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Ranjan M, Girija ASS, Priyadharsini VJ. Predictions of Immunodominant Epitope Peptides From the AsaA Type VI Secretion System in Acinetobacter baumannii: A Computational Approach. Cureus 2024; 16:e59618. [PMID: 38832200 PMCID: PMC11146464 DOI: 10.7759/cureus.59618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 05/03/2024] [Indexed: 06/05/2024] Open
Abstract
Introduction Acinetobacter baumannii, designated as a priority pathogen by the World Health Organization (WHO), is responsible for recalcitrant infections in immunocompromised patients. The type VI secretion system (T6SS) is a class of macromolecular secretion machines, contributing to its virulence. The aim of this study is thus to predict the immune-dominant epitope peptides from the Acinetobacter T6SS-associated protein of A. baumannii (AsaA). Methods AsaA protein retrieval from the bacteria was carried out using computational platforms and the evaluation of antigenicity and allergenicity was performed. The T-cell epitopes of major histocompatibility complex class II binders were identified followed by molecular docking of the immune-dominant epitopes with human leukocyte antigen alleles using the ClusterPro server (https://cluspro.org/help.php). Additionally, the B-cell epitopes were predicted. Results Immune-informatic analysis showed immune-dominant peptides in the most favored regions with promising interactions with HLA alleles DP, DQ, DR, and toll-like receptor showing high binding capacity. Conclusion In the present investigation, epitope 1 (LILFLIGNY) was found to be a promising candidate for the synthesis of vaccines. However, it requires further experimentation for its immunological memory and response.
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Affiliation(s)
- Medha Ranjan
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - A S Smiline Girija
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
| | - Vijayashree J Priyadharsini
- Department of Microbiology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, IND
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Martínez-Trejo A, Ruiz-Ruiz JM, Gonzalez-Avila LU, Saldaña-Padilla A, Hernández-Cortez C, de Jesús Colmenero-Solís R, Bello-López JM, Castro-Escarpulli G. The CRISPR-Cas system in clinical strains of Acinetobacter baumannii: an in-silico analysis. Lett Appl Microbiol 2024; 77:ovae003. [PMID: 38211976 DOI: 10.1093/lambio/ovae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/29/2023] [Accepted: 01/10/2024] [Indexed: 01/13/2024]
Abstract
Acinetobacter baumannii is a relevant bacterium due to its high-resistance profile. It is well known that antimicrobial resistance is primarily linked to mutations and the acquisition of external genomic material, such as plasmids or phages, to which the Clustered Regularly Interspaced Short Palindromic Repeats associated with Cas proteins, or CRISPR-Cas, system is related. It is known that the system can influence the acquisition of foreign genetic material and play a role in various physiological pathways. In this study, we conducted an in-silico analysis using 91 fully assembled genomes of clinical strains obtained from the NCBI database. Among the analyzed genomes, the I-F1 subtype of the CRISPR-Cas system was detected showcasing variations in architecture and phylogeny. Using bioinformatic tools, we determined the presence, distribution, and specific characteristics of the CRISPR-Cas system. We found a possible association of the system with resistance genes but not with virulence determinants. Analysis of the system's components, including spacer sequences, suggests its potential role in protecting against phage infections, highlighting its protective function.
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Affiliation(s)
- Arturo Martínez-Trejo
- Laboratorio de Investigación Clínica y Ambiental, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | - Juan Manuel Ruiz-Ruiz
- Laboratorio Clínico, Unidad Médica de Alta Especialidad, Hospital de Pediatría Dr. Silvestre Frenk Freud, Instituto Mexicano del Seguro Social, Mexico City 06720, Mexico
| | - Luis Uriel Gonzalez-Avila
- Laboratorio de Investigación Clínica y Ambiental, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | - Andres Saldaña-Padilla
- Laboratorio de Investigación Clínica y Ambiental, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 11340, Mexico
- Laboratorio de Bioquímica Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | - Cecilia Hernández-Cortez
- Laboratorio de Bioquímica Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | - Raúl de Jesús Colmenero-Solís
- Laboratorio de Investigación Clínica y Ambiental, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| | | | - Graciela Castro-Escarpulli
- Laboratorio de Investigación Clínica y Ambiental, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City 11340, Mexico
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Kandolo O, Cherrak Y, Filella-Merce I, Le Guenno H, Kosta A, Espinosa L, Santucci P, Verthuy C, Lebrun R, Nilges M, Pellarin R, Durand E. Acinetobacter type VI secretion system comprises a non-canonical membrane complex. PLoS Pathog 2023; 19:e1011687. [PMID: 37769028 PMCID: PMC10564176 DOI: 10.1371/journal.ppat.1011687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 10/10/2023] [Accepted: 09/14/2023] [Indexed: 09/30/2023] Open
Abstract
A. baumannii can rapidly acquire new resistance mechanisms and persist on abiotic surface, enabling the colonization of asymptomatic human host. In Acinetobacter the type VI secretion system (T6SS) is involved in twitching, surface motility and is used for interbacterial competition allowing the bacteria to uptake DNA. A. baumannii possesses a T6SS that has been well studied for its regulation and specific activity, but little is known concerning its assembly and architecture. The T6SS nanomachine is built from three architectural sub-complexes. Unlike the baseplate (BP) and the tail-tube complex (TTC), which are inherited from bacteriophages, the membrane complex (MC) originates from bacteria. The MC is the most external part of the T6SS and, as such, is subjected to evolution and adaptation. One unanswered question on the MC is how such a gigantesque molecular edifice is inserted and crosses the bacterial cell envelope. The A. baumannii MC lacks an essential component, the TssJ lipoprotein, which anchors the MC to the outer membrane. In this work, we studied how A. baumannii compensates the absence of a TssJ. We have characterized for the first time the A. baumannii's specific T6SS MC, its unique characteristic, its membrane localization, and assembly dynamics. We also defined its composition, demonstrating that its biogenesis employs three Acinetobacter-specific envelope-associated proteins that define an intricate network leading to the assembly of a five-proteins membrane super-complex. Our data suggest that A. baumannii has divided the function of TssJ by (1) co-opting a new protein TsmK that stabilizes the MC and by (2) evolving a new domain in TssM for homo-oligomerization, a prerequisite to build the T6SS channel. We believe that the atypical species-specific features we report in this study will have profound implication in our understanding of the assembly and evolutionary diversity of different T6SSs, that warrants future investigation.
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Affiliation(s)
- Ona Kandolo
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS)-UMR 7255, Marseille, France
| | - Yassine Cherrak
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS)-UMR 7255, Marseille, France
| | - Isaac Filella-Merce
- Institut Pasteur, Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Paris, France
- Sorbonne Université, Collège doctoral, Paris, France
| | - Hugo Le Guenno
- Microscopy Core Facility, Aix Marseille Univ, CNRS, Institut de Microbiologie de la Méditerranée, Marseille Cedex 20, France
| | - Artemis Kosta
- Microscopy Core Facility, Aix Marseille Univ, CNRS, Institut de Microbiologie de la Méditerranée, Marseille Cedex 20, France
| | - Leon Espinosa
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Pierre Santucci
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS)-UMR 7255, Marseille, France
| | - Christophe Verthuy
- Proteomic Core Facility IMM, Marseille Protéomique (MaP), Aix Marseille Univ, Marseille Cedex 20, France
| | - Régine Lebrun
- Proteomic Core Facility IMM, Marseille Protéomique (MaP), Aix Marseille Univ, Marseille Cedex 20, France
| | - Michael Nilges
- Institut Pasteur, Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Paris, France
| | - Riccardo Pellarin
- Institut Pasteur, Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, Paris, France
| | - Eric Durand
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS)-UMR 7255, Marseille, France
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Institut National de la Santé et de la Recherche Médicale (INSERM), Marseille, France
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Abstract
Many Gram-negative bacteria deploy a type VI secretion system (T6SS) to inject toxins into target cells to promote their survival and replication in complex environments. Here, we report that Acinetobacter baumannii uses its T6SS to kill fungi and that the effector TafE (ACX60_15365) is responsible for such killing. Although ectopically expressed TafE is toxic to both Escherichia coli and Saccharomyces cerevisiae, deletion of tafE only affects the antifungal activity of A. baumannii. We demonstrate that TafE is a DNase capable of targeting the nuclei of yeast cells and that an Ntox15 domain is essential for its ability to degrade DNA. Furthermore, our findings show that A. baumannii is protected from the toxicity of TafE by elaborating the immunity protein TaeI (ACX60_15360), which antagonizes the activity of the effector by direct binding. The discovery of A. baumannii T6SS effectors capable of killing multiple taxonomically distinct microbes has shed light on a mechanism of the high-level fitness of this pathogen in environments characterized by scarce nutrients and the potential presence of diverse microorganisms. IMPORTANCE Acinetobacter baumannii is an increasing important nosocomial pathogen that is difficult to combat due to its ability to survive in harsh environments and the emergence of isolates that are resistant to multiple antibiotics. A better understanding of the mechanism underlying the toughness of A. baumannii may identify its Achilles' heel, which will facilitate the development of novel preventive and treatment measures. In this study, our findings show that A. baumannii kills fungi with the DNase effector TafE injected into competitor cells by its type VI secretion system. A. baumannii is protected from the activity of TafE by the immunity protein TaeI, which inactivates the effector by direct binding. Our results suggest that inactivation of its T6SS or effectors may reduce the fitness of A. baumannii and increase the effectiveness of treatment by means such as antibiotics. Furthermore, our finding suggests that targeted degradation of TaeI may be an effective strategy to kill A. baumannii.
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Li P, Zhang S, Wang J, Al-Shamiri MM, Han B, Chen Y, Han S, Han L. Uncovering the Secretion Systems of Acinetobacter baumannii: Structures and Functions in Pathogenicity and Antibiotic Resistance. Antibiotics (Basel) 2023; 12:antibiotics12020195. [PMID: 36830106 PMCID: PMC9952577 DOI: 10.3390/antibiotics12020195] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/06/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023] Open
Abstract
Infections led by Acinetobacter baumannii strains are of great concern in healthcare environments due to the strong ability of the bacteria to spread through different apparatuses and develop drug resistance. Severe diseases can be caused by A. baumannii in critically ill patients, but its biological process and mechanism are not well understood. Secretion systems have recently been demonstrated to be involved in the pathogenic process, and five types of secretion systems out of the currently known six from Gram-negative bacteria have been found in A. baumannii. They can promote the fitness and pathogenesis of the bacteria by releasing a variety of effectors. Additionally, antibiotic resistance is found to be related to some types of secretion systems. In this review, we describe the genetic and structural compositions of the five secretion systems that exist in Acinetobacter. In addition, the function and molecular mechanism of each secretion system are summarized to explain how they enable these critical pathogens to overcome eukaryotic hosts and prokaryotic competitors to cause diseases.
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Affiliation(s)
- Pu Li
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China
| | - Sirui Zhang
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China
| | - Jingdan Wang
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China
| | - Mona Mohamed Al-Shamiri
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China
| | - Bei Han
- School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China
| | - Yanjiong Chen
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China
| | - Shaoshan Han
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061, China
| | - Lei Han
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China
- Correspondence:
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6
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Dong JF, Liu CW, Wang P, Li L, Zou QH. The type VI secretion system in Acinetobacter baumannii clinical isolates and its roles in antimicrobial resistance acquisition. Microb Pathog 2022; 169:105668. [PMID: 35811021 DOI: 10.1016/j.micpath.2022.105668] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/29/2022] [Accepted: 07/03/2022] [Indexed: 10/17/2022]
Abstract
Acinetobacter baumannii is a successful pathogen that can acquire various antibiotic resistance in a short time. However, little is known about how it can evolve from an antibiotic sensitive to a resistant phenotype. In this study, we investigated the roles of the type VI secretion system (T6SS) in the acquisition of antibiotic resistance of A. baumannii. T6SS gene cluster was found to be present in 51 of 77 A. baumannii clinical isolates, of which, it was found in 62% (8/13) of the multiple drug resistant (MDR) isolates, 90% (36/40) of the extensively drug-resistant (XDR) isolates and 26% (6/23) of the antibiotic sensitive isolates. There is a close relationship between the antimicrobial resistance and the presence of T6SS. Besides, T6SS + isolates showed lower biofilm formation activity and higher survival ability in the presence of normal human serum than T6SS- isolates. A. baumannii A152 with complete T6SS can outcompete E.coli effectively and can acquire the antibiotic resistance plasmids released by E.coli. In contrast, the T6SS core gene mutant A152Δhcp showed significantly decreased ability to acquire antimicrobial resistance plasmids from the prey bacteria. These results suggest that T6SS mediated bacterial competition plays important roles in the antimicrobial resistance of A. baumannii, which points out a new direction for us to study the antimicrobial resistance of A. baumannii.
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Affiliation(s)
- Jun-Fang Dong
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Cun-Wei Liu
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Ping Wang
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Lei Li
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing, 100730, China
| | - Qing-Hua Zou
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
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7
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Lin L, Capozzoli R, Ferrand A, Plum M, Vettiger A, Basler M. Subcellular localization of Type VI secretion system assembly in response to cell–cell contact. EMBO J 2022; 41:e108595. [PMID: 35634969 PMCID: PMC9251886 DOI: 10.15252/embj.2021108595] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 04/18/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
Bacteria require a number of systems, including the type VI secretion system (T6SS), for interbacterial competition and pathogenesis. The T6SS is a large nanomachine that can deliver toxins directly across membranes of proximal target cells. Since major reassembly of T6SS is necessary after each secretion event, accurate timing and localization of T6SS assembly can lower the cost of protein translocation. Although critically important, mechanisms underlying spatiotemporal regulation of T6SS assembly remain poorly understood. Here, we used super‐resolution live‐cell imaging to show that while Acinetobacter and Burkholderia thailandensis can assemble T6SS at any site, a significant subset of T6SS assemblies localizes precisely to the site of contact between neighboring bacteria. We identified a class of diverse, previously uncharacterized, periplasmic proteins required for this dynamic localization of T6SS to cell–cell contact (TslA). This precise localization is also dependent on the outer membrane porin OmpA. Our analysis links transmembrane communication to accurate timing and localization of T6SS assembly as well as uncovers a pathway allowing bacterial cells to respond to cell–cell contact during interbacterial competition.
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Affiliation(s)
- Lin Lin
- Biozentrum University of Basel Basel Switzerland
| | | | - Alexia Ferrand
- Biozentrum Imaging Core Facility University of Basel Basel Switzerland
| | - Miro Plum
- Biozentrum University of Basel Basel Switzerland
| | | | - Marek Basler
- Biozentrum University of Basel Basel Switzerland
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Roy R, You RI, Chang CH, Yang CY, Lin NT. Carboxy-Terminal Processing Protease Controls Production of Outer Membrane Vesicles and Biofilm in Acinetobacter baumannii. Microorganisms 2021; 9:microorganisms9061336. [PMID: 34203028 PMCID: PMC8234194 DOI: 10.3390/microorganisms9061336] [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: 04/30/2021] [Revised: 06/14/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022] Open
Abstract
Carboxy-terminal processing protease (Ctp) is a serine protease that controls multiple cellular processes through posttranslational modification of proteins. Acinetobacter baumannii ATCC 17978 ctp mutant, namely MR14, is known to cause cell wall defects and autolysis. The objective of this study was to investigate the role of ctp mutation-driven autolysis in regulating biofilms in A. baumannii and to evaluate the vesiculation caused by cell wall defects. We found that in A. baumannii, Ctp is localized in the cytoplasmic membrane, and loss of Ctp function enhances the biofilm-forming ability of A. baumannii. Quantification of the matrix components revealed that extracellular DNA (eDNA) and proteins were the chief constituents of MR14 biofilm, and the transmission electron microscopy further indicated the presence of numerous dead cells compared with ATCC 17978. The large number of MR14 dead cells is potentially the result of compromised outer membrane integrity, as demonstrated by its high sensitivity to sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA). MR14 also exhibited the hypervesiculation phenotype, producing outer-membrane vesicles (OMVs) of large mean size. The MR14 OMVs were more cytotoxic toward A549 cells than ATCC 17978 OMVs. Our overall results indicate that A. baumanniictp negatively controls pathogenic traits through autolysis and OMV biogenesis.
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Affiliation(s)
- Rakesh Roy
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Ren-In You
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Chan-Hua Chang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
| | - Chiou-Ying Yang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
| | - Nien-Tsung Lin
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
- Department of Microbiology, School of Medicine, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
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Cameranesi MM, Paganini J, Limansky AS, Moran-Barrio J, Salcedo SP, Viale AM, Repizo GD. Acquisition of plasmids conferring carbapenem and aminoglycoside resistance and loss of surface-exposed macromolecule structures as strategies for the adaptation of Acinetobacter baumannii CC104 O/CC15 P strains to the clinical setting. Microb Genom 2020; 6. [PMID: 32213259 PMCID: PMC7643966 DOI: 10.1099/mgen.0.000360] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Acinetobacter baumannii (Aba) is an emerging opportunistic pathogen associated to nosocomial infections. The rapid increase in multidrug resistance (MDR) among Aba strains underscores the urgency of understanding how this pathogen evolves in the clinical environment. We conducted here a whole-genome sequence comparative analysis of three phylogenetically and epidemiologically related MDR Aba strains from Argentinean hospitals, assigned to the CC104O/CC15P clonal complex. While the Ab244 strain was carbapenem-susceptible, Ab242 and Ab825, isolated after the introduction of carbapenem therapy, displayed resistance to these last resource β-lactams. We found a high chromosomal synteny among the three strains, but significant differences at their accessory genomes. Most importantly, carbapenem resistance in Ab242 and Ab825 was attributed to the acquisition of a Rep_3 family plasmid carrying a blaOXA-58 gene. Other differences involved a genomic island carrying resistance to toxic compounds and a Tn10 element exclusive to Ab244 and Ab825, respectively. Also remarkably, 44 insertion sequences (ISs) were uncovered in Ab825, in contrast with the 14 and 11 detected in Ab242 and Ab244, respectively. Moreover, Ab825 showed a higher killing capacity as compared to the other two strains in the Galleria mellonella infection model. A search for virulence and persistence determinants indicated the loss or IS-mediated interruption of genes encoding many surface-exposed macromolecules in Ab825, suggesting that these events are responsible for its higher relative virulence. The comparative genomic analyses of the CC104O/CC15P strains conducted here revealed the contribution of acquired mobile genetic elements such as ISs and plasmids to the adaptation of A. baumannii to the clinical setting.
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Affiliation(s)
- María M Cameranesi
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Julian Paganini
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Adriana S Limansky
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Jorgelina Moran-Barrio
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Suzana P Salcedo
- Laboratory of Molecular Microbiology and Structural Biochemistry, CNRS UMR5086, University of Lyon, LyonF-69367, France
| | - Alejandro M Viale
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Guillermo D Repizo
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.,Laboratory of Molecular Microbiology and Structural Biochemistry, CNRS UMR5086, University of Lyon, LyonF-69367, France
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