51
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Sumyk M, Himpich S, Foong WE, Herrmann A, Pos KM, Tam HK. Binding of Tetracyclines to Acinetobacter baumannii TetR Involves Two Arginines as Specificity Determinants. Front Microbiol 2021; 12:711158. [PMID: 34349752 PMCID: PMC8326586 DOI: 10.3389/fmicb.2021.711158] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/23/2021] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii is an important nosocomial pathogen that requires thoughtful consideration in the antibiotic prescription strategy due to its multidrug resistant phenotype. Tetracycline antibiotics have recently been re-administered as part of the combination antimicrobial regimens to treat infections caused by A. baumannii. We show that the TetA(G) efflux pump of A. baumannii AYE confers resistance to a variety of tetracyclines including the clinically important antibiotics doxycycline and minocycline, but not to tigecycline. Expression of tetA(G) gene is regulated by the TetR repressor of A. baumannii AYE (AbTetR). Thermal shift binding experiments revealed that AbTetR preferentially binds tetracyclines which carry a O-5H moiety in ring B, whereas tetracyclines with a 7-dimethylamino moiety in ring D are less well-recognized by AbTetR. Confoundingly, tigecycline binds to AbTetR even though it is not transported by TetA(G) efflux pump. Structural analysis of the minocycline-bound AbTetR-Gln116Ala variant suggested that the non-conserved Arg135 interacts with the ring D of minocycline by cation-π interaction, while the invariant Arg104 engages in H-bonding with the O-11H of minocycline. Interestingly, the Arg135Ala variant exhibited a binding preference for tetracyclines with an unmodified ring D. In contrast, the Arg104Ala variant preferred to bind tetracyclines which carry a O-6H moiety in ring C except for tigecycline. We propose that Arg104 and Arg135, which are embedded at the entrance of the AbTetR binding pocket, play important roles in the recognition of tetracyclines, and act as a barrier to prevent the release of tetracycline from its binding pocket upon AbTetR activation. The binding data and crystal structures obtained in this study might provide further insight for the development of new tetracycline antibiotics to evade the specific efflux resistance mechanism deployed by A. baumannii.
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Affiliation(s)
- Manuela Sumyk
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt, Germany
| | - Stephanie Himpich
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt, Germany
| | - Wuen Ee Foong
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt, Germany
| | - Andrea Herrmann
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt, Germany
| | - Klaas M Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt, Germany
| | - Heng-Keat Tam
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt, Germany
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52
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Comparison of the Acinetobacter baumannii Reference Strains ATCC 17978 and ATCC 19606 in Antimicrobial Resistance Mediated by the AdeABC Efflux Pump. Antimicrob Agents Chemother 2021; 65:e0057021. [PMID: 34097477 DOI: 10.1128/aac.00570-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Acinetobacter baumannii RND efflux pump AdeABC is regulated by the 2-component regulator AdeRS. In this study, we compared the regulation and expression of AdeABC of the reference strains ATCC 17978 and ATCC 19606. A clearly stronger efflux activity was demonstrated for ATCC 19606. An amino acid substitution at residue 172 of adeS was identified as a potential cause for differential expression of the pump. Therefore, we recommend caution with exclusively using single reference strains for research.
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53
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Tetard A, Foley S, Mislin GLA, Brunel JM, Oliva E, Torrealba Anzola F, Zedet A, Cardey B, Pellequer Y, Ramseyer C, Plésiat P, Llanes C. Negative Impact of Citral on Susceptibility of Pseudomonas aeruginosa to Antibiotics. Front Microbiol 2021; 12:709838. [PMID: 34290691 PMCID: PMC8287888 DOI: 10.3389/fmicb.2021.709838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
Essential oils (EOs) or their components are widely used by inhalation or nebulization to fight mild respiratory bacterial infections. However, their interaction with antibiotics is poorly known. In this study we evaluated the effects of citral, the main component of lemongrass oil, on in vitro susceptibility of Pseudomonas aeruginosa to antibiotics. Exposure of strain PA14 to subinhibitory concentrations of citral increased expression of operons encoding the multidrug efflux systems MexEF-OprN and MexXY/OprM, and bacterial resistance to anti-pseudomonal antibiotics including imipenem (twofold), gentamicin (eightfold), tobramycin (eightfold), ciprofloxacin (twofold), and colistin (≥128-fold). Use of pump deletion mutants showed that in addition to efflux other mechanisms were involved in this citral-induced phenotype. Determination of Zeta potential suggested that citral impairs the cell surface binding of aminoglycosides and colistin used at low concentrations (≤10 μg/mL). Moreover, experiments based on Raman spectroscopy and high-resolution mass spectrometry demonstrated formation of a Schiff base between the aldehyde group of citral and amino-groups of tobramycin and colistin. Chemical synthesis of tobracitryl, the imine compound resulting from condensation of citral and tobramycin, confirmed the loss of antibiotic activity due to adduct formation. Altogether these data point to the potential risk concern of self-medication with EOs containing citral in patients suffering from P. aeruginosa chronic lung infections and being treated with aerosols of aminoglycoside or colistin.
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Affiliation(s)
- Alexandre Tetard
- UMR CNRS 6249 Chrono-Environnement, Université Bourgogne Franche-Comté, Besançon, France
| | - Sarah Foley
- UMR CNRS 6249 Chrono-Environnement, Université Bourgogne Franche-Comté, Besançon, France
| | - Gaëtan L A Mislin
- CNRS/Université de Strasbourg UMR 7242 Biotechnologie et Signalisation Cellulaire, Illkirch, France
| | - Jean-Michel Brunel
- UMR_MD1, U-1261, Aix Marseille Université, INSERM, SSA, MCT, Marseille, France
| | - Estefania Oliva
- Plateforme d'Analyse Chimique de Strasbourg-Illkirch (PACSI), Faculté de Pharmacie de Strasbourg, Illkirch, France
| | | | - Andy Zedet
- PEPITE EA4267, Université de Bourgogne Franche-Comté, Besançon, France
| | - Bruno Cardey
- UMR CNRS 6249 Chrono-Environnement, Université Bourgogne Franche-Comté, Besançon, France
| | - Yann Pellequer
- PEPITE EA4267, Université de Bourgogne Franche-Comté, Besançon, France
| | - Christophe Ramseyer
- UMR CNRS 6249 Chrono-Environnement, Université Bourgogne Franche-Comté, Besançon, France
| | - Patrick Plésiat
- UMR CNRS 6249 Chrono-Environnement, Université Bourgogne Franche-Comté, Besançon, France.,Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon, Besançon, France
| | - Catherine Llanes
- UMR CNRS 6249 Chrono-Environnement, Université Bourgogne Franche-Comté, Besançon, France
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54
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Takebayashi Y, Findlay J, Heesom KJ, Warburton PJ, Avison MB, Evans BA. Variability in carbapenemase activity of intrinsic OxaAb (OXA-51-like) β-lactamase enzymes in Acinetobacter baumannii. J Antimicrob Chemother 2021; 76:587-595. [PMID: 33338207 DOI: 10.1093/jac/dkaa502] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/03/2020] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To measure the variability in carbapenem susceptibility conferred by different OxaAb variants, characterize the molecular evolution of oxaAb and elucidate the contribution of OxaAb and other possible carbapenem resistance factors in the clinical isolates using WGS and LC-MS/MS. METHODS Antimicrobial susceptibility tests were performed on 10 clinical Acinetobacter baumannii isolates. Carbapenem MICs were evaluated for all oxaAb variants cloned into A. baumannii CIP70.10 and BM4547, with and without their natural promoters. Molecular evolution analysis of the oxaAb variants was performed using FastTree and SplitsTree4. Resistance determinants were studied in the clinical isolates using WGS and LC-MS/MS. RESULTS Only the OxaAb variants with I129L and L167V substitutions, OxaAb(82), OxaAb(83), OxaAb(107) and OxaAb(110) increased carbapenem MICs when expressed in susceptible A. baumannii backgrounds without an upstream IS element. Carbapenem resistance was conferred with the addition of their natural upstream ISAba1 promoter. LC-MS/MS analysis on the original clinical isolates confirmed overexpression of the four I129L and L167V variants. No other differences in expression levels of proteins commonly associated with carbapenem resistance were detected. CONCLUSIONS Elevated carbapenem MICs were observed by expression of OxaAb variants carrying clinically prevalent substitutions I129L and L167V. To drive carbapenem resistance, these variants required overexpression by their upstream ISAba1 promoter. This study clearly demonstrates that a combination of IS-driven overexpression of oxaAb and the presence of particular amino acid substitutions in the active site to improve carbapenem capture is key in conferring carbapenem resistance in A. baumannii and other mechanisms are not required.
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Affiliation(s)
- Yuiko Takebayashi
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Jacqueline Findlay
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK.,Division of Infection & Immunity, Faculty of Medical Sciences, University College London, UK
| | - Kate J Heesom
- Bristol Proteomics Facility, University of Bristol, Bristol, UK
| | - Philip J Warburton
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,School of Biomedical Sciences, Faculty of Health, University of Plymouth, Plymouth, UK
| | - Matthew B Avison
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Benjamin A Evans
- Department of Biomedical and Forensic Science, Anglia Ruskin University, Cambridge, UK.,Norwich Medical School, University of East Anglia, UK
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55
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Shared and Unique Evolutionary Trajectories to Ciprofloxacin Resistance in Gram-Negative Bacterial Pathogens. mBio 2021; 12:e0098721. [PMID: 34154405 PMCID: PMC8262867 DOI: 10.1128/mbio.00987-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Resistance to the broad-spectrum antibiotic ciprofloxacin is detected at high rates for a wide range of bacterial pathogens. To investigate the dynamics of ciprofloxacin resistance development, we applied a comparative resistomics workflow for three clinically relevant species of Gram-negative bacteria: Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. We combined experimental evolution in a morbidostat with deep sequencing of evolving bacterial populations in time series to reveal both shared and unique aspects of evolutionary trajectories. Representative clone characterization by sequencing and MIC measurements enabled direct assessment of the impact of mutations on the extent of acquired drug resistance. In all three species, we observed a two-stage evolution: (i) early ciprofloxacin resistance reaching 4- to 16-fold the MIC for the wild type, commonly as a result of single mutations in DNA gyrase target genes (gyrA or gyrB), and (ii) additional genetic alterations affecting the transcriptional control of the drug efflux machinery or secondary target genes (DNA topoisomerase parC or parE).
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56
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Abstract
Acinetobacter spp. have become of increased clinical importance as studies have shown the antimicrobial resistant potential of these species. Efflux pumps can lead to reduced susceptibility to a variety of antibiotics and are present in large number across Acinetobacter spp. There are six families of efflux pumps that have been shown to be of clinical relevance: the major facilitator superfamily (MFS), small multidrug resistance (SMR) family, ATP-binding cassette (ABC) family, multidrug and toxic compound extrusion (MATE) family, proteobacterial antimicrobial compound efflux (PACE) family, and the resistance-nodulation-division (RND) family. Much work has been done for understanding and characterizing the roles these efflux pumps play in relation to antimicrobial resistance and the physiology of these bacteria. RND efflux pumps, with their expansive substrate profiles, are a major component of Acinetobacter spp. antimicrobial resistance. New discoveries over the last decade have shed light on the complex regulation of these efflux pumps, leading to greater understanding and the potential of slowing the reduced susceptibility seen in these bacterial species.
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57
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Kim HR, Shin DS, Jang HI, Eom YB. Anti-biofilm and anti-virulence effects of zerumbone against Acinetobacter baumannii. MICROBIOLOGY-SGM 2021; 166:717-726. [PMID: 32463353 DOI: 10.1099/mic.0.000930] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Acinetobacter baumannii is a multidrug-resistant opportunistic pathogen that affects patients with a compromised immune system and is becoming increasingly important as a hospital-derived infection. This pathogen is difficult to treat owing to its intrinsic multidrug resistance and ability to form antimicrobial-tolerant biofilms. In the present study, we aimed to assess the potential use of zerumbone as a novel anti-biofilm and/or anti-virulence agent against A. baumannii. The results showed that zerumbone at sub-inhibitory doses decreased biofilm formation and disrupted established A. baumannii biofilms. The zerumbone-induced decrease in biofilm formation was dose-dependent based on the results of microtitre plate biofilm assays and confocal laser scanning microscopy. In addition, our data validated the anti-virulence efficacy of zerumbone, wherein it significantly interfered with the motility of A. baumannii. To support these phenotypic results, transcriptional analysis revealed that zerumbone downregulated the expression of biofilm- and virulence-associated genes (adeA, adeB, adeC and bap) in A. baumannii. Overall, our findings suggested that zerumbone might be a promising bioactive agent for the treatment of biofilm- and virulence-related infections caused by multidrug-resistant A. baumannii.
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Affiliation(s)
- Hye-Rim Kim
- Department of Medical Sciences, College of Medical Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Da-Seul Shin
- Department of Medical Sciences, College of Medical Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Hye-In Jang
- Department of Medical Sciences, College of Medical Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Yong-Bin Eom
- Department of Medical Sciences, College of Medical Sciences, Soonchunhyang University, Asan 31538, Republic of Korea.,Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
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58
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Lima PG, Oliveira JTA, Amaral JL, Freitas CDT, Souza PFN. Synthetic antimicrobial peptides: Characteristics, design, and potential as alternative molecules to overcome microbial resistance. Life Sci 2021; 278:119647. [PMID: 34043990 DOI: 10.1016/j.lfs.2021.119647] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/08/2021] [Accepted: 05/18/2021] [Indexed: 01/09/2023]
Abstract
Recently, the dramatic emergence of antimicrobial resistance has received attention from World Health Organization. Synthetic antimicrobial peptides (SAMPs) are considered new weapons to fight against infections caused by multi-drug resistant pathogens. Here, the authors provide an overview of the current research on SAMPs. The focus is SAMPs, how to design them, which features must be considered during design, and comparison with natural peptides. This review also includes a discussion about the natural AMPs, mechanisms of action and applications as new drugs or even as adjuvants molecules to enhance commercial drugs activity. The advances in chemical synthesis have reduced the cost to produce synthetic peptides open ways to achieve new antimicrobial agents. Therefore, synthetic peptides are new promising molecules to safeguard human and animal health.
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Affiliation(s)
- Patrícia G Lima
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP 60.440-554 Fortaleza, Ceará, Brazil
| | - Jose T A Oliveira
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP 60.440-554 Fortaleza, Ceará, Brazil
| | - Jackson L Amaral
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP 60.440-554 Fortaleza, Ceará, Brazil
| | - Cleverson D T Freitas
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP 60.440-554 Fortaleza, Ceará, Brazil
| | - Pedro F N Souza
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP 60.440-554 Fortaleza, Ceará, Brazil.
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59
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Gomez-Arrebola C, Solano C, Lasa I. Regulation of gene expression by non-phosphorylated response regulators. Int Microbiol 2021; 24:521-529. [PMID: 33987704 DOI: 10.1007/s10123-021-00180-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/21/2021] [Accepted: 04/26/2021] [Indexed: 12/26/2022]
Abstract
Two-component systems (TCSs) are a prominent sensory system in bacteria. A prototypical TCS comprises a membrane-bound sensor histidine kinase (HK) responsible for sensing the signal and a cytoplasmic response regulator (RR) that controls target gene expression. Signal binding activates a phosphotransfer cascade from the HK to the RR. As a result, the phosphorylated RR undergoes a conformational change that leads to activation of the response. Growing experimental evidence indicates that unphosphorylated RRs may also have regulatory functions, and thus, the classical view that the RR is only active when it is phosphorylated needs to be revisited. In this review, we highlight the most recent findings showing that RRs in the non-phosphorylated state control critical bacterial processes that range from secretion of factors to the host, antibiotic resistance, iron transport, stress response, and cell-wall metabolism to biofilm development.
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Affiliation(s)
- Carmen Gomez-Arrebola
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra (UPNA)-Complejo Hospitalario de Navarra (CHN), IdiSNA, Irunlarrea 3, 31008, Pamplona, Navarra, Spain
| | - Cristina Solano
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra (UPNA)-Complejo Hospitalario de Navarra (CHN), IdiSNA, Irunlarrea 3, 31008, Pamplona, Navarra, Spain
| | - Iñigo Lasa
- Laboratory of Microbial Pathogenesis, Navarrabiomed-Universidad Pública de Navarra (UPNA)-Complejo Hospitalario de Navarra (CHN), IdiSNA, Irunlarrea 3, 31008, Pamplona, Navarra, Spain.
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60
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Alav I, Kobylka J, Kuth MS, Pos KM, Picard M, Blair JMA, Bavro VN. Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria. Chem Rev 2021; 121:5479-5596. [PMID: 33909410 PMCID: PMC8277102 DOI: 10.1021/acs.chemrev.1c00055] [Citation(s) in RCA: 96] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Tripartite efflux pumps and the related type 1 secretion systems (T1SSs) in Gram-negative organisms are diverse in function, energization, and structural organization. They form continuous conduits spanning both the inner and the outer membrane and are composed of three principal components-the energized inner membrane transporters (belonging to ABC, RND, and MFS families), the outer membrane factor channel-like proteins, and linking the two, the periplasmic adaptor proteins (PAPs), also known as the membrane fusion proteins (MFPs). In this review we summarize the recent advances in understanding of structural biology, function, and regulation of these systems, highlighting the previously undescribed role of PAPs in providing a common architectural scaffold across diverse families of transporters. Despite being built from a limited number of basic structural domains, these complexes present a staggering variety of architectures. While key insights have been derived from the RND transporter systems, a closer inspection of the operation and structural organization of different tripartite systems reveals unexpected analogies between them, including those formed around MFS- and ATP-driven transporters, suggesting that they operate around basic common principles. Based on that we are proposing a new integrated model of PAP-mediated communication within the conformational cycling of tripartite systems, which could be expanded to other types of assemblies.
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Affiliation(s)
- Ilyas Alav
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Jessica Kobylka
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Miriam S. Kuth
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Klaas M. Pos
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Martin Picard
- Laboratoire
de Biologie Physico-Chimique des Protéines Membranaires, CNRS
UMR 7099, Université de Paris, 75005 Paris, France
- Fondation
Edmond de Rothschild pour le développement de la recherche
Scientifique, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Jessica M. A. Blair
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Vassiliy N. Bavro
- School
of Life Sciences, University of Essex, Colchester, CO4 3SQ United Kingdom
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61
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Vahhabi A, Hasani A, Rezaee MA, Baradaran B, Hasani A, Samadi Kafil H, Abbaszadeh F, Dehghani L. A plethora of carbapenem resistance in Acinetobacter baumannii: no end to a long insidious genetic journey. J Chemother 2021; 33:137-155. [PMID: 33243098 DOI: 10.1080/1120009x.2020.1847421] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/23/2020] [Accepted: 11/02/2020] [Indexed: 01/21/2023]
Abstract
Acinetobacter baumannii, notorious for causing nosocomial infections especially in patients admitted to intensive care unit (ICU) and burn units, is best at displaying resistance to all existing antibiotic classes. Consequences of high potential for antibiotic resistance has resulted in extensive drug or even pan drug resistant A. baumannii. Carbapenems, mainly imipenem and meropenem, the last resort for the treatment of A. baumannii infections have fallen short due to the emergence of carbapenem resistant A. baumannii (CRAB). Though enzymatic degradation by production of class D β-lactamases (Oxacillinases) and class B β-lactamases (Metallo β-lactamases) is the core mechanism of carbapenem resistance in A. baumannii; however over-expression of efflux pumps such as resistance-nodulation cell division (RND) family and variant form of porin proteins such as CarO have been implicated for CRAB inception. Transduction and outer membrane vesicles-mediated transfer play a role in carbapenemase determinants spread. Colistin, considered as the most promising antibacterial agent, nevertheless faces adverse effects flaws. Cefiderocol, eravacycline, new β-lactam antibiotics, non-β-lactam-β-lactamase inhibitors, polymyxin B-derived molecules and bacteriophages are some other new treatment options streamlined.
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Affiliation(s)
- Abolfazl Vahhabi
- Immunology Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Alka Hasani
- Immunology Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
- Clinical Research Development Unit, Sina Educational, Research and Treatment Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Mohammad Ahangarzadeh Rezaee
- Immunology Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Behzad Baradaran
- Immunology Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Akbar Hasani
- Department of Clinical Biochemistry and Laboratory Sciences, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I. R. Iran
| | - Hossein Samadi Kafil
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Faeze Abbaszadeh
- Department of Bacteriology and Virology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
| | - Leila Dehghani
- Clinical Research Development Unit, Sina Educational, Research and Treatment Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
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62
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De Silva PM, Patidar R, Graham CI, Brassinga AKC, Kumar A. A response regulator protein with antar domain, AvnR, in Acinetobacter baumannii ATCC 17978 impacts its virulence and amino acid metabolism. MICROBIOLOGY-SGM 2021; 166:554-566. [PMID: 32324528 DOI: 10.1099/mic.0.000913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Acinetobacter baumannii, a Gram-negative coccobacillus, is notorious for its involvement in opportunistic infections around the world. Its resistance to antibiotics makes treatment of infections challenging. In this study, we describe a novel response regulator protein, AvnR (A1S_2006) that regulates virulence-related traits in A. baumannii ATCC17978. Sequence analysis suggests that AvnR is a CheY-like response regulator and contains the RNA-binding ANTAR (AmiR and NasR transcription anti-termination regulators) domain. We show that AvnR plays a role in regulating biofilm formation (on glass and plastic surfaces), surface motility, adhesion to A549 cells as well as in nitrogen metabolism in A. baumannii. RNA-Seq analysis revealed that avnR deletion results in altered expression of more than 150 genes (116 upregulated and 42 downregulated). RNA-Seq data suggest that altered biofilm formation and surface motility observed in the avnR deletion mutant is likely mediated by previously unknown pathways. Of note, was the altered expression of genes predicted to be involved in amino acid transport and metabolism in avnR deletion mutant. Biolog phenotypic array showed that deletion of avnR hampered A. baumannii ATCC17978's ability to metabolize various nitrogen sources, particularly that of glutamic acid, serine, histidine, aspartic acid, isoleucine and arginine. Taken together our data show that AvnR, the first ANTAR protein described in A. baumannii, affects virulence phenotypes as well as its ability to metabolize nitrogen sources.
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Affiliation(s)
- P Malaka De Silva
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Rakesh Patidar
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
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63
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Proteolysis and multimerization regulate signaling along the two-component regulatory system AdeRS. iScience 2021; 24:102476. [PMID: 34113820 PMCID: PMC8169943 DOI: 10.1016/j.isci.2021.102476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/15/2021] [Accepted: 04/23/2021] [Indexed: 11/23/2022] Open
Abstract
Bacterial two-component regulatory systems are ubiquitous environment-sensing signal transducers involved in pathogenesis and antibiotic resistance. The Acinetobacter baumannii two-component regulatory system AdeRS is made up of a sensor histidine kinase AdeS and a cognate response regulator AdeR, which together reduce repression of the multidrug-resistant efflux pump AdeABC. Herein we demonstrate that an N-terminal intrinsically disordered tail in AdeR is important for the upregulation of adeABC expression, although it greatly increases the susceptibility of AdeR to proteasome-mediated degradation. We also show that AdeS assembles into a hexameric state that is necessary for its full histidine kinase activity, which appears to occur via cis autophosphorylation. Taken together, this study demonstrates new structural mechanisms through which two-component systems can transduce environmental signals to impact gene expression and enlightens new potential antimicrobial approach by targeting two-component regulatory systems. Crystal structure of AdeR dimer with traceable N-terminal intrinsically disordered region. N-terminal intrinsically disordered region AdeR is involved in proteasome proteolysis. Crystal structure of AdeS catalytic domain demonstrates cis autophosphorylation. AdeS can assemble into hexamer and is crucial for its full kinase activity.
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Haeili M, Abdollahi A, Ahmadi A, Khoshbayan A. Molecular Characterization of Tigecycline Non-Susceptibility among Extensively Drug-Resistant Acinetobacter baumannii Isolates of Clinical Origin. Chemotherapy 2021; 66:99-106. [PMID: 33823517 DOI: 10.1159/000515100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/07/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Tigecycline (TGC) is one of the last-resort therapeutic agents for treating infections caused by extensively drug resistant Acinetobacter baumannii isolates. Although resistance to TGC is not common, non-susceptible A. baumannii (NSAB) isolates have been described. In the current study, we aimed to assess the molecular mechanisms mediating TGC non-susceptibility in 5 clinical isolates of A. baumannii with reduced susceptibility to TGC. METHODS Susceptibility of isolates to TGC as well as various classes of antibiotics was evaluated by broth dilution and disk diffusion methods, respectively. The presence of tetX and tetX1 genes was investigated by PCR. The nucleotide sequences of adeR and adeS genes were assessed by PCR amplicon sequencing. To evaluate the association between reduced susceptibility to TGC and upregulation of AdeABC efflux pump, transcriptional level of adeB gene was quantified by RT-qPCR analysis. RESULTS All 5 TGC-NSAB isolates had a TGC MIC of ≥4 mg/L and were resistant to all antimicrobials tested by disk diffusion method except for minocycline and doxycycline for which a susceptibility rate of 40% and 20% was observed, respectively. The tetX/X1 genes were not detected in any isolates. All TGC non-susceptible isolates harbored genetic alterations in the adeRS operon, including AdeS G186V, N268H, and D60N and AdeR A136V and V120I substitutions among, which G186V and D60N were predicted by PROVEAN tool analysis as inactivating alterations. Reduced TGC susceptibility was associated with upregulation of AdeABC efflux pump in all TGC non-susceptible isolates. CONCLUSION It can be concluded from our results that reduced susceptibility to TGC in the studied isolates was mainly mediated by genetic alterations in the AdeRS system, which resulted in overexpression of AdeABC efflux pump. Emergence of TGC non-susceptibility among isolates that had not been previously exposed to TGC is an issue of great concern.
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Affiliation(s)
- Mehri Haeili
- Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
| | - Ali Abdollahi
- Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
| | - Amin Ahmadi
- Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Amin Khoshbayan
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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Nogbou ND, Phofa DT, Nchabeleng M, Musyoki AM. Investigating multi-drug resistant Acinetobacter baumannii isolates at a tertiary hospital in Pretoria, South Africa. Indian J Med Microbiol 2021; 39:218-223. [PMID: 33832811 DOI: 10.1016/j.ijmmb.2021.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 02/12/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Antimicrobial resistance is now globally recognised amongst the greatest threat to human health. Acinetobacter baumannii's' (A. baumannii) clinical significance has been driven by its ability to obtain and transmit antimicrobial resistance factors. In South Africa, A. baumannii is a leading cause of healthcare associated infections (HAI). In this study, we investigated the genetic determinants of multi-drug resistant A. baumannii (MDRAB) at a teaching hospital in Pretoria, South Africa. METHODS One hundred non repetitive isolates of A. baumannii were collected for the study. Antimicrobial susceptibility testing was performed using the VITEK2 system. The prevalence of antibiotic resistance associated genes and AdeABC efflux pump system were investigated using conventional PCR. Genetic relatedness of isolates was determined using rep-PCR. RESULTS Seventy (70) of 100 isolates collected were confirmed multi-drug resistant and were blaOXA51positive. Phenotypically, the isolates where resistant to almost all tested antibiotics. One isolate showed intermediate susceptibility to tigecycline while all were susceptible to colistin. Oxacillinase gene blaOXA-23 was the most detected at 99% and only 1% was positive for blaOXA-40. For Metallo-betalactamases (MBL), blaVIMwas the most frequently detected at 86% and blaSIM-1 at 3% was the least detected. Fifty-six isolates had the required gene combination for an active efflux pump. The most prevalent clone was clone A at 69% of the isolates. Colistin and tigecycline are the most effective against investigated isolates. CONCLUSION The major genotypic determinant for drug resistances is oxacillinases blaOXA-23. The study reports for the first time, blaOXA-40 and blaSIM-1 detection in A. baumannii in South Africa.
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Affiliation(s)
- Noel-David Nogbou
- Department of Microbiological Pathology, Sefako Makgatho Health Sciences University, Pretoria, South Africa.
| | - Dikwata Thabiso Phofa
- Department of Microbiological Pathology, Sefako Makgatho Health Sciences University, Pretoria, South Africa; National Health Laboratory Service, Dr George Mukhari Tertiary Laboratory, Pretoria, South Africa
| | - Maphoshane Nchabeleng
- Department of Microbiological Pathology, Sefako Makgatho Health Sciences University, Pretoria, South Africa; National Health Laboratory Service, Dr George Mukhari Tertiary Laboratory, Pretoria, South Africa
| | - Andrew Munyalo Musyoki
- Department of Microbiological Pathology, Sefako Makgatho Health Sciences University, Pretoria, South Africa
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Roy S, Chatterjee S, Bhattacharjee A, Chattopadhyay P, Saha B, Dutta S, Basu S. Overexpression of Efflux Pumps, Mutations in the Pumps' Regulators, Chromosomal Mutations, and AAC(6')-Ib-cr Are Associated With Fluoroquinolone Resistance in Diverse Sequence Types of Neonatal Septicaemic Acinetobacter baumannii: A 7-Year Single Center Study. Front Microbiol 2021; 12:602724. [PMID: 33776950 PMCID: PMC7990795 DOI: 10.3389/fmicb.2021.602724] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 01/21/2021] [Indexed: 12/16/2022] Open
Abstract
This study investigates susceptibility toward three fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin), multiple fluoroquinolone-resistance mechanisms, and epidemiological relationship of neonatal septicaemic Acinetobacter baumannii. Previous studies on fluoroquinolone resistance in A. baumannii focused primarily on ciprofloxacin susceptibility and assessed a particular mechanism of resistance; a more holistic approach was taken here. Epidemiological relationship was evaluated by Multi Locus Sequence Typing. Minimum Inhibitory Concentrations of fluoroquinolones was determined with and without efflux pump inhibitors. Overexpression of efflux pumps, resistance-nodulation-cell-division (RND)-type, and multidrug and toxic compound extrusion (MATE)-type efflux pumps were evaluated by reverse transcriptase-qPCR. Mutations within regulatory proteins (AdeRS, AdeN, and AdeL) of RND-pumps were examined. Chromosomal mutations, presence of qnr and aac(6′)-Ib-cr were investigated. A. baumannii were highly diverse as 24 sequence-types with seven novel STs (ST-1440/ST-1441/ST-1481/ST-1482/ST-1483/ST-1484/ST-1486) were identified among 47 A. baumannii. High resistance to ciprofloxacin (96%), levofloxacin (92%), and particularly moxifloxacin (90%) was observed, with multiple mechanisms being active. Resistance to 4th generation fluoroquinolone (moxifloxacin) in neonatal isolates is worrisome. Mutations within GyrA (S83L) and ParC (S80L) were detected in more than 90% of fluoroquinolone-resistant A. baumannii (FQRAB) spread across 10 different clonal complexes (CC1/CC2/CC10/CC25/CC32/CC126/CC149/CC216/CC218/CC513). Efflux-based FQ resistance was found in 65% of FQRAB with ≥2 different active pumps in 38% of strains. Overexpression of adeB was highest (2.2−34-folds) followed by adeJ, adeG, and abeM. Amino acid changes in the regulators (AdeRS/AdeN/AdeL) either as single or multiple substitutions substantiated the overexpression of the pumps. Diverse mutations within AdeRS were detected among different CCs whereas mutations within AdeN linked to CC10 and CC32. Chromosomal mutations and active efflux pumps were detected simultaneously among 64% of FQRAB. Presence of aac(6′)-Ib-cr was also high (74% of FQRAB) but qnrS were absent. As most FQRABs had chromosomal mutations, this was considered predominant, however, isolates where pumps were also active had higher MIC values, establishing the critical role of the efflux pumps. The high variability of FQ susceptibility among FQRAB, possessing the same set of mutations in gyrA, parC, and efflux pump regulators, was also noted. This reveals the complexity of interpreting the interplay of multiple resistance mechanisms in A. baumannii.
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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
| | - Somdatta Chatterjee
- Division of Bacteriology, Indian Council of Medical Research (ICMR)-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Amrita Bhattacharjee
- Division of Bacteriology, Indian Council of Medical Research (ICMR)-National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Pinaki Chattopadhyay
- Department of Neonatology, Institute of Post-Graduate Medical Education and Research, Kolkata, India
| | - Bijan Saha
- Department of Neonatology, Institute of Post-Graduate Medical Education and Research, 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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Acinetobacter baumannii Antibiotic Resistance Mechanisms. Pathogens 2021; 10:pathogens10030373. [PMID: 33808905 PMCID: PMC8003822 DOI: 10.3390/pathogens10030373] [Citation(s) in RCA: 190] [Impact Index Per Article: 63.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative ESKAPE microorganism that poses a threat to public health by causing severe and invasive (mostly nosocomial) infections linked with high mortality rates. During the last years, this pathogen displayed multidrug resistance (MDR), mainly due to extensive antibiotic abuse and poor stewardship. MDR isolates are associated with medical history of long hospitalization stays, presence of catheters, and mechanical ventilation, while immunocompromised and severely ill hosts predispose to invasive infections. Next-generation sequencing techniques have revolutionized diagnosis of severe A. baumannii infections, contributing to timely diagnosis and personalized therapeutic regimens according to the identification of the respective resistance genes. The aim of this review is to describe in detail all current knowledge on the genetic background of A. baumannii resistance mechanisms in humans as regards beta-lactams (penicillins, cephalosporins, carbapenems, monobactams, and beta-lactamase inhibitors), aminoglycosides, tetracyclines, fluoroquinolones, macrolides, lincosamides, streptogramin antibiotics, polymyxins, and others (amphenicols, oxazolidinones, rifamycins, fosfomycin, diaminopyrimidines, sulfonamides, glycopeptide, and lipopeptide antibiotics). Mechanisms of antimicrobial resistance refer mainly to regulation of antibiotic transportation through bacterial membranes, alteration of the antibiotic target site, and enzymatic modifications resulting in antibiotic neutralization. Virulence factors that may affect antibiotic susceptibility profiles and confer drug resistance are also being discussed. Reports from cases of A. baumannii coinfection with SARS-CoV-2 during the COVID-19 pandemic in terms of resistance profiles and MDR genes have been investigated.
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Salehi B, Ghalavand Z, Yadegar A, Eslami G. Characteristics and diversity of mutations in regulatory genes of resistance-nodulation-cell division efflux pumps in association with drug-resistant clinical isolates of Acinetobacter baumannii. Antimicrob Resist Infect Control 2021; 10:53. [PMID: 33691788 PMCID: PMC7944621 DOI: 10.1186/s13756-021-00924-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023] Open
Abstract
Background This study was aimed to characterize the genetic diversity and expression of three putative resistance-nodulation-cell division (RND)-type efflux systems and their contribution to multidrug efflux in clinical isolates of Acinetobacter baumannii. Methods Antimicrobial susceptibility testing of 95 A. baumannii isolates was determined by Kirby-Bauer disk diffusion for 18 antibiotics and minimum inhibitory concentration (MIC) of colistin was determined by the broth microdilution method. Moreover, the MIC of five classes of antibiotics was assessed using E-test strips in the presence and absence of phenylalanine-arginine beta-naphthylamide (PAβN). Regulatory genes of the RND efflux pumps (adeRS, adeL, adeN and baeSR) were subjected to sequencing. The relative expression of adeB, adeG and adeJ genes was determined by quantitative real-time PCR (qRT-PCR). Results Overall, the majority of isolates (94%) were extensively drug-resistant (XDR). In the phenotypic assay, efflux pump activity was observed in 40% of the isolates against multiple antibiotics mainly tigecycline. However, we found no efflux activity against imipenem. Several amino acid substitutions were detected in the products of regulatory genes; except in AdeN. Of note, G186V mutation in AdeS was found to be associated with overexpression of its efflux pump. No insertion sequences were detected. Conclusions Our findings outlined the role of RND efflux pumps in resistance of A. baumannii to multiple antibiotics particularly tigecycline, and pointed out the importance of a variety of single mutations in the corresponding regulatory systems. Further studies are required to decipher the precise role of RND efflux pumps in multidrug-resistant clinical isolates of A. baumannii.
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Affiliation(s)
- Bahare Salehi
- Infectious Diseases and Tropical Medicine Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zohreh Ghalavand
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Gita Eslami
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Pulami D, Schauss T, Eisenberg T, Wilharm G, Blom J, Goesmann A, Kämpfer P, Glaeser SP. Acinetobacter baumannii in manure and anaerobic digestates of German biogas plants. FEMS Microbiol Ecol 2021; 96:5896450. [PMID: 32832994 DOI: 10.1093/femsec/fiaa176] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 08/20/2020] [Indexed: 12/19/2022] Open
Abstract
Studies considering environmental multidrug-resistant Acinetobacter spp. are scarce. The application of manure on agricultural fields is one source of multidrug-resistant bacteria from livestock into the environment. Here, Acinetobacter spp. were quantified by quantitative polymerase chain reaction in manure applied to biogas plants and in the output of the anaerobic digestion, and Acinetobacter spp. isolated from those samples were comprehensively characterized. The concentration of Acinetobacter 16S ribosomal ribonucleic acid (rRNA) gene copies per g fresh weight was in range of 106-108 in manure and decreased (partially significantly) to a still high concentration (105-106) in digestates. 16S rRNA, gyrB-rpoB and blaOXA51-like gene sequencing identified 17 different Acinetobacter spp., including six A. baumannii strains. Multilocus sequence typing showed no close relation of the six strains with globally relevant clonal complexes; however, they represented five novel sequence types. Comparative genomics and physiological tests gave an explanation how Acinetobacter could survive the anaerobic biogas process and indicated copper resistance and the presence of intrinsic beta-lactamases, efflux-pump and virulence genes. However, the A. baumannii strains lacked acquired resistance against carbapenems, colistin and quinolones. This study provided a detailed characterization of Acinetobacter spp. including A. baumannii released via manure through mesophilic or thermophilic biogas plants into the environment.
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Affiliation(s)
- Dipen Pulami
- Institute of Applied Microbiology, Justus Liebig University Giessen, D-35392 Giessen, Germany
| | - Thorsten Schauss
- Institute of Applied Microbiology, Justus Liebig University Giessen, D-35392 Giessen, Germany
| | - Tobias Eisenberg
- Department of Veterinary Medicine, Hessian State Laboratory (LHL), D-35392 Giessen, Germany; Institute of Hygiene and Infectious Diseases of Animals, Justus-Liebig-University Giessen, D-35392, Giessen, Germany
| | - Gottfried Wilharm
- Project Group P2, Robert Koch Institute, Wernigerode Branch, D-38855 Wernigerode, Germany
| | - Jochen Blom
- Institute for Bioinformatics and Systems Biology, D-35392 Giessen, Germany
| | - Alexander Goesmann
- Institute for Bioinformatics and Systems Biology, D-35392 Giessen, Germany
| | - Peter Kämpfer
- Institute of Applied Microbiology, Justus Liebig University Giessen, D-35392 Giessen, Germany
| | - Stefanie P Glaeser
- Institute of Applied Microbiology, Justus Liebig University Giessen, D-35392 Giessen, Germany
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Morgan CE, Glaza P, Leus IV, Trinh A, Su CC, Cui M, Zgurskaya HI, Yu EW. Cryoelectron Microscopy Structures of AdeB Illuminate Mechanisms of Simultaneous Binding and Exporting of Substrates. mBio 2021; 12:e03690-20. [PMID: 33622726 PMCID: PMC8545137 DOI: 10.1128/mbio.03690-20] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 12/31/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative pathogen that has emerged as one of the most highly antibiotic-resistant bacteria worldwide. Multidrug efflux within these highly drug-resistant strains and other opportunistic pathogens is a major cause of failure of drug-based treatments of infectious diseases. The best-characterized multidrug efflux system in A. baumannii is the prevalent Acinetobacterdrug efflux B (AdeB) pump, which is a member of the resistance-nodulation-cell division (RND) superfamily. Here, we report six structures of the trimeric AdeB multidrug efflux pump in the presence of ethidium bromide using single-particle cryoelectron microscopy (cryo-EM). These structures allow us to directly observe various novel conformational states of the AdeB trimer, including the transmembrane region of trimeric AdeB can be associated with form a trimer assembly or dissociated into "dimer plus monomer" and "monomer plus monomer plus monomer" configurations. We also discover that a single AdeB protomer can simultaneously anchor a number of ethidium ligands and that different AdeB protomers can bind ethidium molecules simultaneously. Combined with molecular dynamics (MD) simulations, we reveal a drug transport mechanism that involves multiple multidrug-binding sites and various transient states of the AdeB membrane protein. Our data suggest that each AdeB protomer within the trimer binds and exports drugs independently.IMPORTANCEAcinetobacter baumannii has emerged as one of the most highly antibiotic-resistant Gram-negative pathogens. The prevalent AdeB multidrug efflux pump mediates resistance to a broad spectrum of clinically relevant antimicrobial agents. Here, we report six cryo-EM structures of the trimeric AdeB pump in the presence of ethidium bromide. We discover that a single AdeB protomer can simultaneously anchor a number of ligands, and different AdeB protomers can bind ethidium molecules simultaneously. The results indicate that each AdeB protomer within the trimer recognizes and extrudes drugs independently.
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Affiliation(s)
- Christopher E Morgan
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Przemyslaw Glaza
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Inga V Leus
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Anhthu Trinh
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University School of Pharmacy, Boston, Massachusetts, USA
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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Kirtikliene T, Mierauskaitė A, Razmienė I, Kuisiene N. Multidrug-Resistant Acinetobacter baumannii Genetic Characterization and Spread in Lithuania in 2014, 2016, and 2018. Life (Basel) 2021; 11:life11020151. [PMID: 33669401 PMCID: PMC7920459 DOI: 10.3390/life11020151] [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: 01/18/2021] [Revised: 02/11/2021] [Accepted: 02/14/2021] [Indexed: 12/12/2022] Open
Abstract
Bacterial resistance to antimicrobial agents plays an important role in the treatment of bacterial infections in healthcare institutions. The spread of multidrug-resistant bacteria can occur during inter- and intra-hospital transmissions among patients and hospital personnel. For this reason, more studies must be conducted to understand how resistance occurs in bacteria and how it moves between hospitals by comparing data from different years and looking out for any patterns that might emerge. Multidrug-resistant (MDR) Acinetobacter spp. was studied at 14 healthcare institutions in Lithuania during 2014, 2016, and 2018 using samples from human bloodstream infections. In total, 194 isolates were collected and identified using MALDI-TOF and VITEK2 analyzers as Acinetobacter baumannii group bacteria. After that, the isolates were analyzed for the presence of different resistance genes (20 genes were analyzed) and characterized by using the Rep-PCR and MLVA (multiple-locus variable-number tandem repeat analysis) genotyping methods. The results of the study showed the relatedness of the different Acinetobacter spp. isolates and a possible circulation of resistance genes or profiles during the different years of the study. This study provides essential information, such as variability and diversity of resistance genes, genetic profiling, and clustering of isolates, to better understand the antimicrobial resistance patterns of Acinetobacter spp. These results can be used to strengthen the control of multidrug-resistant infections in healthcare institutions and to prevent potential outbreaks of this pathogen in the future.
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Affiliation(s)
- Tatjana Kirtikliene
- Department of Microbiology and Biotechnology, Institute of Biosciences, Life Sciences Center, Vilnius University, LT-10257 Vilnius, Lithuania;
- Correspondence: ; Tel.: +370-62156858
| | - Aistė Mierauskaitė
- National Public Health Surveillance Laboratory, Clinical Testing Department, LT-10257 Vilnius, Lithuania; (A.M.); (I.R.)
| | - Ilona Razmienė
- National Public Health Surveillance Laboratory, Clinical Testing Department, LT-10257 Vilnius, Lithuania; (A.M.); (I.R.)
| | - Nomeda Kuisiene
- Department of Microbiology and Biotechnology, Institute of Biosciences, Life Sciences Center, Vilnius University, LT-10257 Vilnius, Lithuania;
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Verma P, Tiwari M, Tiwari V. Efflux pumps in multidrug-resistant Acinetobacter baumannii: Current status and challenges in the discovery of efflux pumps inhibitors. Microb Pathog 2021; 152:104766. [PMID: 33545327 DOI: 10.1016/j.micpath.2021.104766] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/13/2021] [Accepted: 01/22/2021] [Indexed: 12/14/2022]
Abstract
Acinetobacter baumannii is an ESKAPE pathogen known to cause fatal nosocomial infections. With the surge of multidrug resistance (MDR) in the bacterial system, effective treatment measures have become very limited. The MDR in A. baumannii is contributed by various factors out of which efflux pumps have gained major attention due to their broad substrate specificity and wide distribution among bacterial species. The efflux pumps are involved in the MDR as well as contribute to other physiological processes in bacteria, therefore, it is critically important to inhibit efflux pumps in order to combat emerging resistance. The present review provides insight about the different efflux pump systems in A. baumannii and their role in multidrug resistance. A major focus has been put on the different strategies and alternate therapeutics to inhibit the efflux system. This includes use of different efflux pump inhibitors-natural, synthetic or combinatorial therapy. The use of phage therapy and nanoparticles for inhibiting efflux pumps have also been discussed here. Moreover, the present review provides the knowledge of barriers in development of efflux pump inhibitors (EPIs) and their approval for commercialization. Here, different prospectives have been discussed to improve the therapeutic development process and make it more compatible for clinical use.
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Affiliation(s)
- Privita Verma
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India.
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McCarthy RR, Larrouy-Maumus GJ, Meiqi Tan MGC, Wareham DW. Antibiotic Resistance Mechanisms and Their Transmission in Acinetobacter baumannii. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1313:135-153. [PMID: 34661894 DOI: 10.1007/978-3-030-67452-6_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The discovery of penicillin over 90 years ago and its subsequent uptake by healthcare systems around the world revolutionised global health. It marked the beginning of a golden age in antibiotic discovery with new antibiotics readily discovered from natural sources and refined into therapies that saved millions of lives. Towards the end of the last century, the rate of discovery slowed to a near standstill. The lack of discovery is compounded by the rapid emergence and spread of bacterial pathogens that exhibit resistance to multiple antibiotic therapies and threaten the sustainability of global healthcare systems. Acinetobacter baumannii is an opportunistic pathogen whose prevalence and impact has grown significantly over the last 20 years. It is recognised as a barometer of the antibiotic resistance crisis due to the diverse array of mechanisms by which it can become resistant.
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Affiliation(s)
- Ronan R McCarthy
- Division of Biosciences, Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge, UK.
| | - Gerald J Larrouy-Maumus
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Mei Gei C Meiqi Tan
- Antimicrobial Research Group, Blizard Institute, Queen Mary University London, London, UK
| | - David W Wareham
- Antimicrobial Research Group, Blizard Institute, Queen Mary University London, London, UK
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Leus IV, Adamiak J, Trinh AN, Smith RD, Smith L, Richardson S, Ernst RK, Zgurskaya HI. Inactivation of AdeABC and AdeIJK efflux pumps elicits specific nonoverlapping transcriptional and phenotypic responses in Acinetobacter baumannii. Mol Microbiol 2020; 114:1049-1065. [PMID: 32858760 DOI: 10.1111/mmi.14594] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/17/2020] [Indexed: 12/24/2022]
Abstract
Multidrug resistant (MDR) strains of Acinetobacter baumannii present a serious clinical challenge. The development of antibiotic resistance in this species is enabled by efflux pumps of the Resistance-Nodulation-Division (RND) superfamily of proteins creating an efficient permeability barrier for antibiotics. At least three RND pumps, AdeABC, AdeIJK, and AdeFGH are encoded in the A. baumannii genome and are reported to contribute to antibiotic resistance in clinical isolates. In this study, we analyzed the contributions of AdeABC and AdeIJK in antibiotic resistance and growth physiology of the two MDR strains, AYE and AB5075. We found that not only the two pumps have nonoverlapping substrate specificities, their inactivation leads to specific nonoverlapping changes in gene expression as determined by RNA sequencing and confirmed by gene knockouts and growth phenotypes. Our results suggest that inactivation of AdeIJK elicits broader changes in the abundances of mRNAs and this response is modified in the absence of AdeB. In contrast, inactivation of AdeB leads to a focused cellular response, which is not sensitive to the activity of AdeIJK. We identified additional efflux pumps and transcriptional regulators that contribute to MDR phenotype of clinical A. baumannii isolates.
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Affiliation(s)
- Inga V Leus
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Justyna Adamiak
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Anhthu N Trinh
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Richard D Smith
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD, USA
| | - Lauren Smith
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Sophie Richardson
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, Baltimore, MD, USA
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
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75
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Barlow VL, Lai SJ, Chen CY, Tsai CH, Wu SH, Tsai YH. Effect of membrane fusion protein AdeT1 on the antimicrobial resistance of Escherichia coli. Sci Rep 2020; 10:20464. [PMID: 33235243 PMCID: PMC7687900 DOI: 10.1038/s41598-020-77339-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 11/10/2020] [Indexed: 01/03/2023] Open
Abstract
Acinetobacter baumannii is a prevalent pathogen that can rapidly acquire resistance to antibiotics. Indeed, multidrug-resistant A. baumannii is a major cause of hospital-acquired infections and has been recognised by the World Health Organization as one of the most threatening bacteria to our society. Resistance-nodulation-division (RND) type multidrug efflux pumps have been demonstrated to convey antibiotic resistance to a wide range of pathogens and are the primary resistance mechanism employed by A. baumannii. A component of an RND pump in A. baumannii, AdeT1, was previously demonstrated to enhance the antimicrobial resistance of Escherichia coli. Here, we report the results of experiments which demonstrate that wild-type AdeT1 does not confer antimicrobial resistance in E. coli, highlighting the importance of verifying protein production when determining minimum inhibitory concentrations (MICs) especially by broth dilution. Nevertheless, using an agar-based MIC assay, we found that propionylation of Lys280 on AdeT1 renders E. coli cells more resistant to erythromycin.
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Affiliation(s)
| | - Shu-Jung Lai
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan.,Research Center for Cancer Biology, China Medical University, Taichung, Taiwan.,Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chia-Yu Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Cheng-Han Tsai
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Shih-Hsiung Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yu-Hsuan Tsai
- School of Chemistry, Cardiff University, Cardiff, UK.
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76
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Azimi L, Tahbaz SV, Alaghehbandan R, Alinejad F, Lari AR. Synergistic Effect of Tazobactam on Amikacin MIC in Acinetobacter baumannii Isolated from Burn Patients in Tehran, Iran. Curr Pharm Biotechnol 2020; 21:997-1004. [PMID: 32077820 DOI: 10.2174/1389201021666200220121122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/31/2020] [Accepted: 02/01/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Burn is still an important global public health challenge. Wound colonization of antibiotic resistant bacteria such as Acinetobacter baumannii can lead to high morbidity and mortality in burn patients. The aim of this study was to evaluate the inhibitory effect of tazobactam on efflux pump, which can cause aminoglycoside resistant in A. baumannii isolated from burn patients. METHODS In this study, 47 aminoglycoside resistant A. baumannii spp. were obtained from burn patients, admitted to the Shahid Motahari Burns Hospital in Tehran, Iran, during June-August 2018. The inhibitory effect of tazobactam against adeB such as efflux pump was evaluated by Minimum Inhibitory Concentration (MIC) determination of amikacin alone and in combination with tazobactam. Fractional Inhibitory Concentration index (FIC) was used to determine the efficacy of tazobactam/ amikacin combination. Further, semi-quantitative Real- Time PCR was performed to quantify the expression rates of the adeB gene before and after addition of tazobactam/amikacin. RESULTS The MIC values were significantly reduced when a combined amikacin and tazobactam was utilized. The most common interaction observed was synergistic (78.2%), followed by.additive effects (21.8%), as per FIC results. The adeB mRNA expression levels were found to be downregulated in 60.7% of isolates treated with tazobactam. CONCLUSION Tazobactam can have impact on resistance to aminoglycoside by inhibiting efflux pump. Thus, the combination of tazobactam with amikacin can be used as an alternative treatment approach in multidrug resistant A. baumannii infections.
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Affiliation(s)
- Leila Azimi
- Paediatric Infections Research Center, Research Institute for Children's Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sahel V Tahbaz
- Department of Microbiology, Islamic Azad University, North Tehran Branch, Tehran, Iran
| | - Reza Alaghehbandan
- Department of Pathology, University of British Columbia, Royal Columbian Hospital, Vancouver, BC, Canada
| | - Farank Alinejad
- Burn Research Center, Iran University of Medical sciences, Tehran, Iran
| | - Abdolaziz R Lari
- Department of Microbiology, Iran University of Medical Sciences, Tehran, Iran
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77
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Montaña S, Vilacoba E, Fernandez JS, Traglia GM, Sucari A, Pennini M, Iriarte A, Centron D, Melano RG, Ramírez MS. Genomic analysis of two Acinetobacter baumannii strains belonging to two different sequence types (ST172 and ST25). J Glob Antimicrob Resist 2020; 23:154-161. [PMID: 32966912 DOI: 10.1016/j.jgar.2020.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/27/2020] [Accepted: 09/04/2020] [Indexed: 10/23/2022] Open
Abstract
OBJECTIVES Acinetobacter baumannii is an opportunistic nosocomial pathogen that is the main focus of attention in clinical settings owing to its intrinsic ability to persist in the hospital environment and its capacity to acquire determinants of resistance and virulence. Here we present the genomic sequencing, molecular characterisation and genomic comparison of two A. baumannii strains belonging to two different sequence types (STs), one sporadic and one widely distributed in our region. METHODS Whole-genome sequencing (WGS) of Ab42 and Ab376 was performed using Illumina MiSeq-I and the genomes were assembled with SPAdes. ARG-ANNOT, CARD-RGI, ISfinder, PHAST, PlasmidFinder, plasmidSPAdes and IslandViewer were used to analyse both genomes. RESULTS Genome analysis revealed that Ab42 belongs to ST172, an uncommon ST, whilst Ab376 belongs to ST25, a widely distributed ST. Molecular characterisation showed the presence of two antibiotic resistance genes in Ab42 and nine in Ab376. No insertion sequences were detected in Ab42, however 22 were detected in Ab376. Moreover, two prophages were found in Ab42 and three in Ab376. In addition, a CRISPR-cas type I-Fb and two plasmids, one of which harboured an AbGRI1-like island, were found in Ab376. CONCLUSIONS We present WGS analysis of twoA. baumannii strains belonging to two different STs. These findings allowed us to characterise a previously undescribed ST (ST172) and provide new insights to the widely studied ST25.
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Affiliation(s)
- Sabrina Montaña
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Buenos Aires, Argentina; Laboratorio de Bacteriología Clínica, Departamento de Bioquímica Clínica, Hospital de Clínicas José de San Martín, Facultad de Farmacia y Bioquímica, Buenos Aires, Argentina
| | - Elisabet Vilacoba
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Jennifer S Fernandez
- Department of Biological Science, California State University Fullerton, 800 N. State College Blvd, Fullerton, CA 92834-6850, USA
| | - German M Traglia
- Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República. Montevideo, Uruguay
| | - Adriana Sucari
- Unidad Microbiología, Laboratorio Stamboulian, Buenos Aires, Argentina
| | - Magdalena Pennini
- Unidad Microbiología, Laboratorio Stamboulian, Buenos Aires, Argentina
| | - Andres Iriarte
- Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República. Montevideo, Uruguay
| | - Daniela Centron
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | | | - María Soledad Ramírez
- Department of Biological Science, California State University Fullerton, 800 N. State College Blvd, Fullerton, CA 92834-6850, USA.
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78
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A Diverse Panel of Clinical Acinetobacter baumannii for Research and Development. Antimicrob Agents Chemother 2020; 64:AAC.00840-20. [PMID: 32718956 DOI: 10.1128/aac.00840-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/18/2020] [Indexed: 12/20/2022] Open
Abstract
Over the past two decades, Acinetobacter baumannii has emerged as a leading cause of nosocomial infections worldwide. Of particular concern are panresistant strains, leading the World Health Organization (WHO) to designate carbapenem-resistant A. baumannii as a priority 1 (critical) pathogen for research and development of new antibiotics. A key component in supporting this effort is accessibility to diverse and clinically relevant strains for testing. Here, we describe a panel of 100 diverse A. baumannii strains for use in this endeavor. Whole-genome sequencing was performed on 3,505 A. baumannii isolates housed at the Multidrug-Resistant Organism Repository and Surveillance Network. Isolates were cultured from clinical samples at health care facilities around the world between 2001 and 2017. Core-genome multilocus sequence typing and high-resolution single nucleotide polymorphism (SNP)-based phylogenetic analyses were used to select a final panel of 100 strains that captured the genetic diversity of the collection. Comprehensive antibiotic susceptibility testing was also performed on all 100 isolates using 14 clinically relevant antibiotics. The final 100-strain diversity panel contained representative strains from 70 different traditional Pasteur scheme multilocus sequence types, including major epidemic clones. This diversity was also reflected in antibiotic susceptibility and antimicrobial resistance (AMR) gene content, with phenotypes ranging from pansensitive to panresistant, and over 100 distinct AMR gene alleles identified from 32 gene families. This panel provides the most diverse and comprehensive set of A. baumannii strains for use in developing solutions for combating antibiotic resistance. The panel and all available metadata, including genome sequences, will be available to industry and academic institutions and federal and other laboratories free of charge.
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79
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Puja H, Comment G, Chassagne S, Plésiat P, Jeannot K. Coordinate overexpression of two
RND
efflux systems,
ParXY
and
TtgABC
, is responsible for multidrug resistance in
Pseudomonas putida. Environ Microbiol 2020; 22:5222-5231. [DOI: 10.1111/1462-2920.15200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 12/28/2022]
Affiliation(s)
- Hélène Puja
- UMR 6249 Chrono‐environnement UFR Santé, Université de Bourgogne‐Franche Comté Besançon France
| | - Gwendoline Comment
- UMR 6249 Chrono‐environnement UFR Santé, Université de Bourgogne‐Franche Comté Besançon France
| | - Sophie Chassagne
- UMR 6249 Chrono‐environnement UFR Santé, Université de Bourgogne‐Franche Comté Besançon France
| | - Patrick Plésiat
- UMR 6249 Chrono‐environnement UFR Santé, Université de Bourgogne‐Franche Comté Besançon France
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon Besançon France
| | - Katy Jeannot
- UMR 6249 Chrono‐environnement UFR Santé, Université de Bourgogne‐Franche Comté Besançon France
- Centre National de Référence de la Résistance aux Antibiotiques, Centre Hospitalier Universitaire de Besançon Besançon France
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80
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Roe C, Williamson CHD, Vazquez AJ, Kyger K, Valentine M, Bowers JR, Phillips PD, Harrison V, Driebe E, Engelthaler DM, Sahl JW. Bacterial Genome Wide Association Studies (bGWAS) and Transcriptomics Identifies Cryptic Antimicrobial Resistance Mechanisms in Acinetobacter baumannii. Front Public Health 2020; 8:451. [PMID: 33014966 PMCID: PMC7493718 DOI: 10.3389/fpubh.2020.00451] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/21/2020] [Indexed: 12/14/2022] Open
Abstract
Antimicrobial resistance (AMR) in the nosocomial pathogen, Acinetobacter baumannii, is becoming a serious public health threat. While some mechanisms of AMR have been reported, understanding novel mechanisms of resistance is critical for identifying emerging resistance. One of the first steps in identifying novel AMR mechanisms is performing genotype/phenotype association studies; however, performing these studies is complicated by the plastic nature of the A. baumannii pan-genome. In this study, we compared the antibiograms of 12 antimicrobials associated with multiple drug families for 84 A. baumannii isolates, many isolated in Arizona, USA. in silico screening of these genomes for known AMR mechanisms failed to identify clear correlations for most drugs. We then performed a bacterial genome wide association study (bGWAS) looking for associations between all possible 21-mers; this approach generally failed to identify mechanisms that explained the resistance phenotype. In order to decrease the genomic noise associated with population stratification, we compared four phylogenetically-related pairs of isolates with differing susceptibility profiles. RNA-Sequencing (RNA-Seq) was performed on paired isolates and differentially-expressed genes were identified. In these isolate pairs, five different potential mechanisms were identified, highlighting the difficulty of broad AMR surveillance in this species. To verify and validate differential expression, amplicon sequencing was performed. These results suggest that a diagnostic platform based on gene expression rather than genomics alone may be beneficial in certain surveillance efforts. The implementation of such advanced diagnostics coupled with increased AMR surveillance will potentially improve A. baumannii infection treatment and patient outcomes.
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Affiliation(s)
- Chandler Roe
- Northern Arizona University, Flagstaff, AZ, United States
| | | | | | - Kristen Kyger
- Northern Arizona University, Flagstaff, AZ, United States
| | - Michael Valentine
- Translational Genomics Research Institute, Flagstaff, AZ, United States
| | - Jolene R. Bowers
- Translational Genomics Research Institute, Flagstaff, AZ, United States
| | | | - Veronica Harrison
- Translational Genomics Research Institute, Flagstaff, AZ, United States
| | - Elizabeth Driebe
- Translational Genomics Research Institute, Flagstaff, AZ, United States
| | | | - Jason W. Sahl
- Northern Arizona University, Flagstaff, AZ, United States
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81
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Ranjbar R, Zayeri S, Afshar D. High Frequency of AdeA, AdeB and AdeC Genes among Acinetobacter baumannii Isolates. IRANIAN JOURNAL OF PUBLIC HEALTH 2020; 49:1539-1545. [PMID: 33083331 PMCID: PMC7554404 DOI: 10.18502/ijph.v49i8.3898] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background: Efflux pumps are involved in resistance of Acinetobacter baumannii isolates to antimicrobial agents. AdeABC efflux pump is one of the RND superfamily efflux pump and consists of adeA (membrane fusion), adeB (multidrug transporter) and adeC (outer membrane) genes. In this study, the frequency of adeA, adeB and adeC genes among A. baumannii isolates with resistance to erythromycin, trimethoprim, meropenem and imipenem was investigated. Methods: Overall, 79 strains of A. baumannii were isolated from patients admitted to two major hospitals in Tehran during 2016. Antibiotic susceptibility testing was determined by disc diffusion and microdilution methods according to Clinical and Laboratory Standards Institute (CLSI) guideline. The presence of adeA, adeB and adeC genes was also determined using Multiplex PCR assay. Results: The highest and the lowest resistance among A. baumannii isolates were to trimethoprim (93%) and erythromycin (53%), respectively. The frequency of adeA, adeB and adeC genes was 96.2%, 96.2% and 91.1 % respectively. There was a significant relationship between imipenem resistance and presence of efflux pump genes (P<0.05). Conclusion: According to the high prevalence of the AdeABC efflux system genes, it may involve in resistance of clinical isolates of A. baumannii to imipenem, especially.
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Affiliation(s)
- Reza Ranjbar
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Shahin Zayeri
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Davoud Afshar
- Department of Microbiology and Virology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
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82
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Kongthai P, Thummeepak R, Leungtongkam U, Pooarlai R, Kitti T, Thanwisai A, Chantratita N, Millard AD, Sitthisak S. Insight into Molecular Epidemiology, Antimicrobial Resistance, and Virulence Genes of Extensively Drug-Resistant Acinetobacter baumannii in Thailand. Microb Drug Resist 2020; 27:350-359. [PMID: 32716693 DOI: 10.1089/mdr.2020.0064] [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] [Indexed: 12/21/2022] Open
Abstract
Extensively drug-resistant Acinetobacter baumannii (XDR-AB) is a major threat to public health worldwide. A retrospective study for 27 XDR-AB isolates from four tertiary hospitals in Thailand was conducted. Beta-lactamase and virulence genes were characterized by PCR. The blaADC, blaOXA-51, and blaOXA-23 were detected in all isolates, whereas blaPER-1 and blaNDM-1 genes were present in 7.4% and 3.7% of isolates. All isolates had virulence genes, including genes in iron acquisition system, biofilm formation and secretion systems. The plasmids in XDR-AB belonged to GR2 (100%), GR6 (40.7%), and GR1 (7.4%). Multilocus sequence typing sequence types (STs) were further investigated. The data demonstrated that XDR-AB isolates had nine STs: ST195 (n = 4), ST208 (n = 4), ST368 (n = 1), ST451 (n = 5), ST457 (n = 2), ST1947 (n = 1), ST1166 (n = 7), including two novel STs namely ST1682 (n = 2) and ST1684 (n = 1). We observed that the majority ST1166 (25.9%) was associated with the prevalence of GR2 and GR6 plasmids and traU virulence gene. Genome-based single nucleotide polymorphism phylogenetic analysis of the isolates with two novel ST types indicated that the two isolates belonged to the international clone II (IC2) within the same cluster. In conclusion, our data showed the dissemination of XDR-AB isolates harbored virulence genes and antibiotic resistance genes among four hospitals in Thailand. The results highlighted the difficulty posed for the empirical treatment of the patients with the A. baumannii infection.
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Affiliation(s)
- Phattaraporn Kongthai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Rapee Thummeepak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Udomluk Leungtongkam
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Renuka Pooarlai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Thawatchai Kitti
- Faculty of Oriental Medicine, Chiang Rai College, Chiang Rai, Thailand
| | - Aunchalee Thanwisai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Andrew D Millard
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, Leicester, United Kingdom
| | - Sutthirat Sitthisak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand.,Center of Excellence in Medical Biotechnology, Naresuan University, Phitsanulok, Thailand
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83
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Abstract
Active efflux of antibiotics preventing their accumulation to toxic intracellular concentrations contributes to clinically relevant multidrug resistance. Inhibition of active efflux potentiates antibiotic activity, indicating that efflux inhibitors could be used in combination with antibiotics to reverse drug resistance. Expression of ramA by Salmonella enterica serovar Typhimurium increases in response to efflux inhibition, irrespective of the mode of inhibition. We hypothesized that measuring ramA promoter activity could act as a reporter of efflux inhibition. A rapid, inexpensive, and high-throughput green fluorescent protein (GFP) screen to identify efflux inhibitors was developed, validated, and implemented. Two chemical compound libraries were screened for compounds that increased GFP production. Fifty of the compounds in the 1,200-compound Prestwick chemical library were identified as potential efflux inhibitors, including the previously characterized efflux inhibitors mefloquine and thioridazine. There were 107 hits from a library of 47,168 proprietary compounds from L. Hoffmann La Roche; 45 were confirmed hits, and a dose response was determined. Dye efflux and accumulation assays showed that 40 Roche and three Prestwick chemical library compounds were efflux inhibitors. Most compounds had specific efflux-inhibitor-antibiotic combinations and/or species-specific synergy in antibiotic disc diffusion and checkerboard assays performed with Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and Salmonella Typhimurium. These data indicate that both narrow-spectrum and broad-spectrum combinations of efflux inhibitors with antibiotics can be found. Eleven novel efflux inhibitor compounds potentiated antibiotic activities against at least one species of Gram-negative bacteria, and data revealing an E. coli mutant with loss of AcrB function suggested that these are AcrB inhibitors.IMPORTANCE Multidrug-resistant Gram-negative bacteria pose a serious threat to human and animal health. Molecules that inhibit multidrug efflux offer an alternative approach to resolving the challenges caused by antibiotic resistance, by potentiating the activity of old, licensed, and new antibiotics. We have developed, validated, and implemented a high-throughput screen and used it to identify efflux inhibitors from two compound libraries selected for their high chemical and pharmacological diversity. We found that the new high-throughput screen is a valuable tool to identify efflux inhibitors, as evidenced by the 43 new efflux inhibitors described in this study.
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84
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Liu L, Shen P, Zheng B, Yu W, Ji J, Xiao Y. Comparative Genomic Analysis of 19 Clinical Isolates of Tigecycline-Resistant Acinetobacter baumannii. Front Microbiol 2020; 11:1321. [PMID: 32733395 PMCID: PMC7358374 DOI: 10.3389/fmicb.2020.01321] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 05/25/2020] [Indexed: 02/01/2023] Open
Abstract
To assess the genomic profiles of tigecycline (Tgc)-resistant Acinetobacter baumannii, including antibiotic resistance (AR) genes and virulence factors (VF), whole-genome shotgun sequencing was performed on 19 Tgc-resistant (TgcR) A. baumannii strains collected in a tertiary hospital during the early phase of the clinical introduction of Tgc in China from late 2012 to mid-2014. The major sample types containing TgcR strains were sputum and drain fluid. Data from an average of 624 Mbp of sequence was generated on each bacterial genome, with Q30 quality of 90%, and an average coverage of 96.6%. TCDC-AB0715 was used as a reference genome. The genome sequences were annotated for functional elements including AR genes, VFs, genome islands, and inserted sequences before they were comparatively analyzed. The antibiotic susceptibility phenotypes of the strains were examined by a broth microdilution method to determine the minimal inhibitory concentration (MIC) of strains against major clinical antibiotics. The AR genes (ARGs) were annotated using the Comprehensive Antibiotic Resistance Database (CARD). Thirty-three ARGs were shared by all 19 TgcR strains, and 24 ARGs were distributed differently among strains. A total of 391 VFs were found to be diversely distributed in all TgcR strains. Based on ARG number distribution, the 19 TgcR strains were divided into several groups. Highly differentiated genes included gpi, mphG, armA, msrE, adec, catB8, aadA, sul1, blaOXA–435, aph3i, and blaTEM–1, which may represent gene markers for TgcR A. baumannii sub-types. In addition, when compared with Tgc-sensitive (TgcS) strains collected during the same period, TgcR strains featured enrichment of ARGs including aph6id, aph3ib, and teta. Compared with 26 other whole-genome sequences of A. baumannii deposited in GeneBank, TgcR strains in this study commonly lacked the EF-Tu mutation for elfamycin resistance. Previous investigation of three A. baumannii strains isolated from one patient indicated genomic exchange and a homologous recombination event associated with generation of tigecycline resistance. This study further analyzed additional TgcR strains. Phylogenetic analysis revealed a close evolutionary relationship between 19 TgcR strains and to isolates in East and Northeast China. In short, the comprehensive functional and comparative genomic analysis of 19 clinical TgcR A. baumannii strains isolated in the early stage of Tgc usage in China revealed their close phylogenetic relationship yet variable genetic background involving multiple resistance mechanisms. Using a simple ARG or VF gene number diversity method and marker genes, TgcR strain sub-types can be identified. The distinct characteristics of TgcR A. baumannii strains with versatile genomic resistance and regulation patterns raise concern regarding prediction and control of Tgc resistance in the clinic.
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Affiliation(s)
- Lin Liu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
| | - Ping Shen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
| | - Beiwen Zheng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
| | - Wei Yu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
| | - Jinru Ji
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
| | - Yonghong Xiao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
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85
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Antibiotic Resistance Profiles, Molecular Mechanisms and Innovative Treatment Strategies of Acinetobacter baumannii. Microorganisms 2020; 8:microorganisms8060935. [PMID: 32575913 PMCID: PMC7355832 DOI: 10.3390/microorganisms8060935] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 12/18/2022] Open
Abstract
Antibiotic resistance is one of the biggest challenges for the clinical sector and industry, environment and societal development. One of the most important pathogens responsible for severe nosocomial infections is Acinetobacter baumannii, a Gram-negative bacterium from the Moraxellaceae family, due to its various resistance mechanisms, such as the β-lactamases production, efflux pumps, decreased membrane permeability and altered target site of the antibiotic. The enormous adaptive capacity of A. baumannii and the acquisition and transfer of antibiotic resistance determinants contribute to the ineffectiveness of most current therapeutic strategies, including last-line or combined antibiotic therapy. In this review, we will present an update of the antibiotic resistance profiles and underlying mechanisms in A. baumannii and the current progress in developing innovative strategies for combating multidrug-resistant A. baumannii (MDRAB) infections.
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86
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Hamidian M, Nigro SJ. Emergence, molecular mechanisms and global spread of carbapenem-resistant Acinetobacter baumannii. Microb Genom 2020; 5. [PMID: 31599224 PMCID: PMC6861865 DOI: 10.1099/mgen.0.000306] [Citation(s) in RCA: 152] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen that has emerged as a global threat because of high levels of resistance to many antibiotics, particularly those considered to be last-resort antibiotics, such as carbapenems. Although alterations in the efflux pump and outer membrane proteins can cause carbapenem resistance, the main mechanism is the acquisition of carbapenem-hydrolyzing oxacillinase-encoding genes. Of these, oxa23 is by far the most widespread in most countries, while oxa24 and oxa58 appear to be dominant in specific regions. Historically, much of the global spread of carbapenem resistance has been due to the dissemination of two major clones, known as global clones 1 and 2, although new lineages are now common in some parts of the world. The analysis of all publicly available genome sequences performed here indicates that ST2, ST1, ST79 and ST25 account for over 71 % of all genomes sequenced to date, with ST2 by far the most dominant type and oxa23 the most widespread carbapenem resistance determinant globally, regardless of clonal type. Whilst this highlights the global spread of ST1 and ST2, and the dominance of oxa23 in both clones, it could also be a result of preferential selection of carbapenem-resistant strains, which mainly belong to the two major clones. Furthermore, ~70 % of the sequenced strains have been isolated from five countries, namely the USA, PR China, Australia, Thailand and Pakistan, with only a limited number from other countries. These genomes are a vital resource, but it is currently difficult to draw an accurate global picture of this important superbug, highlighting the need for more comprehensive genome sequence data and genomic analysis.
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Affiliation(s)
- Mohammad Hamidian
- The ithree institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Steven J Nigro
- Communicable Diseases Branch, Health Protection NSW, St Leonards, NSW 2065, Australia
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87
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M Campos JC, Antunes LCM, Ferreira RBR. Global priority pathogens: virulence, antimicrobial resistance and prospective treatment options. Future Microbiol 2020; 15:649-677. [DOI: 10.2217/fmb-2019-0333] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Salmonella spp. are part of a group of pathogens that pose a major threat to human health due to the emergence of multidrug-resistant strains. Moreover, these bacteria have several virulence factors that allow them to successfully colonize their hosts, such as toxins and the ability to produce biofilms, resulting in an urgent need to develop new strategies to fight these pathogens. In this review, we compile the most up-to-date information on the epidemiology, virulence and resistance of these clinically important microorganisms. Additionally, we address new therapeutic alternatives, with a focus on molecules with antivirulence activity, which are considered promising to combat multidrug-resistant bacteria.
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Affiliation(s)
- Juliana C de M Campos
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luis CM Antunes
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Rosana BR Ferreira
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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88
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Álvarez VE, Quiroga MP, Galán AV, Vilacoba E, Quiroga C, Ramírez MS, Centrón D. Crucial Role of the Accessory Genome in the Evolutionary Trajectory of Acinetobacter baumannii Global Clone 1. Front Microbiol 2020; 11:342. [PMID: 32256462 PMCID: PMC7093585 DOI: 10.3389/fmicb.2020.00342] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 02/17/2020] [Indexed: 01/08/2023] Open
Abstract
Acinetobacter baumannii is one of the most important nosocomial pathogens able to rapidly develop extensive drug resistance. Here, we study the role of accessory genome in the success of the globally disseminated clone 1 (GC1) with functional and genomic approaches. Comparative genomics was performed with available GC1 genomes (n = 106) against other A. baumannii high-risk and sporadic clones. Genetic traits related to accessory genome were found common and conserved along time as two novel regions of genome plasticity, and a CRISPR-Cas system acquired before clonal diversification located at the same loci as “sedentary” modules. Although identified within hotspot for recombination, other block of accessory genome was also “sedentary” in lineage 1 of GC1 with signs of microevolution as the AbaR0-type genomic island (GI) identified in A144 and in A155 strains which were maintained one month in independent experiments without antimicrobial pressure. The prophage YMC/09/02/B1251_ABA_BP was found to be “mobile” since, although it was shared by all GC1 genomes, it showed high intrinsic microevolution as well as mobility to different insertion sites. Interestingly, a wide variety of Insertion Sequences (IS), probably acquired by the flow of plasmids related to Rep_3 superfamily was found. These IS showed dissimilar genomic location amongst GC1 genomes presumably associated with promptly niche adaptation. On the other hand, a type VI secretion system and three efflux pumps were subjected to deep processes of genomic loss in A. baumannii but not in GC1. As a whole, these findings suggest that preservation of some genetic modules of accessory genome harbored by strains from different continents in combination with great plasticity of IS and varied flow of plasmids, may be central features of the genomic structure of GC1. Competition of A144 and A155 versus A118 (ST 404/ND) without antimicrobial pressure suggested a higher ability of GC1 to grow over a clone with sporadic behavior which explains, from an ecological perspective, the global achievement of this successful pandemic clone in the hospital habitat. Together, these data suggest an essential role of still unknown properties of “mobile” and “sedentary” accessory genome that is preserved over time under different antibiotic or stress conditions.
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Affiliation(s)
- Verónica Elizabeth Álvarez
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - María Paula Quiroga
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Angélica Viviana Galán
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Elisabet Vilacoba
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Cecilia Quiroga
- Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - María Soledad Ramírez
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA, United States
| | - Daniela Centrón
- Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
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89
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Ayoub Moubareck C, Hammoudi Halat D. Insights into Acinetobacter baumannii: A Review of Microbiological, Virulence, and Resistance Traits in a Threatening Nosocomial Pathogen. Antibiotics (Basel) 2020; 9:antibiotics9030119. [PMID: 32178356 PMCID: PMC7148516 DOI: 10.3390/antibiotics9030119] [Citation(s) in RCA: 201] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/01/2020] [Accepted: 03/02/2020] [Indexed: 12/12/2022] Open
Abstract
Being a multidrug-resistant and an invasive pathogen, Acinetobacter baumannii is one of the major causes of nosocomial infections in the current healthcare system. It has been recognized as an agent of pneumonia, septicemia, meningitis, urinary tract and wound infections, and is associated with high mortality. Pathogenesis in A. baumannii infections is an outcome of multiple virulence factors, including porins, capsules, and cell wall lipopolysaccharide, enzymes, biofilm production, motility, and iron-acquisition systems, among others. Such virulence factors help the organism to resist stressful environmental conditions and enable development of severe infections. Parallel to increased prevalence of infections caused by A. baumannii, challenging and diverse resistance mechanisms in this pathogen are well recognized, with major classes of antibiotics becoming minimally effective. Through a wide array of antibiotic-hydrolyzing enzymes, efflux pump changes, impermeability, and antibiotic target mutations, A. baumannii models a unique ability to maintain a multidrug-resistant phenotype, further complicating treatment. Understanding mechanisms behind diseases, virulence, and resistance acquisition are central to infectious disease knowledge about A. baumannii. The aims of this review are to highlight infections and disease-producing factors in A. baumannii and to touch base on mechanisms of resistance to various antibiotic classes.
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Affiliation(s)
- Carole Ayoub Moubareck
- College of Natural and Health Sciences, Zayed University, Dubai P.O. Box 144534, UAE
- Correspondence: ; Tel.: +971-4-402-1745
| | - Dalal Hammoudi Halat
- Department of Pharmaceutical Sciences, School of Pharmacy, Lebanese International University, Beirut, Bekaa Campuses 1103, Lebanon;
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90
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Yilmaz Ş, Hasdemir U, Aksu B, Altınkanat Gelmez G, Söyletir G. Alterations in AdeS and AdeR regulatory proteins in 1-(1-naphthylmethyl)-piperazine responsive colistin resistance of Acinetobacter baumannii. J Chemother 2020; 32:286-293. [PMID: 32131715 DOI: 10.1080/1120009x.2020.1735118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Colistin resistant Acinetobacter baumannii strains are of great concern worldwide. However, the role of efflux pumps in colistin resistance needs to be elucidated. We investigated the changes in colistin MICs of 29 colistin resistant A. baumannii isolates in response to resistance-nodulation-division (RND)-type efflux pump inhibitor (EPI) and the alterations in AdeR and AdeS two-component regulatory proteins previously associated with the overproduction of AdeAB. The EPI, 1-(1-naphthylmethyl)-piperazine (NMP), led to significant reductions in colistin MICs. At least one of the following amino acid substitutions was found in AdeS proteins from 18 of the isolates: L172P, A94V, V27I, V32I, G186V, and G164A. Besides, A136V and V120I alterations were identified in AdeR from five isolates. Therefore, EPI-responsive colistin resistance in our isolates is most likely due to the action of an RND-type efflux system. The underlying mechanism of resistance might be the result of certain AdeRS alterations, leading to AdeAB overexpression.
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Affiliation(s)
- Şerife Yilmaz
- Department of Medical Microbiology, Karabuk University Training and Research Hospital, Karabuk, Turkey
| | - Ufuk Hasdemir
- Department of Medical Microbiology, Marmara University, School of Medicine, Istanbul, Turkey
| | - Burak Aksu
- Department of Medical Microbiology, Marmara University, School of Medicine, Istanbul, Turkey
| | | | - Güner Söyletir
- Department of Medical Microbiology, Marmara University, School of Medicine, Istanbul, Turkey
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91
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Khazaal SS, Al-Kadmy IM, Aziz SN. Mechanism of pathogenesis in multidrug resistant Acinetobacter baumannii isolated from intensive care unit. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2019.100557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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92
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Abdi SN, Ghotaslou R, Ganbarov K, Mobed A, Tanomand A, Yousefi M, Asgharzadeh M, Kafil HS. Acinetobacter baumannii Efflux Pumps and Antibiotic Resistance. Infect Drug Resist 2020; 13:423-434. [PMID: 32104014 PMCID: PMC7024869 DOI: 10.2147/idr.s228089] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/13/2019] [Indexed: 01/03/2023] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen and gram-negative coccobacillus that is responsible for opportunistic infections, pneumonia, and infections of the urinary tract, bloodstream, skin, and soft tissue. This bacterium poses a major public health problem due to inducing resistance to several drugs, isolates, multidrug treatment, and occasionally pan drugs. Drug resistance is not only a major concern caused by A. baumannii but also is considered as the main challenge in many other pathogens. Several factors such as the efflux pump are associated with antibiotic resistance, biofilm production, and genetic mutations. In this review, A. baumannii is introduced in then some of the practical works conducted on the existing efflux pump are reviewed. The importance of the efflux pump is considered in this paper in relation to the antibiotic resistance and mechanisms developed for the inhibition of these pumps as well.
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Affiliation(s)
- Seyyed Naser Abdi
- Drug Applied Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.,Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Reza Ghotaslou
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Khudaverdi Ganbarov
- Department of Microbiology, Baku State University, Baku, Republic of Azerbaijan
| | - Ahmad Mobed
- Drug Applied Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Asghar Tanomand
- Department of Basic Sciences, Maragheh University of Medical Sciences, Maragheh, Iran
| | - Mehdi Yousefi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Asgharzadeh
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hossein Samadi Kafil
- Drug Applied Research Center, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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93
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Zhu Y, Lu J, Zhao J, Zhang X, Yu HH, Velkov T, Li J. Complete genome sequence and genome-scale metabolic modelling of Acinetobacter baumannii type strain ATCC 19606. Int J Med Microbiol 2020; 310:151412. [PMID: 32081464 DOI: 10.1016/j.ijmm.2020.151412] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/29/2019] [Accepted: 02/03/2020] [Indexed: 12/11/2022] Open
Abstract
Multidrug-resistant (MDR) Acinetobacter baumannii is a critical threat to global health. The type strain ATCC 19606 has been widely used in studying the virulence, pathogenesis and mechanisms of antimicrobial resistance in A. baumannii. However, the lack of a complete genome sequence is a hindrance towards detailed bioinformatic studies. Here we report the generation of a complete genome for ATCC 19606 using PacBio sequencing. ATCC 19606 genome consists of a 3,980,848-bp chromosome and a 9,450-bp plasmid pMAC, and harbours a chromosomal dihydropteroate synthase gene sul2 conferring resistance to sulphonamides and a plasmid-borne ohr gene conferring resistance to peroxides. The genome also contains 69 virulence genes involved in surface adherence, biofilm formation, extracellular phospholipase, iron uptake, immune evasion and quorum sensing. Insertion sequences ISCR2 and ISAba11 are embedded in a 36.1-Kb genomic island, suggesting an IS-mediated large-scale DNA recombination. Furthermore, a genome-scale metabolic model (GSMM) iATCC19606v2 was constructed using the complete genome annotation. The model iATCC19606v2 incorporated a periplasmic compartment, 1,422 metabolites, 2,114 reactions and 1,009 genes, and a set of protein crowding constraints taking into account enzyme abundance limitation. The prediction of bacterial growth on 190 carbon and 95 nitrogen sources achieved a high accuracy of 85.6% compared to Biolog experiment results. Based upon two transposon mutant libraries of AB5075 and ATCC 17978, the predictions of essential genes reached the accuracy of 87.6% and 82.1%, respectively. Together, the complete genome sequence and high-quality GSMM iATCC19606v2 provide valuable tools for antimicrobial systems pharmacological investigations on A. baumannii.
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Affiliation(s)
- Yan Zhu
- Biomedicine Discovery Institute, Infection & Immunity Program and Department of Microbiology, Monash University, Melbourne, VIC, 3800, Australia.
| | - Jing Lu
- Biomedicine Discovery Institute, Infection & Immunity Program and Department of Microbiology, Monash University, Melbourne, VIC, 3800, Australia.
| | - Jinxin Zhao
- Biomedicine Discovery Institute, Infection & Immunity Program and Department of Microbiology, Monash University, Melbourne, VIC, 3800, Australia.
| | - Xinru Zhang
- Biomedicine Discovery Institute, Infection & Immunity Program and Department of Microbiology, Monash University, Melbourne, VIC, 3800, Australia.
| | - Heidi H Yu
- Biomedicine Discovery Institute, Infection & Immunity Program and Department of Microbiology, Monash University, Melbourne, VIC, 3800, Australia.
| | - Tony Velkov
- Department of Pharmacology and Therapeutics, University of Melbourne, Melbourne, VIC, 3010, Australia.
| | - Jian Li
- Biomedicine Discovery Institute, Infection & Immunity Program and Department of Microbiology, Monash University, Melbourne, VIC, 3800, Australia.
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94
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Antimicrobial and antibiofilm activities of Clostridium butyricum supernatant against Acinetobacter baumannii. Arch Microbiol 2020; 202:1059-1068. [PMID: 32020245 DOI: 10.1007/s00203-020-01823-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 01/15/2020] [Accepted: 01/28/2020] [Indexed: 01/03/2023]
Abstract
Acinetobacter baumannii is the major nosocomial pathogen that causes serious infections such as ventilator-associated pneumonia and bacteremia due to its biofilms. Hence, this study investigated the antimicrobial and antibiofilm potentials of cell-free supernatants (CFS) obtained from Clostridium butyricum, as probiotic, against A. baumannii. Our results demonstrated that C. butyricum CFS inhibited A. baumannii cell growth in planktonic culture. Also, C. butyricum CFS not only inhibited the biofilm development and dispersed mature biofilms, but also suppressed the metabolic activity of biofilm cells, showing antibiofilm activity. The biofilm components reduced by C. butyricum CFS were observed via confocal laser scanning microscopy. In addition, C. butyricum CFS exhibited antivirulence effect by inhibiting the motility of A. baumannii. Furthermore, C. butyricum CFS significantly downregulated the expression of efflux pump-related genes including adeA, adeB and adeC in A. baumannii. Our data demonstrate that C. butyricum CFS showed antimicrobial and antibiofilm effects on A. baumannii. These effects are closely associated with suppression of motility and efflux pump-related genes in A. baumannii. The findings suggest that C. butyricum CFS can be used as a new therapeutic alternative against biofilm-associated infection caused by multidrug-resistant A. baumannii.
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95
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Tsai YK, Liou CH, Lin JC, Fung CP, Chang FY, Siu LK. Effects of different resistance mechanisms on antimicrobial resistance in Acinetobacter baumannii: a strategic system for screening and activity testing of new antibiotics. Int J Antimicrob Agents 2020; 55:105918. [PMID: 32007593 DOI: 10.1016/j.ijantimicag.2020.105918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/14/2020] [Accepted: 01/25/2020] [Indexed: 01/08/2023]
Abstract
A total of 50 engineered strains with various antimicrobial resistance mechanisms were constructed by in-frame deletion, site-directed mutagenesis and plasmid transformation from two fully-susceptible strains (Acinetobacter baumannii KAB1544 and ATCC 17978), including 31 strains with chromosomally-mediated resistance and 19 with plasmid-mediated resistance. Each of the 50 resistance mechanisms showed similar effects on the minimum inhibitory concentrations (MICs) of KAB1544 and ATCC 17978. Compared with the parental strains, the engineered strains related to some efflux pumps showed a significant (≥4-fold) difference in the MICs of β-lactams, quinolones, aminoglycosides, tetracyclines, folate pathway inhibitors and/or phenicols, whereas no significant effects on the MICs were found for the engineered strains lacking OmpA, CarO, Omp25, Omp33, OmpW or OprD. Mechanisms due to GyrA/ParC mutations, β-lactamases, aminoglycoside-modifying enzymes, 16S rRNA methylases and tet resistance genes contributed their corresponding resistance, as previously published. In conclusion, strains constructed in this study have clear resistance mechanisms and can be used to screen and assess compounds against specific resistance mechanisms for treating Acinetobacter. In addition to our previously published system for Enterobacteriaceae, the combination of these two systems could increase the coverage of bacterial types for drug assessment and facilitate the selection process of new candidates in drug development against drug-resistant superbugs.
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Affiliation(s)
- Yu-Kuo Tsai
- KeMyth Biotech Company, Incubation Center, National Health Research Institutes, Miaoli, Taiwan
| | - Ci-Hong Liou
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Jung-Chung Lin
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Chang-Phone Fung
- Section 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
| | - L Kristopher Siu
- KeMyth Biotech Company, Incubation Center, National Health Research Institutes, Miaoli, Taiwan; Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan; National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan.
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96
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Shi Y, Hua X, Xu Q, Yang Y, Zhang L, He J, Mu X, Hu L, Leptihn S, Yu Y. Mechanism of eravacycline resistance in Acinetobacter baumannii mediated by a deletion mutation in the sensor kinase adeS, leading to elevated expression of the efflux pump AdeABC. INFECTION GENETICS AND EVOLUTION 2020; 80:104185. [PMID: 31923725 DOI: 10.1016/j.meegid.2020.104185] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 12/10/2019] [Accepted: 01/06/2020] [Indexed: 11/17/2022]
Abstract
Acinetobacter baumannii is an important pathogen and presents a major burden in healthcare as strains frequently cause hospital associated opportunistic infections with high mortality rates. Due to increasing numbers of drug resistant A. baumannii strains, newly developed antibiotics are being used to treat infections caused by such strains. One novel synthetic antibiotic of the tetracycline class with activity against A. baumannii is eravacycline. To investigate possible mechanisms of eravacycline resistance, we performed an in vitro evolution experiment to select for an eravacycline resistant strain, with the clinical isolate MDR-ZJ06 as parental strain. We obtained a strain designated MDR-ZJ06-E6 that was able to grow in 64-fold MIC. Genomic mutations were identified by whole genome sequencing, where we found a deletion mutation in the gene adeS. Using complementation experiments, including growth rate determination and antibiotics susceptibility testing, we could confirm that this mutation was responsible for eravacycline resistance of strain MDR-ZJ06-E6. As a mechanism of resistance, we identified a significant overexpression of the efflux pump AdeABC which seems to be regulated by the mutation in adeS in A. baumannii.
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Affiliation(s)
- Yue Shi
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China.
| | - Qingye Xu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yunxing Yang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Linyue Zhang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Jintao He
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Xinli Mu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Lihua Hu
- Department of critical care medicine, Hangzhou General Hospital of Chinese People's Armed Police, Hangzhou, China
| | - Sebastian Leptihn
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Hangzhou, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China; State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
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97
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Amin M, Navidifar T, Shooshtari FS, Rashno M, Savari M, Jahangirmehr F, Arshadi M. Association Between Biofilm Formation, Structure, and the Expression Levels of Genes Related to biofilm formation and Biofilm-Specific Resistance of Acinetobacter baumannii Strains Isolated from Burn Infection in Ahvaz, Iran. Infect Drug Resist 2019; 12:3867-3881. [PMID: 31853190 PMCID: PMC6914661 DOI: 10.2147/idr.s228981] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/15/2019] [Indexed: 12/18/2022] Open
Abstract
Background The ability of biofilm formation is an effective way for Acinetobacter baumannii survival from stressed conditions. This present study was aimed to evaluate the association between biofilm formation, structure, the expression levels of genes related to biofilm formation and biofilm-specific resistance of A. baumannii strains isolated from burn infections in Ahvaz, Iran. Methods In this study, we assessed the antibiotic susceptibilities, ERIC-PCR typing, capacity of biofilm formation and biofilm structure of 64 A. baumannii isolates collected from burn infections. The distribution and the expression levels of genes involved in the biofilm formation including bap, ompA, abaI, pgaA and csuE were assessed by PCR and real-time PCR, respectively. Results We classified A. baumannii isolates in 14 clonal types of ERIC-PCR. Most A. baumannii isolates were resistant to all antibiotics tested except to tigecycline and colistin and had the biofilm formation capability but with different capacities. There was a significant inverse relationship between resistance to antibiotic agents and biofilm formation. The biofilm matrix of 50 strains consisted of polysaccharides together with DNA or proteins. The genes involved in the biofilm formation were detected in both biofilm-forming and non-biofilm forming; however, the expression levels of these genes were higher in biofilm producers compared with non-producers. Conclusion The biofilm cells exhibited dramatically decreased susceptibility to antibiotic agents; hence, they have great significance for public health. Therefore, the determination of antibiotic susceptibilities in biofilm and planktonic mode, molecular typing, and capacity of biofilm formation in clinical setting is essential.
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Affiliation(s)
- Mansour Amin
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Tahereh Navidifar
- Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Cellular and Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Farkhondeh Saleh Shooshtari
- Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Infertility Research and Treatment Center of Jahad Daneshgahi, Ahvaz, Khuzestan, Iran
| | - Mohammad Rashno
- Cellular and Molecular Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Department of Immunology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohammad Savari
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Fatemeh Jahangirmehr
- Pain Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mania Arshadi
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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98
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Penesyan A, Nagy SS, Kjelleberg S, Gillings MR, Paulsen IT. Rapid microevolution of biofilm cells in response to antibiotics. NPJ Biofilms Microbiomes 2019; 5:34. [PMID: 31728201 PMCID: PMC6834608 DOI: 10.1038/s41522-019-0108-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/03/2019] [Indexed: 02/08/2023] Open
Abstract
Infections caused by Acinetobacter baumannii are increasingly antibiotic resistant, generating a significant public health problem. Like many bacteria, A. baumannii adopts a biofilm lifestyle that enhances its antibiotic resistance and environmental resilience. Biofilms represent the predominant mode of microbial life, but research into antibiotic resistance has mainly focused on planktonic cells. We investigated the dynamics of A. baumannii biofilms in the presence of antibiotics. A 3-day exposure of A. baumannii biofilms to sub-inhibitory concentrations of antibiotics had a profound effect, increasing biofilm formation and antibiotic resistance in the majority of biofilm dispersal isolates. Cells dispersing from biofilms were genome sequenced to identify mutations accumulating in their genomes, and network analysis linked these mutations to their phenotypes. Transcriptomics of biofilms confirmed the network analysis results, revealing novel gene functions of relevance to both resistance and biofilm formation. This approach is a rapid and objective tool for investigating resistance dynamics of biofilms.
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Affiliation(s)
- Anahit Penesyan
- 1Department of Molecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109 Australia.,2School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052 Australia
| | - Stephanie S Nagy
- 1Department of Molecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109 Australia
| | - Staffan Kjelleberg
- 3Singapore Centre for Environmental Life Sciences Engineering, 60 Nanyang Drive, SBS-01N-27, Singapore, 637551 Singapore.,4School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore.,5School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052 Australia
| | - Michael R Gillings
- 6Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109 Australia
| | - Ian T Paulsen
- 1Department of Molecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109 Australia
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99
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Abdi SN, Ghotaslou R, Asgharzadeh M, Mehramouz B, Hasani A, Baghi HB, Tanomand A, Narenji H, Yousefi B, Gholizadeh P, Yousefi M, Bastami M, Ganbarov K, Samadi Kafil H. AdeB efflux pump gene knockdown by mRNA mediated peptide nucleic acid in multidrug resistance Acinetobacter baumannii. Microb Pathog 2019; 139:103825. [PMID: 31706000 DOI: 10.1016/j.micpath.2019.103825] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/25/2019] [Accepted: 10/28/2019] [Indexed: 12/01/2022]
Abstract
Multidrug-resistant Acinetobacter baumannii isolates cause critical problems in health-care environments. AdeABC is a resistance-nodulation-cell division (RND)-type multidrug efflux pump conferring resistance to clinically essential antibiotics in A. baumannii, such as ciprofloxacin. This study aimed to target adeB gene with antisense peptide nucleic acid (PNA) and investigate its effect on resistance to antibiotics. NCBI database was used to design appropriate PNA to target adeB gene, by connecting PNA to mRNA, the translation of mRNA can be prevented. Three clinical isolates and A. baumannii ATCC 17978 were treated with the designed PNA by electroporation and competence procedure. Minimum Inhibitory concentration (MIC) of ciprofloxacin, colistin, and tetracycline were determined by microbroth dilution method. In addition, the expression level of adeB gene was measured by quantitative real-time PCR (qRT-PCR). Isolates used in this study had mutations in gyrA and parC genes corresponding to resistance to ciprofloxacin. MIC of resistance to ciprofloxacin after treatment with PNA was reduced from 32 μg/ml to16 μg/ml in A. baumannii ATCC 17978 isolate. Susceptibility level of tetracycline, in the 2 clinical isolates was decreased from 64 μg/ml to 32 μg/ml and in the other isolate was reduced from 128 μg/ml to 64 μg/ml. The expression level of adeB gene was decreased in A. baumannii ATCC 17978 (P > 0.01) but not in clinical isolate (P = 0.107). Findings of the present study indicate overexpression of adeB efflux pump has extra effect on resistance to antibiotics in isolates with a defined mechanism of resistance. Antisense technology is a feasible technique to suppress the function of these genes, which may be further exploited to control multidrug-resistant isolates.
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Affiliation(s)
- Seyed Naser Abdi
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran; Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Reza Ghotaslou
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Asgharzadeh
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Bahareh Mehramouz
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Alka Hasani
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Asghar Tanomand
- Department of Microbiology, Maragheh University of Medical Sciences, Maragheh, Iran
| | - Hanar Narenji
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Bahman Yousefi
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Pourya Gholizadeh
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mehdi Yousefi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Milad Bastami
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Hossein Samadi Kafil
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
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100
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Lima WG, Silva Alves GC, Sanches C, Antunes Fernandes SO, de Paiva MC. Carbapenem-resistant Acinetobacter baumannii in patients with burn injury: A systematic review and meta-analysis. Burns 2019; 45:1495-1508. [DOI: 10.1016/j.burns.2019.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/09/2019] [Accepted: 07/03/2019] [Indexed: 12/25/2022]
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