilm and anti-virulent metabolites from extracts of wild Mangifera indica (mango) brine pickle bacteria that diminishes pathogenesis and resistance of A. baumannii.Aim. This study reports anti-biofilm and anti-quorum sensing (QS) efficacy of secondary metabolites from bacterial isolates of fermented food origin.Method. Cell-free supernatants (CFS) of 13 bacterial isolates from fermented mango brine pickles were screened for their efficiency in inhibiting biofilm formation and GC-MS was used to identify its metabolites. Anti-biofilm metabolite was tested on early and mature biofilms, pellicle formation, extra polymeric substances (EPS), cellular adherence, motility and resistance of A. baumannii. Gene expression and in silico studies were also carried out to validate the compounds efficacy.Results. CFS of TMP6b identified as Bacillus vallismortis, inhibited biofilm production (83.02 %). Of these, major compound was identified as 2,4-Di-tert-butyl phenol (2,4-DBP). At sub-lethal concentrations, 2,4-DBP disrupted both early and mature biofilm formation. Treatment with 2,4-DBP destructed in situ biofilm formed on glass and plastic. In addition, key virulence traits like pellicle (77.5 %), surfactant (95.3 %), EPS production (3-fold) and cell adherence (65.55 %) reduced significantly. A. baumannii cells treated with 2,4-DBP showed enhanced sensitivity towards antibiotics, oxide radicals and blood cells. Expression of biofilm-concomitant virulence genes like csuA/B, pgaC, pgaA, bap, bfmR, katE and ompA along with QS genes abaI, abaR significantly decreased. The in silico studies further validated the higher binding affinity of 2,4-DBP to the AbaR protein than the cognate ligand molecule.Conclusion. To our knowledge, this is the first report to demonstrate 2,4- DBP has anti-pathogenic potential alone and with antibiotics by in vitro, and in silico studies against A. baumannii. It also indicates its potential use in therapeutics and bio-preservatives.
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Affiliation(s)
- Nisha Kumari Jha
- Department of Food Science and Technology, Pondicherry University, Pondicherry-605014, India
| | - Venkadesaperumal Gopu
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Chandran Sivasankar
- Department of Public Health, College of Veterinary Medicine, Jeonbuk National University, Iksan-54596, Republic of Korea
| | - Satya Ranjan Singh
- Department of Bioinformatics, Pondicherry University, Pondicherry-605014, India
| | - Palanisamy Bruntha Devi
- Department of Food Science and Technology, Pondicherry University, Pondicherry-605014, India
| | - Ayaluru Murali
- Department of Bioinformatics, Pondicherry University, Pondicherry-605014, India
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Nayak S, Aanice D, Andria D, Pai A, Maiti B. Polymerase chain reaction-based typing methods and protein profiling analysis of Acinetobacter baumannii isolated from environmental and clinical sources from South India. Can J Microbiol 2023; 69:449-462. [PMID: 37364377 DOI: 10.1139/cjm-2023-0010] [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] [Indexed: 06/28/2023]
Abstract
Acinetobacter baumannii is an opportunistic pathogen known for causing hospital-acquired infections. The natural habitat includes soil, water, sewage, and drains, but it is also detected in infected individuals' blood, pus, and respiratory pathways. Due to its resilient nature, it is known to be a causative agent for outbreaks. Therefore, it is crucial to understand the genetic similarity between clinical and environmental isolates. The study aimed to find the genetic relationships between clinical and environmental isolates using PCR-based typing methods such as enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR), random amplified polymorphic DNA (RAPD), and repetitive extragenic palindromic sequence-based PCR (Rep-PCR). Additionally, outer membrane protein (OMP) and whole cell protein (WCP) profiles were also used. The PCR-based methods, ERIC-PCR and Rep-PCR, showed decreased genetic similarity between clinical and environmental isolates (66% and 58%, respectively). However, RAPD showed relatively higher genetic similarity (91%). The OMP and WCP profiles showed varied banding patterns between the clinical and environmental isolates in the 29-43 kDa region. The PCR-based methods proved to be a reliable and reproducible technique. The OMP and WCP profiles, though not as discriminatory as the molecular typing methods, could help identify the most and least commonly occurring protein bands and thus help in typing clinical and environmental A. baumannii isolates.
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Affiliation(s)
- Srajana Nayak
- Nitte (Deemed to be University), Division of Infectious Diseases, Nitte University Centre for Science Education and Research (NUCSER), Deralakatte, Mangaluru, Karnataka 575018, India
| | - D'Almeida Aanice
- Nitte (Deemed to be University), Division of Infectious Diseases, Nitte University Centre for Science Education and Research (NUCSER), Deralakatte, Mangaluru, Karnataka 575018, India
| | - Dsouza Andria
- Nitte (Deemed to be University), Division of Infectious Diseases, Nitte University Centre for Science Education and Research (NUCSER), Deralakatte, Mangaluru, Karnataka 575018, India
| | - Archana Pai
- Nitte (Deemed to be University), Division of Infectious Diseases, Nitte University Centre for Science Education and Research (NUCSER), Deralakatte, Mangaluru, Karnataka 575018, India
| | - Biswajit Maiti
- Nitte (Deemed to be University), Division of Infectious Diseases, Nitte University Centre for Science Education and Research (NUCSER), Deralakatte, Mangaluru, Karnataka 575018, India
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Nageeb WM, AlHarbi N, Alrehaili AA, Zakai SA, Elfadadny A, Hetta HF. Global genomic epidemiology of chromosomally mediated non-enzymatic carbapenem resistance in Acinetobacter baumannii: on the way to predict and modify resistance. Front Microbiol 2023; 14:1271733. [PMID: 37869654 PMCID: PMC10587612 DOI: 10.3389/fmicb.2023.1271733] [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: 08/02/2023] [Accepted: 09/05/2023] [Indexed: 10/24/2023] Open
Abstract
Introduction Although carbapenemases are frequently reported in resistant A. baumannii clinical isolates, other chromosomally mediated elements of resistance that are considered essential are frequently underestimated. Having a wide substrate range, multidrug efflux pumps frequently underlie antibiotic treatment failure. Recognizing and exploiting variations in multidrug efflux pumps and penicillin-binding proteins (PBPs) is an essential approach in new antibiotic drug discovery and engineering to meet the growing challenge of multidrug-resistant Gram-negative bacteria. Methods A total of 980 whole genome sequences of A. baumannii were analyzed. Nucleotide sequences for the genes studied were queried against a custom database of FASTA sequences using the Bacterial and Viral Bioinformatics Resource Center (BV-BRC) system. The correlation between different variants and carbapenem Minimum Inhibitory Concentrations (MICs) was studied. PROVEAN and I-Mutant predictor suites were used to predict the effect of the studied amino acid substitutions on protein function and protein stability. Both PsiPred and FUpred were used for domain and secondary structure prediction. Phylogenetic reconstruction was performed using SANS serif and then visualized using iTOL and Phandango. Results Exhibiting the highest detection rate, AdeB codes for an important efflux-pump structural protein. T48V, T584I, and P660Q were important variants identified in the AdeB-predicted multidrug efflux transporter pore domains. These can act as probable targets for designing new efflux-pump inhibitors. Each of AdeC Q239L and AdeS D167N can also act as probable targets for restoring carbapenem susceptibility. Membrane proteins appear to have lower predictive potential than efflux pump-related changes. OprB and OprD changes show a greater effect than OmpA, OmpW, Omp33, and CarO changes on carbapenem susceptibility. Functional and statistical evidence make the variants T636A and S382N at PBP1a good markers for imipenem susceptibility and potential important drug targets that can modify imipenem resistance. In addition, PBP3_370, PBP1a_T636A, and PBP1a_S382N may act as potential drug targets that can be exploited to counteract imipenem resistance. Conclusion The study presents a comprehensive epidemiologic and statistical analysis of potential membrane proteins and efflux-pump variants related to carbapenem susceptibility in A. baumannii, shedding light on their clinical utility as diagnostic markers and treatment modification targets for more focused studies of candidate elements.
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Affiliation(s)
- Wedad M. Nageeb
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Nada AlHarbi
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Amani A. Alrehaili
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Shadi A. Zakai
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ahmed Elfadadny
- Department of Animal Internal Medicine, Faculty of Veterinary Medicine, Damanhour University, Damanhour, El-Beheira, Egypt
| | - Helal F. Hetta
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt
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Colistin Resistance in Acinetobacter baumannii: Molecular Mechanisms and Epidemiology. Antibiotics (Basel) 2023; 12:antibiotics12030516. [PMID: 36978383 PMCID: PMC10044110 DOI: 10.3390/antibiotics12030516] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/17/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Acinetobacter baumannii is recognized as a clinically significant pathogen causing a wide spectrum of nosocomial infections. Colistin was considered a last-resort antibiotic for the treatment of infections caused by multidrug-resistant A. baumannii. Since the reintroduction of colistin, a number of mechanisms of colistin resistance in A. baumannii have been reported, including complete loss of LPS by inactivation of the biosynthetic pathway, modifications of target LPS driven by the addition of phosphoethanolamine (PEtN) moieties to lipid A mediated by the chromosomal pmrCAB operon and eptA gene-encoded enzymes or plasmid-encoded mcr genes and efflux of colistin from the cell. In addition to resistance to colistin, widespread heteroresistance is another feature of A. baumannii that leads to colistin treatment failure. This review aims to present a critical assessment of relevant published (>50 experimental papers) up-to-date knowledge on the molecular mechanisms of colistin resistance in A. baumannii with a detailed review of implicated mutations and the global distribution of colistin-resistant strains.
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Peykov S, Strateva T. Whole-Genome Sequencing-Based Resistome Analysis of Nosocomial Multidrug-Resistant Non-Fermenting Gram-Negative Pathogens from the Balkans. Microorganisms 2023; 11:microorganisms11030651. [PMID: 36985224 PMCID: PMC10051916 DOI: 10.3390/microorganisms11030651] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/06/2023] Open
Abstract
Non-fermenting Gram-negative bacilli (NFGNB), such as Pseudomonas aeruginosa and Acinetobacter baumannii, are among the major opportunistic pathogens involved in the global antibiotic resistance epidemic. They are designated as urgent/serious threats by the Centers for Disease Control and Prevention and are part of the World Health Organization’s list of critical priority pathogens. Also, Stenotrophomonas maltophilia is increasingly recognized as an emerging cause for healthcare-associated infections in intensive care units, life-threatening diseases in immunocompromised patients, and severe pulmonary infections in cystic fibrosis and COVID-19 individuals. The last annual report of the ECDC showed drastic differences in the proportions of NFGNB with resistance towards key antibiotics in different European Union/European Economic Area countries. The data for the Balkans are of particular concern, indicating more than 80% and 30% of invasive Acinetobacter spp. and P. aeruginosa isolates, respectively, to be carbapenem-resistant. Moreover, multidrug-resistant and extensively drug-resistant S. maltophilia from the region have been recently reported. The current situation in the Balkans includes a migrant crisis and reshaping of the Schengen Area border. This results in collision of diverse human populations subjected to different protocols for antimicrobial stewardship and infection control. The present review article summarizes the findings of whole-genome sequencing-based resistome analyses of nosocomial multidrug-resistant NFGNBs in the Balkan countries.
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Affiliation(s)
- Slavil Peykov
- Department of Genetics, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 8, Dragan Tzankov Blvd., 1164 Sofia, Bulgaria
- Department of Medical Microbiology, Faculty of Medicine, Medical University of Sofia, 2, Zdrave Str., 1431 Sofia, Bulgaria
- BioInfoTech Laboratory, Sofia Tech Park, 111, Tsarigradsko Shosse Blvd., 1784 Sofia, Bulgaria
- Correspondence: (S.P.); (T.S.); Tel.: +359-87-6454492 (S.P.); +359-2-9172750 (T.S.)
| | - Tanya Strateva
- Department of Medical Microbiology, Faculty of Medicine, Medical University of Sofia, 2, Zdrave Str., 1431 Sofia, Bulgaria
- Correspondence: (S.P.); (T.S.); Tel.: +359-87-6454492 (S.P.); +359-2-9172750 (T.S.)
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Lai SJ, Tu IF, Tseng TS, Tsai YH, Wu SH. The deficiency of poly-β-1,6-N-acetyl-glucosamine deacetylase trigger A. baumannii to convert to biofilm-independent colistin-tolerant cells. Sci Rep 2023; 13:2800. [PMID: 36797306 PMCID: PMC9935895 DOI: 10.1038/s41598-023-30065-5] [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: 11/02/2022] [Accepted: 02/15/2023] [Indexed: 02/18/2023] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen that can be resistant to antibiotics by rapidly modulating its anti-drug mechanisms. The multidrug-resistant A. baumannii has been considered one of the most threatening pathogens to our society. Biofilm formation and persistent cells within the biofilm matrix are recognized as intractable problems, especially in hospital-acquired infections. Poly-β-1,6-N-acetyl-glucosamine (PNAG) is one of the important building blocks in A. baumannii's biofilm. Here, we discover a protein phosphoryl-regulation on PNAG deacetylase, AbPgaB1, in which residue Ser411 was phosphorylated. The phosphoryl-regulation on AbPgaB1 modulates the product turnover rate in which deacetylated PNAG is produced and reflected in biofilm production. We further uncovered the PgaB deficient A. baumannii strain shows the lowest level of biofilm production but has a high minimal inhibition concentration to antibiotic colistin and tetracycline. Based on bactericidal post-antibiotic effects and time-dependent killing assays with antibacterial drugs, we claim that the PgaB-deficient A. baumannii converts to colistin-tolerant cells. This study utilizes a biofilm-independent colistin-tolerant model of A. baumannii to further investigate its characteristics and mechanisms to better understand clinical outcomes.
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Affiliation(s)
- Shu-Jung Lai
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, 404333, Taiwan. .,Research Center for Cancer Biology, China Medical University, Taichung, 404333, Taiwan.
| | - I-Fan Tu
- grid.28665.3f0000 0001 2287 1366Institute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan
| | - Tien-Sheng Tseng
- grid.260542.70000 0004 0532 3749Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
| | - Yu-Hsuan Tsai
- grid.510951.90000 0004 7775 6738Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, 518132 China
| | - Shih-Hsiung Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan. .,Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan.
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Abstract
Class C β-lactamases or cephalosporinases can be classified into two functional groups (1, 1e) with considerable molecular variability (≤20% sequence identity). These enzymes are mostly encoded by chromosomal and inducible genes and are widespread among bacteria, including Proteobacteria in particular. Molecular identification is based principally on three catalytic motifs (64SXSK, 150YXN, 315KTG), but more than 70 conserved amino-acid residues (≥90%) have been identified, many close to these catalytic motifs. Nevertheless, the identification of a tiny, phylogenetically distant cluster (including enzymes from the genera Legionella, Bradyrhizobium, and Parachlamydia) has raised questions about the possible existence of a C2 subclass of β-lactamases, previously identified as serine hydrolases. In a context of the clinical emergence of extended-spectrum AmpC β-lactamases (ESACs), the genetic modifications observed in vivo and in vitro (point mutations, insertions, or deletions) during the evolution of these enzymes have mostly involved the Ω- and H-10/R2-loops, which vary considerably between genera, and, in some cases, the conserved triplet 150YXN. Furthermore, the conserved deletion of several amino-acid residues in opportunistic pathogenic species of Acinetobacter, such as A. baumannii, A. calcoaceticus, A. pittii and A. nosocomialis (deletion of residues 304-306), and in Hafnia alvei and H. paralvei (deletion of residues 289-290), provides support for the notion of natural ESACs. The emergence of higher levels of resistance to β-lactams, including carbapenems, and to inhibitors such as avibactam is a reality, as the enzymes responsible are subject to complex regulation encompassing several other genes (ampR, ampD, ampG, etc.). Combinations of resistance mechanisms may therefore be at work, including overproduction or change in permeability, with the loss of porins and/or activation of efflux systems.
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Liu Y, Wang S, Yang F, Chi W, Ding L, Liu T, Zhu F, Ji D, Zhou J, Fang Y, Zhang J, Xiang P, Zhang Y, Zhao H. Antimicrobial resistance patterns and genetic elements associated with the antibiotic resistance of Helicobacter pylori strains from Shanghai. Gut Pathog 2022; 14:14. [PMID: 35354484 PMCID: PMC8966258 DOI: 10.1186/s13099-022-00488-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 03/21/2022] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Shanghai, in east China, has one of the world's highest burdens of Helicobacter pylori infection. While multidrug regimens can effectively eradicate H. pylori, the increasing prevalence of antibiotic resistance (AR) in H. pylori has been recognized by the WHO as 'high priority' for urgent need of new therapies. Moreover, the genetic characteristics of H. pylori AR in Shanghai is under-reported. The purpose of this study was to determine the resistance prevalence, re-substantiate resistance-conferring mutations, and investigate novel genetic elements associated with H. pylori AR. RESULTS We performed whole genome sequencing and antimicrobial susceptibility testing of 112 H. pylori strains isolated from gastric biopsy specimens from Shanghai patients with different gastric diseases. No strains were resistant to amoxicillin. Levofloxacin, metronidazole and clarithromycin resistance was observed in 39 (34.8%), 73 (65.2%) and 18 (16.1%) strains, respectively. There was no association between gastroscopy diagnosis and resistance phenotypes. We reported the presence or absence of several subsystem protein coding genes including hopE, hofF, spaB, cagY and pflA, and a combination of CRISPRs, which were potentially correlated with resistance phenotypes. The H. pylori strains were also annotated for 80 genome-wide AR genes (ARGs). A genome-wide ARG analysis was performed for the three antibiotics by correlating the phenotypes with the genetic variants, which identified the well-known intrinsic mutations conferring resistance to levofloxacin (N87T/I and/or D91G/Y mutations in gyrA), metronidazole (I38V mutation in fdxB), and clarithromycin (A2143G and/or A2142G mutations in 23S rRNA), and added 174 novel variations, including 23 non-synonymous SNPs and 48 frameshift Indels that were significantly enriched in either the antibiotic-resistant or antibiotic-susceptible bacterial populations. The variant-level linkage disequilibrium analysis highlighted variations in a protease Lon with strong co-occurring correlation with a series of resistance-associated variants. CONCLUSION Our study revealed multidrug antibiotic resistance in H. pylori strains from Shanghai, which was characterized by high metronidazole and moderate levofloxacin resistance, and identified specific genomic characteristics in relation to H. pylori AR. Continued surveillance of H. pylori AR in Shanghai is warranted in order to establish appropriate eradication treatment regimens for this population.
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Affiliation(s)
- Yixin Liu
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China
- Research Center on Aging and Medicine, Fudan University, Shanghai, China
| | - Su Wang
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
| | - Feng Yang
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China
- Research Center on Aging and Medicine, Fudan University, Shanghai, China
| | - Wenjing Chi
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
| | - Li Ding
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
| | - Tao Liu
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
| | - Feng Zhu
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
| | - Danian Ji
- Department of Endoscopy, Huadong Hospital, Fudan University, Shanghai, China
| | - Jun Zhou
- Department of Endoscopy, Huadong Hospital, Fudan University, Shanghai, China
| | - Yi Fang
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
| | - Jinghao Zhang
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China
| | - Ping Xiang
- Department of Endoscopy, Huadong Hospital, Fudan University, Shanghai, China
| | - Yanmei Zhang
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China.
- Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China.
- Research Center on Aging and Medicine, Fudan University, Shanghai, China.
| | - Hu Zhao
- Department of Laboratory Medicine, Huadong Hospital, Fudan University, Shanghai, China.
- Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China.
- Research Center on Aging and Medicine, Fudan University, Shanghai, China.
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Bahr G, González LJ, Vila AJ. Metallo-β-lactamases in the Age of Multidrug Resistance: From Structure and Mechanism to Evolution, Dissemination, and Inhibitor Design. Chem Rev 2021; 121:7957-8094. [PMID: 34129337 PMCID: PMC9062786 DOI: 10.1021/acs.chemrev.1c00138] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Antimicrobial resistance is one of the major problems in current practical medicine. The spread of genes coding for resistance determinants among bacteria challenges the use of approved antibiotics, narrowing the options for treatment. Resistance to carbapenems, last resort antibiotics, is a major concern. Metallo-β-lactamases (MBLs) hydrolyze carbapenems, penicillins, and cephalosporins, becoming central to this problem. These enzymes diverge with respect to serine-β-lactamases by exhibiting a different fold, active site, and catalytic features. Elucidating their catalytic mechanism has been a big challenge in the field that has limited the development of useful inhibitors. This review covers exhaustively the details of the active-site chemistries, the diversity of MBL alleles, the catalytic mechanism against different substrates, and how this information has helped developing inhibitors. We also discuss here different aspects critical to understand the success of MBLs in conferring resistance: the molecular determinants of their dissemination, their cell physiology, from the biogenesis to the processing involved in the transit to the periplasm, and the uptake of the Zn(II) ions upon metal starvation conditions, such as those encountered during an infection. In this regard, the chemical, biochemical and microbiological aspects provide an integrative view of the current knowledge of MBLs.
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Affiliation(s)
- Guillermo Bahr
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
| | - Lisandro J. González
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
| | - Alejandro J. Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
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11
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Takebayashi Y, Findlay J, Heesom KJ, Warburton PJ, Avison MB, Evans BA. Variability in carbapenemase activity of intrinsic OxaAb (OXA-51-like) β-lactamase enzymes in Acinetobacter baumannii. J Antimicrob Chemother 2021; 76:587-595. [PMID: 33338207 DOI: 10.1093/jac/dkaa502] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/03/2020] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To measure the variability in carbapenem susceptibility conferred by different OxaAb variants, characterize the molecular evolution of oxaAb and elucidate the contribution of OxaAb and other possible carbapenem resistance factors in the clinical isolates using WGS and LC-MS/MS. METHODS Antimicrobial susceptibility tests were performed on 10 clinical Acinetobacter baumannii isolates. Carbapenem MICs were evaluated for all oxaAb variants cloned into A. baumannii CIP70.10 and BM4547, with and without their natural promoters. Molecular evolution analysis of the oxaAb variants was performed using FastTree and SplitsTree4. Resistance determinants were studied in the clinical isolates using WGS and LC-MS/MS. RESULTS Only the OxaAb variants with I129L and L167V substitutions, OxaAb(82), OxaAb(83), OxaAb(107) and OxaAb(110) increased carbapenem MICs when expressed in susceptible A. baumannii backgrounds without an upstream IS element. Carbapenem resistance was conferred with the addition of their natural upstream ISAba1 promoter. LC-MS/MS analysis on the original clinical isolates confirmed overexpression of the four I129L and L167V variants. No other differences in expression levels of proteins commonly associated with carbapenem resistance were detected. CONCLUSIONS Elevated carbapenem MICs were observed by expression of OxaAb variants carrying clinically prevalent substitutions I129L and L167V. To drive carbapenem resistance, these variants required overexpression by their upstream ISAba1 promoter. This study clearly demonstrates that a combination of IS-driven overexpression of oxaAb and the presence of particular amino acid substitutions in the active site to improve carbapenem capture is key in conferring carbapenem resistance in A. baumannii and other mechanisms are not required.
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Affiliation(s)
- Yuiko Takebayashi
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Jacqueline Findlay
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.,Division of Infection & Immunity, Faculty of Medical Sciences, University College London, UK
| | - Kate J Heesom
- Bristol Proteomics Facility, University of Bristol, Bristol, UK
| | - Philip J Warburton
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,School of Biomedical Sciences, Faculty of Health, University of Plymouth, Plymouth, UK
| | - Matthew B Avison
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Benjamin A Evans
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,Norwich Medical School, University of East Anglia, UK
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12
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Vahhabi A, Hasani A, Rezaee MA, Baradaran B, Hasani A, Samadi Kafil H, Abbaszadeh F, Dehghani L. A plethora of carbapenem resistance in Acinetobacter baumannii: no end to a long insidious genetic journey. J Chemother 2021; 33:137-155. [PMID: 33243098 DOI: 10.1080/1120009x.2020.1847421] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/23/2020] [Accepted: 11/02/2020] [Indexed: 01/21/2023]
Abstract
Acinetobacter baumannii, notorious for causing nosocomial infections especially in patients admitted to intensive care unit (ICU) and burn units, is best at displaying resistance to all existing antibiotic classes. Consequences of high potential for antibiotic resistance has resulted in extensive drug or even pan drug resistant A. baumannii. Carbapenems, mainly imipenem and meropenem, the last resort for the treatment of A. baumannii infections have fallen short due to the emergence of carbapenem resistant A. baumannii (CRAB). Though enzymatic degradation by production of class D β-lactamases (Oxacillinases) and class B β-lactamases (Metallo β-lactamases) is the core mechanism of carbapenem resistance in A. baumannii; however over-expression of efflux pumps such as resistance-nodulation cell division (RND) family and variant form of porin proteins such as CarO have been implicated for CRAB inception. Transduction and outer membrane vesicles-mediated transfer play a role in carbapenemase determinants spread. Colistin, considered as the most promising antibacterial agent, nevertheless faces adverse effects flaws. Cefiderocol, eravacycline, new β-lactam antibiotics, non-β-lactam-β-lactamase inhibitors, polymyxin B-derived molecules and bacteriophages are some other new treatment options streamlined.
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Affiliation(s)
- Abolfazl Vahhabi
- Immunology Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Alka Hasani
- Immunology Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
- Clinical Research Development Unit, Sina Educational, Research and Treatment Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Mohammad Ahangarzadeh Rezaee
- Immunology Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Behzad Baradaran
- Immunology Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Akbar Hasani
- Department of Clinical Biochemistry and Laboratory Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I. R. Iran
| | - Hossein Samadi Kafil
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Faeze Abbaszadeh
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Leila Dehghani
- Clinical Research Development Unit, Sina Educational, Research and Treatment Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
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Acinetobacter baumannii Antibiotic Resistance Mechanisms. Pathogens 2021; 10:pathogens10030373. [PMID: 33808905 PMCID: PMC8003822 DOI: 10.3390/pathogens10030373] [Citation(s) in RCA: 203] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative ESKAPE microorganism that poses a threat to public health by causing severe and invasive (mostly nosocomial) infections linked with high mortality rates. During the last years, this pathogen displayed multidrug resistance (MDR), mainly due to extensive antibiotic abuse and poor stewardship. MDR isolates are associated with medical history of long hospitalization stays, presence of catheters, and mechanical ventilation, while immunocompromised and severely ill hosts predispose to invasive infections. Next-generation sequencing techniques have revolutionized diagnosis of severe A. baumannii infections, contributing to timely diagnosis and personalized therapeutic regimens according to the identification of the respective resistance genes. The aim of this review is to describe in detail all current knowledge on the genetic background of A. baumannii resistance mechanisms in humans as regards beta-lactams (penicillins, cephalosporins, carbapenems, monobactams, and beta-lactamase inhibitors), aminoglycosides, tetracyclines, fluoroquinolones, macrolides, lincosamides, streptogramin antibiotics, polymyxins, and others (amphenicols, oxazolidinones, rifamycins, fosfomycin, diaminopyrimidines, sulfonamides, glycopeptide, and lipopeptide antibiotics). Mechanisms of antimicrobial resistance refer mainly to regulation of antibiotic transportation through bacterial membranes, alteration of the antibiotic target site, and enzymatic modifications resulting in antibiotic neutralization. Virulence factors that may affect antibiotic susceptibility profiles and confer drug resistance are also being discussed. Reports from cases of A. baumannii coinfection with SARS-CoV-2 during the COVID-19 pandemic in terms of resistance profiles and MDR genes have been investigated.
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Uppalapati SR, Sett A, Pathania R. The Outer Membrane Proteins OmpA, CarO, and OprD of Acinetobacter baumannii Confer a Two-Pronged Defense in Facilitating Its Success as a Potent Human Pathogen. Front Microbiol 2020; 11:589234. [PMID: 33123117 PMCID: PMC7573547 DOI: 10.3389/fmicb.2020.589234] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/11/2020] [Indexed: 12/12/2022] Open
Abstract
Of all the ESKAPE pathogens, carbapenem-resistant and multidrug-resistant Acinetobacter baumannii is the leading cause of hospital-acquired and ventilator-associated pneumonia. A. baumannii infections are notoriously hard to eradicate due to its propensity to rapidly acquire multitude of resistance determinants and the virulence factor cornucopia elucidated by the bacterium that help it fend off a wide range of adverse conditions imposed upon by host and environment. One such weapon in the arsenal of A. baumannii is the outer membrane protein (OMP) compendium. OMPs in A. baumannii play distinctive roles in facilitating the bacterial acclimatization to antibiotic- and host-induced stresses, albeit following entirely different mechanisms. OMPs are major immunogenic proteins in bacteria conferring bacteria host-fitness advantages including immune evasion, stress tolerance, and resistance to antibiotics and antibacterials. In this review, we summarize the current knowledge of major A. baumannii OMPs and discuss their versatile role in antibiotic resistance and virulence. Specifically, we explore how OmpA, CarO, and OprD-like porins mediate antibiotic and amino acid shuttle and host virulence.
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Affiliation(s)
- Siva R Uppalapati
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
| | - Abhiroop Sett
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
| | - Ranjana Pathania
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
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15
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Antibiotic Resistance Profiles, Molecular Mechanisms and Innovative Treatment Strategies of Acinetobacter baumannii. Microorganisms 2020; 8:microorganisms8060935. [PMID: 32575913 PMCID: PMC7355832 DOI: 10.3390/microorganisms8060935] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 12/18/2022] Open
Abstract
Antibiotic resistance is one of the biggest challenges for the clinical sector and industry, environment and societal development. One of the most important pathogens responsible for severe nosocomial infections is Acinetobacter baumannii, a Gram-negative bacterium from the Moraxellaceae family, due to its various resistance mechanisms, such as the β-lactamases production, efflux pumps, decreased membrane permeability and altered target site of the antibiotic. The enormous adaptive capacity of A. baumannii and the acquisition and transfer of antibiotic resistance determinants contribute to the ineffectiveness of most current therapeutic strategies, including last-line or combined antibiotic therapy. In this review, we will present an update of the antibiotic resistance profiles and underlying mechanisms in A. baumannii and the current progress in developing innovative strategies for combating multidrug-resistant A. baumannii (MDRAB) infections.
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16
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Ramirez MS, Bonomo RA, Tolmasky ME. Carbapenemases: Transforming Acinetobacter baumannii into a Yet More Dangerous Menace. Biomolecules 2020; 10:biom10050720. [PMID: 32384624 PMCID: PMC7277208 DOI: 10.3390/biom10050720] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 02/07/2023] Open
Abstract
Acinetobacter baumannii is a common cause of serious nosocomial infections. Although community-acquired infections are observed, the vast majority occur in people with preexisting comorbidities. A. baumannii emerged as a problematic pathogen in the 1980s when an increase in virulence, difficulty in treatment due to drug resistance, and opportunities for infection turned it into one of the most important threats to human health. Some of the clinical manifestations of A. baumannii nosocomial infection are pneumonia; bloodstream infections; lower respiratory tract, urinary tract, and wound infections; burn infections; skin and soft tissue infections (including necrotizing fasciitis); meningitis; osteomyelitis; and endocarditis. A. baumannii has an extraordinary genetic plasticity that results in a high capacity to acquire antimicrobial resistance traits. In particular, acquisition of resistance to carbapenems, which are among the antimicrobials of last resort for treatment of multidrug infections, is increasing among A. baumannii strains compounding the problem of nosocomial infections caused by this pathogen. It is not uncommon to find multidrug-resistant (MDR, resistance to at least three classes of antimicrobials), extensively drug-resistant (XDR, MDR plus resistance to carbapenems), and pan-drug-resistant (PDR, XDR plus resistance to polymyxins) nosocomial isolates that are hard to treat with the currently available drugs. In this article we review the acquired resistance to carbapenems by A. baumannii. We describe the enzymes within the OXA, NDM, VIM, IMP, and KPC groups of carbapenemases and the coding genes found in A. baumannii clinical isolates.
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Affiliation(s)
- Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA;
| | - Robert A. Bonomo
- Medical Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA;
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics; Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- WRU-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, California State University Fullerton, Fullerton, CA 92831, USA;
- Correspondence: ; Tel.: +657-278-5263
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17
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M Campos JC, Antunes LCM, Ferreira RBR. Global priority pathogens: virulence, antimicrobial resistance and prospective treatment options. Future Microbiol 2020; 15:649-677. [DOI: 10.2217/fmb-2019-0333] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Salmonella spp. are part of a group of pathogens that pose a major threat to human health due to the emergence of multidrug-resistant strains. Moreover, these bacteria have several virulence factors that allow them to successfully colonize their hosts, such as toxins and the ability to produce biofilms, resulting in an urgent need to develop new strategies to fight these pathogens. In this review, we compile the most up-to-date information on the epidemiology, virulence and resistance of these clinically important microorganisms. Additionally, we address new therapeutic alternatives, with a focus on molecules with antivirulence activity, which are considered promising to combat multidrug-resistant bacteria.
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Affiliation(s)
- Juliana C de M Campos
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luis CM Antunes
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Rosana BR Ferreira
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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18
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Rodríguez D, Maneiro M, Vázquez-Ucha JC, Beceiro A, González-Bello C. 6-Arylmethylidene Penicillin-Based Sulfone Inhibitors for Repurposing Antibiotic Efficiency in Priority Pathogens. J Med Chem 2020; 63:3737-3755. [PMID: 32196336 DOI: 10.1021/acs.jmedchem.0c00127] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability of 6-(aryl)methylidene penicillin-based sulfones 1-7 to repurpose β-lactam antibiotics activity with bacterial species that carry carbapenem-hydrolyzing class D β-lactamases (OXA-23, OXA-24/40 and OXA-48), as well as with class A (TEM-1, CTX-M-2) and class C (CMY-2, DHA-1) enzymes, is reported. The combinations imipenem/3 and imipenem/4 restored almost completely the antibiotic efficacy in OXA-23 and OXA-24/40 carbapenemase-producing A. baumannii strains (1 μg mL-1) and also provided good results for OXA-48 carbapenemase-producing K. pneumoniae strains (4 μg mL-1). Compounds 2-6 in combinations with ceftazidime and ampicillin were also efficient in restoring antibiotic efficacy in E. coli strains carrying class C (CMY-2 and DHA-1) and class A (TEM-1 and CTX-M-2) β-lactamase enzymes, respectively. Kinetic and inhibition studies with the OXA-24/40 enzyme, protein mass spectrometry analysis and docking studies allowed us to gain an insight into the inhibition mechanism and the experimentally observed differences between the ligands.
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Affiliation(s)
- Diana Rodríguez
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, 15782 Santiago de Compostela, Spain
| | - María Maneiro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, 15782 Santiago de Compostela, Spain
| | - Juan C Vázquez-Ucha
- Servicio de Microbiología do Complexo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (INIBIC), Xubias de Arriba, 84, 15006 A Coruña, Spain
| | - Alejandro Beceiro
- Servicio de Microbiología do Complexo Hospitalario Universitario da Coruña (CHUAC), Instituto de Investigación Biomédica da Coruña (INIBIC), Xubias de Arriba, 84, 15006 A Coruña, Spain
| | - Concepción González-Bello
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Jenaro de la Fuente s/n, 15782 Santiago de Compostela, Spain
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Fernández-Cuenca F, Pérez-Palacios P, Galán-Sánchez F, López-Cerero L, López-Hernández I, López Rojas R, Arca-Suárez J, Díaz-de Alba P, Rodríguez Iglesias M, Pascual A. First identification of bla NDM-1 carbapenemase in bla OXA-94-producing Acinetobacter baumannii ST85 in Spain. Enferm Infecc Microbiol Clin 2019; 38:11-15. [PMID: 31060865 DOI: 10.1016/j.eimc.2019.03.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/04/2019] [Accepted: 03/08/2019] [Indexed: 01/09/2023]
Abstract
INTRODUCTION NDM-1 carbapenemase is spreading rapidly all over the world, but this metallo-beta-lactamase has just been detected for the first time in an Acinetobacter baumannii (Ab) isolate of the ST85 clone in Spain. The aim of this study was to characterize a NDM-1-producing carbapenem-resistant A. baumannii (CR-Ab) isolate submitted to the Andalusian PIRASOA [infection prevention program] referral laboratory. METHODS Carbapenemases were detected by PCR and Sanger DNA sequencing. Whole genome sequencing was performed by NGS (Miseq, Illumina). Resistance genes were identified with RESfinder, while MLSTfinder was used for sequence typing (ST). The genetic location of blaNDM-1 was determined by nuclease S-1/PFGE/hybridization with specific probe. RESULTS The isolate was susceptible to amikacin and tigecycline and belonged to the ST85 clone. blaOXA-94 and blaNDM-1 were identified by PCR and Sanger DNA sequencing, respectively. The resistance genes aadB, blaADC-25, blaNDM-1, blaOXA-94, msr(E), mph(E) and floR,sul2 were identified by NGS. The chromosome of the isolate contained a defective Tn125 transposon with blaNDM-1 flanked by the insertion sequences ISAbA125 and ISAba14. The blaNDM-1 gene was only detected in the chromosomal DNA. CONCLUSION This is the first time that blaNDM-1 has been detected and characterized in a blaOXA-94-producing CR-Ab isolate belonging to the ST85 clone in Spain.
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Affiliation(s)
- Felipe Fernández-Cuenca
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain; Hospital Universitario Virgen Macarena/Centro Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Sevilla, Spain; Spanish Network for Research in Infectious Diseases (REIPI; RD16/0016/0001), Spain.
| | - Patricia Pérez-Palacios
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain; Hospital Universitario Virgen Macarena/Centro Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Sevilla, Spain
| | - Fátima Galán-Sánchez
- Spanish Network for Research in Infectious Diseases (REIPI; RD16/0016/0001), Spain
| | - Lorena López-Cerero
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain; Hospital Universitario Virgen Macarena/Centro Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Sevilla, Spain; Spanish Network for Research in Infectious Diseases (REIPI; RD16/0016/0001), Spain
| | - Inmaculada López-Hernández
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain; Hospital Universitario Virgen Macarena/Centro Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Sevilla, Spain; Spanish Network for Research in Infectious Diseases (REIPI; RD16/0016/0001), Spain
| | - Rafael López Rojas
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain; Hospital Universitario Virgen Macarena/Centro Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Sevilla, Spain; Spanish Network for Research in Infectious Diseases (REIPI; RD16/0016/0001), Spain
| | - Jorge Arca-Suárez
- Hospital Universitario Puerta del Mar, Servicio de Microbiología, Cádiz, Spain
| | - Paula Díaz-de Alba
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain; Hospital Universitario Virgen Macarena/Centro Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Sevilla, Spain
| | | | - Alvaro Pascual
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Sevilla, Spain; Instituto de Biomedicina de Sevilla (IBiS), Sevilla, Spain; Hospital Universitario Virgen Macarena/Centro Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Sevilla, Spain; Spanish Network for Research in Infectious Diseases (REIPI; RD16/0016/0001), Spain
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Fernández-Cuenca F, Tomás M, Caballero-Moyano FJ, Bou G, Pascual Á. Reporting antimicrobial susceptibilities and resistance phenotypes in Acinetobacter spp: a nationwide proficiency study. J Antimicrob Chemother 2019; 73:692-697. [PMID: 29244131 DOI: 10.1093/jac/dkx464] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/07/2017] [Indexed: 01/30/2023] Open
Abstract
Objectives To evaluate the proficiency of Spanish microbiology laboratories with respect to the antimicrobial susceptibility testing (AST) of Acinetobacter spp. Methods Eight Acinetobacter spp. with different resistance mechanisms were sent to 48 Spanish centres which were asked to report: (i) the AST system used; (ii) MICs; (iii) breakpoints used (CLSI versus EUCAST); (iv) clinical category; and (v) resistance mechanisms inferred. Minor, major and very major errors (mE, ME and VME, respectively) were determined. Results The greatest percentages of discrepancies were: (i) by AST method: 18.5% Etest, 14.3% Vitek 2 and Sensititre; (ii) by breakpoints: 20.5% (CLSI) and 10.8% (EUCAST); and (iii) by antimicrobial agent: ampicillin/sulbactam (56.2% CLSI), minocycline (40.7% CLSI), tobramycin (38.7% CLSI, 16.8% EUCAST), imipenem (27.8% CLSI, 30.0% EUCAST) and meropenem (25.4% CLSI, 20.8% EUCAST). Categorical error rates: (i) by AST method ranged from 30.0% (Phoenix) to 100% (Sensititre and disc diffusion) for mE, 0.0% (Etest, Sensititre, disc diffusion) to 40% (Phoenix) for ME, and 0.0% (Sensititre and disc diffusion) to 30% (Phoenix) for VME; (ii) by breakpoints: mE (80.1% CLSI, 58.4% EUCAST), ME (3.5% CLSI, 12.4% EUCAST) and VME (16.4% CLSI, 29.2% EUCAST); and (iii) by antimicrobial agent: mE (100% levofloxacin/CLSI, 100% levofloxacin and meropenem/EUCAST), ME (35.3% colistin/CLSI, 25.0% colistin/EUCAST) and VME (64.7% colistin/CLSI, 86.7% gentamicin/EUCAST). Conclusions Clinical microbiology laboratories must improve their ability to determine antimicrobial susceptibilities of Acinetobacter spp. isolates. Higher discrepancies using CLSI when compared with EUCAST are mainly due to mE and to a much lesser extent to ME or VME.
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Affiliation(s)
- Felipe Fernández-Cuenca
- Unidad Clínica de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain.,Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain.,Spanish Network for the Research in Infectious Diseases (REIPIRD12/0015), Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Biomedicina de Sevilla (IBIs), Sevilla, Spain
| | - María Tomás
- Spanish Network for the Research in Infectious Diseases (REIPIRD12/0015), Instituto de Salud Carlos III, Madrid, Spain.,Servicio de Microbiología, Complexo Hospitalario Universitario de A Coruña (CHUAC), A Coruña, Spain.,Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain
| | - Francisco-Javier Caballero-Moyano
- Unidad Clínica de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain.,Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain
| | - Germán Bou
- Spanish Network for the Research in Infectious Diseases (REIPIRD12/0015), Instituto de Salud Carlos III, Madrid, Spain.,Servicio de Microbiología, Complexo Hospitalario Universitario de A Coruña (CHUAC), A Coruña, Spain.,Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain
| | - Álvaro Pascual
- Unidad Clínica de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain.,Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain.,Spanish Network for the Research in Infectious Diseases (REIPIRD12/0015), Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Biomedicina de Sevilla (IBIs), Sevilla, Spain
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Jamal S, Al Atrouni A, Rafei R, Dabboussi F, Hamze M, Osman M. Molecular mechanisms of antimicrobial resistance in Acinetobacter baumannii, with a special focus on its epidemiology in Lebanon. J Glob Antimicrob Resist 2018; 15:154-163. [PMID: 29859266 DOI: 10.1016/j.jgar.2018.05.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/24/2018] [Accepted: 05/22/2018] [Indexed: 10/16/2022] Open
Abstract
Acinetobacter baumannii is an opportunistic bacterium involved in several types of infection with high mortality and morbidity, especially in intensive care units. Treatment of these infections remains a challenge due to the worldwide emergence of broad-spectrum resistance to many antibiotics. Following the implementation of molecular techniques to study A. baumannii outbreaks, it has been shown that they are mainly caused by specific clones such as international clones I, II and III. The present work aims to review the available data on the mechanisms underlying antimicrobial resistance in A. baumannii, with a special focus on the molecular epidemiology of this species in Lebanon.
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Affiliation(s)
- Sabah Jamal
- Laboratoire Microbiologie Santé et Environnement (LMSE), Ecole Doctorale des Sciences et de Technologie, Faculté de Santé Publique, Université Libanaise, Tripoli, Lebanon
| | - Ahmad Al Atrouni
- Laboratoire Microbiologie Santé et Environnement (LMSE), Ecole Doctorale des Sciences et de Technologie, Faculté de Santé Publique, Université Libanaise, Tripoli, Lebanon
| | - Rayane Rafei
- Laboratoire Microbiologie Santé et Environnement (LMSE), Ecole Doctorale des Sciences et de Technologie, Faculté de Santé Publique, Université Libanaise, Tripoli, Lebanon
| | - Fouad Dabboussi
- Laboratoire Microbiologie Santé et Environnement (LMSE), Ecole Doctorale des Sciences et de Technologie, Faculté de Santé Publique, Université Libanaise, Tripoli, Lebanon
| | - Monzer Hamze
- Laboratoire Microbiologie Santé et Environnement (LMSE), Ecole Doctorale des Sciences et de Technologie, Faculté de Santé Publique, Université Libanaise, Tripoli, Lebanon.
| | - Marwan Osman
- Laboratoire Microbiologie Santé et Environnement (LMSE), Ecole Doctorale des Sciences et de Technologie, Faculté de Santé Publique, Université Libanaise, Tripoli, Lebanon
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22
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An Z, Su J. Acinetobacter baumannii outer membrane protein 34 elicits NLRP3 inflammasome activation via mitochondria-derived reactive oxygen species in RAW264.7 macrophages. Microbes Infect 2018; 21:143-153. [PMID: 30439507 DOI: 10.1016/j.micinf.2018.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 10/19/2018] [Accepted: 10/26/2018] [Indexed: 12/21/2022]
Abstract
Acinetobacter baumannii (A. baumannii) is a Gram-negative bacterium, which acts as an opportunistic pathogen and causes hospital-acquired pneumonia and bacteremia by infecting the alveoli of epithelial cells and macrophages. Evidence reveals that A. baumannii outer membrane protein 34 (Omp34) elicits cellular immune responses and inflammation. The innate immunity NOD-like receptor 3 (NLRP3) inflammasome exerts critical function against pneumonia caused by A. baumannii infection, however, the role of Omp34 in the activation of the NLRP3 inflammasome and its corresponding regulatory mechanism are not clearly elucidated. The present study aimed to investigate whether Omp34 elicited NLRP3 inflammasome activation through the mitochondria-derived reactive oxygen species (ROS). Our results showed that Omp34 triggered cell pyroptosis by up-regulating the expression of NLRP3 inflammasome-associated proteins and IL-1β release in a time- and dose-dependent manner. Omp34 induced the expression of caspase-1-p10 and IL-1β, which was significantly attenuated by NLRP3 gene silencing in RAW264.7 mouse macrophage cells. Additionally, Omp34 stimulated RAW264.7 mitochondria to generate ROS, while the ROS scavenger Mito-TEMPO inhibited the Omp34-triggered expression of NLRP3 inflammasome-associated proteins and IL-1β synthesis. The above findings indicate that mitochondria-derived ROS play an important role in the process of NLRP3 inflammasome activation. In summary, our study demonstrates that the A. baumannii pathogen pattern recognition receptor Omp34 activates NLRP3 inflammasome via mitochondria-derived ROS in RAW264.7 cells. Accordingly, down-regulating the mitochondria-derived ROS prevents the severe infection consequences caused by A. baumannii-induced NLRP3 inflammasome hyper-activation.
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Affiliation(s)
- Zhiyuan An
- Medical Research Center, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
| | - Jianrong Su
- Clinical Laboratory Center, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China.
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23
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Singkham-In U, Chatsuwan T. Mechanisms of carbapenem resistance in Acinetobacter pittii and Acinetobacter nosocomialis isolates from Thailand. J Med Microbiol 2018; 67:1667-1672. [PMID: 30311872 DOI: 10.1099/jmm.0.000845] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PURPOSE The emergence of carbapenem resistance in non-baumannii Acinetobacter has increased in clinical settings worldwide. We investigated the prevalence and mechanisms of carbapenem resistance in A. pittii and A. nosocomialis Thai isolates. METHODOLOGY Acinetobacter calcoaceticus-Acinetobacter baumannii (Acb) complex isolates were identified by gyrB mulitplex PCR. Carbapenem susceptibilities were studied by the agar dilution method and carbapenemase genes were detected by multiplex PCR. Reductions of the outer membrane proteins (OMPs) were evaluated by SDS-PAGE. Overexpressions of efflux pumps were detected by using efflux pump inhibitors and RT-PCR. RESULTS Of the 346 Acb isolates, 22 and 19 were A. pittii and A. nosocomialis, respectively. The carbapenem resistance rates were 22.7 % in A. pittii and 26.3 % in A. nosocomialis. Three carbapenem-resistant A. pittii carried blaOXA-23. One carbapenem-resistant A. pittii harboured blaOXA-58, while another isolate co-harboured blaOXA-58 and blaIMP-14a. blaOXA-58 was also found in three carbapenem-susceptible A. pittii. Five carbapenem-resistant A. nosocomialis carried blaOXA-23. Eighteen A. pittii isolates carried blaOXA-213-like. Reduced OMPs were found in carbapenem-resistant and -susceptible A. pittii carrying blaOXA-58, but were not detected in carbapenem-resistant A. nosocomialis isolates. Overexpression of adeE was found in carbapenem-resistant A. pittii. No efflux pump genes were present in carbapenem-resistant A. nosocomialis. CONCLUSION The major mechanisms of carbapenem resistance in A. pittii and A. nosocomialis were the production of OXA-23 and OXA-58. Overexpression of adeE played a role in carbapenem resistance in A. pittii. Since blaOXA-58 was found in carbapenem-susceptible A. pittii, using carbapenems in the treatment of A. pittii infection should be considered.
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Affiliation(s)
- Uthaibhorn Singkham-In
- 1Interdisciplinary Program of Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Tanittha Chatsuwan
- 2Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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24
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Abellón-Ruiz J, Zahn M, Baslé A, van den Berg B. Crystal structure of theAcinetobacter baumanniiouter membrane protein Omp33. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2018; 74:852-860. [DOI: 10.1107/s205979831800904x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 06/20/2018] [Indexed: 12/31/2022]
Abstract
Acinetobacter baumanniiis becoming a major threat to human health due to its multidrug resistance. This is owing in a large part to the low permeability of its outer membrane (OM), which prevents high internal antibiotic concentrations and makes antibiotic-resistance mechanisms more effective. To exploit OM channels as potential delivery vehicles for future antibiotics, structural information is required. One abundant OM protein inA. baumanniiis Omp33. This protein has been reported to be important for thein vivofitness and virulence ofA. baumannii, but its structure is not known. Here, the X-ray crystal structure of Omp33 is reported at a resolution of 2.1 Å. Omp33 has a 14-β-stranded barrel without stable extracellular loop constrictions. Instead, an extended and unusual periplasmic turn connecting β-strands 2 and 3 is present, which folds into the pore lumen and completely blocks the aqueous channel. The Omp33 structure helps in understanding howA. baumanniiOM proteins contribute to the low permeability of the cell envelope of this bacterium and suggests that Omp33 might function as a gated channel.
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25
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Novović K, Mihajlović S, Dinić M, Malešević M, Miljković M, Kojić M, Jovčić B. Acinetobacter spp. porin Omp33-36: Classification and transcriptional response to carbapenems and host cells. PLoS One 2018; 13:e0201608. [PMID: 30071077 PMCID: PMC6072067 DOI: 10.1371/journal.pone.0201608] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 07/18/2018] [Indexed: 01/11/2023] Open
Abstract
Acinetobacter baumannii has been recognized as one of the most challeging pathogens in clinical settings worldwide. Outer membrane porins play a significant role in Acinetobacter antibiotic resistance and virulence. A. baumannii carbapenem resistance and virulence factor porin Omp33-36 was the subject of this study. We investigated the omp33-36 gene transcriptional response in the growth phase, its response to carbapenems, and the effect of contact with host cells. Additionally, the cytotoxic effect of A. baumannii towards keratinocytes was assessed, as well as correlation between omp33-36 gene transcription and cytotoxicity. Further, Acinetobacter spp. Omp33-36 was classified and its characteristics relevant for vaccine candidature were determined. The level of the omp33-36 gene transcription varied between growth phases, but a common pattern could not be established among different strains. Treatment with subinhibitory concentrations of carbapenems decreased, while contact with keratinocytes increased omp33-36 expression in the analysed A. baumannii strains. Variations in omp33-36 mRNA levels did not correlate with cytotoxicity levels. Decrease of omp33-36 mRNA during treatment with subinhibitory concentrations of carbapenems, indicated the importance of transcriptional changes in reversible resistance to carbapenems due to the absence of Omp33-36. The transcription of omp33-36 increased after contact with keratinocytes, indicating the important role of de novo transcription during the initial phase of A. baumannii infection. Primary structural analysis of Acinetobacter spp. Omp33-36 revealed three distinct groups (among four A. baumannii variants). Although we have shown that Omp33-36 was highly polymorphic, we propose a potential antigen (PLAEAAFL motif) for vaccine development. According to PROVEAN analysis, the highly polymorphic structure of Omp33-36 porin should not influence its function significantly.
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Affiliation(s)
- Katarina Novović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Sanja Mihajlović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Miroslav Dinić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Milka Malešević
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Marija Miljković
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Milan Kojić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Branko Jovčić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
- * E-mail:
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26
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Distribution of virulence-associated genes and antimicrobial susceptibility in clinical Acinetobacter baumannii isolates. Oncotarget 2018; 9:21663-21673. [PMID: 29774093 PMCID: PMC5955172 DOI: 10.18632/oncotarget.24651] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/26/2018] [Indexed: 12/15/2022] Open
Abstract
Acinetobacter baumannii is undoubtedly one of the most clinically significant pathogens. The multidrug resistance and virulence potential of A. baumannii are responsible for hospital-acquired nosocomial infections. Unlike numerous investigations on the drug-resistant epidemiology of A. baumanni, virulence molecular epidemiology is less studied. Here, we collected 88 A. baumannii clinical isolates, tested their antimicrobial susceptibility to 10 commonly used antibiotics and analyzed the distribution of 9 selected virulence-associated genes, aims to investigate the primary characteristics of the virulence-associated genes that exist in clinically multidrug resistant (MDR) and non-MDR isolates of A. baumannii. The MIC results showed the resistance rates of ciprofloxacin (68.2%, 60/88), gentamicin (67.0%, 59/88), amikacin (58.0%, 51/88), tobramycin (58.0%, 51/88), doxycycline (67.0%, 59/88), meropenem (54.5%, 48/88) and imipenem (65.9%, 58/88) were all above 50%, except for levofloxacin (34.1%, 30/88), minocycline (1.1%, 1/88) and polymyxin B (0%, 0/88). The Pulsed field gel electrophoresis (PFGE) analysis revealed that the resistance rate of MDR A. baumannii isolates in the Epidemic group was predominant (79.5%, 44/58), but in the Sporadic group was only 6.7% (2/30). Further investigation on the distribution of virulence genes showed the virulence genes bap (95.5%), surA1 (92.0%), BasD (92.0%), paaE (88.6%), pld (87.5%), BauA (62.5%), omp33-36 (59.1%) and pglC (53.4%) were accounted for high proportion, except for traT (0%). Overall, our results revealed that MDR isolates predominated in the Epidemic A. baumannii isolates, and contained a very high proportion of virulence genes, which may lead to high risk, high pathogenicity and high treatment challenge.
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Fernández-Cuenca F, Tomás M, Tormo N, Gimeno C, Bou G, Pascual Á. Reporting identification of Acinetobacter spp genomic species: A nationwide proficiency study in Spain. Enferm Infecc Microbiol Clin 2018; 37:89-92. [PMID: 29605096 DOI: 10.1016/j.eimc.2018.02.004] [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: 12/22/2017] [Revised: 02/01/2018] [Accepted: 02/07/2018] [Indexed: 11/25/2022]
Abstract
Acinetobacter baumannii is the most important genomic species of Acinetobacter from a clinical and epidemiological point of view. Nevertheless, genomic species other than A. baumannii are increasingly recognized as nosocomial pathogens. Molecular methods of identification (genotypic and proteomic assays) are more accurate and reliable and have greater discriminatory power than phenotypic methods. Eleven genomic species of Acinetobacter spp. (8 A. baumannii, 1 A. pittii, 1 A. nosocomialis and 1 A. lwoffii) with different antimicrobial resistance phenotypes and mechanisms of resistance to antimicrobial agents were sent to 48 participating Spanish centers to evaluate their ability for correct identification at the genomic species level. Identification of the genomic species was performed at the two Clinical Microbiology reference laboratories (Hospital Universitario Virgen Macarena, Seville, Spain; and Complejo Hospitalario Universitario de A Coruña, A Coruña, Spain) by partial DNA sequencing of the rpoB gene and MALDI-TOF. The mean percentage of agreement was 76.1%. Fifty percent of CC-01 (A. pittii) and 50% of CC-02 (A. nosocomialis) identification results were reported as A. baumannii. Discrepancies by type of systems used for identification were: MicroScan WA (51.1%), Vitek 2 (19.5%), MALDI-TOF (18.0%), Phoenix (4.5%), Wider (3.8%) and API 20 NE (3.0%). In conclusion, clinical microbiology laboratories must improve their ability to correctly identify the most prevalent non A. baumannii genomic species.
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Affiliation(s)
- Felipe Fernández-Cuenca
- Unidad Clínica de Enfermedades Infecciosas y Microbiología Clínica y Medicina, Hospital Universitario Virgen Macarena, Sevilla, Spain; Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain; Spanish Network for the Research in Infectious Diseases (REIPIRD12/0015), Instituto de Salud Carlos III, Madrid, Spain; Instituto de Biomedicina de Sevilla IBIs, Sevilla, Spain.
| | - María Tomás
- Spanish Network for the Research in Infectious Diseases (REIPIRD12/0015), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Complexo Hospitalario Universitario de A Coruña (CHUAC), A Coruña, Spain; Instituto de Investigación Biomédica (INIBIC) , A Coruña, Spain
| | - Nuria Tormo
- Servicio de Microbiología, Hospital General de Valencia, Valencia, Spain
| | - Concha Gimeno
- Servicio de Microbiología, Hospital General de Valencia, Valencia, Spain
| | - Germán Bou
- Spanish Network for the Research in Infectious Diseases (REIPIRD12/0015), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Complexo Hospitalario Universitario de A Coruña (CHUAC), A Coruña, Spain; Instituto de Investigación Biomédica (INIBIC) , A Coruña, Spain
| | - Álvaro Pascual
- Unidad Clínica de Enfermedades Infecciosas y Microbiología Clínica y Medicina, Hospital Universitario Virgen Macarena, Sevilla, Spain; Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain; Spanish Network for the Research in Infectious Diseases (REIPIRD12/0015), Instituto de Salud Carlos III, Madrid, Spain; Instituto de Biomedicina de Sevilla IBIs, Sevilla, Spain
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Jahangiri A, Rasooli I, Owlia P, Fooladi AAI, Salimian J. An integrative in silico approach to the structure of Omp33-36 in Acinetobacter baumannii. Comput Biol Chem 2018; 72:77-86. [DOI: 10.1016/j.compbiolchem.2018.01.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 01/07/2018] [Accepted: 01/10/2018] [Indexed: 01/01/2023]
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Jahangiri A, Rasooli I, Owlia P, Imani Fooladi AA, Salimian J. Highly conserved exposed immunogenic peptides of Omp34 against Acinetobacter baumannii: An innovative approach. J Microbiol Methods 2018; 144:79-85. [DOI: 10.1016/j.mimet.2017.11.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 11/06/2017] [Accepted: 11/09/2017] [Indexed: 11/16/2022]
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Ambrosi C, Scribano D, Aleandri M, Zagaglia C, Di Francesco L, Putignani L, Palamara AT. Acinetobacter baumannii Virulence Traits: A Comparative Study of a Novel Sequence Type with Other Italian Endemic International Clones. Front Microbiol 2017; 8:1977. [PMID: 29075243 PMCID: PMC5643476 DOI: 10.3389/fmicb.2017.01977] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/25/2017] [Indexed: 01/20/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAb) have emerged in recent decades as major causes of nosocomial infections. Resistance is mainly due to overexpression of intrinsic and/or acquired carbapenemases, especially oxacillinases (OXA). In Italy, although the sequence type (ST) 2 and the ST78 are the most frequently detected, we recently reported ST632, a single locus variant of ST2. Therefore, this study was aimed at unraveling common bacterial surface virulence factors involved in pathogenesis and antibiotic resistance in representative CRAb of these ST genotypes. Outer membrane protein (OMP) composition together with motility, biofilm formation, in vitro adherence to, invasion of, and survival within pneumocytes were analyzed. Differently from the carbapenem-susceptible reference strain ATCC 17978, either overexpressed OXA-51 or both OXA-23 and OXA-51 co-purified with OMPs in CRAb. This tight association ensures their maximal concentration on the inner surface of the outer membrane to provide the best protection against carbapenems. These findings led us to propose for the first time a common behavior of OXA enzymes in CRAb. Despite the presence of both OmpA and phosphorylcholine-porinD and the ability of all the strains to adhere to cells, invasion, and survival within pneumocytes was shown only by ST2 and ST78 isolates, sharing the highest number of identified OMPs. Conversely, notwithstanding genetic and OMPs similarities with ST2, ST632 was unable to invade and survive within epithelial cells. Overall, our study shows that different STs share a specific OMP composition, also shaped by overexpressed OXA, that is needed for invasiveness and survival of CRAb.
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Affiliation(s)
- Cecilia Ambrosi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.,Dani Di Giò Foundation-Onlus, Rome, Italy
| | - Daniela Scribano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.,Department of Medical, Oral and Biotechnological Sciences, Università degli Studi "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Marta Aleandri
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Carlo Zagaglia
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Laura Di Francesco
- Unit of Human Microbiome, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Lorenza Putignani
- Unit of Human Microbiome, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.,Unit of Parasitology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Anna Teresa Palamara
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory Affiliated to Institute Pasteur Italia, Cenci-Bolognetti Foundation, Rome, Italy.,San Raffaele Pisana, IRCCS, Telematic University, Rome, Italy
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Lee CR, Lee JH, Park M, Park KS, Bae IK, Kim YB, Cha CJ, Jeong BC, Lee SH. Biology of Acinetobacter baumannii: Pathogenesis, Antibiotic Resistance Mechanisms, and Prospective Treatment Options. Front Cell Infect Microbiol 2017; 7:55. [PMID: 28348979 PMCID: PMC5346588 DOI: 10.3389/fcimb.2017.00055] [Citation(s) in RCA: 517] [Impact Index Per Article: 73.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/13/2017] [Indexed: 12/27/2022] Open
Abstract
Acinetobacter baumannii is undoubtedly one of the most successful pathogens responsible for hospital-acquired nosocomial infections in the modern healthcare system. Due to the prevalence of infections and outbreaks caused by multi-drug resistant A. baumannii, few antibiotics are effective for treating infections caused by this pathogen. To overcome this problem, knowledge of the pathogenesis and antibiotic resistance mechanisms of A. baumannii is important. In this review, we summarize current studies on the virulence factors that contribute to A. baumannii pathogenesis, including porins, capsular polysaccharides, lipopolysaccharides, phospholipases, outer membrane vesicles, metal acquisition systems, and protein secretion systems. Mechanisms of antibiotic resistance of this organism, including acquirement of β-lactamases, up-regulation of multidrug efflux pumps, modification of aminoglycosides, permeability defects, and alteration of target sites, are also discussed. Lastly, novel prospective treatment options for infections caused by multi-drug resistant A. baumannii are summarized.
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Affiliation(s)
- Chang-Ro Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Jung Hun Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Moonhee Park
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji UniversityYongin, South Korea; DNA Analysis Division, Seoul Institute, National Forensic ServiceSeoul, South Korea
| | - Kwang Seung Park
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Il Kwon Bae
- Department of Dental Hygiene, College of Health and Welfare, Silla University Busan, South Korea
| | - Young Bae Kim
- Biotechnology Program, North Shore Community College Danvers, MA, USA
| | - Chang-Jun Cha
- Department of Systems Biotechnology, College of Biotechnology and Natural Resources, Chung-Ang University Anseong, South Korea
| | - Byeong Chul Jeong
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
| | - Sang Hee Lee
- National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea
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Sato Y, Unno Y, Kawakami S, Ubagai T, Ono Y. Virulence characteristics of Acinetobacter baumannii clinical isolates vary with the expression levels of omps. J Med Microbiol 2017; 66:203-212. [PMID: 27902395 DOI: 10.1099/jmm.0.000394] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE We investigated the expression levels of virulence factors (ompA, omp33-36 and carO) in five clinical isolates and in a standard ATCC 19606 strain of Acinetobacter baumannii to determine their effect on the virulence characteristics of the isolates. METHODOLOGY The mRNA levels of omps and proinflammatory cytokines were analyzed by quantitative real-time PCR. For adherence assay, after human lung epithelial cells (A549) were co-cultured with A. baumannii at 37 °C for 2 h, the cell-adherent bacteria was counted. Pearson correlation analysis was used to compare the omps mRNA levels, the proinflammatory cytokines and the number of adherent bacteria. RESULTS The mRNA levels of ompA in the clinical isolates were higher and similar compared with those in ATCC 19606, whereas the mRNA levels of omp33-36 in the clinical isolates were lower and similar compared with those in ATCC 19606. The mRNA levels of carO in the clinical isolates were significantly higher than those in ATCC 19606. The number of cell-adherent clinical isolates was higher than that of cell-adherent ATCC 19606. Furthermore, the number of cell-adherent clinical isolates was positively and significantly correlated with ompA mRNA level. The mRNA levels of TNF-α, IL-6 and IL-8 in A549 cells co-cultured with the clinical isolates were lower than those in A549 cells co-cultured with ATCC 19606. Moreover, the mRNA levels of TNF-α, IL-6 and IL-8 were negatively and significantly correlated with those of carO in the isolates. CONCLUSION These results provide insights into the renewed virulence characteristics of A. baumannii clinical isolates that depend on cell adherence capacity and the expression level of omp mRNAs.
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Affiliation(s)
- Yoshinori Sato
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yuka Unno
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Sayoko Kawakami
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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The Acinetobacter Outer Membrane Contains Multiple Specific Channels for Carbapenem β-Lactams as Revealed by Kinetic Characterization Analyses of Imipenem Permeation into Acinetobacter baylyi Cells. Antimicrob Agents Chemother 2017; 61:AAC.01737-16. [PMID: 28069648 DOI: 10.1128/aac.01737-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 12/28/2016] [Indexed: 12/31/2022] Open
Abstract
The number and type of outer membrane (OM) channels responsible for carbapenem uptake in Acinetobacter are still not well defined. Here, we addressed these questions by using Acinetobacter baylyi as a model species and a combination of methodologies aimed to characterize OM channels in their original membrane environment. Kinetic and competition analyses of imipenem (IPM) uptake by A. baylyi whole cells allowed us to identify different carbapenem-specific OM uptake sites. Comparative analyses of IPM uptake by A. baylyi wild-type (WT) cells and ΔcarO mutants lacking CarO indicated that this OM protein provided a carbapenem uptake site displaying saturable kinetics and common binding sites for basic amino acids compatible with a specific channel. The kinetic analysis uncovered another carbapenem-specific channel displaying a somewhat lower affinity for IPM than that of CarO and, in addition, common binding sites for basic amino acids as determined by competition studies. The use of A. baylyi gene deletion mutants lacking OM proteins proposed to function in carbapenem uptake in Acinetobacter baumannii indicated that CarO and OprD/OccAB1 mutants displayed low but consistent reductions in susceptibility to different carbapenems, including IPM, meropenem, and ertapenem. These two mutants also showed impaired growth on l-Arg but not on other carbon sources, further supporting a role of CarO and OprD/OccAB1 in basic amino acid and carbapenem uptake. A multiple-carbapenem-channel scenario may provide clues to our understanding of the contribution of OM channel loss or mutation to the carbapenem-resistant phenotype evolved by pathogenic members of the Acinetobacter genus.
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Wu X, Chavez JD, Schweppe DK, Zheng C, Weisbrod CR, Eng JK, Murali A, Lee SA, Ramage E, Gallagher LA, Kulasekara HD, Edrozo ME, Kamischke CN, Brittnacher MJ, Miller SI, Singh PK, Manoil C, Bruce JE. In vivo protein interaction network analysis reveals porin-localized antibiotic inactivation in Acinetobacter baumannii strain AB5075. Nat Commun 2016; 7:13414. [PMID: 27834373 PMCID: PMC5114622 DOI: 10.1038/ncomms13414] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 09/30/2016] [Indexed: 12/13/2022] Open
Abstract
The nosocomial pathogen Acinetobacter baumannii is a frequent cause of hospital-acquired infections worldwide and is a challenge for treatment due to its evolved resistance to antibiotics, including carbapenems. Here, to gain insight on A. baumannii antibiotic resistance mechanisms, we analyse the protein interaction network of a multidrug-resistant A. baumannii clinical strain (AB5075). Using in vivo chemical cross-linking and mass spectrometry, we identify 2,068 non-redundant cross-linked peptide pairs containing 245 intra- and 398 inter-molecular interactions. Outer membrane proteins OmpA and YiaD, and carbapenemase Oxa-23 are hubs of the identified interaction network. Eighteen novel interactors of Oxa-23 are identified. Interactions of Oxa-23 with outer membrane porins OmpA and CarO are verified with co-immunoprecipitation analysis. Furthermore, transposon mutagenesis of oxa-23 or interactors of Oxa-23 demonstrates changes in meropenem or imipenem sensitivity in strain AB5075. These results provide a view of porin-localized antibiotic inactivation and increase understanding of bacterial antibiotic resistance mechanisms.
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Affiliation(s)
- Xia Wu
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - Juan D. Chavez
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - Devin K. Schweppe
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - Chunxiang Zheng
- Department of Chemistry, University of Washington, Seattle, Washington 98109, USA
| | - Chad R. Weisbrod
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - Jimmy K. Eng
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - Ananya Murali
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - Samuel A. Lee
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - Elizabeth Ramage
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - Larry A. Gallagher
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | | | - Mauna E. Edrozo
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA
| | | | | | - Samuel I. Miller
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Pradeep K. Singh
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | - Colin Manoil
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
| | - James E. Bruce
- Department of Genome Sciences, University of Washington, 850 Republican Street, Brotman Building Room 154, Seattle, Washington 98109, USA
- Department of Chemistry, University of Washington, Seattle, Washington 98109, USA
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Immunization with a 22-kDa outer membrane protein elicits protective immunity to multidrug-resistant Acinetobacter baumannii. Sci Rep 2016; 6:20724. [PMID: 26853590 PMCID: PMC4745112 DOI: 10.1038/srep20724] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 01/11/2016] [Indexed: 11/28/2022] Open
Abstract
A. baumannii infections are becoming more and more serious health issues with rapid emerging of multidrug and extremely drug resistant strains, and therefore, there is an urgent need for the development of nonantibiotic-based intervention strategies. This study aimed at identifying whether an outer membrane protein with molecular weight of about 22 kDa (Omp22) holds the potentials to be an efficient vaccine candidate and combat A. baumannii infection. Omp22 which has a molecule length of 217 amino acids kept more than 95% conservation in totally 851 reported A. baumannii strains. Recombinant Omp22 efficiently elicited high titers of specific IgG in mice. Both active and passive immunizations of Omp22 increased the survival rates of mice, suppressed the bacterial burdens in the organs and peripheral blood, and reduced the levels of serum inflammatory cytokines and chemokines. Opsonophagocytosis assays showed in vitro that Omp22 antiserum had highly efficient bactericidal activities on clonally distinct clinical A. baumannii isolates, which were partly complements-dependent and opsonophagocytic killing effects. Additionally, administration with as high as 500 μg of Omp22 didn’t cause obvious pathological changes in mice. In conclusion, Omp22 is a novel conserved and probably safe antigen for developing effective vaccines or antisera to control A. baumannii infections.
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Kamolvit W, Sidjabat HE, Paterson DL. Molecular Epidemiology and Mechanisms of Carbapenem Resistance ofAcinetobacterspp. in Asia and Oceania. Microb Drug Resist 2015; 21:424-34. [DOI: 10.1089/mdr.2014.0234] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Witchuda Kamolvit
- UQ Centre of Clinical Research, The University of Queensland, Brisbane, Australia
- Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Hanna E. Sidjabat
- UQ Centre of Clinical Research, The University of Queensland, Brisbane, Australia
| | - David L. Paterson
- UQ Centre of Clinical Research, The University of Queensland, Brisbane, Australia
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Lopes BS, Al-Agamy MH, Ismail MA, Shibl AM, Al-Qahtani AA, Al-Ahdal MN, Forbes KJ. The transferability of blaOXA-23 gene in multidrug-resistant Acinetobacter baumannii isolates from Saudi Arabia and Egypt. Int J Med Microbiol 2015; 305:581-8. [PMID: 26253451 DOI: 10.1016/j.ijmm.2015.07.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 07/24/2015] [Accepted: 07/28/2015] [Indexed: 11/25/2022] Open
Abstract
Carbapenem-resistant Acinetobacter spp. have been increasingly reported worldwide including Saudi Arabia and Egypt. We examined 64, non-repetitive, Acinetobacter baumannii isolates collected in 2013 and 2014 from four different medical centres (two from Saudi Arabia and two from Egypt). All the isolates were resistant to ceftazidime and ciprofloxacin. The intI1 harbouring blaGES-11 and aac-6'-1b was detected in 19% (n=12) of the isolates. ISAba1 over-expression of blaADC gene was observed in 65% (n=42) of isolates. Of all the isolates 19% (n=12) had ISAba1 upstream of the blaOXA-51-like gene, 69% (n=44) carried the blaOXA-23 gene within the Tn2006 structure, 8% (n=5) had blaOXA-24-like gene and 9% (n=6) harboured either blaVIM-2 or blaNDM-1 gene. Eighty nine percent (n=57) of isolates were resistant to imipenem and had an MIC of ≥8mg/L. Pulsed-field gel electrophoresis (PFGE) typing revealed the presence of 23 different PFGE. Three PFGE types were very widespread, ST236 (CC104) (PFGE type 1, n=15), ST208 (CC92) (PFGE type 2, n=10), ST884 (CC unassigned) (PFGE type 3, n=7) in and across all four medical centres. The blaOXA-23 gene was found to be present on a 60kb transferable plasmid in both PFGE type 1 and 2 but was absent in PFGE type 3. This is the first study to report on the emergence of ST236 in Saudi Arabia and Egypt, and spread of distinct carbapenem resistant A. baumannii clones belonging to ST884, ST945 and ST1096 in Saudi Arabia.
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Affiliation(s)
| | - Mohamed H Al-Agamy
- College of Pharmacy, King Saud University, 11451 Riyadh 2457, Saudi Arabia; Department of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Muhammad A Ismail
- Medical Microbiology, Polwarth Building, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Atef M Shibl
- College of Pharmacy, King Saud University, 11451 Riyadh 2457, Saudi Arabia; Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia
| | - Ahmed A Al-Qahtani
- Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia
| | - Mohammed N Al-Ahdal
- Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia
| | - Ken J Forbes
- Medical Microbiology, Polwarth Building, Foresterhill, Aberdeen AB25 2ZD, UK
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Vallejo JA, Beceiro A, Rumbo-Feal S, Rodríguez-Palero MJ, Russo TA, Bou G. Optimisation of the Caenorhabditis elegans model for studying the pathogenesis of opportunistic Acinetobacter baumannii. Int J Antimicrob Agents 2015:S0924-8579(15)00241-1. [PMID: 26213382 DOI: 10.1016/j.ijantimicag.2015.05.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/12/2015] [Accepted: 05/15/2015] [Indexed: 11/30/2022]
Abstract
This study aimed to increase the sensitivity of Caenorhabditis elegans as an infection model for detection of minor differences in virulence or fitness between different Acinetobacter baumannii strains with known resistance and virulence mechanisms. Selected A. baumannii strains and mutants, comprising wild-type strains (ATCC 17978 and 19606), colistin-resistant strains (ATCC 19606 ΔlpxA and ATCC 19606 ΔlpxC), a clinical encapsulated isolate (AB307-0294), an imipenem-resistant strain (ATCC 17978 Δomp33-36) and an sRNA knock-out strain (ATCC 17978 Δ13573), were employed in developing killing and fertility assays in a C. elegans infection model. Because virulence levels of the strains were known, they could be used to assess assays in the nematode model for their ability to discriminate between degrees of virulence. The model was validated by microscopic analysis and in a murine sepsis infection model. The fertility assay, specifically utilising nematode growth medium, was able to detect virulence differences between the wild-type strains, ATCC 19606 ΔlpxA and isolate AB307-0294. Moreover, modification of an alternative culture medium by incremental changes in osmolarity facilitated detection of subtle virulence differences between isogenic mutants (ATCC 17978 Δomp33-36 and 17978 Δ13573). The success of the proposed fertility model depends on establishing a balance between optimal C. elegans reproduction and environmental stress leading to maximum pathogen-induced damage. This invertebrate model may reduce the need for mammalian in vivo studies of A. baumannii resistance and pathogenicity and may additionally be validated for the study of other low-virulence bacterial pathogens.
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Affiliation(s)
- J A Vallejo
- Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias s/n, 15006 A Coruña, Spain
| | - A Beceiro
- Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias s/n, 15006 A Coruña, Spain.
| | - S Rumbo-Feal
- Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias s/n, 15006 A Coruña, Spain
| | - M J Rodríguez-Palero
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC), Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Seville, Spain
| | - T A Russo
- Veterans Administration Western Healthcare System, Departments of Medicine and Microbiology & Immunology, The University at Buffalo-State University of New York, Buffalo, NY, USA
| | - G Bou
- Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universitario A Coruña (CHUAC), As Xubias s/n, 15006 A Coruña, Spain.
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Li XZ, Plésiat P, Nikaido H. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria. Clin Microbiol Rev 2015; 28:337-418. [PMID: 25788514 PMCID: PMC4402952 DOI: 10.1128/cmr.00117-14] [Citation(s) in RCA: 939] [Impact Index Per Article: 104.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Patrick Plésiat
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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Overexpression of an outer membrane protein associated with decreased susceptibility to carbapenems in Proteus mirabilis. PLoS One 2015; 10:e0120395. [PMID: 25756370 PMCID: PMC4355480 DOI: 10.1371/journal.pone.0120395] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/21/2015] [Indexed: 11/19/2022] Open
Abstract
Proteus mirabilis isolates commonly have decreased susceptibility to imipenem. Previously, we found P. mirabilis hfq mutant was more resistant to imipenem and an outer membrane protein (OMP) could be involved. Therefore, we investigated the role of this OMP in carbapenem susceptibility. By SDS-PAGE we found this OMP (named ImpR) was increased in hfq mutant and LC-MS/MS revealed it to be the homologue of Salmonella YbfM, which is a porin for chitobiose and subject to MicM (a small RNA) regulation. We demonstrated that ImpR overexpression resulted in increased carbapenem MICs in the laboratory strain and clinical isolates. Chitobiose induced expression of chb (a chitobiose utilization operon). Real-time RT-PCR and SDS-PAGE were performed to elucidate the relationship of hfq, impR, chb and MicM in P. mirabilis. We found MicM RNA was decreased in hfq mutant and chbBC-intergenic region (chbBC-IGR) overexpression strain (chbIGRov), while impR mRNA was increased in hfq mutant, micM mutant and chbIGRov strain. In addition, mutation of hfq or micM and overexpression of chbBC-IGR increased ImpR protein level. Accordingly, chitobiose made wild-type have higher levels of ImpR protein and are more resistant to carbapenems. Hfq- and MicM-complemented strains restored wild-type MICs. Mutation of both impR and hfq eliminated the increase in carbapenem MICs observed in hfq mutant and ImpR-complementation of hfq/impR double mutant resulted in MICs as hfq mutant, indicating that the ImpR-dependent decreased carbapenem susceptibility of hfq mutant. These indicate MicM was antisense to impR mRNA and was negatively-regulated by chbBC-IGR. Together, overexpression of ImpR contributed to the decreased carbapenem susceptibility in P. mirabilis.
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Lin MF, Lan CY. Antimicrobial resistance in Acinetobacter baumannii: From bench to bedside. World J Clin Cases 2014; 2:787-814. [PMID: 25516853 PMCID: PMC4266826 DOI: 10.12998/wjcc.v2.i12.787] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 08/25/2014] [Accepted: 10/27/2014] [Indexed: 02/05/2023] Open
Abstract
Acinetobacter baumannii (A. baumannii) is undoubtedly one of the most successful pathogens in the modern healthcare system. With invasive procedures, antibiotic use and immunocompromised hosts increasing in recent years, A. baumannii has become endemic in hospitals due to its versatile genetic machinery, which allows it to quickly evolve resistance factors, and to its remarkable ability to tolerate harsh environments. Infections and outbreaks caused by multidrug-resistant A. baumannii (MDRAB) are prevalent and have been reported worldwide over the past twenty or more years. To address this problem effectively, knowledge of species identification, typing methods, clinical manifestations, risk factors, and virulence factors is essential. The global epidemiology of MDRAB is monitored by persistent surveillance programs. Because few effective antibiotics are available, clinicians often face serious challenges when treating patients with MDRAB. Therefore, a deep understanding of the resistance mechanisms used by MDRAB can shed light on two possible strategies to combat the dissemination of antimicrobial resistance: stringent infection control and antibiotic treatments, of which colistin-based combination therapy is the mainstream strategy. However, due to the current unsatisfying therapeutic outcomes, there is a great need to develop and evaluate the efficacy of new antibiotics and to understand the role of other potential alternatives, such as antimicrobial peptides, in the treatment of MDRAB infections.
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Eijkelkamp BA, Stroeher UH, Hassan KA, Paulsen IT, Brown MH. Comparative analysis of surface-exposed virulence factors of Acinetobacter baumannii. BMC Genomics 2014; 15:1020. [PMID: 25422040 PMCID: PMC4256060 DOI: 10.1186/1471-2164-15-1020] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 11/14/2014] [Indexed: 01/19/2023] Open
Abstract
Background Acinetobacter baumannii is a significant hospital pathogen, particularly due to the dissemination of highly multidrug resistant isolates. Genome data have revealed that A. baumannii is highly genetically diverse, which correlates with major variations seen at the phenotypic level. Thus far, comparative genomic studies have been aimed at identifying resistance determinants in A. baumannii. In this study, we extend and expand on these analyses to gain greater insight into the virulence factors across eight A. baumannii strains which are clonally, temporally and geographically distinct, and includes an isolate considered non-pathogenic and a community-acquired A. baumannii. Results We have identified a large number of genes in the A. baumannii genomes that are known to play a role in virulence in other pathogens, such as the recently studied proline-alanine-alanine-arginine (PAAR)-repeat domains of the type VI secretion systems. Not surprising, many virulence candidates appear to be part of the A. baumannii core genome of virulent isolates but were often found to be insertionally disrupted in the avirulent A. baumannii strain SDF. Our study also reveals that many known or putative virulence determinants are restricted to specific clonal lineages, which suggests that these virulence determinants may be crucial for the success of these widespread common clones. It has previously been suggested that the high level of intrinsic and adaptive resistance has enabled the widespread presence of A. baumannii in the hospital environment. This appears to have facilitated the expansion of its repertoire of virulence traits, as in general, the nosocomial strains in this study possess more virulence genes compared to the community-acquired isolate. Conclusions Major genetic variation in known or putative virulence factors was seen across the eight strains included in this study, suggesting that virulence mechanisms are complex and multifaceted in A. baumannii. Overall, these analyses increase our understanding of A. baumannii pathogenicity and will assist in future studies determining the significance of virulence factors within clonal lineages and/or across the species. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1020) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | - Melissa H Brown
- School of Biological Sciences, Flinders University, Adelaide, Australia.
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The Acinetobacter baumannii Omp33-36 porin is a virulence factor that induces apoptosis and modulates autophagy in human cells. Infect Immun 2014; 82:4666-80. [PMID: 25156738 DOI: 10.1128/iai.02034-14] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Acinetobacter baumannii is an extracellular opportunistic human pathogen that is becoming increasingly problematic in hospitals. In the present study, we demonstrate that the A. baumannii Omp 33- to 36-kDa protein (Omp33-36) is a porin that acts as a channel for the passage of water. The protein is found on the cell surface and is released along with other porins in the outer membrane vesicles (OMVs). In immune and connective cell tissue, this protein induced apoptosis by activation of caspases and modulation of autophagy, with the consequent accumulation of p62/SQSTM1 (sequestosome 1) and LC3B-II (confirmed by use of autophagy inhibitors). Blockage of autophagy enables the bacterium to persist intracellularly (inside autophagosomes), with the subsequent development of cytotoxicity. Finally, we used macrophages and a mouse model of systemic infection to confirm that Omp33-36 is a virulence factor in A. baumannii. Overall, the study findings show that Omp33-36 plays an important role in the pathogenesis of A. baumannii infections.
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Abbott I, Cerqueira GM, Bhuiyan S, Peleg AY. Carbapenem resistance inAcinetobacter baumannii: laboratory challenges, mechanistic insights and therapeutic strategies. Expert Rev Anti Infect Ther 2014; 11:395-409. [DOI: 10.1586/eri.13.21] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Types and prevalence of carbapenem-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex in Northern Taiwan. Antimicrob Agents Chemother 2013; 58:201-4. [PMID: 24145535 DOI: 10.1128/aac.00779-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The frequency of the carbapenem-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii (CRACB) complex increases annually in our hospitals. However, the types and prevalence of carbapenemases among isolates still remain unclear. In this study, we identified and collected 672 carbapenem-resistant isolates from a medical center in Northern Taiwan between April and December of 2010. There were 577 genospecies 2 (Acinetobacter baumannii), 79 genospecies 13TU, and 16 genospecies 3 isolates. The isolates had an acquired blaOXA-24-like gene, which was confirmed by sequencing for the encoded OXA-72 carbapenemase, and were often associated with high-level carbapenem resistance. These CRACB complex isolates remained susceptible to colistin (100%). The genotyping of isolates was conducted using pulsed-field gel electrophoresis with ApaI digestion. In most clonally related groups, patients were from both branch hospitals. The results indicate that interhospital dissemination of clones occurred. This study provides updated data on the types and prevalence of the CRACB complex. In addition, it presents a warning on the emergence and spread of CRACB complex harboring blaOXA-24-like genes in northern Taiwan.
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Contribution of efflux pumps, porins, and β-lactamases to multidrug resistance in clinical isolates of Acinetobacter baumannii. Antimicrob Agents Chemother 2013; 57:5247-57. [PMID: 23939894 DOI: 10.1128/aac.00730-13] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We investigated the mechanisms of resistance to carbapenems, aminoglycosides, glycylcyclines, tetracyclines, and quinolones in 90 multiresistant clinical strains of Acinetobacter baumannii isolated from two genetically unrelated A. baumannii clones: clone PFGE-ROC-1 (53 strains producing the OXA-58 β-lactamase enzyme and 18 strains with the OXA-24 β-lactamase) and clone PFGE-HUI-1 (19 strains susceptible to carbapenems). We used real-time reverse transcriptase PCR to correlate antimicrobial resistance (MICs) with expression of genes encoding chromosomal β-lactamases (AmpC and OXA-51), porins (OmpA, CarO, Omp33, Dcap-like, OprB, Omp25, OprC, OprD, and OmpW), and proteins integral to six efflux systems (AdeABC, AdeIJK, AdeFGH, CraA, AbeM, and AmvA). Overexpression of the AdeABC system (level of expression relative to that by A. baumannii ATCC 17978, 30- to 45-fold) was significantly associated with resistance to tigecycline, minocycline, and gentamicin and other biological functions. However, hyperexpression of the AdeIJK efflux pump (level of expression relative to that by A. baumannii ATCC 17978, 8- to 10-fold) was significantly associated only with resistance to tigecycline and minocycline (to which the TetB efflux system also contributed). TetB and TetA(39) efflux pumps were detected in clinical strains and were associated with resistance to tetracyclines and doxycycline. The absence of the AdeABC system and the lack of expression of other mechanisms suggest that tigecycline-resistant strains of the PFGE-HUI-1 clone may be associated with a novel resistance-nodulation-cell efflux pump (decreased MICs in the presence of the inhibitor Phe-Arg β-naphthylamide dihydrochloride) and the TetA(39) system.
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Sousa D, Castelo-Corral L, Gutierrez-Urbon JM, Molina F, Lopez-Calvino B, Bou G, Llinares P. Impact of ertapenem use on Pseudomonas aeruginosa and Acinetobacter baumannii imipenem susceptibility rates: collateral damage or positive effect on hospital ecology? J Antimicrob Chemother 2013; 68:1917-25. [DOI: 10.1093/jac/dkt091] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Beceiro A, Tomás M, Bou G. Antimicrobial resistance and virulence: a successful or deleterious association in the bacterial world? Clin Microbiol Rev 2013; 26:185-230. [PMID: 23554414 PMCID: PMC3623377 DOI: 10.1128/cmr.00059-12] [Citation(s) in RCA: 630] [Impact Index Per Article: 57.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hosts and bacteria have coevolved over millions of years, during which pathogenic bacteria have modified their virulence mechanisms to adapt to host defense systems. Although the spread of pathogens has been hindered by the discovery and widespread use of antimicrobial agents, antimicrobial resistance has increased globally. The emergence of resistant bacteria has accelerated in recent years, mainly as a result of increased selective pressure. However, although antimicrobial resistance and bacterial virulence have developed on different timescales, they share some common characteristics. This review considers how bacterial virulence and fitness are affected by antibiotic resistance and also how the relationship between virulence and resistance is affected by different genetic mechanisms (e.g., coselection and compensatory mutations) and by the most prevalent global responses. The interplay between these factors and the associated biological costs depend on four main factors: the bacterial species involved, virulence and resistance mechanisms, the ecological niche, and the host. The development of new strategies involving new antimicrobials or nonantimicrobial compounds and of novel diagnostic methods that focus on high-risk clones and rapid tests to detect virulence markers may help to resolve the increasing problem of the association between virulence and resistance, which is becoming more beneficial for pathogenic bacteria.
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Chopra S, Ramkissoon K, Anderson DC. A systematic quantitative proteomic examination of multidrug resistance in Acinetobacter baumannii. J Proteomics 2013; 84:17-39. [PMID: 23542354 DOI: 10.1016/j.jprot.2013.03.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 02/18/2013] [Accepted: 03/17/2013] [Indexed: 12/29/2022]
Abstract
UNLABELLED Multidrug-resistant Acinetobacter baumannii strains have been examined at the DNA sequence level, but seldom using large-scale quantitative proteomics. We have compared the proteome of the multidrug resistant strain BAA-1605, with the proteome of the drug-sensitive strain ATCC 17978, using iTRAQ labeling and online 2D LC/MS/MS for peptide/protein identification. Of 1484 proteins present in at least 2 of 4 independent experiments, 114 are 2-fold to 66-fold more abundant in BAA-1605, and 99 are 2-fold to 50-fold less abundant. Proteins with 2-fold or greater abundance in the multidrug resistant strain include drug-, antibiotic-, and heavy metal-resistance proteins, stress-related proteins, porins, membrane transporters, proteins important for acquisition of foreign DNA, biofilm-related proteins, cell-wall and exopolysaccharide-related proteins, lipoproteins, metabolic proteins, and many with no annotated function. The porin CarO, inactivated in carbapenem-resistant strains, is 2.3-fold more abundant in BAA-1605. Likewise, the porin OmpW, less abundant in carbapenem- and colistin-resistant A. baumannii strains, is 3-fold more abundant in BAA-1605. Nine proteins, all present in the drug-sensitive strain but from 2.2-fold to 16-fold more abundant in the MDR strain, can potentially account for the observed resistance of BAA-1605 to 18 antibiotics. BIOLOGICAL SIGNIFICANCE Multidrug resistant (MDR) strains of the pathogen Acinetobacter baumannii are a significant cause of hospital-acquired infections, are associated with increased mortality and length of stay, and may be a major factor underlying the spread of this pathogen, which is difficult to eradicate from clinical settings. To obtain a better understanding of antimicrobial resistance mechanisms in MDR A. baumannii, we report the first large scale 2D LC/MS/MS-based quantitative proteomics comparison of a drug-sensitive strain and an MDR strain of this pathogen. Ca. 20% of the expressed proteome changes 2-fold or more between the compared strains, including 42 proteins with literature or informatics annotations related to resistance mechanisms, modification of xenobiotics, or drug transport. Other categories of proteins differing 2-fold or more between strains include stress-response related proteins, porins, OMPs, transporters and secretion-related proteins, cell wall- and expolysaccharide-related proteins, lipoproteins, and DNA- and plasmid-related proteins. While the compared strains also differ in other aspects than multi-drug resistance, the observed differences, combined with protein functional annotation, suggest that complex protein expression changes may accompany the MDR phenotype. Expression changes of nine proteins in the MDR strain can potentially account for the observed resistance to 18 antibiotics.
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Affiliation(s)
- Sidharth Chopra
- Center for Infectious Disease and Biodefense Research, SRI International, 333 Ravenswood, Avenue, Menlo Park, CA 94025, USA
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Richmond GE, Chua KL, Piddock LJV. Efflux in Acinetobacter baumannii can be determined by measuring accumulation of H33342 (bis-benzamide). J Antimicrob Chemother 2013; 68:1594-600. [PMID: 23467176 PMCID: PMC3682688 DOI: 10.1093/jac/dkt052] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Objectives Overexpression of efflux pumps in Acinetobacter baumannii is a common mechanism of multidrug resistance in this nosocomial pathogen. Increased efflux pump expression is often assumed from MICs of antibiotics and dyes, without measurement of efflux levels. This study describes a safe, rapid and simple 96-well plate assay that measures the accumulation of a fluorescent dye, Hoechst (H) 33342. Methods The growth kinetics of three resistant and three susceptible Singaporean clinical isolates of A. baumannii in the presence of carbonyl cyanide-m-chlorophenylhydrazone (CCCP) and phenylalanine-arginine-β-naphthylamide (PAβN) were studied to determine non-inhibitory concentrations for use in the assay. Accumulation of H33342 was measured in these clinical isolates with and without efflux inhibitors. Accumulation was also measured in an adeB efflux pump deletion mutant and its parental strain to assess the ability of the assay to identify altered efflux in strains lacking efflux pumps. Results were compared with data from accumulation assays with ethidium bromide and norfloxacin. Results Increased accumulation, indicative of reduced efflux, was observed in AB211ΔadeB compared with parental strain AB211. Clinical isolates demonstrated different levels of accumulation of H33342. The addition of both CCCP and PAβN significantly increased the accumulation of H33342. The pattern of norfloxacin accumulation broadly reflected H33342 accumulation. Ethidium bromide showed a different pattern of accumulation in clinical isolates. Conclusions The measurement of the intracellular accumulation of H33342 in real time allowed a comparison of efflux activity between strains of A. baumannii.
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Affiliation(s)
- G E Richmond
- Antimicrobial Agents Research Group, School of Immunity and Infection and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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