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Hwang D, Kim HJ. Increased antimicrobial resistance of acid-adapted pathogenic Escherichia coli, and transcriptomic analysis of polymyxin-resistant strain. Microb Pathog 2024; 196:106974. [PMID: 39307200 DOI: 10.1016/j.micpath.2024.106974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 09/11/2024] [Accepted: 09/20/2024] [Indexed: 09/27/2024]
Abstract
This study investigated the acid adaptation and antimicrobial resistance of seven pathogenic Escherichia coli strains and one commensal strain under nutrient-rich acidic conditions. After acid adaptation, three pathogenic E. coli survived during 100 h incubation in tryptic soy broth at pH 3.25. Acid-adapted (AA) strains showed increased resistance to antimicrobials including ampicillin, ciprofloxacin and especially polymyxins (colistin and polymyxin B), the last resort antimicrobial for multidrug-resistant Gram-negative bacteria. Enterotoxigenic E. coli strain (NCCP 13717) showed significantly increased resistance to acids and polymyxins. Transcriptome analysis of the AA NCCP 13717 revealed upregulation of genes related to the acid fitness island and the arn operon, which reduces lipopolysaccharide binding affinity at the polymyxin site of action. Genes such as eptA, tolC, and ompCF were also upregulated to alter the structure of the cell membrane, reducing the outer membrane permeability compared to the control, which is likely to be another mechanism for polymyxin resistance. This study highlights the emergence of antimicrobial resistance in AA pathogenic E. coli strains, particularly polymyxin resistance, and the mechanisms behind the increased antimicrobial resistance, providing important insights for the development of risk management strategies to effectively control the antimicrobial resistant foodborne pathogens.
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Affiliation(s)
- Daekeun Hwang
- Korea Food Research Institute, Wanju, Jeolla-buk, 55365, South Korea; Department of Food Biotechnology, University of Science and Technology, Daejeon, 34113, South Korea
| | - Hyun Jung Kim
- Korea Food Research Institute, Wanju, Jeolla-buk, 55365, South Korea; Department of Food Biotechnology, University of Science and Technology, Daejeon, 34113, South Korea.
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2
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Wang X, Meng T, Dai Y, Ou HY, Wang M, Tang B, Sun J, Cheng D, Pan T, Tan R, Qu H. High prevalence of polymyxin-heteroresistant carbapenem-resistant Klebsiella pneumoniae and its within-host evolution to resistance among critically ill scenarios. Infection 2024:10.1007/s15010-024-02365-z. [PMID: 39143437 DOI: 10.1007/s15010-024-02365-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Accepted: 07/29/2024] [Indexed: 08/16/2024]
Abstract
PURPOSE We aimed to explore the prevalence and within-host evolution of resistance in polymyxin-heteroresistant carbapenem-resistant Klebsiella pneumoniae (PHR-CRKP) in critically ill patients. METHODS We performed an epidemiological analysis of consecutive patients with PHR-CRKP from clinical cases. Our study investigated the within-host resistance evolution and its clinical significance during polymyxin exposure. Furthermore, we explored the mechanisms underlying the dynamic evolution of polymyxin resistance at both subpopulation and genetic levels, involved population analysis profile test, time-killing assays, competition experiments, and sanger sequencing. Additionally, comparative genomic analysis was performed on 713 carbapenemase-producing K. pneumoniae strains. RESULTS We enrolled 109 consecutive patients, and PHR-CRKP was found in 69.7% of patients without previous polymyxin exposure. 38.1% of PHR-CRKP isolates exhibited polymyxin resistance and led to therapeutic failure in critically ill scenarios. An increased frequency of resistant subpopulations was detected during PHR-CRKP evolution, with rapid regrowth of resistant subpopulations under high polymyxin concentrations, and a fitness cost in an antibiotic-free environment. Mechanistic analysis revealed that diverse mgrB insertions and pmrB hypermutations contributed to the dynamic changes in polymyxin susceptibility in dominant resistant subpopulations during PHR evolution, which were validated by comparative genomic analysis. Several deleterious mutations (e.g. pmrBLeu82Arg, pmrBSer85Arg) were firstly detected during PHR-CRKP evolution. Indeed, specific sequence types of K. pneumoniae demonstrated unique deletions and deleterious mutations. CONCLUSIONS Our study emphasizes the high prevalence of pre-existing heteroresistance in CRKP, which can lead to polymyxin resistance and fatal outcomes. Hence, it is essential to continuously monitor and observe the treatment response to polymyxins in appropriate critically ill scenarios.
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Affiliation(s)
- Xiaoli Wang
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin ER Road, Shanghai, 200025, China
| | - Tianjiao Meng
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin ER Road, Shanghai, 200025, China
| | - Yunqi Dai
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin ER Road, Shanghai, 200025, China
| | - Hong-Yu Ou
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Meng Wang
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Bin Tang
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin ER Road, Shanghai, 200025, China
| | - Jingyong Sun
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Decui Cheng
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin ER Road, Shanghai, 200025, China
| | - Tingting Pan
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin ER Road, Shanghai, 200025, China.
| | - Ruoming Tan
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin ER Road, Shanghai, 200025, China.
| | - Hongping Qu
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin ER Road, Shanghai, 200025, China.
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3
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Jiménez-Castellanos JC, Waclaw B, Meynert A, McAteer SP, Schneiders T. Rapid evolution of colistin resistance in a bioreactor model of infection of Klebsiella pneumoniae. Commun Biol 2024; 7:794. [PMID: 38951173 PMCID: PMC11217424 DOI: 10.1038/s42003-024-06378-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/23/2024] [Indexed: 07/03/2024] Open
Abstract
Colistin remains an important antibiotic for the therapeutic management of drug-resistant Klebsiella pneumoniae. Despite the numerous reports of colistin resistance in clinical strains, it remains unclear exactly when and how different mutational events arise resulting in reduced colistin susceptibility. Using a bioreactor model of infection, we modelled the emergence of colistin resistance in a susceptible isolate of K. pneumoniae. Genotypic, phenotypic and mathematical analyses of the antibiotic-challenged and un-challenged population indicates that after an initial decline, the population recovers within 24 h due to a small number of "founder cells" which have single point mutations mainly in the regulatory genes encoding crrB and pmrB that when mutated results in up to 100-fold reduction in colistin susceptibility. Our work underlines the rapid development of colistin resistance during treatment or exposure of susceptible K. pneumoniae infections having implications for the use of cationic antimicrobial peptides as a monotherapy.
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Affiliation(s)
- Juan-Carlos Jiménez-Castellanos
- Chemical Biology of Antibiotics, Centre for Infection & Immunity (CIIL), Pasteur Institute, INSERM U1019-CNRS UMR 9017, Lille, France
| | - Bartlomiej Waclaw
- School of Physics and Astronomy, The University of Edinburgh, JCMB, Edinburgh, UK.
- Dioscuri Centre for Physics and Chemistry of Bacteria, Institute of Physical Chemistry, Warsaw, Poland.
| | - Alison Meynert
- MRC Human Genetics Unit, MRC Institute of Genetics and Cancer, The University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Sean P McAteer
- Department of Bacteriology, The Roslin Institute and R(D) SVS, The University of Edinburgh, Easter Bush Campus, Midlothian, Edinburgh, UK
| | - Thamarai Schneiders
- Centre for Inflammation Research, Institute of Regeneration and Repair, Edinburgh Medical School, The University of Edinburgh, Edinburgh, UK.
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4
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Karami-Zarandi M, Rahdar HA, Esmaeili H, Ranjbar R. Klebsiella pneumoniae: an update on antibiotic resistance mechanisms. Future Microbiol 2023; 18:65-81. [PMID: 36632990 DOI: 10.2217/fmb-2022-0097] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Klebsiella pneumoniae colonizes mucosal surfaces of healthy humans and is responsible for one third of all Gram-negative infections in hospitalized patients. K. pneumoniae is compatible with acquiring antibiotic resistance elements such as plasmids and transposons encoding various β-lactamases and efflux pumps. Mutations in different proteins such as β-lactamases, efflux proteins, outer membrane proteins, gene replication enzymes, protein synthesis complexes and transcription enzymes also generate resistance to antibiotics. Biofilm formation is another strategy that facilitates antibiotic resistance. Resistant strains can be treated by combination therapy using available antibiotics, though proper management of antibiotic consumption in hospitals is important to reduce the emergence and proliferation of resistance to current antibiotics.
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Affiliation(s)
- Morteza Karami-Zarandi
- Department of Microbiology, School of Medicine, Zanjan University of Medical Sciences, Zanjan, 4513956111, Iran
| | - Hossein Ali Rahdar
- Department of Microbiology, School of Medicine, Iranshahr University of Medical Sciences, Iranshahr, 7618815676, Iran
| | - Hadi Esmaeili
- Applied Virology Research Center, Baqiyatallah University of Medical Sciences, Tehran, 1435916471, Iran
| | - Reza Ranjbar
- Molecular Biology Research Center, Systems Biology & Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, 1435916471, Iran
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Xu X, Zhu R, Lian S, Zhang H, Chen X, Fan L, Chen P, Cao Y. Risk Factors and Molecular Mechanism of Polymyxin B Resistance in Carbapenem-Resistant Klebsiella pneumoniae Isolates from a Tertiary Hospital in Fujian, China. Infect Drug Resist 2022; 15:7485-7494. [PMID: 36544993 PMCID: PMC9762268 DOI: 10.2147/idr.s391674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
Background The emergence of polymyxin B resistance among carbapenem-resistant Klebsiella pneumoniae (CRKP) causes clinical treatment to be more difficult. We aimed to investigate the risk factors and resistance mechanisms in the polymyxin resistant CRKP (PR-CRKP) strains. Methods From January 2021 to January 2022, 239 CRKP strains were selected, all of which were analyzed using antimicrobial susceptibility testing and clinical data. Polymerase chain reaction (PCR) was performed for the detection of resistance genes. RT-qPCR was used to quantify transcriptional levels of polymyxin resistance genes. Risk factors for polymyxin B resistant isolates were identified by logistic regression analysis. Results The resistance rate of polymyxin B was 5.02%. In all CRKP strains, 41.84% came from the ICU. The percentage of carbapenemase producing strains was 93.72%. The main carbapenem resistance gene was blaKPC (90.79%). In the 12 strains of PR-CRKP screened, pmrB and pmrK were overexpressed in all samples which were linked with polymyxin B resistance. Multivariate analysis showed that coronary heart disease may be an independent risk factor predisposing patients to polymyxin B resistance. Conclusion We determine the multifaceted mechanism and risk factors of polymyxin B resistance in CRKP. Polymyxin resistance is a complex and changing problem, and more research is required.
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Affiliation(s)
- Xiaohong Xu
- Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China
| | - Rongping Zhu
- Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China
| | - Siyan Lian
- Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China
| | - Hui Zhang
- Medical Technology and Engineering, Fujian Medical University, Fuzhou, Fujian, People’s Republic of China
| | - Xin Chen
- Medical Technology and Engineering, Fujian Medical University, Fuzhou, Fujian, People’s Republic of China
| | - Lingfang Fan
- Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China
| | - Peisong Chen
- Medical Technology and Engineering, Fujian Medical University, Fuzhou, Fujian, People’s Republic of China
| | - Yingping Cao
- Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China,Correspondence: Yingping Cao, Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China, Tel +86-133-6591-0806, Email
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Yasir M, Turner AK, Bastkowski S, Lott M, Holden ER, Telatin A, Page AJ, Webber MA, Charles IG. Genome-Wide Analysis of Innate Susceptibility Mechanisms of Escherichia coli to Colistin. Antibiotics (Basel) 2022; 11:antibiotics11111668. [PMID: 36421312 PMCID: PMC9687012 DOI: 10.3390/antibiotics11111668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/08/2022] [Accepted: 11/16/2022] [Indexed: 11/22/2022] Open
Abstract
Colistin is an antibiotic that has seen increasing clinical use for the treatment of human infections caused by Gram-negative pathogens, particularly due to the emergence of multidrug-resistant pathogens. Colistin resistance is also a growing problem and typically results from alterations to lipopolysaccharides mediated by phosphoethanolamine (pETn) transferase enzymes which can be encoded on the chromosome, or plasmids. In this study, we used 'TraDIS-Xpress' (Transposon Directed Insertion site Sequencing with expression), where a high-density transposon mutant library including outward facing promoters in Escherichia coli BW25113 identified genes involved in colistin susceptibility. We examined the genome-wide response of E. coli following exposure to a range of concentrations of colistin. Our TraDIS-Xpress screen confirmed the importance of overexpression of the two-component system basSR (which regulates pETn transferases) but also identified a wider range of genes important for survival in the presence of colistin, including genes encoding membrane associated proteins, DNA repair machinery, various transporters, RNA helicases, general stress response genes, fimbriae and phosphonate metabolism. Validation experiments supported a role in colistin susceptibility for novel candidate genes tested. TraDIS-Xpress is a powerful tool that expands our understanding of the wider landscape of genes involved in response to colistin susceptibility mechanisms.
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Affiliation(s)
- Muhammad Yasir
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
- Correspondence: ; Tel.: +44-1603255391
| | - A. Keith Turner
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
| | - Sarah Bastkowski
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
| | - Martin Lott
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
| | - Emma R. Holden
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
| | - Andrea Telatin
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
| | - Andrew J. Page
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
| | - Mark A. Webber
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
- Norwich Medical School, Norwich Research Park, Colney Lane, Norwich NR4 7TJ, UK
| | - Ian G. Charles
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich NR4 7UQ, UK
- Norwich Medical School, Norwich Research Park, Colney Lane, Norwich NR4 7TJ, UK
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7
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Meletiadis J, Paranos P, Tsala M, Pournaras S, Vourli S. Pharmacodynamics of colistin resistance in carbapenemase-producing Klebsiella pneumoniae: the double-edged sword of heteroresistance and adaptive resistance. J Med Microbiol 2022; 71. [PMID: 36201344 DOI: 10.1099/jmm.0.001565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Introduction. The presence of heteroresistant subpopulations and the development of resistance during drug exposure (adaptive resistance) limits colistin's efficacy against carbapenemase-producing Klebsiella pneumoniae (CP-Kp) isolates.Hypothesis/Gap statement. The pharmacokinetic/pharmacodynamic (PK/PD) characteristics of both types of colistin resistance against CP-Kp are unknown.Aim. We therefore studied the PK/PD characteristics of colistin resistance in an in vitro PK/PD model simulating clinical colistin exposures.Methods. Two K. pneumoniae clinical isolates, one non-CP-Kp and one CP-Kp, with colistin MICs of 0.5-1 mg l-1 at a final inoculum of 107 c.f.u. ml-1 were used in an in vitro PK/PD dialysis/diffusion closed model simulating 4.5 MU q12h and 3 MU q8h clinical dosing regimens. Heteroresistant (HRS, bacteria with stable high-level resistance present before drug exposure) and adaptive resistant (ARS, bacteria with reversible low-level resistance emerging after drug exposure) subpopulations were measured and optimal PK/PD targets for reducing both ARS and HRS were determined. Cumulative fractional response (CFR) was calculated with Monte Carlo simulation for 9 MU q24h, 4.5 MU q12h and 3 MU q8h clinical dosing regimens.Results. A 2-5 log10c.f.u. ml-1 decrease of the total bacterial population was observed within the first 2 h of exposure, followed by regrowth at 12 h. Colistin exposure was positively and negatively correlated with HRS and ARS 24-0 h c.f.u. ml-1 changes, respectively. An optimal PK/PD (~0.5log10 increase) target of 35 fAUC/MIC (the ratio of the area under the unbound concentration-time curve to the MIC) was found for reducing both HRS and ARS of high-level resistance (MIC >16 mg l-1). The 4.5 MU q12h regimen had slightly higher CFR (74 %) compared to the other dosing regimens.Conclusions. High colistin exposures reduced high-level adaptive resistance at the expense of selection of heteroresistant subpopulations.
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Affiliation(s)
- Joseph Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens 157 72, Greece.,Department of Medical Microbiology, Erasmus MC, Rotterdam, Netherlands
| | - Paschalis Paranos
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens 157 72, Greece
| | - Marilena Tsala
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens 157 72, Greece
| | - Spyros Pournaras
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens 157 72, Greece
| | - Sofia Vourli
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens 157 72, Greece
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8
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MgrB Mutations and Altered Cell Permeability in Colistin Resistance in Klebsiella pneumoniae. Cells 2022; 11:cells11192995. [PMID: 36230959 PMCID: PMC9564205 DOI: 10.3390/cells11192995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 11/25/2022] Open
Abstract
There has been a resurgence in the clinical use of polymyxin antibiotics such as colistin due to the limited treatment options for infections caused by carbapenem-resistant Enterobacterales (CRE). However, this last-resort antibiotic is currently confronted with challenges which include the emergence of chromosomal and plasmid-borne colistin resistance. Colistin resistance in Klebsiella pneumoniae is commonly caused by the mutations in the chromosomal gene mgrB. MgrB spans the inner membrane and negatively regulates PhoP phosphorylation, which is essential for bacterial outer membrane lipid biosynthesis. The present review intends to draw attention to the role of mgrB chromosomal mutations in membrane permeability in K. pneumoniae that confer colistin resistance. With growing concern regarding the global emergence of colistin resistance, deciphering physical changes of the resistant membrane mediated by mgrB inactivation may provide new insights for the discovery of novel antimicrobials that are highly effective at membrane penetration, in addition to finding out how this can help in alleviating the resistance situation.
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9
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Chen X, Li P, Sun Z, Xu X, Jiang J, Su J. Insertion sequence mediating mrgB disruption is the major mechanism of polymyxin resistance in carbapenem-resistant Klebsiella pneumoniae isolates from China. J Glob Antimicrob Resist 2022; 30:357-362. [PMID: 35817263 DOI: 10.1016/j.jgar.2022.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 06/11/2022] [Accepted: 07/01/2022] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES Infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) pose a huge health challenge worldwide. The aim of this study was to evaluate the incidence of polymyxin resistance in clinical CRKP isolates in China and to characterize the molecular mechanisms underlying these polymyxin-resistant CRKP (PR-CRKP) isolates. METHODS A total of 493 CRKP clinical isolates from patients were collected from six tertiary-care hospitals in China during 2017-2018. Minimum inhibitory concentrations of polymyxin B and colistin were determined using the broth microdilution method. PR-CRKP isolates were identified and subjected to whole-genome sequencing. Quantitative real-time PCR and structural modelling analysis were also performed. RESULTS We observed a 2.2% (11/493) polymyxin resistance rate in this multicentre cohort. Polymyxin B MICs ranged from 4 to 64 μg/mL and colistin MICs ranged from 8 to 128 μg/mL in 11 PR-CRKP isolates. Key genetic variations identified in PR-CRKP isolates involved eight disruptions (seven insertional inactivation by an insertion sequence [IS] element, one frameshift deletion) in mgrB, and three missense mutations in pmrA, pmrB, and phoP. ISKpn26 was the predominant IS (4/7), and three of these occurred in nucleotide position 74 in the mgrB gene. In addition, we reported a novel mutation S62R in pmrB that may confer polymyxin resistance in K. pneumoniae. CONCLUSIONS Our findings highlight the multifaceted molecular mechanisms of polymyxin resistance in CRKP.
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Affiliation(s)
- Xin Chen
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Pei Li
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhewei Sun
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaogang Xu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Jianping Jiang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.
| | - Jiachun Su
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.
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10
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Ghazal F, Farooq S, Wahab AT, Maharjan R, Zafar H, Siddiqui H, Shafi S, Choudhary MI. Identification of quinoline derivatives as growth inhibitors of MDR pathogen Klebsiella pneumoniae. Future Microbiol 2022; 17:843-859. [PMID: 35796056 DOI: 10.2217/fmb-2021-0111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aims: This study was aimed to identify compounds with significant inhibitory potential against multidrug-resistant (MDR), multidrug-sensitive, and clinical isolates of Klebsiella pneumoniae. Materials & methods: Antibacterial activity of the nitroquinoline derivatives was assessed by micro-plate Alamar Blue assay. Results: Nitroquinoline derivatives 9, 11 and 14 showed inhibitory activity against MDR K. pneumoniae. Docking studies of these compounds with topoisomerase IV of K. pneumonia indicated the interactions of these compounds at the active site residues of enzyme near to cofactor (Mg+2). Furthermore, compound 11 was identified as a reactive oxygen species (ROS) inducer. None of the compounds showed hemolytic effect. Conclusion: This study was designed to identify compounds active against MDR K. pneumoniae which causes infections, such as pneumonia and urinary tract infections.
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Affiliation(s)
- Farzeen Ghazal
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Saba Farooq
- Dr Panjwani Center for Molecular Medicine and Drug Research, International Center of Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Atia-Tul Wahab
- Dr Panjwani Center for Molecular Medicine and Drug Research, International Center of Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Rukesh Maharjan
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Humaira Zafar
- Dr Panjwani Center for Molecular Medicine and Drug Research, International Center of Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Hina Siddiqui
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Sara Shafi
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - M I Choudhary
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.,Dr Panjwani Center for Molecular Medicine and Drug Research, International Center of Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.,Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
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11
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Stojowska-Swędrzyńska K, Łupkowska A, Kuczyńska-Wiśnik D, Laskowska E. Antibiotic Heteroresistance in Klebsiella pneumoniae. Int J Mol Sci 2021; 23:449. [PMID: 35008891 PMCID: PMC8745652 DOI: 10.3390/ijms23010449] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 12/12/2022] Open
Abstract
Klebsiella pneumoniae is one of the most common pathogens responsible for infections, including pneumonia, urinary tract infections, and bacteremias. The increasing prevalence of multidrug-resistant K. pneumoniae was recognized in 2017 by the World Health Organization as a critical public health threat. Heteroresistance, defined as the presence of a subpopulation of cells with a higher MIC than the dominant population, is a frequent phenotype in many pathogens. Numerous reports on heteroresistant K. pneumoniae isolates have been published in the last few years. Heteroresistance is difficult to detect and study due to its phenotypic and genetic instability. Recent findings provide strong evidence that heteroresistance may be associated with an increased risk of recurrent infections and antibiotic treatment failure. This review focuses on antibiotic heteroresistance mechanisms in K. pneumoniae and potential therapeutic strategies against antibiotic heteroresistant isolates.
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Affiliation(s)
| | | | | | - Ewa Laskowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (K.S.-S.); (A.Ł.); (D.K.-W.)
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12
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Missense Mutations in the CrrB Protein Mediate Odilorhabdin Derivative Resistance in Klebsiella pneumoniae. Antimicrob Agents Chemother 2021; 65:AAC.00139-21. [PMID: 33685902 PMCID: PMC8092918 DOI: 10.1128/aac.00139-21] [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] [Indexed: 11/20/2022] Open
Abstract
NOSO-502 is a preclinical antibiotic candidate of the Odilorhabdin class. This compound exhibits activity against Enterobacteriaceae pathogens, including carbapenemase-producing bacteria and most of the Colistin (CST)-resistant strains. Among a collection of CST-resistant Klebsiella pneumoniae strains harboring mutations on genes pmrAB, mgrB, phoPQ, and crrB, only those bearing mutations in gene crrB were found to be resistant to NOSO-502.CrrB is a histidine kinase which acts with the response regulator CrrA to modulate the PmrAB system, which finally induces the restructuring of the lipopolysaccharide present on the outer membrane and thus leading to CST resistance. Moreover, crrB mutations also enhance the transcription of neighboring genes such as H239_3063, an ABC transporter transmembrane region; H239_3064, a putative efflux pump also known as KexD; and H239_3065, a N-acetyltransferase.To elucidate the mechanism of resistance to NOSO-502 induced by CrrB missense mutations in K. pneumoniae, mutants of NCTC 13442 and ATCC BAA-2146 strains resistant to NOSO-502 and CST with single amino acid substitutions in CrrB (S8N, F33Y, Y34N, W140R, N141I, P151A, P151L, P151S, P151T, F303Y) were selected. Full susceptibility to NOSO-502 was restored in crrA or crrB deleted K. pneumoniae NCTC 13442 CrrB(P151L) mutants, confirming the role of CrrAB in controlling this resistance pathway. Deletion of kexD (but no other neighboring genes) in the same mutant also restored NOSO-502-susceptibility. Upregulation of the kexD gene expression was observed for all CrrB mutants. Finally, plasmid expression of kexD in a K. pneumoniae strain missing the locus crrABC and kexD significantly increased resistance to NOSO-502.
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Raro OHF, Collar GS, da Silva RMC, Vezzaro P, Mott MP, da Cunha GR, Riche CVW, Dias C, Caierão J. Performance of polymyxin B agar-based tests among carbapenem-resistant Enterobacterales. Lett Appl Microbiol 2021; 72:767-773. [PMID: 33629416 DOI: 10.1111/lam.13467] [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: 09/04/2020] [Revised: 02/19/2021] [Accepted: 02/22/2021] [Indexed: 01/10/2023]
Abstract
Therapeutic options for infections caused by Carbapenem-resistant Enterobacterales (CRE) are restricted and include polymyxins-centred schemes. Evaluation of in vitro susceptibility is difficult and time consuming. Agar-based methodologies are an alternative to broth microdilution (BMD) and we aimed to evaluate the accuracy of those methods among Enterobacterales. A total of 137 non-duplicated CRE were subjected to polymyxin B BMD, agar screening test (Mueller Hinton plates containing 3 µg ml-1 of polymyxin B) and agar dilution (antibiotic serially diluted 0·25-64 µg ml-1 ). CRE of 42·3% were resistant to polymyxin B (MICs range: 0·25->64 µg ml-1 ) and 16·8% presented borderline MICs. Sensitivity, specificity, PPV and NPV were 86·2, 98·7, 98 and 90·7% for screening test and 86·2, 97·5, 96·1 and 90·6% for agar dilution. ME was 0·73 and 1·5% for screening and agar dilution respectively; VME was 5·8% for both techniques. In general, agar-based methods had a good performance. As far as we know, this is the first study to propose an agar screening test using polymyxin B instead of colistin.
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Affiliation(s)
- O H F Raro
- Department of Basic Health Sciences, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - G S Collar
- Department of Analysis, Faculty of Pharmacy, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - R M C da Silva
- Department of Basic Health Sciences, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - P Vezzaro
- Department of Basic Health Sciences, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - M P Mott
- Department of Basic Health Sciences, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil.,Department of Microbiology, Ernesto Dornelles Hospital, Porto Alegre, Brazil
| | - G R da Cunha
- Department of Microbiology, Ernesto Dornelles Hospital, Porto Alegre, Brazil
| | - C V W Riche
- Department of Basic Health Sciences, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil.,Department of Microbiology, Ernesto Dornelles Hospital, Porto Alegre, Brazil
| | - C Dias
- Department of Basic Health Sciences, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - J Caierão
- Department of Analysis, Faculty of Pharmacy, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Post-Graduation Program of Pharmaceutical Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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Azam M, Gaind R, Yadav G, Sharma A, Upmanyu K, Jain M, Singh R. Colistin Resistance Among Multiple Sequence Types of Klebsiella pneumoniae Is Associated With Diverse Resistance Mechanisms: A Report From India. Front Microbiol 2021; 12:609840. [PMID: 33692764 PMCID: PMC7937630 DOI: 10.3389/fmicb.2021.609840] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/22/2021] [Indexed: 12/25/2022] Open
Abstract
Background: The resistance to colistin and carbapenems in Klebsiella pneumoniae infections have been associated with increased morbidity and mortality worldwide. A retrospective observational study was conducted to determine the prevalence and molecular events contributing to colistin resistance. Methods: Clinical samples were screened for colistin resistance and underlying mechanisms were studied by PCR-based amplification and sequence analysis of genes of two-component regulatory system (phoPQ and pmrAB), regulatory transmembrane protein-coding mgrB, and mobilized colistin resistance genes (mcr-1-8). Gene expression of pmrC and pmrK was analyzed by qRT-PCR, and the genetic relationship was assessed by MLST. The putative effect of amino-acid substitutions was predicted by a combination of bioinformatics tools. Results: Of 335 Klebsiella spp. screened, 11 (3.2%) were identified as colistin-resistant (MIC range, 8 to >128 μg/ml). K. pneumoniae isolates belonged to clonal complex-11 (CC11) with sequence types (STs): 14, 16, 43, 54, 147 and 395, whereby four isolates conferred three novel STs (3986, 3987 and 3988) profiles. Sequence analysis revealed non-synonymous potentially deleterious mutations in phoP (T151A), phoQ (del87–90, del263–264, L30Q, and A351D), pmrA (G53S), pmrB (D150V, T157P, L237R, G250C, A252G, R315P, and Q331H), and mgrB (C28G) genes. The mgrB gene in three strains was disrupted by insertion sequences encoding IS1-like and IS5/IS1182 family-like transposase genes. All 11 isolates showed an elevation in the transcription level of pmrC gene. Mobilized colistin-resistance (mcr) genes were not detected. All but one of the colistin-resistant isolates was also resistant to carbapenems; β-lactamase genes blaNDM-1-like, blaOXA-48-like, and blaCTX-M-like were detected in eight, five, and nine isolates, respectively. Conclusion: All the studied colistin- and carbapenem-resistant K. pneumoniae isolates were genetically distinct, and various mechanisms of colistin resistance were detected, indicating its spontaneous emergence in this bacterial species.
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Affiliation(s)
- Mudsser Azam
- ICMR-National Institute of Pathology, New Delhi, India
| | - Rajni Gaind
- Department of Microbiology, VMMC and Safdarjung Hospital, New Delhi, India
| | - Gulshan Yadav
- ICMR-National Institute of Pathology, New Delhi, India
| | - Amit Sharma
- Department of Microbiology, VMMC and Safdarjung Hospital, New Delhi, India
| | - Kirti Upmanyu
- ICMR-National Institute of Pathology, New Delhi, India
| | - Manisha Jain
- Department of Microbiology, VMMC and Safdarjung Hospital, New Delhi, India
| | - Ruchi Singh
- ICMR-National Institute of Pathology, New Delhi, India
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Lopes SP, Jorge P, Sousa AM, Pereira MO. Discerning the role of polymicrobial biofilms in the ascent, prevalence, and extent of heteroresistance in clinical practice. Crit Rev Microbiol 2021; 47:162-191. [PMID: 33527850 DOI: 10.1080/1040841x.2020.1863329] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antimicrobial therapy is facing a worrisome and underappreciated challenge, the phenomenon of heteroresistance (HR). HR has been gradually documented in clinically relevant pathogens (e.g. Pseudomonas aeruginosa, Staphylococcus aureus, Burkholderia spp., Acinetobacter baumannii, Klebsiella pneumoniae, Candida spp.) towards several drugs and is believed to complicate the clinical picture of chronic infections. This type of infections are typically mediated by polymicrobial biofilms, wherein microorganisms inherently display a wide range of physiological states, distinct metabolic pathways, diverging refractory levels of stress responses, and a complex network of chemical signals exchange. This review aims to provide an overview on the relevance, prevalence, and implications of HR in clinical settings. Firstly, related terminologies (e.g. resistance, tolerance, persistence), sometimes misunderstood and overlapped, were clarified. Factors generating misleading HR definitions were also uncovered. Secondly, the recent HR incidences reported in clinically relevant pathogens towards different antimicrobials were annotated. The potential mechanisms underlying such occurrences were further elucidated. Finally, the link between HR and biofilms was discussed. The focus was to recognize the presence of heterogeneous levels of resistance within most biofilms, as well as the relevance of polymicrobial biofilms in chronic infectious diseases and their role in resistance spreading. These topics were subject of a critical appraisal, gaining insights into the ascending clinical implications of HR in antimicrobial resistance spreading, which could ultimately help designing effective therapeutic options.
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Affiliation(s)
- Susana Patrícia Lopes
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Paula Jorge
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Ana Margarida Sousa
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratory of Research in Biofilms Rosário Oliveira, University of Minho, Braga, Portugal
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Emerging Transcriptional and Genomic Mechanisms Mediating Carbapenem and Polymyxin Resistance in Enterobacteriaceae: a Systematic Review of Current Reports. mSystems 2020; 5:5/6/e00783-20. [PMID: 33323413 PMCID: PMC7771540 DOI: 10.1128/msystems.00783-20] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The spread of carbapenem- and polymyxin-resistant Enterobacteriaceae poses a significant threat to public health, challenging clinicians worldwide with limited therapeutic options. This review describes the current coding and noncoding genetic and transcriptional mechanisms mediating carbapenem and polymyxin resistance, respectively. The spread of carbapenem- and polymyxin-resistant Enterobacteriaceae poses a significant threat to public health, challenging clinicians worldwide with limited therapeutic options. This review describes the current coding and noncoding genetic and transcriptional mechanisms mediating carbapenem and polymyxin resistance, respectively. A systematic review of all studies published in PubMed database between 2015 to October 2020 was performed. Journal articles evaluating carbapenem and polymyxin resistance mechanisms, respectively, were included. The search identified 171 journal articles for inclusion. Different New Delhi metallo-β-lactamase (NDM) carbapenemase variants had different transcriptional and affinity responses to different carbapenems. Mutations within the Klebsiella pneumoniae carbapenemase (KPC) mobile transposon, Tn4401, affect its promoter activity and expression levels, increasing carbapenem resistance. Insertion of IS26 in ardK increased imipenemase expression 53-fold. ompCF porin downregulation (mediated by envZ and ompR mutations), micCF small RNA hyperexpression, efflux upregulation (mediated by acrA, acrR, araC, marA, soxS, ramA, etc.), and mutations in acrAB-tolC mediated clinical carbapenem resistance when coupled with β-lactamase activity in a species-specific manner but not when acting without β-lactamases. Mutations in pmrAB, phoPQ, crrAB, and mgrB affect phosphorylation of lipid A of the lipopolysaccharide through the pmrHFIJKLM (arnBCDATEF or pbgP) cluster, leading to polymyxin resistance; mgrB inactivation also affected capsule structure. Mobile and induced mcr, efflux hyperexpression and porin downregulation, and Ecr transmembrane protein also conferred polymyxin resistance and heteroresistance. Carbapenem and polymyxin resistance is thus mediated by a diverse range of genetic and transcriptional mechanisms that are easily activated in an inducing environment. The molecular understanding of these emerging mechanisms can aid in developing new therapeutics for multidrug-resistant Enterobacteriaceae isolates.
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Conceição-Neto OC, da Costa BS, Pontes LS, Santos ICO, Silveira MC, Cordeiro-Moura JR, Pereira NF, Tavares-Teixeira CB, Picão RC, Rocha-de-Souza CM, Carvalho-Assef APD. Difficulty in detecting low levels of polymyxin resistance in clinical Klebsiella pneumoniae isolates: evaluation of Rapid Polymyxin NP test, Colispot Test and SuperPolymyxin medium. New Microbes New Infect 2020; 36:100722. [PMID: 32642069 PMCID: PMC7334411 DOI: 10.1016/j.nmni.2020.100722] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/06/2020] [Accepted: 06/22/2020] [Indexed: 01/29/2023] Open
Abstract
Polymyxins are important therapeutic options for treating infections, mainly those caused by carbapenem-resistant Klebsiella pneumoniae. Specific chemical characteristics of polymyxins make it difficult to perform antimicrobial susceptibility testing, especially within the clinical laboratory. Here we aimed to evaluate the performance of three phenotypic methods: Rapid NP Polymyxin Test, ColiSpot test and the SuperPolymyxin medium. To accomplish this, 170 non-duplicate clinical K. pneumoniae isolates were analysed (123 colistin-resistant and 47 susceptible). The sensitivity and specificity obtained for Rapid Polymyxin NP Test, Colispot and SuperPolymyxin medium were, respectively, 90% and 94%, 74% and 100%, and 82% and 85%. Very major errors occurred more frequently in low-level colistin-resistant isolates (MICs 4 and 8 μg/mL). Rapid Polymyxin NP proved to be a method capable of identifying colistin-resistant strains in acceptable categorical agreement. However, major errors and very major errors of this method were considered unacceptable for colistin-resistance screening. Although the Colispot test is promising and easy to perform and interpret, the results did not reproduce well in the isolates tested. The colistin-containing selective medium (SuperPolymyxin) showed limitations, including quantification of mucoid colonies and poor stability. Nevertheless, Colispot and SuperPolymyxin medium methods did not present acceptable sensitivity, specificity and categorical agreement. It is essential to use analytical tools that faithfully reproduce bacterial resistance in vitro, especially in last-line drugs, such as polymyxins, when misinterpretation of a test can result in therapeutic ineffectiveness.
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Affiliation(s)
- O C Conceição-Neto
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - B S da Costa
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - L S Pontes
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - I C O Santos
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - M C Silveira
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - J R Cordeiro-Moura
- Laboratório de Investigação em Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - N F Pereira
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - C B Tavares-Teixeira
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - R C Picão
- Laboratório de Investigação em Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - C M Rocha-de-Souza
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
| | - A P D Carvalho-Assef
- Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, Brazil
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18
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Klebsiella pneumoniae type VI secretion system-mediated microbial competition is PhoPQ controlled and reactive oxygen species dependent. PLoS Pathog 2020; 16:e1007969. [PMID: 32191774 PMCID: PMC7108748 DOI: 10.1371/journal.ppat.1007969] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 03/31/2020] [Accepted: 02/17/2020] [Indexed: 12/21/2022] Open
Abstract
Klebsiella pneumoniae is recognized as an urgent threat to human health due to the increasing isolation of multidrug resistant strains. Hypervirulent strains are a major concern due to their ability to cause life-threating infections in healthy hosts. The type VI secretion system (T6SS) is widely implicated in microbial antagonism, and it mediates interactions with host eukaryotic cells in some cases. In silico search for genes orthologous to T6SS component genes and T6SS effector genes across 700 K. pneumoniae genomes shows extensive diversity in T6SS genes across the K. pneumoniae species. Temperature, oxygen tension, pH, osmolarity, iron levels, and NaCl regulate the expression of the T6SS encoded by a hypervirulent K. pneumoniae strain. Polymyxins and human defensin 3 also increase the activity of the T6SS. A screen for regulators governing T6SS uncover the correlation between the transcription of the T6SS and the ability to kill E. coli prey. Whereas H-NS represses the T6SS, PhoPQ, PmrAB, Hfq, Fur, RpoS and RpoN positively regulate the T6SS. K. pneumoniae T6SS mediates intra and inter species bacterial competition. This antagonism is only evident when the prey possesses an active T6SS. The PhoPQ two component system governs the activation of K. pneumoniae T6SS in bacterial competitions. Mechanistically, PhoQ periplasmic domain, and the acid patch within, is essential to activate K. pneumoniae T6SS. Klebsiella T6SS also mediates anti-fungal competition. We have delineated the contribution of each of the individual VgrGs in microbial competition and identified VgrG4 as a T6SS effector. The DUF2345 domain of VgrG4 is sufficient to intoxicate bacteria and yeast. ROS generation mediates the antibacterial effects of VgrG4, and the antitoxin Sel1E protects against the toxic activity of VgrG4. Our findings provide a better understanding of the regulation of the T6SS in bacterial competitions, and place ROS as an early event in microbial competition. Klebsiella pneumoniae has been singled out as an “urgent threat to human health” due to extremely drug resistant strains. Numerous studies investigate the molecular mechanisms underlying antibiotic resistance in K. pneumoniae, while others dissect the virulence strategies of this pathogen. However, there is still limited knowledge on the fitness of Klebsiella in the environment, and, particularly, the competition of Klebsiella with other species. Here, we demonstrate that Klebsiella exploits the type VI secretion system (T6SS) nanoweapon to kill bacterial competitors and fungi. K. pneumoniae perceives T6SS attacks from bacterial competitors, resulting in retaliation against the aggressive cell. The perception of the attack involved the sensor PhoPQ and led to the up-regulation of the T6SS. We identified one of the toxins deployed by the T6SS to antagonize other microbes and revealed how Klebsiella protects itself from this toxin. Our findings provide a better understanding of the T6SS role in microbial competition and uncover new aspects on how bacteria regulate T6SS-mediated microbial antagonism.
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Abstract
Klebsiella pneumoniae is a common cause of antimicrobial-resistant opportunistic infections in hospitalized patients. The species is naturally resistant to penicillins, and members of the population often carry acquired resistance to multiple antimicrobials. However, knowledge of K. pneumoniae ecology, population structure or pathogenicity is relatively limited. Over the past decade, K. pneumoniae has emerged as a major clinical and public health threat owing to increasing prevalence of healthcare-associated infections caused by multidrug-resistant strains producing extended-spectrum β-lactamases and/or carbapenemases. A parallel phenomenon of severe community-acquired infections caused by 'hypervirulent' K. pneumoniae has also emerged, associated with strains expressing acquired virulence factors. These distinct clinical concerns have stimulated renewed interest in K. pneumoniae research and particularly the application of genomics. In this Review, we discuss how genomics approaches have advanced our understanding of K. pneumoniae taxonomy, ecology and evolution as well as the diversity and distribution of clinically relevant determinants of pathogenicity and antimicrobial resistance. A deeper understanding of K. pneumoniae population structure and diversity will be important for the proper design and interpretation of experimental studies, for interpreting clinical and public health surveillance data and for the design and implementation of novel control strategies against this important pathogen.
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20
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Acquired Resistance to Colistin via Chromosomal And Plasmid-Mediated Mechanisms in Klebsiella pneumoniae. ACTA ACUST UNITED AC 2019. [DOI: 10.1097/im9.0000000000000002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Boinett CJ, Cain AK, Hawkey J, Do Hoang NT, Khanh NNT, Thanh DP, Dordel J, Campbell JI, Lan NPH, Mayho M, Langridge GC, Hadfield J, Chau NVV, Thwaites GE, Parkhill J, Thomson NR, Holt KE, Baker S. Clinical and laboratory-induced colistin-resistance mechanisms in Acinetobacter baumannii. Microb Genom 2019; 5. [PMID: 30720421 PMCID: PMC6421349 DOI: 10.1099/mgen.0.000246] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The increasing incidence and emergence of multi-drug resistant (MDR) Acinetobacter baumannii has become a major global health concern. Colistin is a historic antimicrobial that has become commonly used as a treatment for MDR A. baumannii infections. The increase in colistin usage has been mirrored by an increase in colistin resistance. We aimed to identify the mechanisms associated with colistin resistance in A. baumannii using multiple high-throughput-sequencing technologies, including transposon-directed insertion site sequencing (TraDIS), RNA sequencing (RNAseq) and whole-genome sequencing (WGS) to investigate the genotypic changes of colistin resistance in A. baumannii. Using TraDIS, we found that genes involved in drug efflux (adeIJK), and phospholipid (mlaC, mlaF and mlaD) and lipooligosaccharide synthesis (lpxC and lpsO) were required for survival in sub-inhibitory concentrations of colistin. Transcriptomic (RNAseq) analysis revealed that expression of genes encoding efflux proteins (adeI, adeC, emrB, mexB and macAB) was enhanced in in vitro generated colistin-resistant strains. WGS of these organisms identified disruptions in genes involved in lipid A (lpxC) and phospholipid synthesis (mlaA), and in the baeS/R two-component system (TCS). We additionally found that mutations in the pmrB TCS genes were the primary colistin-resistance-associated mechanisms in three Vietnamese clinical colistin-resistant A. baumannii strains. Our results outline the entire range of mechanisms employed in A. baumannii for resistance against colistin, including drug extrusion and the loss of lipid A moieties by gene disruption or modification.
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Affiliation(s)
- Christine J Boinett
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,3Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Amy K Cain
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,4Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
| | - Jane Hawkey
- 5Centre for Systems Genomics, University of Melbourne, Melbourne, Victoria, Australia.,6Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia.,7Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Nhu Tran Do Hoang
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nhu Nguyen Thi Khanh
- 8School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Duy Pham Thanh
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Janina Dordel
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,9Department of Biology, Drexel University, Philadelphia 19104, PA, USA
| | - James I Campbell
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,3Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Nguyen Phu Huong Lan
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,10Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Matthew Mayho
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Gemma C Langridge
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,11Norwich Medical School, University of East Anglia, Norwich, UK
| | - James Hadfield
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | | | - Guy E Thwaites
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,3Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Julian Parkhill
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Nicholas R Thomson
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,12Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Kathryn E Holt
- 5Centre for Systems Genomics, University of Melbourne, Melbourne, Victoria, Australia.,6Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Stephen Baker
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,13Medicine, The University of Cambridge, Cambridge, UK.,3Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
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