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Lucidi M, Visaggio D, Migliaccio A, Capecchi G, Visca P, Imperi F, Zarrilli R. Pathogenicity and virulence of Acinetobacter baumannii: Factors contributing to the fitness in healthcare settings and the infected host. Virulence 2024; 15:2289769. [PMID: 38054753 PMCID: PMC10732645 DOI: 10.1080/21505594.2023.2289769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 11/27/2023] [Indexed: 12/07/2023] Open
Abstract
Acinetobacter baumannii is a common cause of healthcare-associated infections and hospital outbreaks, particularly in intensive care units. Much of the success of A. baumannii relies on its genomic plasticity, which allows rapid adaptation to adversity and stress. The capacity to acquire novel antibiotic resistance determinants and the tolerance to stresses encountered in the hospital environment promote A. baumannii spread among patients and long-term contamination of the healthcare setting. This review explores virulence factors and physiological traits contributing to A. baumannii infection and adaptation to the hospital environment. Several cell-associated and secreted virulence factors involved in A. baumannii biofilm formation, cell adhesion, invasion, and persistence in the host, as well as resistance to xeric stress imposed by the healthcare settings, are illustrated to give reasons for the success of A. baumannii as a hospital pathogen.
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Affiliation(s)
- Massimiliano Lucidi
- Department of Science, Roma Tre University, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
| | - Daniela Visaggio
- Department of Science, Roma Tre University, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Santa Lucia Foundation IRCCS, Rome, Italy
| | | | | | - Paolo Visca
- Department of Science, Roma Tre University, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Santa Lucia Foundation IRCCS, Rome, Italy
| | - Francesco Imperi
- Department of Science, Roma Tre University, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Santa Lucia Foundation IRCCS, Rome, Italy
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples Federico II, Naples, Italy
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2
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Green HD, Van Horn GT, Williams T, Eberly A, Morales GH, Mann R, Hauter IM, Hadjifrangiskou M, Schmitz JE. Intra-strain colony biofilm heterogeneity in uropathogenic Escherichia coli and the effect of the NlpI lipoprotein. Biofilm 2024; 8:100214. [PMID: 39184815 PMCID: PMC11344014 DOI: 10.1016/j.bioflm.2024.100214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/25/2024] [Accepted: 07/09/2024] [Indexed: 08/27/2024] Open
Abstract
Biofilm growth facilitates the interaction of uropathogenic Escherichia coli (UPEC) with the host environment. The extracellular polymeric substances (EPS) of UPEC biofilms are composed prominently of curli amyloid fiber and cellulose polysaccharide. When the organism is propagated as a colony biofilm on agar media, these macromolecules can generate pronounced macroscopic structures. Moreover, curli/cellulose associate tightly with Congo red, generating a characteristic pink-to-red staining pattern when the media is supplemented with this dye. Among different clinical isolates of UPEC, changes in the abundance of curli/cellulose can lead to diverse colony biofilm phenotypes on a strain-by-strain basis. Nevertheless, for any given isolate, these phenotypes are classically homogenous throughout the colony biofilm. Here, we report that a subset of clinical UPEC isolates display heterogenous 'peppermint' colony biofilms, with distinct pale and red subpopulations. Through isolation of these subpopulations and whole genome sequencing, we demonstrate various emergent mutations associated with the phenomenon, including within the gene encoding the outer membrane lipoprotein nlpI. Deletion of nlpI within independent strain-backgrounds increased biofilm rugosity, while its overexpression induced the peppermint phenotype. Upregulation of EPS-associated proteins and transcripts was likewise observed in the absence of nlpI. Overall, these results demonstrate that EPS elaboration in UPEC is impacted by nlpI. More broadly, this phenomenon of intra-strain colony biofilm heterogeneity may be leveraged as a tool to identify additional members within the broad collection of genes that regulate or otherwise affect biofilm formation.
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Affiliation(s)
- Hamilton D. Green
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Gerald T. Van Horn
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Center for Personalized Microbiology, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Timothy Williams
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Allison Eberly
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Grace H. Morales
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Robert Mann
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Indiana M. Hauter
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Maria Hadjifrangiskou
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Vanderbilt Institute for Infection, Immunology & Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Center for Personalized Microbiology, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jonathan E. Schmitz
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Vanderbilt Institute for Infection, Immunology & Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Center for Personalized Microbiology, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
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3
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Duller S, Kumpitsch C, Moissl-Eichinger C, Wink L, Koskinen Mora K, Mahnert A. In-hospital areas with distinct maintenance and staff/patient traffic have specific microbiome profiles, functions, and resistomes. mSystems 2024; 9:e0072624. [PMID: 38980054 PMCID: PMC11334533 DOI: 10.1128/msystems.00726-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 06/11/2024] [Indexed: 07/10/2024] Open
Abstract
Hospitals are subject to strict microbial control. Stringent cleaning and confinement measures in hospitals lead to a decrease in microbial diversity, but an increase in resistance genes. Given the rise of antimicrobial resistances and healthcare-associated infections, understanding the hospital microbiome and its resistome is crucial. This study compared the microbiome and resistome at different levels of confinement (CL) within a single hospital. Using amplicon sequencing, shotgun metagenomics, and genome/plasmid reconstruction, we demonstrate that microbial composition differs in a stable way between the CLs and that the most restrictive confinement level CL1 had the lowest microbial but the highest functional diversity. This CL also exhibited a greater abundance of functions related to virulence, disease, defense, and stress response. Comparison of antibiotic resistance also showed differences among CLs in terms of the selection process and specific mechanisms for antimicrobial/antibiotic resistance. The resistances found in the samples of CL1 were mostly mediated via antibiotic efflux pumps and were mainly located on chromosomes, whereas in the other, less restrictive CL antibiotic resistances were more present on plasmids. This could be of particular importance for patient-related areas (CL2), as the potential spread of antibiotic resistances could be a major concern in this area. Our results show that there are differences in the microbiome and resistome even within a single hospital, reflecting room utilization and confinement. Since restrictive confinement selects for resistant microorganisms, strategies are required to deepen our understanding of dynamic processes of microbiome and resistome within hospital environments. IMPORTANCE Effective measures to combat antibiotic resistances and healthcare-associated infections are urgently needed, including optimization of microbial control. However, previous studies have indicated that stringent control can lead to an increase in the resistance capacities of microbiomes on surfaces. This study adds to previous knowledge by focusing on the conditions in a single hospital, resolving the microbiomes and their resistomes in three different confinement levels (CL): operating room, patient-related areas, and non-patient-related areas. We were able to identify stable key taxa; profiled the capacities of taxa, functions, and antimicrobial resistances (AMR); and reconstruct genomes and plasmids in each CL. Our results show that the most restrictive CL indeed had the highest functional diversity, but that resistances were mostly encoded on chromosomes, indicating a lower possibility of resistance spread. However, clever strategies are still required to strike a balance between microbial control and selective pressures in environments where patients need protection.
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Affiliation(s)
- Stefanie Duller
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Christina Kumpitsch
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Christine Moissl-Eichinger
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Lisa Wink
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Kaisa Koskinen Mora
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Alexander Mahnert
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
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Farrokhi Y, Neshati Z, Saniee P, Makhdoumi A. The potential of Bacillus and Enterococcus probiotic strains to combat helicobacter pylori attachment to the biotic and abiotic surfaces. Int Microbiol 2023; 26:907-915. [PMID: 36943595 DOI: 10.1007/s10123-023-00347-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/04/2022] [Accepted: 03/16/2023] [Indexed: 03/23/2023]
Abstract
The prevention of biofilm formation plays a pivotal role in managing Helicobacter pylori inside the body and the environment. This study showed in vitro potentials of two recently isolated probiotic strains, Bacillus sp. 1630F and Enterococcus sp. 7C37, to form biofilm and combat H. pylori attachment to the abiotic and biotic surfaces. Lactobacillus casei and Bifidobacterium bifidum were used as the reference probiotics. The biofilm rates were the highest in the solid-liquid interface for Lactobacillus and Bifidobacterium and the air-liquid interface for Bacillus and Enterococcus. The highest tolerances to the environmental conditions were observed during the biofilm formations of Enterococcus and Bifidobacterium (pH), Enterococcus and Bacillus (bile), and Bifidobacterium and Lactobacillus (NaCl) on the polystyrene and glass substratum, respectively. Biofilms occurred more quickly by Bacillus and Enterococcus strains than reference strains on the polystyrene and glass substratum, respectively. Enterococcus (competition) and Bacillus (exclusion) achieved the most inhibition of H. pylori biofilm formations on the polystyrene and AGS cells, respectively. Expression of luxS was promoted by Bacillus (exclusion, 3.2 fold) and Enterococcus (competition, 2.0 fold). Expression of ropD was decreased when H. pylori biofilm was excluded by Bacillus (0.4 fold) and Enterococcus (0.2 fold) cells. This study demonstrated the ability of Bacillus and Enterococcus probiotic bacteria to form biofilm and combat H. pylori biofilm formation.
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Affiliation(s)
- Yeganeh Farrokhi
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Zeinab Neshati
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
- Novel Diagnostics and Therapeutics Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Parastoo Saniee
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Science and Biotechnology, Shahid Beheshti University G. C, Tehran, Iran
| | - Ali Makhdoumi
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran.
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Diorio-Toth L, Wallace MA, Farnsworth CW, Wang B, Gul D, Kwon JH, Andleeb S, Burnham CAD, Dantas G. Intensive care unit sinks are persistently colonized with multidrug resistant bacteria and mobilizable, resistance-conferring plasmids. mSystems 2023; 8:e0020623. [PMID: 37439570 PMCID: PMC10469867 DOI: 10.1128/msystems.00206-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/02/2023] [Indexed: 07/14/2023] Open
Abstract
Contamination of hospital sinks with microbial pathogens presents a serious potential threat to patients, but our understanding of sink colonization dynamics is largely based on infection outbreaks. Here, we investigate the colonization patterns of multidrug-resistant organisms (MDROs) in intensive care unit sinks and water from two hospitals in the USA and Pakistan collected over 27 months of prospective sampling. Using culture-based methods, we recovered 822 bacterial isolates representing 104 unique species and genomospecies. Genomic analyses revealed long-term colonization by Pseudomonas spp. and Serratia marcescens strains across multiple rooms. Nanopore sequencing uncovered examples of long-term persistence of resistance-conferring plasmids in unrelated hosts. These data indicate that antibiotic resistance (AR) in Pseudomonas spp. is maintained both by strain colonization and horizontal gene transfer (HGT), while HGT maintains AR within Acinetobacter spp. and Enterobacterales, independent of colonization. These results emphasize the importance of proactive, genomic-focused surveillance of built environments to mitigate MDRO spread. IMPORTANCE Hospital sinks are frequently linked to outbreaks of antibiotic-resistant bacteria. Here, we used whole-genome sequencing to track the long-term colonization patterns in intensive care unit (ICU) sinks and water from two hospitals in the USA and Pakistan collected over 27 months of prospective sampling. We analyzed 822 bacterial genomes, representing over 100 different species. We identified long-term contamination by opportunistic pathogens, as well as transient appearance of other common pathogens. We found that bacteria recovered from the ICU had more antibiotic resistance genes (ARGs) in their genomes compared to matched community spaces. We also found that many of these ARGs are harbored on mobilizable plasmids, which were found shared in the genomes of unrelated bacteria. Overall, this study provides an in-depth view of contamination patterns for common nosocomial pathogens and identifies specific targets for surveillance.
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Affiliation(s)
- Luke Diorio-Toth
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Meghan A. Wallace
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Christopher W. Farnsworth
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Bin Wang
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Danish Gul
- Atta ur Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Jennie H. Kwon
- Department of Medicine, Washington University School of Medicine in St Louis, St. Louis, Missouri, USA
| | - Saadia Andleeb
- Atta ur Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Carey-Ann D. Burnham
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Medicine, Washington University School of Medicine in St Louis, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine in St Louis, St. Louis, Missouri, USA
- Department of Pediatrics, Washington University School of Medicine in St Louis, St. Louis, Missouri, USA
| | - Gautam Dantas
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Molecular Microbiology, Washington University School of Medicine in St Louis, St. Louis, Missouri, USA
- Department of Pediatrics, Washington University School of Medicine in St Louis, St. Louis, Missouri, USA
- Department of Biomedical Engineering, Washington University in St Louis, St. Louis, Missouri, USA
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6
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Ng HK, Puah SM, Teh CSJ, Idris N, Chua KH. Comparative Transcriptomic Profiling of Pellicle and Planktonic Cells from Carbapenem-Resistant Acinetobacter baumannii. Antibiotics (Basel) 2023; 12:1185. [PMID: 37508281 PMCID: PMC10375965 DOI: 10.3390/antibiotics12071185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/24/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
Acinetobacter baumannii forms air-liquid interface pellicles that boost its ability to withstand desiccation and increase survival under antibiotic pressure. This study aims to delve into the transcriptomic profiles of pellicle cells from clinical strains of carbapenem-resistant A. baumannii (CRAB). The total RNA was extracted from pellicle cells from three pellicle-forming CRAB strains and planktonic cells from three non-pellicle-forming CRAB strains, subject to RNA sequencing using Illumina HiSeq 2500 system. A transcriptomic analysis between pellicle and planktonic cells, along with differential expression genes (DEGs) analysis and enrichment analysis of annotated COGs, GOs, and KEGGs, was performed. Our analysis identified 366 DEGs in pellicle cells: 162 upregulated genes and 204 downregulated genes. The upregulated ABUW_1624 (yiaY) gene and downregulated ABUW_1550 gene indicated potential involvement in fatty acid degradation during pellicle formation. Another upregulated ABUW_2820 (metQ) gene, encoding the D-methionine transporter system, hinted at its contribution to pellicle formation. The upregulation of two-component systems, CusSR and KdpDE, which implies the regulation of copper and potassium ions in a CRAB pellicle formation was also observed. These findings provide valuable insights into the regulation of gene expression during the formation of pellicles in CRAB, and these are potential targets that may aid in the eradication of CRAB infections.
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Affiliation(s)
- Heng Kang Ng
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Suat Moi Puah
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Cindy Shuan Ju Teh
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Nuryana Idris
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Kek Heng Chua
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
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Cavallo I, Oliva A, Pages R, Sivori F, Truglio M, Fabrizio G, Pasqua M, Pimpinelli F, Di Domenico EG. Acinetobacter baumannii in the critically ill: complex infections get complicated. Front Microbiol 2023; 14:1196774. [PMID: 37425994 PMCID: PMC10325864 DOI: 10.3389/fmicb.2023.1196774] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/05/2023] [Indexed: 07/11/2023] Open
Abstract
Acinetobacter baumannii is increasingly associated with various epidemics, representing a serious concern due to the broad level of antimicrobial resistance and clinical manifestations. During the last decades, A. baumannii has emerged as a major pathogen in vulnerable and critically ill patients. Bacteremia, pneumonia, urinary tract, and skin and soft tissue infections are the most common presentations of A. baumannii, with attributable mortality rates approaching 35%. Carbapenems have been considered the first choice to treat A. baumannii infections. However, due to the widespread prevalence of carbapenem-resistant A. baumannii (CRAB), colistin represents the main therapeutic option, while the role of the new siderophore cephalosporin cefiderocol still needs to be ascertained. Furthermore, high clinical failure rates have been reported for colistin monotherapy when used to treat CRAB infections. Thus, the most effective antibiotic combination remains disputed. In addition to its ability to develop antibiotic resistance, A. baumannii is also known to form biofilm on medical devices, including central venous catheters or endotracheal tubes. Thus, the worrisome spread of biofilm-producing strains in multidrug-resistant populations of A. baumannii poses a significant treatment challenge. This review provides an updated account of antimicrobial resistance patterns and biofilm-mediated tolerance in A. baumannii infections with a special focus on fragile and critically ill patients.
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Affiliation(s)
- Ilaria Cavallo
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Alessandra Oliva
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Rebecca Pages
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Francesca Sivori
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Mauro Truglio
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Giorgia Fabrizio
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Martina Pasqua
- Department of Biology and Biotechnology "C. Darwin" Sapienza University of Rome, Rome, Italy
| | - Fulvia Pimpinelli
- Microbiology and Virology, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
| | - Enea Gino Di Domenico
- Department of Biology and Biotechnology "C. Darwin" Sapienza University of Rome, Rome, Italy
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8
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Rakovitsky N, Lurie-Weinberger MN, Hameir A, Wulffhart L, Keren Paz A, Schwartz D, Carmeli Y. Phenotypic and Genomic Characterization of Nine String-Positive Carbapenem-Resistant Acinetobacter baumannii Isolates from Israel. Microbiol Spectr 2023; 11:e0300222. [PMID: 36719216 PMCID: PMC10100839 DOI: 10.1128/spectrum.03002-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 01/09/2023] [Indexed: 02/01/2023] Open
Abstract
A positive "string test" indicates the ability of bacterial colonies grown on agar plates to form viscous strings of >5 mm when stretched. This phenotype is strongly associated with hypervirulence in Klebsiella pneumoniae but has never been described in carbapenem-resistant Acinetobacter baumannii (CRAB), an emerging human pathogen of high clinical significance. In this work, we screened 1,000 CRAB isolates, among which we identified and characterized 9 string-positive CRAB (stCRAB) isolates. Phenotypic and genotypic analyses revealed that the isolates were not phylogenetically related and possessed different antibiotic resistance and virulence profiles. Transmission electron microscopy (TEM) showed the presence of capsule in string-positive isolates. String-positive isolates were more motile but did not form more biofilm than non-string-positive isolates. They were less virulent in a murine thigh fitness model and a Galleria mellonella survival assay. In conclusion, here, we describe string-positive A. baumannii isolates and their phenotypic and molecular characteristics. We found that unlike K. pneumoniae, stCRAB isolates were not associated with increased virulence. IMPORTANCE Acinetobacter baumannii has been considered a major health care threat in recent years. Despite many efforts, the pathogenesis and molecular mechanism of A. baumannii virulence remain poorly understood. Moreover, the plasticity of its genome frequently gives rise to new and more virulent isolates. Our current study is of significant importance as it concerns a previously undescribed A. baumannii phenotype. The string-positive phenotype is strongly associated with increased fitness and virulence in other Gram-negative bacteria such as K. pneumoniae. Although no clear correlation with virulence or fitness was found in our 9 stCRAB isolates, this could have been due to the limited statistical power of our research. We suggest that this phenotype should be taken into consideration as due to its genome plasticity, the next change can give rise to string-positive and hypervirulent strains, as is known for K. pneumoniae. Additional future research is needed regarding its possible consequences.
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Affiliation(s)
- Nadya Rakovitsky
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Mor N. Lurie-Weinberger
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Amichay Hameir
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Liat Wulffhart
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Alona Keren Paz
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - David Schwartz
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Yehuda Carmeli
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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9
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Chiang TT, Huang TW, Sun JR, Kuo SC, Cheng A, Liu CP, Liu YM, Yang YS, Chen TL, Lee YT, Wang YC. Biofilm formation is not an independent risk factor for mortality in patients with Acinetobacter baumannii bacteremia. Front Cell Infect Microbiol 2022; 12:964539. [PMID: 36189355 PMCID: PMC9523115 DOI: 10.3389/fcimb.2022.964539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/31/2022] [Indexed: 12/01/2022] Open
Abstract
In the past decades, due to the high prevalence of the antibiotic-resistant isolates of Acinetobacter baumannii, it has emerged as one of the most troublesome pathogens threatening the global healthcare system. Furthermore, this pathogen has the ability to form biofilms, which is another effective mechanism by which it survives in the presence of antibiotics. However, the clinical impact of biofilm-forming A. baumannii isolates on patients with bacteremia is largely unknown. This retrospective study was conducted at five medical centers in Taiwan over a 9-year period. A total of 252 and 459 patients with bacteremia caused by biofilm- and non-biofilm-forming isolates of A. baumannii, respectively, were enrolled. The clinical demographics, antimicrobial susceptibility, biofilm-forming ability, and patient clinical outcomes were analyzed. The biofilm-forming ability of the isolates was assessed using a microtiter plate assay. Multivariate analysis revealed the higher APACHE II score, shock status, lack of appropriate antimicrobial therapy, and carbapenem resistance of the infected strain were independent risk factors of 28-day mortality in the patients with A. baumannii bacteremia. However, there was no significant difference between the 28-day survival and non-survival groups, in terms of the biofilm forming ability. Compared to the patients infected with non-biofilm-forming isolates, those infected with biofilm-forming isolates had a lower in-hospital mortality rate. Patients with either congestive heart failure, underlying hematological malignancy, or chemotherapy recipients were more likely to become infected with the biofilm-forming isolates. Multivariate analysis showed congestive heart failure was an independent risk factor of infection with biofilm-forming isolates, while those with arterial lines tended to be infected with non-biofilm-forming isolates. There were no significant differences in the sources of infection between the biofilm-forming and non-biofilm-forming isolate groups. Carbapenem susceptibility was also similar between these groups. In conclusion, the patients infected with the biofilm-forming isolates of the A. baumannii exhibited different clinical features than those infected with non-biofilm-forming isolates. The biofilm-forming ability of A. baumannii may also influence the antibiotic susceptibility of its isolates. However, it was not an independent risk factor for a 28-day mortality in the patients with bacteremia.
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Affiliation(s)
- Tsung-Ta Chiang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Tzu-Wen Huang
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jun-Ren Sun
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Shu-Chen Kuo
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institute, Maoli County, Taiwan
| | - Aristine Cheng
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
- College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chang-Pan Liu
- Division of Infectious Diseases, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan
- Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
| | - Yuag-Meng Liu
- Division of Infectious Diseases, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan
| | - Ya-Sung Yang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Te-Li Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Yi-Tzu Lee
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- *Correspondence: Yung-Chih Wang, ; Yi-Tzu Lee,
| | - Yung-Chih Wang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
- *Correspondence: Yung-Chih Wang, ; Yi-Tzu Lee,
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10
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Dolma KG, Khati R, Paul AK, Rahmatullah M, de Lourdes Pereira M, Wilairatana P, Khandelwal B, Gupta C, Gautam D, Gupta M, Goyal RK, Wiart C, Nissapatorn V. Virulence Characteristics and Emerging Therapies for Biofilm-Forming Acinetobacter baumannii: A Review. BIOLOGY 2022; 11:biology11091343. [PMID: 36138822 PMCID: PMC9495682 DOI: 10.3390/biology11091343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/04/2022] [Accepted: 09/08/2022] [Indexed: 11/20/2022]
Abstract
Simple Summary Acinetobacter baumannii (A. baumannii) is one of the ESKAPE organisms and has the competency to build biofilms. These biofilms account for the most nosocomial infections all over the world. This review reflects on the various physicochemical and environmental factors such as adhesion, pili expression, growth surfaces, drug-resistant genes, and virulence factors that profoundly affect its resistant forte. Emerging drug-resistant issues and limitations to newer drugs are other factors affecting the hospital environment. Here, we discuss newer and alternative methods that can significantly enhance the susceptibility to Acinetobacter spp. Many new antibiotics are under trials, such as GSK-3342830, The Cefiderocol (S-649266), Fimsbactin, and similar. On the other hand, we can also see the impact of traditional medicine and the secondary metabolites of these natural products’ application in searching for new treatments. The field of nanoparticles has demonstrated effective antimicrobial actions and has exhibited encouraging results in the field of nanomedicine. The use of various phages such as vWUPSU and phage ISTD as an alternative treatment for its specificity and effectiveness is being investigated. Cathelicidins obtained synthetically or from natural sources can effectively produce antimicrobial activity in the micromolar range. Radioimmunotherapy and photodynamic therapy have boundless prospects if explored as a therapeutic antimicrobial strategy. Abstract Acinetobacter species is one of the most prevailing nosocomial pathogens with a potent ability to develop antimicrobial resistance. It commonly causes infections where there is a prolonged utilization of medical devices such as CSF shunts, catheters, endotracheal tubes, and similar. There are several strains of Acinetobacter (A) species (spp), among which the majority are pathogenic to humans, but A. baumannii are entirely resistant to several clinically available antibiotics. The crucial mechanism that renders them a multidrug-resistant strain is their potent ability to synthesize biofilms. Biofilms provide ample opportunity for the microorganisms to withstand the harsh environment and further cause chronic infections. Several studies have enumerated multiple physiological and virulence factors responsible for the production and maintenance of biofilms. To further enhance our understanding of this pathogen, in this review, we discuss its taxonomy, pathogenesis, current treatment options, global resistance rates, mechanisms of its resistance against various groups of antimicrobials, and future therapeutics.
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Affiliation(s)
- Karma G. Dolma
- Department of Microbiology, Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok 737102, Sikkim, India
| | - Rachana Khati
- Department of Microbiology, Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok 737102, Sikkim, India
| | - Alok K. Paul
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, TAS 7001, Australia
| | - Mohammed Rahmatullah
- Department of Biotechnology & Genetic Engineering, University of Development Alternative, Lalmatia, Dhaka 1207, Bangladesh
| | - Maria de Lourdes Pereira
- CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
- Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Correspondence: (P.W.); (V.N.)
| | - Bidita Khandelwal
- Department of Medicine, Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok 737102, Sikkim, India
| | - Chamma Gupta
- Department of Biotechnology, Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok 737102, Sikkim, India
| | - Deepan Gautam
- Department of Microbiology, Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok 737102, Sikkim, India
| | - Madhu Gupta
- Department of Pharmaceutics, Delhi Pharmaceutical Sciences and Research University, New Delhi 110017, India
| | - Ramesh K. Goyal
- Department of Pharmaceutics, Delhi Pharmaceutical Sciences and Research University, New Delhi 110017, India
| | - Christophe Wiart
- Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Veeranoot Nissapatorn
- School of Allied Health Sciences and World Union for Herbal Drug Discovery (WUHeDD), Walailak University, Nakhon Si Thammarat 80160, Thailand
- Correspondence: (P.W.); (V.N.)
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11
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Li Y, Wang H, Xu C, Sun SH, Xiao K, Huang X. Two strategies of stubborn biofouling strains surviving from NaClO membrane cleaning: EPS shielding and/or quorum sensing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156421. [PMID: 35660590 DOI: 10.1016/j.scitotenv.2022.156421] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
The declined performance of repeated chemically-enhanced-backwashing (CEB) seriously hampered the sustainable operation of membrane bioreactor (MBR) in long-term, and could be partially attributed to the strengthened anti-cleaning properties of residual stubborn microbes. Although plenty of research has been done towards either the model strains or the whole post-CEB microbial community, little was known about the resisting behavior of practical stubborn strains when confronting oxidative stresses induced by NaClO. Hence, this study isolated 21 strains from samples in a large-scale MBR plant with routine CEB treatment. To unravel how they survive and affect membrane fouling, their anti-oxidation ability, fouling potential and quorum sensing (QS) effect before and after NaClO stimuli were evaluated. The composition and molecular weight distribution of extracellular polymeric substance (EPS) were also investigated to understand their roles during the anti-CEB process. It was found that typical stubborn strains tended to secrete more EPS as protective shields, where polysaccharides (especially the ones >1 kDa) made major contribution. However, sometimes EPS could not well resist the stimuli, with consequent low survival rate and high intracellular ROS level. Under such circumstances, stubborn strains would rather choose to be sensitive with surged QS level and quick population regrowth to maintain vitality under the oxidative stresses. Both strategies aggravated biofouling and eventually enhanced the anti-cleaning properties of biofilm.
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Affiliation(s)
- Yufang Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Han Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Beijing OriginWater Membrane Technology Co., Ltd., Product and Technology Center, Beijing 101407, China
| | - Chenyang Xu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Shih-Han Sun
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Kang Xiao
- Beijing Yanshan Earth Critical Zone National Research Station, College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Xia Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Research and Application Center for Membrane Technology, School of Environment, Tsinghua University, Beijing 100084, China.
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12
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Mehmet Bektas, Orhan F, Baris O. Isolation of Biological Control Agents and Biotechnological Bacteria from Aquatic Insect Gut Microbiota (Coleoptera: Helophoridae, Hydrophilidae). BIOL BULL+ 2022. [DOI: 10.1134/s1062359022060036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Romero M, Mayer C, Heeb S, Wattanavaekin K, Cámara M, Otero A, Williams P. Mushroom-shaped structures formed in Acinetobacter baumannii biofilms grown in a roller bioreactor are associated with quorum sensing-dependent Csu-pilus assembly. Environ Microbiol 2022; 24:4329-4339. [PMID: 35352448 PMCID: PMC9790458 DOI: 10.1111/1462-2920.15985] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/11/2022] [Accepted: 03/21/2022] [Indexed: 12/31/2022]
Abstract
There is currently a need to develop simple biofilm models that facilitate investigation of the architecture/biology of mature bacterial biofilms in a consistent/standardized manner given their environmental and clinical importance and the need for new anti-biofilm interventions. This study introduces a novel biofilm culture system termed the rolling biofilm bioreactor (RBB). This easily operated system allows adherent microbial cells to be repeatedly exposed to air/solid/liquid interfaces optimizing biofilm growth. The RBB was exploited to investigate biofilm formation in Acinetobacter baumannii. High levels of A. baumannii biofilm biomass reproducibly accumulate in the RBB and, importantly, undergo a maturation step to form large mushroom-shaped structures that had not been observed in other models. Based on image analysis of biofilm development and genetic manipulation, we show how N-acylhomoserine lactone-dependent quorum sensing (QS) impacts on biofilm differentiation, composition and antibiotic tolerance. Our results indicate that extracellular DNA (eDNA) is a key matrix component in mature Acinetobacter biofilms as the mushroom-like structures consist of dense cellular masses encased in an eDNA mesh. Moreover, this study reveals the contribution of QS to A. baumannii biofilm differentiation through Csu pilus assembly regulation. Understanding the mechanisms of structural development of mature biofilms helps to identify new biofilm eradication and removal strategies.
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Affiliation(s)
- Manuel Romero
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life SciencesUniversity of NottinghamNottinghamUK
| | - Celia Mayer
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life SciencesUniversity of NottinghamNottinghamUK,Instituto de Investigacion Sanitaria de Santiago de Compostela (IDIS)Santiago de CompostelaSpain
| | - Stephan Heeb
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life SciencesUniversity of NottinghamNottinghamUK
| | | | - Miguel Cámara
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life SciencesUniversity of NottinghamNottinghamUK
| | - Ana Otero
- Departamento de Microbioloxía e Parasitoloxía, Facultade de Bioloxía, Edificio CIBUSUniversidade de Santiago de CompostelaSantiago de CompostelaSpain
| | - Paul Williams
- National Biofilms Innovation Centre, Biodiscovery Institute and School of Life SciencesUniversity of NottinghamNottinghamUK
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14
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Dekić Rozman S, Butorac A, Bertoša R, Hrenović J, Markeš M. Loss of thermotolerance in antibiotic-resistant Acinetobacter baumannii. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2022; 32:1581-1593. [PMID: 33719791 DOI: 10.1080/09603123.2021.1898550] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Bacterium Acinetobacter baumannii is a leading cause of nosocomial infections. The occurrence of antibiotic-resistant A. baumannii isolates outside hospitals suggests that monitoring of this pathogen in environmental samples is needed. Survival of pandrug-resistant A. baumannii was followed on selective plates with and without carbapenems in water and soil. After a few days of starvation, A. baumannii lost the ability to be cultivated at 44°C on plates supplemented with carbapenems. Once cultivated on plates without carbapenems and/or at 36°C, A. baumannii could grow again at 44°C in the presence of carbapenems. Comparative proteomic analysis revealed that impaired membrane integrity and reduced function of efflux pumps due to elevated temperature combined with antibiotic exposure were the main reasons for this phenomenon. Loss of thermotolerance in the presence of antibiotics points to the need for temperature adjustment in long-term monitoring of A. baumannii in environmental samples, to avoid the underestimation of viable bacteria.
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Affiliation(s)
| | - Ana Butorac
- BIOCentre Ltd., Bioanalytical Laboratory II - Proteomics, Zagreb, Croatia
| | - Rea Bertoša
- BIOCentre Ltd., Bioanalytical Laboratory II - Proteomics, Zagreb, Croatia
| | - Jasna Hrenović
- Faculty of Science, Department of Biology, University of Zagreb, Zagreb, Croatia
| | - Marina Markeš
- BIOCentre Ltd., Bioanalytical Laboratory II - Proteomics, Zagreb, Croatia
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15
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Chen X, Liu M, Zhang P, Xu M, Yuan W, Bian L, Liu Y, Xia J, Leung SSY. Phage-Derived Depolymerase as an Antibiotic Adjuvant Against Multidrug-Resistant Acinetobacter baumannii. Front Microbiol 2022; 13:845500. [PMID: 35401491 PMCID: PMC8990738 DOI: 10.3389/fmicb.2022.845500] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/08/2022] [Indexed: 11/29/2022] Open
Abstract
Bacteriophage-encoded depolymerases are responsible for degrading capsular polysaccharides (CPS), lipopolysaccharides (LPS), and exopolysaccharides (EPS) of the host bacteria during phage invasion. They have been considered as promising antivirulence agents in controlling bacterial infections, including those caused by multidrug-resistant (MDR) bacteria. This feature inspires hope of utilizing these enzymes to disarm the polysaccharide capsules of the bacterial cells, which then strengthens the action of antibiotics. Here we have identified, cloned, and expressed a depolymerase Dpo71 from a bacteriophage specific for the gram-negative bacterium Acinetobacter baumannii in a heterologous host Escherichia coli. Dpo71 sensitizes the MDR A. baumannii to the host immune attack, and also acts as an adjuvant to assist or boost the action of antibiotics, for example colistin. Specifically, Dpo71 at 10 μg/ml enables a complete bacterial eradication by human serum at 50% volume ratio. A mechanistic study shows that the enhanced bactericidal effect of colistin is attributed to the improved outer membrane destabilization capacity and binding rate to bacteria after stripping off the bacterial capsule by Dpo71. Dpo71 inhibits biofilm formation and disrupts the pre-formed biofilm. Combination of Dpo71 could significantly enhance the antibiofilm activity of colistin and improve the survival rate of A. baumannii infected Galleria mellonella. Dpo71 retains the strain-specificity of the parent phage from which Dpo71 is derived: the phage-sensitive A. baumannii strains respond to Dpo71 treatment, whereas the phage-insensitive strains do not. In summary, our work demonstrates the feasibility of using recombinant depolymerases as an antibiotic adjuvant to supplement the development of new antibacterials and to battle against MDR pathogens.
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Affiliation(s)
- Xi Chen
- Department of Chemistry, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China
| | - Miao Liu
- Department of Chemistry, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China
| | - Pengfei Zhang
- School of Pharmacy, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China
| | - Miao Xu
- School of Pharmacy, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China
| | - Weihao Yuan
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China
| | - Liming Bian
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China
| | - Yannan Liu
- Emergency Medicine Clinical Research Center, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Jiang Xia
- Department of Chemistry, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China
| | - Sharon S Y Leung
- School of Pharmacy, The Chinese University of Hong Kong, Sha Tin, Hong Kong SAR, China
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16
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Roy S, Chowdhury G, Mukhopadhyay AK, Dutta S, Basu S. Convergence of Biofilm Formation and Antibiotic Resistance in Acinetobacter baumannii Infection. Front Med (Lausanne) 2022; 9:793615. [PMID: 35402433 PMCID: PMC8987773 DOI: 10.3389/fmed.2022.793615] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/31/2022] [Indexed: 07/30/2023] Open
Abstract
Acinetobacter baumannii (A. baumannii) is a leading cause of nosocomial infections as this pathogen has certain attributes that facilitate the subversion of natural defenses of the human body. A. baumannii acquires antibiotic resistance determinants easily and can thrive on both biotic and abiotic surfaces. Different resistance mechanisms or determinants, both transmissible and non-transmissible, have aided in this victory over antibiotics. In addition, the propensity to form biofilms (communities of organism attached to a surface) allows the organism to persist in hospitals on various medical surfaces (cardiac valves, artificial joints, catheters, endotracheal tubes, and ventilators) and also evade antibiotics simply by shielding the bacteria and increasing its ability to acquire foreign genetic material through lateral gene transfer. The biofilm formation rate in A. baumannii is higher than in other species. Recent research has shown how A. baumannii biofilm-forming capacity exerts its effect on resistance phenotypes, development of resistome, and dissemination of resistance genes within biofilms by conjugation or transformation, thereby making biofilm a hotspot for genetic exchange. Various genes control the formation of A. baumannii biofilms and a beneficial relationship between biofilm formation and "antimicrobial resistance" (AMR) exists in the organism. This review discusses these various attributes of the organism that act independently or synergistically to cause hospital infections. Evolution of AMR in A. baumannii, resistance mechanisms including both transmissible (hydrolyzing enzymes) and non-transmissible (efflux pumps and chromosomal mutations) are presented. Intrinsic factors [biofilm-associated protein, outer membrane protein A, chaperon-usher pilus, iron uptake mechanism, poly-β-(1, 6)-N-acetyl glucosamine, BfmS/BfmR two-component system, PER-1, quorum sensing] involved in biofilm production, extrinsic factors (surface property, growth temperature, growth medium) associated with the process, the impact of biofilms on high antimicrobial tolerance and regulation of the process, gene transfer within the biofilm, are elaborated. The infections associated with colonization of A. baumannii on medical devices are discussed. Each important device-related infection is dealt with and both adult and pediatric studies are separately mentioned. Furthermore, the strategies of preventing A. baumannii biofilms with antibiotic combinations, quorum sensing quenchers, natural products, efflux pump inhibitors, antimicrobial peptides, nanoparticles, and phage therapy are enumerated.
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Affiliation(s)
- Subhasree Roy
- Division of Bacteriology, Indian Council of Medical Research (ICMR)-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Goutam Chowdhury
- Division of Molecular Microbiology, Indian Council of Medical Research (ICMR)-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Asish K. Mukhopadhyay
- Division of Molecular Microbiology, Indian Council of Medical Research (ICMR)-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Shanta Dutta
- Division of Bacteriology, Indian Council of Medical Research (ICMR)-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Sulagna Basu
- Division of Bacteriology, Indian Council of Medical Research (ICMR)-National Institute of Cholera and Enteric Diseases, Kolkata, India
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17
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Robin B, Nicol M, Le H, Tahrioui A, Schaumann A, Vuillemenot JB, Vergoz D, Lesouhaitier O, Jouenne T, Hardouin J, Potron A, Perrot V, Dé E. MacAB-TolC Contributes to the Development of Acinetobacter baumannii Biofilm at the Solid–Liquid Interface. Front Microbiol 2022; 12:785161. [PMID: 35095797 PMCID: PMC8792954 DOI: 10.3389/fmicb.2021.785161] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/22/2021] [Indexed: 12/14/2022] Open
Abstract
Acinetobacter baumannii has emerged as one of the most problematic bacterial pathogens responsible for hospital-acquired and community infections worldwide. Besides its high capacity to acquire antibiotic resistance mechanisms, it also presents high adhesion abilities on inert and living surfaces leading to biofilm development. This lifestyle confers additional protection against various treatments and allows it to persist for long periods in various hospital niches. Due to their remarkable antimicrobial tolerance, A. baumannii biofilms are difficult to control and ultimately eradicate. Further insights into the mechanism of biofilm development will help to overcome this challenge and to develop novel antibiofilm strategies. To unravel critical determinants of this sessile lifestyle, the proteomic profiles of two A. baumannii strains (ATTC17978 and SDF) grown in planktonic stationary phase or in mature solid–liquid (S-L) biofilm were compared using a semiquantitative proteomic study. Of interest, among the 69 common proteins determinants accumulated in the two strains at the S-L interface, we sorted out the MacAB-TolC system. This tripartite efflux pump played a role in A. baumannii biofilm formation as demonstrated by using ΔmacAB-tolC deletion mutant. Complementary approaches allowed us to get an overview of the impact of macAB-tolC deletion in A. baumannii physiology. Indeed, this efflux pump appeared to be involved in the envelope stress response occurring in mature biofilm. It contributes to maintain wild type (WT) membrane rigidity and provides tolerance to high osmolarity conditions. In addition, this system is probably involved in the maintenance of iron and sulfur homeostasis. MacAB-TolC might help this pathogen face and adapt to deleterious conditions occurring in mature biofilms. Increasing our knowledge of A. baumannii biofilm formation will undoubtedly help us develop new therapeutic strategies to tackle this emerging threat to human health.
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Affiliation(s)
- Brandon Robin
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
| | - Marion Nicol
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
| | - Hung Le
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
| | - Ali Tahrioui
- Normandie Univ, UNIROUEN, LMSM EA4312, Evreux, France
| | - Annick Schaumann
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
| | | | - Delphine Vergoz
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
| | | | - Thierry Jouenne
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
| | - Julie Hardouin
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
| | - Anaïs Potron
- UMR 6249 Chrono-Environnement, CNRS-Université de Bourgogne/Franche-Comté, Besançon, France
| | - Valérie Perrot
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- *Correspondence: Valérie Perrot,
| | - Emmanuelle Dé
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- Emmanuelle Dé,
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18
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Ye Z, Silva DM, Traini D, Young P, Cheng S, Ong HX. An adaptable microreactor to investigate the influence of interfaces on Pseudomonas aeruginosa biofilm growth. Appl Microbiol Biotechnol 2022; 106:1067-1077. [PMID: 35015140 PMCID: PMC8817054 DOI: 10.1007/s00253-021-11746-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 11/24/2021] [Accepted: 12/14/2021] [Indexed: 12/19/2022]
Abstract
Abstract Biofilms are ubiquitous and notoriously difficult to eradicate and control, complicating human infections and industrial and agricultural biofouling. However, most of the study had used the biofilm model that attached to solid surface and developed in liquid submerged environments which generally have neglected the impact of interfaces. In our study, a reusable dual-chamber microreactor with interchangeable porous membranes was developed to establish multiple growth interfaces for biofilm culture and test. Protocol for culturing Pseudomonas aeruginosa (PAO1) on the air–liquid interface (ALI) and liquid–liquid interface (LLI) under static environmental conditions for 48 h was optimized using this novel device. This study shows that LLI model biofilms are more susceptible to physical disruption compared to ALI model biofilm. SEM images revealed a unique “dome-shaped” microcolonies morphological feature, which is more distinct on ALI biofilms than LLI. Furthermore, the study showed that ALI and LLI biofilms produced a similar amount of extracellular polymeric substances (EPS). As differences in biofilm structure and properties may lead to different outcomes when using the same eradication approaches, the antimicrobial effect of an antibiotic, ciprofloxacin (CIP), was chosen to test the susceptibility of a 48-h-old P. aeruginosa biofilms grown on ALI and LLI. Our results show that the minimum biofilm eradication concentration (MBEC) of 6-h CIP exposure for ALI and LLI biofilms is significantly different, which are 400 μg/mL and 200 μg/mL, respectively. These results highlight the importance of growth interface when developing more targeted biofilm management strategies, and our novel device provides a promising tool that enables manipulation of realistic biofilm growth. Key points • A novel dual-chamber microreactor device that enables the establishment of different interfaces for biofilm culture has been developed. • ALI model biofilms and LLI model biofilms show differences in resistance to physical disruption and antibiotic susceptibility.
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Affiliation(s)
- Zhang Ye
- School of Mechanical Engineering, Faculty of Engineering, Macquarie University, Sydney, NSW, 2113, Australia
- Woolcock Institute of Medical Research, Sydney, Australia
| | - Dina M Silva
- Woolcock Institute of Medical Research, Sydney, Australia
| | - Daniela Traini
- Woolcock Institute of Medical Research, Sydney, Australia
- Department of Biomedical Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, 2113, Australia
| | - Paul Young
- Woolcock Institute of Medical Research, Sydney, Australia
- Department of Marketing, Macquarie Business School, Macquarie University, Sydney, NSW, Australia
| | - Shaokoon Cheng
- School of Mechanical Engineering, Faculty of Engineering, Macquarie University, Sydney, NSW, 2113, Australia.
| | - Hui Xin Ong
- Woolcock Institute of Medical Research, Sydney, Australia.
- Department of Biomedical Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, 2113, Australia.
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19
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Ohmura T, Nishigami Y, Ichikawa M. Simple dynamics underlying the survival behaviors of ciliates. Biophys Physicobiol 2022; 19:e190026. [PMID: 36160323 PMCID: PMC9465405 DOI: 10.2142/biophysico.bppb-v19.0026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/05/2022] [Indexed: 12/01/2022] Open
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20
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Rostami T, Ranjbar M, Ghourchian S, Darzi F, Douraghi M, Nateghi-Rostami M. Upregulation of abeM, amvA, and qacEΔ1 efflux pump genes associated with resistance of Acinetobacter baumannii strains to disinfectants. Health Sci Rep 2021; 4:e395. [PMID: 34622028 PMCID: PMC8485592 DOI: 10.1002/hsr2.395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/22/2021] [Accepted: 08/31/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND AND AIMS Acinetobacter baumannii is among the most concerning cause of nosocomial infections due to its high level of antibiotic resistance and high mortality. The aim of this study was to determine the role of efflux pumps in resistance of A. baumannii strains to three disinfectants, including MICROZED ID-MAX, NANOSIL D2, and OPIDEX OPA. METHODS Twenty-eight environmental and clinical isolates of A. baumannii were collected from selected hospitals of central Iran. The minimum inhibitory concentrations of the disinfectants were determined and real time reverse transcriptase-PCR was performed to investigate the expression level of qacEΔ1, amvA, abeM, and adeB efflux pump genes. RESULTS Considering both clinical and environmental isolates, there was a significant difference in the mean expression level of qacEΔ1 gene between susceptible and resistant strains to MICROZED ID-MAX disinfectant, of amvA and abeM genes between susceptible and resistant strains to NANOSIL D2 disinfectant and of abeM gene in susceptible and resistant strains to OPIDEX OPA disinfectant (all P ˂ .05). The expression levels of abeM and amvA genes were higher in the environmental isolates that were resistant to NANOSIL D2 disinfectant compared to those that were susceptible (P ˂ .05). CONCLUSIONS This study provided evidence for the role of abeM and amvA genes in the resistance of environmental isolates to disinfectants, particularly hydrogen peroxide derivatives.
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Affiliation(s)
- Tahereh Rostami
- Faculty of Biotechnology Amol University of Special Modern Technologies Amol Iran
| | - Mojtaba Ranjbar
- Faculty of Biotechnology Amol University of Special Modern Technologies Amol Iran
| | - Sedighe Ghourchian
- Department of Pathobiology School of Public Health, Tehran University of Medical Sciences Tehran Iran
| | - Fatemeh Darzi
- Department of Parasitology Pasteur Institute of Iran Tehran Iran
| | - Masoumeh Douraghi
- Department of Pathobiology School of Public Health, Tehran University of Medical Sciences Tehran Iran
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Islam MM, Kim K, Lee JC, Shin M. LeuO, a LysR-Type Transcriptional Regulator, Is Involved in Biofilm Formation and Virulence of Acinetobacter baumannii. Front Cell Infect Microbiol 2021; 11:738706. [PMID: 34708004 PMCID: PMC8543017 DOI: 10.3389/fcimb.2021.738706] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/23/2021] [Indexed: 12/05/2022] Open
Abstract
Acinetobacter baumannii is an important nosocomial pathogen that can survive in different environmental conditions and poses a severe threat to public health due to its multidrug resistance properties. Research on transcriptional regulators, which play an essential role in adjusting to new environments, could provide new insights into A. baumannii pathogenesis. LysR-type transcriptional regulators (LTTRs) are structurally conserved among bacterial species and regulate virulence in many pathogens. We identified a novel LTTR, designated as LeuO encoded in the A. baumannii genome. After construction of LeuO mutant strain, transcriptome analysis showed that LeuO regulates the expression of 194 upregulated genes and 108 downregulated genes responsible for various functions and our qPCR validation of several differentially expressed genes support transcriptome data. Our results demonstrated that disruption of LeuO led to increased biofilm formation and increased pathogenicity in an animal model. However, the adherence and surface motility of the LeuO mutant were reduced compared with those of the wild-type strain. We observed some mutations on amino acids sequence of LeuO in clinical isolates. These mutations in the A. baumannii biofilm regulator LeuO may cause hyper-biofilm in the tested clinical isolates. This study is the first to demonstrate the association between the LTTR member LeuO and virulence traits of A. baumannii.
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Affiliation(s)
- Md Maidul Islam
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Kyeongmin Kim
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Je Chul Lee
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Minsang Shin
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu, South Korea
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Sun X, Xiang J. Mechanism Underlying the Role of LuxR Family Transcriptional Regulator abaR in Biofilm Formation by Acinetobacter baumannii. Curr Microbiol 2021; 78:3936-3944. [PMID: 34522977 PMCID: PMC8439540 DOI: 10.1007/s00284-021-02654-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 09/02/2021] [Indexed: 11/26/2022]
Abstract
Our study attempted to explore the mechanism underlying the role of LuxR family transcriptional regulator abaR in biofilm formation by Acinetobacter baumannii. The abaR gene was knocked out in ATCC 17978 strain using homologous recombination method. The growth curve and biofilm formation were measured in the wild type and abaR gene knockdown strains. Transcriptome sequencing was performed in the wild type and abaR gene knockdown strains following 8 h of culture. The growth curve in the abaR gene knockdown strain was similar to that of the wild-type strain. Biofilm formation significantly declined in the abaR gene knockdown strain at 8 and 48 h after culture. A total of 137 differentially expressed genes (DEGs) were obtained including 20 downregulated DEGs and 117 upregulated DEGs. Genes with differential expression were closely related to viral procapsid maturation (GO:0046797), acetoin catabolism (GO:0045150), carbon metabolism (ko01200), and the glycolysis/gluconeogenesis (ko00010)-related pathways. The results of the eight verified expression DEGs were consistent with the results predicted by bioinformatics. AbaR gene knockdown significantly affected biofilm formation by A. baumannii ATCC 17978 strain. The glycolysis/gluconeogenesis pathways were significantly dysregulated and induced by abaR gene knockdown in A. baumannii.
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Affiliation(s)
- Xu Sun
- Department of Burn, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Xiang
- Department of Burn, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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23
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Insights into Acinetobacter baumannii fatty acid synthesis 3-oxoacyl-ACP reductases. Sci Rep 2021; 11:7050. [PMID: 33782435 PMCID: PMC8007833 DOI: 10.1038/s41598-021-86400-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/08/2021] [Indexed: 11/08/2022] Open
Abstract
Treatments for 'superbug' infections are the focus for innovative research, as drug resistance threatens human health and medical practices globally. In particular, Acinetobacter baumannii (Ab) infections are repeatedly reported as difficult to treat due to increasing antibiotic resistance. Therefore, there is increasing need to identify novel targets in the development of different antimicrobials. Of particular interest is fatty acid synthesis, vital for the formation of phospholipids, lipopolysaccharides/lipooligosaccharides, and lipoproteins of Gram-negative envelopes. The bacterial type II fatty acid synthesis (FASII) pathway is an attractive target for the development of inhibitors and is particularly favourable due to the differences from mammalian type I fatty acid synthesis. Discrete enzymes in this pathway include two reductase enzymes: 3-oxoacyl-acyl carrier protein (ACP) reductase (FabG) and enoyl-ACP reductase (FabI). Here, we investigate annotated FabG homologs, finding a low-molecular weight 3-oxoacyl-ACP reductase, as the most likely FASII FabG candidate, and high-molecular weight 3-oxoacyl-ACP reductase (HMwFabG), showing differences in structure and coenzyme preference. To date, this is the second bacterial high-molecular weight FabG structurally characterized, following FabG4 from Mycobacterium. We show that ΔAbHMwfabG is impaired for growth in nutrient rich media and pellicle formation. We also modelled a third 3-oxoacyl-ACP reductase, which we annotated as AbSDR. Despite containing residues for catalysis and the ACP coordinating motif, biochemical analyses showed limited activity against an acetoacetyl-CoA substrate in vitro. Inhibitors designed to target FabG proteins and thus prevent fatty acid synthesis may provide a platform for use against multidrug-resistant pathogens including A. baumannii.
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Varshney S, Sain A, Gupta D, Sharma S. Factors Affecting Bacterial Adhesion on Selected Textile Fibres. Indian J Microbiol 2021; 61:31-37. [PMID: 33505090 PMCID: PMC7810813 DOI: 10.1007/s12088-020-00903-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 08/18/2020] [Indexed: 10/23/2022] Open
Abstract
In sectors like healthcare and hospitality, it has been realized that fabrics play a pivotal role in transfer of nosocomial infections. However, there is a major gap in drawing correlation between different fibre types and their interaction with microorganisms. Such information is important to formulate guidelines for textile materials for use in these sectors. In the current study, the adherence of four important bacteria, Staphylococcus aureus, Acinetobacter calcoaceticus, Escherichia coli, and Pseudomonas aeruginosa was studied on six different fibre types namely polyester, wool, polypropylene, viscose, silk and cotton. Among these fibres, viscose showed maximum adherence while silk fibres showed the least attachment of bacterial strains. Bacterial adhesion was correlated with the surface characteristics (surface charge, hydrophobicity etc.) of bacteria, and nanoroughness of fibres. Adhesion of these bacteria was tested on five hydrocarbons of different hydrophobicities. E. coli, the weakest biofilm producer, and with the highest surface energy and lowest hydrophobicity amongst the bacteria compared in the study, had the lowest load on all fibres. Scanning electron microscopy revealed non-uniform binding of gram-negative and gram-positive bacteria. Nanoroughness of fibres favored bacterial adhesion. The study showed correlation between surface properties and adherence of bacteria on fibres, with the results being of direct significance to medical and hospitality sectors.
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Affiliation(s)
- Swati Varshney
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016 India
| | - Abhineet Sain
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016 India
| | - Deepti Gupta
- Department of Textile and Fibre Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016 India
| | - Shilpi Sharma
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016 India
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25
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Alam P, Alqahtani AS, Mabood Husain F, Tabish Rehman M, Alajmi MF, Noman OM, El Gamal AA, Al-Massarani SM, Shavez Khan M. Siphonocholin isolated from red sea sponge Siphonochalina siphonella attenuates quorum sensing controlled virulence and biofilm formation. Saudi Pharm J 2020; 28:1383-1391. [PMID: 33250645 PMCID: PMC7679466 DOI: 10.1016/j.jsps.2020.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/07/2020] [Indexed: 01/25/2023] Open
Abstract
Increasing incidence of multi-drug resistant bacterial pathogens, especially in clinical settings, has been developed into a grave health situation. The drug resistance problem demands the necessity for alternative unique therapeutic policies. One such tactic is targeting the quorum sensing (QS) controlled virulence and biofilm production. In this study, we evaluated a marine steroid Siphonocholin (Syph-1) isolated from Siphonochalina siphonella against Chromobacterium violaceum (CV) 12472, Pseudomonas aeruginosa (PAO1), Methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii (BAA) for biofilm and pellicle formation inhibition, and anti-QS property. MIC of Syph-1 against MRSA, CV, PAO1 was found as 64 µg/mL and 256 µg/mL against BAA. At selected sub-MICs, Syph-1 significantly (P ≤ 0.05) decreased the production of QS regulated virulence functions of CV12472 (violacein) and PAO1 [elastase, total protease, pyocyanin, chitinase, exopolysaccharides, and swarming motility]. The Syph-1 significantly decreased (p = 0.005) biofilm formation ability of tested bacterial pathogens, at sub-MIC level (PAO1 > MRSA > CV > BAA) and pellicle formation in A. baumannii (at 128 µg/mL). Molecular docking and simulation results indicated that Siph-1 was bound at the active site of BfmR N-terminal domain with high affinity. This study highlights the anti-QS and anti-biofilm activity of Syph-1 against bacterial pathogens reflecting its broad spectrum anti-infective potential.
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Affiliation(s)
- Perwez Alam
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ali S. Alqahtani
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Fohad Mabood Husain
- Department of Food Science and Nutrition, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Md. Tabish Rehman
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohamed F. Alajmi
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Omar M. Noman
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ali A. El Gamal
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Shaza M. Al-Massarani
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohammad Shavez Khan
- National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, India
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Prem Anand K, Suthindhiran K. Biofilm formation and pathogenicity of marine-derived Acinetobacter sp. VITRSA1 in Paratelphusa hydrodromous and its toluene remediation. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2020. [DOI: 10.1016/j.bcab.2020.101723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Raorane CJ, Lee JH, Lee J. Rapid Killing and Biofilm Inhibition of Multidrug-Resistant Acinetobacter baumannii Strains and Other Microbes by Iodoindoles. Biomolecules 2020; 10:biom10081186. [PMID: 32824104 PMCID: PMC7465641 DOI: 10.3390/biom10081186] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 12/12/2022] Open
Abstract
Multi-drug resistant Acinetobacter baumannii is well-known for its rapid acclimatization in hospital environments. The ability of the bacterium to endure desiccation and starvation on dry surfaces for up to a month results in outbreaks of health care-associated infections. Previously, indole and its derivatives were shown to inhibit other persistent bacteria. We found that among 16 halogenated indoles, 5-iodoindole swiftly inhibited A. baumannii growth, constrained biofilm formation and motility, and killed the bacterium as effectively as commercial antibiotics such as ciprofloxacin, colistin, and gentamicin. 5-Iodoindole treatment was found to induce reactive oxygen species, resulting in loss of plasma membrane integrity and cell shrinkage. In addition, 5-iodoindole rapidly killed three Escherichia coli strains, Staphylococcus aureus, and the fungus Candida albicans, but did not inhibit the growth of Pseudomonas aeruginosa. This study indicates the mechanism responsible for the activities of 5-iodoindole warrants additional study to further characterize its bactericidal effects on antibiotic-resistant A. baumannii and other microbes.
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Affiliation(s)
| | | | - Jintae Lee
- Correspondence: ; Tel.: +82-53-810-2533; Fax: +82-53-810-4631
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28
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Synthesis and antibiofilm evaluation of 3-hydroxy-2,3-dihydroquinazolin-4(1H)-one derivatives against opportunistic pathogen Acinetobacter baumannii. Bioorg Med Chem 2020; 28:115606. [PMID: 32690261 DOI: 10.1016/j.bmc.2020.115606] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 06/20/2020] [Accepted: 06/23/2020] [Indexed: 11/23/2022]
Abstract
The emergence of multidrug resistant microorganisms has triggered the impending need for new aitimicrobial strategies. The antivirulence strategy with the benefite of alleviating the drug resistance becomes the focus of research. In this study, 22 quorum sensing inhibitors were synthesized by mimicking the structure of autoinducer and acinetobactin and up to 34% biofilm inhibition was observed with 5u. The biofilm inhibition effect was further demonstrated with extracellular polysaccharides inhibition and synergism with Gentamycin sulphate.
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29
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Dassanayake RP, Falkenberg SM, Stasko JA, Shircliff AL, Lippolis JD, Briggs RE. Identification of a reliable fixative solution to preserve the complex architecture of bacterial biofilms for scanning electron microscopy evaluation. PLoS One 2020; 15:e0233973. [PMID: 32470063 PMCID: PMC7259777 DOI: 10.1371/journal.pone.0233973] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/16/2020] [Indexed: 12/16/2022] Open
Abstract
Bacterial biofilms are organized sessile communities of bacteria enclosed in extracellular polymeric substances (EPS). To analyze organization of bacteria and EPS in high resolution and high magnification by scanning electron microscopy (SEM), it is important to preserve the complex architecture of biofilms. Therefore, fixation abilities of formalin, glutaraldehyde, and Methacarn (methanol/chloroform/acetic acid-6:3:1) fixatives were evaluated to identify which fixative would best preserve the complex structure of bacterial biofilms. Economically important Gram-negative Mannheimia haemolytica, the major pathogen associated with bovine respiratory disease complex, and Gram-positive Staphylococcus aureus, the major cause of chronic mastitis in cattle, bacteria were selected since both form biofilms on solid-liquid interface. For SEM analysis, round glass coverslips were placed into the wells of 24-well plates and diluted M. haemolytica or S. aureus cultures were added, and incubated at 37°C for 48–72 h under static growth conditions. Culture media were aspirated and biofilms were fixed with an individual fixative for 48 h. SEM examination revealed that all three fixatives were effective preserving the bacterial cell morphology, however only Methacarn fixative could consistently preserve the complex structure of biofilms. EPS layers were clearly visible on the top, in the middle, and in the bottom of the biofilms with Methacarn fixative. Biomass and three-dimensional structure of the biofilms were further confirmed spectrophotometrically following crystal violet staining and by confocal microscopy after viability staining. These findings demonstrate that Methacarn fixative solution is superior to the other fixatives evaluated to preserve the complex architecture of biofilms grown on glass coverslips for SEM evaluation.
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Affiliation(s)
- Rohana P. Dassanayake
- Ruminant Diseases and Immunology Research Unit, National Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Ames, Iowa, United States of America
- * E-mail:
| | - Shollie M. Falkenberg
- Ruminant Diseases and Immunology Research Unit, National Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Ames, Iowa, United States of America
| | - Judith A. Stasko
- Microscopy Services Laboratory, National Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Ames, Iowa, United States of America
| | - Adrienne L. Shircliff
- Microscopy Services Laboratory, National Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Ames, Iowa, United States of America
| | - John D. Lippolis
- Ruminant Diseases and Immunology Research Unit, National Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Ames, Iowa, United States of America
| | - Robert E. Briggs
- Ruminant Diseases and Immunology Research Unit, National Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Ames, Iowa, United States of America
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30
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Lin MF, Lin YY, Lan CY. Characterization of biofilm production in different strains of Acinetobacter baumannii and the effects of chemical compounds on biofilm formation. PeerJ 2020; 8:e9020. [PMID: 32523805 PMCID: PMC7261477 DOI: 10.7717/peerj.9020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 03/28/2020] [Indexed: 12/23/2022] Open
Abstract
Acinetobacter baumannii, an important emerging pathogen of nosocomial infections, is known for its ability to form biofilms. Biofilm formation increases the survival rate of A. baumannii on dry surfaces and may contribute to its persistence in the hospital environment, which increases the probability of nosocomial infections and outbreaks. This study was undertaken to characterize the biofilm production of different strains of A. baumannii and the effects of chemical compounds, especially antibiotics, on biofilm formation. In this study, no statistically significant relationship was observed between the ability to form a biofilm and the antimicrobial susceptibility of the A. baumannii clinical isolates. Biofilm formation caused by A. baumannii ATCC 17978 after gene knockout of two-component regulatory system gene baeR, efflux pump genes emrA/emrB and outer membrane coding gene ompA revealed that all mutant strains had less biofilm formation than the wild-type strain, which was further supported by the images from scanning electron microscopy and confocal laser scanning microscopy. The addition of amikacin, colistin, LL-37 or tannic acid decreased the biofilm formation ability of A. baumannii. In contrast, the addition of lower subinhibitory concentration tigecycline increased the biofilm formation ability of A. baumannii. Minimum biofilm eradication concentrations of amikacin, imipenem, colistin, and tigecycline were increased obviously for both wild type and multidrug resistant clinical strain A. baumannii VGH2. In conclusion, the biofilm formation ability of A. baumannii varied in different strains, involved many genes and could be influenced by many chemical compounds.
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Affiliation(s)
- Ming-Feng Lin
- Department of Medicine, National Taiwan University Hospital Chu-Tung Branch, Hsinchu County, Taiwan
| | - Yun-You Lin
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Chung-Yu Lan
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan.,Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
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31
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Chen J, Wang Y. Genetic determinants of Salmonella enterica critical for attachment and biofilm formation. Int J Food Microbiol 2020; 320:108524. [PMID: 32000116 DOI: 10.1016/j.ijfoodmicro.2020.108524] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 12/21/2022]
Abstract
Salmonella is a bacterial pathogen frequently involved in human gastrointestinal infections including those associated with low-moisture foods such as dehydrated food powders/spices, vegetable seeds, and tree nuts. The survival/persistence of Salmonella on low moisture foods and in dry environments is enhanced by its ability in developing biofilms. This study was undertaken to identify the genetic determinants critical for Salmonella attachment and biofilm formation. E. coli SM10 lambda pir, with a kanamycin resistant marker on mini-Tn10 (mini-Tn10:lacZ:kanr), an ampicillin resistant marker on the mini-Tn10-bearing suicidal plasmid pLBT and a streptomycin sensitive marker on the SM10 chromosome, was used as a donor (ampr, kanr, streps), and three Salmonella strains (amps, kans, strepr) were used as recipients in a transposon mutagenesis study. The donor and each recipient were co-incubated overnight on tryptic soy agar at 37 °C, and mutant colonies (amps, kanr, strepr) were subsequently selected. A single-banded degenerate PCR product, amplified from each mutant genome using oligonucleotide primers derived from the end of min-Tn10 and restriction enzyme EcoR I- or Pst I-recognizing sequence, were analyzed using the Sanger sequencing technology. Acquired DNA sequences were compared to those deposited in the Genbank using BLAST search. Cells of Salmonella mutants accumulated either significantly more or less (P < 0.05) biofilms than their parent cells on polystyrene surface. Sequence analysis of degenerate PCR products revealed that the mini-Tn10 from pLBT had inserted into the cdg, trx, fadI or rxt on Salmonella chromosomes. Results of the research will likely help strategize future antimicrobial intervention for control of pathogen attachment and biofilm formation.
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Affiliation(s)
- Jinru Chen
- Department of Food Science and Technology, The University of Georgia, 1109 Experiment St., Griffin, GA 30223-1797, USA.
| | - Yin Wang
- Department of Food Science and Technology, The University of Georgia, 1109 Experiment St., Griffin, GA 30223-1797, USA
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32
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Raorane CJ, Lee JH, Kim YG, Rajasekharan SK, García-Contreras R, Lee J. Antibiofilm and Antivirulence Efficacies of Flavonoids and Curcumin Against Acinetobacter baumannii. Front Microbiol 2019; 10:990. [PMID: 31134028 PMCID: PMC6517519 DOI: 10.3389/fmicb.2019.00990] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/18/2019] [Indexed: 01/08/2023] Open
Abstract
Acinetobacter baumannii is well adapted to hospital environments, and the persistence of its chronic infections is mainly due to its ability to form biofilms resistant to conventional antibiotics and host immune systems. Hence, the inhibitions of biofilm formation and virulence characteristics provide other means of addressing infections. In this study, the antibiofilm activities of twelve flavonoids were initially investigated. Three most active flavonoids, namely, fisetin, phloretin, and curcumin, dose-dependently inhibited biofilm formation by a reference A. baumannii strain and by several clinical isolates, including four multidrug-resistant isolates. Furthermore, the antibiofilm activity of curcumin (the most active flavonoid) was greater than that of the well-known biofilm inhibitor gallium nitrate. Curcumin inhibited pellicle formation and the surface motility of A. baumannii. Interestingly, curcumin also showed antibiofilm activity against Candida albicans and mixed cultures of C. albicans and A. baumannii. In silico molecular docking of the biofilm response regulator BfmR showed that the binding efficacy of flavonoids with BfmR was correlated with antibiofilm efficacy. In addition, curcumin treatment diminished A. baumannii virulence in an in vivo Caenorhabditis elegans model without cytotoxicity. The study shows curcumin and other flavonoids have potential for controlling biofilm formation by and the virulence of A. baumannii.
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Affiliation(s)
| | - Jin-Hyung Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan, South Korea
| | - Yong-Guy Kim
- School of Chemical Engineering, Yeungnam University, Gyeongsan, South Korea
| | | | - Rodolfo García-Contreras
- Department of Microbiology and Parasitology, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - Jintae Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan, South Korea
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33
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Eze EC, Chenia HY, El Zowalaty ME. Acinetobacter baumannii biofilms: effects of physicochemical factors, virulence, antibiotic resistance determinants, gene regulation, and future antimicrobial treatments. Infect Drug Resist 2018; 11:2277-2299. [PMID: 30532562 PMCID: PMC6245380 DOI: 10.2147/idr.s169894] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is a leading cause of nosocomial infections due to its increased antibiotic resistance and virulence. The ability of A. baumannii to form biofilms contributes to its survival in adverse environmental conditions including hospital environments and medical devices. A. baumannii has undoubtedly propelled the interest of biomedical researchers due to its broad range of associated infections especially in hospital intensive care units. The interplay among microbial physicochemistry, alterations in the phenotype and genotypic determinants, and the impact of existing ecological niche and the chemistry of antimicrobial agents has led to enhanced biofilm formation resulting in limited access of drugs to their specific targets. Understanding the triggers to biofilm formation is a step towards limiting and containing biofilm-associated infections and development of biofilm-specific countermeasures. The present review therefore focused on explaining the impact of environmental factors, antimicrobial resistance, gene alteration and regulation, and the prevailing microbial ecology in A. baumannii biofilm formation and gives insights into prospective anti-infective treatments.
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Affiliation(s)
- Emmanuel C Eze
- Virology and Microbiology Research Group, School of Health Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa,
| | - Hafizah Y Chenia
- Discipline of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Mohamed E El Zowalaty
- Virology and Microbiology Research Group, School of Health Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa,
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Sung JY. Molecular Characterization and Antimicrobial Susceptibility of Biofilm-forming Acinetobacter baumannii Clinical Isolates from Daejeon, Korea. KOREAN JOURNAL OF CLINICAL LABORATORY SCIENCE 2018. [DOI: 10.15324/kjcls.2018.50.2.100] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Ji Youn Sung
- Department of Biomedical Laboratory Science, Far East University, Eumseong, Korea
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Mosharaf MK, Tanvir MZH, Haque MM, Haque MA, Khan MAA, Molla AH, Alam MZ, Islam MS, Talukder MR. Metal-Adapted Bacteria Isolated From Wastewaters Produce Biofilms by Expressing Proteinaceous Curli Fimbriae and Cellulose Nanofibers. Front Microbiol 2018; 9:1334. [PMID: 29988579 PMCID: PMC6026672 DOI: 10.3389/fmicb.2018.01334] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 05/31/2018] [Indexed: 11/13/2022] Open
Abstract
Bacterial biofilm plays a pivotal role in bioremediation of heavy metals from wastewaters. In this study, we isolated and identified different biofilm producing bacteria from wastewaters. We also characterized the biofilm matrix [i.e., extracellular polymeric substances (EPS)] produced by different bacteria. Out of 40 isolates from different wastewaters, only 11 (27.5%) isolates (static condition at 28°C) and 9 (22.5%) isolates (agitate and static conditions at 28 and 37°C) produced air–liquid (AL) and solid–air–liquid (SAL) biofilms, respectively, only on salt-optimized broth plus 2% glycerol (SOBG) but not in other media tested. Biomass biofilms and bacteria coupled with AL biofilms were significantly (P ≤ 0.001) varied in these isolates. Escherichia coli (isolate ENSD101 and ENST501), Enterobacter asburiae (ENSD102), Enterobacter ludwigii (ENSH201), Pseudomonas fluorescens (ENSH202 and ENSG304), uncultured Vitreoscilla sp. (ENSG301 and ENSG305), Acinetobacter lwoffii (ENSG302), Klebsiella pneumoniae (ENSG303), and Bacillus thuringiensis (ENSW401) were identified based on 16S rRNA gene sequencing. Scanning electron microscope (SEM) images revealed that biofilm matrix produced by E. asburiae ENSD102, uncultured Vitreoscilla sp. ENSG301, A. lwoffii ENSG302, and K. pneumoniae ENSG303 are highly fibrous, compact, and nicely interlinked as compared to the biofilm developed by E. ludwigii ENSH201 and B. thuringiensis ENSW401. X-ray diffraction (XRD) results indicated that biofilm matrix produced by E. asburiae ENSD102, uncultured Vitreoscilla sp. ENSG301, and A. lwoffii ENSG302 are non-crystalline amorphous nature. Fourier transform infrared (FTIR) spectroscopy showed that proteins and polysaccharides are the main components of the biofilms. Congo red binding results suggested that all these bacteria produced proteinaceous curli fimbriae and cellulose-rich polysaccharide. Production of cellulose was also confirmed by Calcofluor binding- and spectrophotometric assays. E. asburiae ENSD102, Vitreoscilla sp. ENSG301, and A. lwoffii ENSG302 were tested for their abilities to form the biofilms exposure to 0 to 2000 mg/L of copper sulfate (for Cu), zinc sulfate (for Zn), lead nitrate (for Pb), nickel chloride (for Ni), and potassium dichromate (for Cr), several concentrations of these metals activated the biofilm formation. The polysaccharides is known to sequester the heavy metals thus, these bacteria might be applied to remove the heavy metals from wastewater.
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Affiliation(s)
- M K Mosharaf
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M Z H Tanvir
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M M Haque
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M A Haque
- Department of Agro-Processing, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M A A Khan
- Department of Plant Pathology, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - A H Molla
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - Mohammad Z Alam
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M S Islam
- Bangladesh Jute Research Institute, Dhaka, Bangladesh
| | - M R Talukder
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
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Wang YC, Huang TW, Yang YS, Kuo SC, Chen CT, Liu CP, Liu YM, Chen TL, Chang FY, Wu SH, How CK, Lee YT. Biofilm formation is not associated with worse outcome in Acinetobacter baumannii bacteraemic pneumonia. Sci Rep 2018; 8:7289. [PMID: 29740176 PMCID: PMC5940913 DOI: 10.1038/s41598-018-25661-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/20/2018] [Indexed: 02/07/2023] Open
Abstract
The effect of biofilm formation on bacteraemic pneumonia caused by A. baumannii is unknown. We conducted a 4-year multi-center retrospective study to analyze 71 and 202 patients with A. baumannii bacteraemic pneumonia caused by biofilm-forming and non-biofilm-forming isolates, respectively. The clinical features and outcomes of patients were investigated. Biofilm formation was determined by a microtitre plate assay. The antimicrobial susceptibilities of biofilm-associated cells were assessed using the minimum biofilm eradication concentration (MBEC) assay. Whole-genome sequencing was conducted to identify biofilm-associated genes and their promoters. Quantitative reverse transcription polymerase chain reaction was performed to confirm the expression difference of biofilm-associated genes. There was no significant difference in the clinical characteristics or the outcomes between patients infected with biofilm-forming and non-biofilm-forming strains. Compared with non-biofilm-forming isolates, biofilm-forming isolates exhibited lower resistance to most antimicrobials tested, including imipenem, meropenem, ceftazidime, ciprofloxacin and gentamicin; however, the MBEC assay confirmed the increased antibiotic resistance of the biofilm-embedded bacteria. Biofilm-associated genes and their promoters were detected in most isolates, including the non-biofilm-forming strains. Biofilm-forming isolates showed higher levels of expression of the biofilm-associated genes than non-biofilm-forming isolates. The biofilm-forming ability of A. baumannii isolates might not be associated with worse outcomes in patients with bacteraemic pneumonia.
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Affiliation(s)
- Yung-Chih Wang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.,Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Tzu-Wen Huang
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Ya-Sung Yang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shu-Chen Kuo
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institute, Maoli County, Taiwan
| | - Chung-Ting Chen
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chang-Pan Liu
- Division of Infectious Diseases, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan.,Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
| | - Yuag-Meng Liu
- Division of Infectious Diseases, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan
| | - Te-Li Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.,Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Feng-Yee Chang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shih-Hsiung Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chorng-Kuang How
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Tzu Lee
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. .,Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
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Ju M, Hou D, Chen S, Wang Y, Tang X, Liu J, Chen C, Song Y, Li H. Risk factors for mortality in ICU patients with Acinetobacter baumannii ventilator-associated pneumonia: impact of bacterial cytotoxicity. J Thorac Dis 2018; 10:2608-2617. [PMID: 29997922 DOI: 10.21037/jtd.2018.04.86] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Background Acinetobacter baumannii (A. baumannii) ventilator-associated pneumonia (VAP) in intensive care unit (ICU) is associated with high morbidity and mortality in patients with critical illness. However, the literatures that focused on the short-term prognosis and the risk factors for mortality are limited. The aim of this study was to evaluate the risk factors for mortality in ICU patients with A. baumannii VAP. Methods A retrospective cohort study was conducted in the medical/surgical ICU at Zhongshan Hospital in Shanghai, China. Adult patients meeting the criteria of A. baumannii VAP from January 2012 to October 2015 were enrolled. Apart from collecting clinical and microbiologic data, we performed biofilm-formation and cytotoxicity testing using A. baumannii strains which are isolated from patients. Multivariate logistic regression analysis was used to determine the independent risk factors for 30-day mortality in ICU. Results Seventy-eight patients were included in this study. The 30-day mortality rate in ICU for the patients was 37.2%. Multivariate analysis revealed that short-term mortality was significantly associated with prior surgery [OR, 0.277; 95% confidence interval (CI), 0.089-0.866; P=0.027], higher APACHEII score (OR, 1.140; 95% CI, 1.007-1.291; P=0.038) and an increased bacterial cytotoxicity (OR, 1.029 ; 95% CI, 1.001-1.058; P=0.047). Conclusions The main finding of our study was that increased bacterial cytotoxicity might be a risk factor for short-term mortality in ICU patients with A. baumannii VAP.
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Affiliation(s)
- Mohan Ju
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Dongni Hou
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Shu Chen
- Department of Infectious Disease, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Ying Wang
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xinjun Tang
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jie Liu
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Cuicui Chen
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Yuanlin Song
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Huayin Li
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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Abstract
Single-celled microorganisms are important in ecosystems, and their behaviors impact the Earth’s environments. To survive in harsh environments, these organisms frequently act as though exercising discretion. How do they achieve such intelligent behaviors? In this work, we focused on the accumulation of ciliates on solid/fluid interfaces, where they can obtain sufficient nutrients and a stable environment. This phenomenon is not described in the standard hydrodynamics of microswimmers. Our experiment and simulation revealed that simple principles, the anisotropic shape of the cell and the mechanosensing nature of cilia, induce the accumulation of ciliates on solid/fluid interfaces. The contribution of our work is that a simple response of the cellular apparatus and fluid dynamics explain the apparently clever behavior of ciliates. An important habit of ciliates, namely, their behavioral preference for walls, is revealed through experiments and hydrodynamic simulations. A simple mechanical response of individual ciliary beating (i.e., the beating is stalled by the cilium contacting a wall) can solely determine the sliding motion of the ciliate along the wall and result in a wall-preferring behavior. Considering ciliate ethology, this mechanosensing system is likely an advantage in the single cell’s ability to locate nutrition. In other words, ciliates can skillfully use both the sliding motion to feed on a surface and the traveling motion in bulk water to locate new surfaces according to the single “swimming” mission.
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Bogdan M, Drenjancevic D, Harsanji Drenjancevic I, Bedenic B, Zujic Atalic V, Talapko J, Vukovic D. In vitro effect of subminimal inhibitory concentrations of antibiotics on the biofilm formation ability of Acinetobacter baumannii clinical isolates. J Chemother 2017; 30:16-24. [PMID: 28956494 DOI: 10.1080/1120009x.2017.1378835] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The ability of A cinetobacter baumannii strains to form biofilm is one of the most important virulence factor which enables bacterial survival in a harsh environment and decreases antibiotic concentration as well. Subminimal inhibitory concentrations (subMICs) of antibiotics may change bacterial ultrastructure or have an influence on some different molecular mechanisms resulting in morphological or physiological changes in bacteria itself. The aim of this study was to determine effects of 1/2, 1/4, 1/8 and 1/16 minimal inhibitory concentrationsof imipenem, ampicillin-sulbactam, azithromycin, rifampicin and colistin on biofilm formation ability of 22 biofilm non-producing and 46 biofilm producing A. baumannii strains (30 weak producing strains and 16 moderate producing strains). Results of this study indicate that 1/2-1/16 MICs of imipenem, azithromycin, and rifampicin can reduce bacterial biofilm formation ability in moderate producing strains (p < 0.05), whereas 1/16 MIC of imipenem and 1/4-1/8 MICs of rifampicin reduce the biofilm formation in weak producing strains (p < 0.05). Statisticaly significant effect was detected among biofilm non-producing strains after their exposure to 1/16 MIC of azithromycin (p = 0.039). SubMICs of ampicillin-sulbactam and colistin did not have any significant effect on biofilm formation among tested A. baumannii strains.
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Affiliation(s)
- Maja Bogdan
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia.,b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Domagoj Drenjancevic
- b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia.,c Department of Transfusion Medicine , Osijek University Hospital , Osijek , Croatia
| | - Ivana Harsanji Drenjancevic
- d Department of Anesthesiology, Reanimatology and Intensive Medicine , Osijek University Hospital , Osijek , Croatia.,e Faculty of Medicine, Department of Anesthesiology, Reanimatology and Intensive Medicine , University of Osijek , Osijek , Croatia
| | - Branka Bedenic
- f Department of Clinical and Molecular Microbiology , University Hospital Center Zagreb , Zagreb , Croatia.,g Department of Microbiology and Parasitology , School of Medicine, University of Zagreb , Zagreb , Croatia
| | - Vlasta Zujic Atalic
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia.,b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Jasminka Talapko
- b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Dubravka Vukovic
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia
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40
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Revathy T, Jacob JJ, Jayasri MA, Suthindhiran K. Microbial biofilm prevention on wound dressing by nanobiocoating using magnetosomes‐coupled lemon grass extract. IET Nanobiotechnol 2017. [DOI: 10.1049/iet-nbt.2016.0236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Theerthagiri Revathy
- Marine Biotechnology and Bioproducts LabSchool of Biosciences and TechnologyVIT UniversityVellore632014TamilnaduIndia
| | - Jobin John Jacob
- Marine Biotechnology and Bioproducts LabSchool of Biosciences and TechnologyVIT UniversityVellore632014TamilnaduIndia
| | | | - Krishnamurthy Suthindhiran
- Marine Biotechnology and Bioproducts LabSchool of Biosciences and TechnologyVIT UniversityVellore632014TamilnaduIndia
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Biofilm is a Major Virulence Determinant in Bacterial Colonization of Chronic Skin Ulcers Independently from the Multidrug Resistant Phenotype. Int J Mol Sci 2017; 18:ijms18051077. [PMID: 28513576 PMCID: PMC5454986 DOI: 10.3390/ijms18051077] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 05/06/2017] [Accepted: 05/11/2017] [Indexed: 01/28/2023] Open
Abstract
Bacterial biofilm is a major factor in delayed wound healing and high levels of biofilm production have been repeatedly described in multidrug resistant organisms (MDROs). Nevertheless, a quantitative correlation between biofilm production and the profile of antimicrobial drug resistance in delayed wound healing remains to be determined. Microbial identification, antibiotic susceptibility and biofilm production were assessed in 135 clinical isolates from 87 patients. Gram-negative bacteria were the most represented microorganisms (60.8%) with MDROs accounting for 31.8% of the total isolates. Assessment of biofilm production revealed that 80% of the strains were able to form biofilm. A comparable level of biofilm production was found with both MDRO and not-MDRO with no significant differences between groups. All the methicillin-resistant Staphylococcus aureus (MRSA) and 80% of Pseudomonas aeruginosa MDR strains were found as moderate/high biofilm producers. Conversely, less than 17% of Klebsiella pneumoniae extended-spectrum beta-lactamase (ESBL), Escherichia coli-ESBL and Acinetobacter baumannii were moderate/high biofilm producers. Notably, those strains classified as non-biofilm producers, were always associated with biofilm producer bacteria in polymicrobial colonization. This study shows that biofilm producers were present in all chronic skin ulcers, suggesting that biofilm represents a key virulence determinant in promoting bacterial persistence and chronicity of ulcerative lesions independently from the MDRO phenotype.
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Kentache T, Ben Abdelkrim A, Jouenne T, Dé E, Hardouin J. Global Dynamic Proteome Study of a Pellicle-forming Acinetobacter baumannii Strain. Mol Cell Proteomics 2017; 16:100-112. [PMID: 27799293 PMCID: PMC5217776 DOI: 10.1074/mcp.m116.061044] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 09/23/2016] [Indexed: 12/21/2022] Open
Abstract
For several decades, many bacteria, among which A. baumannii, have shown their ability to colonize the upper surface of static liquids, forming a biofilm at the air-liquid interface named pellicle. Despite the ubiquity of these pellicles in both natural and artificial environments, few studies have investigated this biofilm type. The present data set provides the first description of the whole proteome of A. baumannii cells grown as pellicle, using a label-free mass spectrometry approach. Results are in accord with the general findings reporting that sessile bacteria are far more resistant to detrimental conditions than their planktonic counterparts, by the accumulation of stress proteins. The present investigation also confirmed previous studies suggesting a correlation between the pellicle forming ability and the bacterial virulence. Indeed, we showed the up-regulation of numerous virulence factors during the pellicle growth, e.g. phospholipases, adhesion factors, as well as those of the GacAS Two-Component System (TCS) and Type 6 Secretion System (T6SS). We also highlighted that Bam and Tam systems, both related to the OM insertion machinery, play a critical role during pellicle biogenesis. Moreover, sessile bacteria activate several pathways, e.g. iron, magnesium, phosphate pathways, which allows for increasing the panel of nutrient sources.
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Affiliation(s)
- Takfarinas Kentache
- From the ‡CNRS; UMR 6270 Polymères, Biopolymères, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France
- §Normandie University, UR, France
| | - Ahmed Ben Abdelkrim
- From the ‡CNRS; UMR 6270 Polymères, Biopolymères, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France
- §Normandie University, UR, France
| | - Thierry Jouenne
- From the ‡CNRS; UMR 6270 Polymères, Biopolymères, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France
- §Normandie University, UR, France
- ¶PISSARO proteomic facility, IRIB, F-76821 Mont-Saint-Aignan, France
| | - Emmanuelle Dé
- From the ‡CNRS; UMR 6270 Polymères, Biopolymères, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France
- §Normandie University, UR, France
- ¶PISSARO proteomic facility, IRIB, F-76821 Mont-Saint-Aignan, France
| | - Julie Hardouin
- From the ‡CNRS; UMR 6270 Polymères, Biopolymères, Surfaces Laboratory, F-76821 Mont-Saint-Aignan, France;
- §Normandie University, UR, France
- ¶PISSARO proteomic facility, IRIB, F-76821 Mont-Saint-Aignan, France
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Kaplan JB, Sampathkumar V, Bendaoud M, Giannakakis AK, Lally ET, Balashova NV. In vitro characterization of biofilms formed by Kingella kingae. Mol Oral Microbiol 2016; 32:341-353. [PMID: 27714987 DOI: 10.1111/omi.12176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2016] [Indexed: 01/29/2023]
Abstract
The Gram-negative bacterium Kingella kingae is part of the normal oropharyngeal mucosal flora of children <4 years old. K. kingae can enter the submucosa and cause infections of the skeletal system in children, including septic arthritis and osteomyelitis. The organism is also associated with infective endocarditis in children and adults. Although biofilm formation has been coupled with pharyngeal colonization, osteoarticular infections, and infective endocarditis, no studies have investigated biofilm formation in K. kingae. In this study we measured biofilm formation by 79 K. kingae clinical isolates using a 96-well microtiter plate crystal violet binding assay. We found that 37 of 79 strains (47%) formed biofilms. All strains that formed biofilms produced corroding colonies on agar. Biofilm formation was inhibited by proteinase K and DNase I. DNase I also caused the detachment of pre-formed K. kingae biofilm colonies. A mutant strain carrying a deletion of the pilus gene cluster pilA1pilA2fimB did not produce corroding colonies on agar, autoaggregate in broth, or form biofilms. Biofilm forming strains have higher levels of pilA1 expression. The extracellular components of biofilms contained 490 μg cm-2 of protein, 0.68 μg cm-2 of DNA, and 0.4 μg cm-2 of total carbohydrates. We concluded that biofilm formation is common among K. kingae clinical isolates, and that biofilm formation is dependent on the production of proteinaceous pili and extracellular DNA. Biofilm development may have relevance to the colonization, transmission, and pathogenesis of this bacterium. Extracellular DNA production by K. kingae may facilitate horizontal gene transfer within the oral microbial community.
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Affiliation(s)
- J B Kaplan
- Department of Biology, American University, Washington, DC, USA
| | - V Sampathkumar
- Department of Oral Biology, Rutgers School of Dental Medicine, Rutgers University, Newark, NJ, USA
| | - M Bendaoud
- Department of Oral Biology, Rutgers School of Dental Medicine, Rutgers University, Newark, NJ, USA
| | - A K Giannakakis
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - E T Lally
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - N V Balashova
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Selasi GN, Nicholas A, Jeon H, Na SH, Kwon HI, Kim YJ, Heo ST, Oh MH, Lee JC. Differences in Biofilm Mass, Expression of Biofilm-Associated Genes, and Resistance to Desiccation between Epidemic and Sporadic Clones of Carbapenem-Resistant Acinetobacter baumannii Sequence Type 191. PLoS One 2016; 11:e0162576. [PMID: 27622249 PMCID: PMC5021322 DOI: 10.1371/journal.pone.0162576] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 08/24/2016] [Indexed: 11/18/2022] Open
Abstract
Understanding the biology behind the epidemicity and persistence of Acinetobacter baumannii in the hospital environment is critical to control outbreaks of infection. This study investigated the contributing factors to the epidemicity of carbapenem-resistant A. baumannii (CRAB) sequence type (ST) 191 by comparing the differences in biofilm formation, expression of biofilm-associated genes, and resistance to desiccation between major epidemic (n = 16), minor epidemic (n = 12), and sporadic (n = 12) clones. Biofilm mass was significantly greater in the major epidemic than the minor epidemic and sporadic clones. Major and minor epidemic clones expressed biofilm-associated genes, abaI, bap, pgaABCD, and csuA/BABCDE, higher than the sporadic clones in sessile conditions. The csuC, csuD, and csuE genes were more highly expressed in the major epidemic than minor epidemic clones. Interestingly, minor epidemic clones expressed more biofilm-associated genes than the major epidemic clone under planktonic conditions. Major epidemic clones were more resistant to desiccation than minor epidemic and sporadic clones on day 21. In conclusion, the epidemic CRAB ST191 clones exhibit a higher capacity to form biofilms, express the biofilm-associated genes under sessile conditions, and resist desiccation than sporadic clones. These phenotypic and genotypic characteristics of CRAB ST191 may account for the epidemicity of specific CRAB ST191 clones in the hospital.
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Affiliation(s)
- Gati Noble Selasi
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Asiimwe Nicholas
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Hyejin Jeon
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Seok Hyeon Na
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Hyo Il Kwon
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Yoo Jeong Kim
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Sang Taek Heo
- Department of Internal Medicine, Jeju National University School of Medicine, Jeju, Republic of Korea
| | - Man Hwan Oh
- Department of Nanobiomedical Science, Dankook University, Cheonan, Republic of Korea
| | - Je Chul Lee
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
- * E-mail:
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Kaliterna V, Kaliterna M, Hrenović J, Barišić Z, Tonkić M, Goic-Barisic I. Acinetobacter baumanniiin Southern Croatia: clonal lineages, biofilm formation, and resistance patterns. Infect Dis (Lond) 2015; 47:902-7. [DOI: 10.3109/23744235.2015.1078906] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Giles SK, Stroeher UH, Eijkelkamp BA, Brown MH. Identification of genes essential for pellicle formation in Acinetobacter baumannii. BMC Microbiol 2015; 15:116. [PMID: 26047954 PMCID: PMC4457973 DOI: 10.1186/s12866-015-0440-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/11/2015] [Indexed: 12/11/2022] Open
Abstract
Background Acinetobacter baumannii is an opportunistic pathogen, which has the ability to persist in the clinical environment, causing acute and chronic infections. A possible mechanism contributing to survival of A. baumannii is its ability to form a biofilm-like structure at the air/liquid interface, known as a pellicle. This study aimed to identify and characterise the molecular mechanisms required for pellicle formation in A. baumannii and to assess a broad range of clinical A. baumannii strains for their ability to form these multicellular structures. Results Random transposon mutagenesis was undertaken on a previously identified hyper-motile variant of A. baumannii ATCC 17978 designated 17978hm. In total three genes critical for pellicle formation were identified; cpdA, a phosphodiesterase required for degradation of cyclic adenosine monophosphate (cAMP), and A1S_0112 and A1S_0115 which are involved in the production of a secondary metabolite. While motility of the A1S_0112::Tn and A1S_0115::Tn mutant strains was abolished, the cpdA::Tn mutant strain displayed a minor alteration in its motility pattern. Determination of cAMP levels in the cpdA::Tn strain revealed a ~24-fold increase in cellular cAMP, confirming the role CpdA plays in catabolising this secondary messenger molecule. Interestingly, transcriptional analysis of the cpdA::Tn strain showed significant down-regulation of the operon harboring the A1S_0112 and A1S_0115 genes, revealing a link between these three genes and pellicle formation. Examination of our collection of 54 clinical A. baumannii strains revealed that eight formed a measurable pellicle; all of these strains were motile. Conclusions This study shows that pellicle formation is a rare trait in A. baumannii and that a limited number of genes are essential for the expression of this phenotype. Additionally, an association between pellicle formation and motility was identified. The level of the signalling molecule cAMP was found to be controlled, in part, by the cpdA gene product, in addition to playing a critical role in pellicle formation, cellular hydrophobicity and motility. Furthermore, cAMP was identified as a novel regulator of the operon A1S_0112-0118. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0440-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sarah K Giles
- School of Biological Sciences, Flinders University, GPO Box 2100, 5001, Adelaide, SA, Australia.
| | - Uwe H Stroeher
- School of Biological Sciences, Flinders University, GPO Box 2100, 5001, Adelaide, SA, Australia.
| | - Bart A Eijkelkamp
- School of Biological Sciences, Flinders University, GPO Box 2100, 5001, Adelaide, SA, Australia. .,Research Centre for Infectious Diseases, School of Biological Sciences University of Adelaide, Adelaide, Australia.
| | - Melissa H Brown
- School of Biological Sciences, Flinders University, GPO Box 2100, 5001, Adelaide, SA, Australia.
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Biofilm Formation and Quorum-Sensing-Molecule Production by Clinical Isolates of Serratia liquefaciens. Appl Environ Microbiol 2015; 81:3306-15. [PMID: 25746999 DOI: 10.1128/aem.00088-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 02/26/2015] [Indexed: 02/06/2023] Open
Abstract
Serratia spp. are opportunistic human pathogens responsible for an increasing number of nosocomial infections. However, little is known about the virulence factors and regulatory circuits that may enhance the establishment and long-term survival of Serratia liquefaciens in the hospital environment. In this study, two reporter strains, Chromobacterium violaceum CV026 and VIR24, and high-resolution triple-quadrupole liquid chromatography-mass spectrometry (LC-MS) were used to detect and to quantify N-acyl-homoserine lactone (AHL) quorum-sensing signals in 20 S. liquefaciens strains isolated from clinical samples. Only four of the strains produced sufficient amounts of AHLs to activate the sensors. Investigation of two of the positive strains by high-performance liquid chromatography (HPLC)-MS confirmed the presence of significant amounts of short-acyl-chain AHLs (N-butyryl-l-homoserine lactone [C4-HSL] and N-hexanoyl-l-homoserine lactone [C6-HSL]) in both strains, which exhibited a complex and strain-specific signal profile that included minor amounts of other short-acyl-chain AHLs (N-octanoyl-l-homoserine lactone [C8-HSL] and N-3-oxohexanoyl-l-homoserine lactone [OC6-HSL]) and long-acyl-chain (C10, C12, and C14) AHLs. No correlation between biofilm formation and the production of large amounts of AHLs could be established. Fimbria-like structures were observed by transmission electron microscopy, and the presence of the type 1 fimbrial adhesin gene fimH in all strains was confirmed by PCR. The ability of S. liquefaciens to adhere to abiotic surfaces and to form biofilms likely contributes to its persistence in the hospital environment, increasing the probability of causing nosocomial infections. Therefore, a better understanding of the adherence properties of this species will provide greater insights into the diseases it causes.
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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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Nait Chabane Y, Marti S, Rihouey C, Alexandre S, Hardouin J, Lesouhaitier O, Vila J, Kaplan JB, Jouenne T, Dé E. Characterisation of pellicles formed by Acinetobacter baumannii at the air-liquid interface. PLoS One 2014; 9:e111660. [PMID: 25360550 PMCID: PMC4216135 DOI: 10.1371/journal.pone.0111660] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 09/25/2014] [Indexed: 11/18/2022] Open
Abstract
The clinical importance of Acinetobacter baumannii is partly due to its natural ability to survive in the hospital environment. This persistence may be explained by its capacity to form biofilms and, interestingly, A. baumannii can form pellicles at the air-liquid interface more readily than other less pathogenic Acinetobacter species. Pellicles from twenty-six strains were morphologically classified into three groups: I) egg-shaped (27%); II) ball-shaped (50%); and III) irregular pellicles (23%). One strain representative of each group was further analysed by Brewster’s Angle Microscopy to follow pellicle development, demonstrating that their formation did not require anchoring to a solid surface. Total carbohydrate analysis of the matrix showed three main components: Glucose, GlcNAc and Kdo. Dispersin B, an enzyme that hydrolyzes poly-N-acetylglucosamine (PNAG) polysaccharide, inhibited A. baumannii pellicle formation, suggesting that this exopolysaccharide contributes to pellicle formation. Also associated with the pellicle matrix were three subunits of pili assembled by chaperon-usher systems: the major CsuA/B, A1S_1510 (presented 45% of identity with the main pilin F17-A from enterotoxigenic Escherichia coli pili) and A1S_2091. The presence of both PNAG polysaccharide and pili systems in matrix of pellicles might contribute to the virulence of this emerging pathogen.
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Affiliation(s)
- Yassine Nait Chabane
- Unité Mixte de Recherche 6270 CNRS - Laboratory “Polymères, Biopolymères, Surfaces”, University of Rouen, Mont-Saint-Aignan, France
| | - Sara Marti
- Unité Mixte de Recherche 6270 CNRS - Laboratory “Polymères, Biopolymères, Surfaces”, University of Rouen, Mont-Saint-Aignan, France
- * E-mail: (SM); (ED)
| | - Christophe Rihouey
- Unité Mixte de Recherche 6270 CNRS - Laboratory “Polymères, Biopolymères, Surfaces”, University of Rouen, Mont-Saint-Aignan, France
| | - Stéphane Alexandre
- Unité Mixte de Recherche 6270 CNRS - Laboratory “Polymères, Biopolymères, Surfaces”, University of Rouen, Mont-Saint-Aignan, France
| | - Julie Hardouin
- Unité Mixte de Recherche 6270 CNRS - Laboratory “Polymères, Biopolymères, Surfaces”, University of Rouen, Mont-Saint-Aignan, France
| | - Olivier Lesouhaitier
- Laboratory of “Microbiologie Signaux et Micro-Environnement” - Equipe d’Accueil 4312, University of Rouen, Evreux, France
| | - Jordi Vila
- Department of Microbiology, Hospital Clinic, Barcelona, Spain
| | - Jeffrey B. Kaplan
- Department of Biology, American University, Washington, District of Columbia, United States of America
| | - Thierry Jouenne
- Unité Mixte de Recherche 6270 CNRS - Laboratory “Polymères, Biopolymères, Surfaces”, University of Rouen, Mont-Saint-Aignan, France
| | - Emmanuelle Dé
- Unité Mixte de Recherche 6270 CNRS - Laboratory “Polymères, Biopolymères, Surfaces”, University of Rouen, Mont-Saint-Aignan, France
- * E-mail: (SM); (ED)
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Zhang HZ, Zhang JS, Qiao L. The Acinetobacter baumannii group: a systemic review. World J Emerg Med 2014; 4:169-74. [PMID: 25215113 PMCID: PMC4129852 DOI: 10.5847/wjem.j.issn.1920-8642.2013.03.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 06/21/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The Acinetobacter baumannii group, including Acinetobacter baumannii, Acinetobacter genomospecies 3 and 13TU, is phenotypically indistinguishable and uniformly identified as Acinetobacter baumannii by laboratories of clinical microbiology. This review aimed to demonstrate the differences among them. METHODS Literatures associated with the Acinetobacter baumannii group were identified and selected from PubMed databases and relevant journals. RESULTS Acinetobacter genospecies 3 and 13TU possess a certain proportion in clinical isolates. There were considerable differences in epidemiologic features, clinical manifestations, antimicrobial resistances and therapeutic options among the Acinetobacter baumannii group. Compared with Acinetobacter genomospecies 3 and 13TU, Acinetobacter baumannii with a higher resistance to antimicrobial agents are easier to be treated inappropriately, and present a worse outcome in patients. CONCLUSION The Acinetobacter baumannii group comprises three distinct clinical entities, and their clinical value are not equal.
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Affiliation(s)
- Hua-Zhong Zhang
- Department of Emergency Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
| | - Jin-Song Zhang
- Department of Emergency Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
| | - Li Qiao
- Department of Emergency Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
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