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Barceló IM, Escobar-Salom M, Cabot G, Perelló-Bauzà P, Jordana-Lluch E, Taltavull B, Torrens G, Rojo-Molinero E, Zamorano L, Pérez A, Oliver A, Juan C. Transferable AmpCs in Klebsiella pneumoniae: interplay with peptidoglycan recycling, mechanisms of hyperproduction, and virulence implications. Antimicrob Agents Chemother 2024; 68:e0131523. [PMID: 38517189 PMCID: PMC11064642 DOI: 10.1128/aac.01315-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 02/29/2024] [Indexed: 03/23/2024] Open
Abstract
Chromosomal and transferable AmpC β-lactamases represent top resistance mechanisms in different gram-negatives, but knowledge regarding the latter, mostly concerning regulation and virulence-related implications, is far from being complete. To fill this gap, we used Klebsiella pneumoniae (KP) and two different plasmid-encoded AmpCs [DHA-1 (AmpR regulator linked, inducible) and CMY-2 (constitutive)] as models to perform a study in which we show that blockade of peptidoglycan recycling through AmpG permease inactivation abolished DHA-1 inducibility but did not affect CMY-2 production and neither did it alter KP pathogenic behavior. Moreover, whereas regular production of both AmpC-type enzymes did not attenuate KP virulence, when blaDHA-1 was expressed in an ampG-defective mutant, Galleria mellonella killing was significantly (but not drastically) attenuated. Spontaneous DHA-1 hyperproducer mutants were readily obtained in vitro, showing slight or insignificant virulence attenuations together with high-level resistance to β-lactams only mildly affected by basal production (e.g., ceftazidime, ceftolozane/tazobactam). By analyzing diverse DHA-1-harboring clinical KP strains, we demonstrate that the natural selection of these hyperproducers is not exceptional (>10% of the collection), whereas mutational inactivation of the typical AmpC hyperproduction-related gene mpl was the most frequent underlying mechanism. The potential silent dissemination of this kind of strains, for which an important fitness cost-related contention barrier does not seem to exist, is envisaged as a neglected threat for most β-lactams effectiveness, including recently introduced combinations. Analyzing whether this phenomenon is applicable to other transferable β-lactamases and species as well as determining the levels of conferred resistance poses an essential topic to be addressed.IMPORTANCEAlthough there is solid knowledge about the regulation of transferable and especially chromosomal AmpC β-lactamases in Enterobacterales, there are still gaps to fill, mainly related to regulatory mechanisms and virulence interplays of the former. This work addresses them using Klebsiella pneumoniae as model, delving into a barely explored conception: the acquisition of a plasmid-encoded inducible AmpC-type enzyme whose production can be increased through selection of chromosomal mutations, entailing dramatically increased resistance compared to basal expression but minor associated virulence costs. Accordingly, we demonstrate that clinical K. pneumoniae DHA-1 hyperproducer strains are not exceptional. Through this study, we warn for the first time that this phenomenon may be a neglected new threat for β-lactams effectiveness (including some recently introduced ones) silently spreading in the clinical context, not only in K. pneumoniae but potentially also in other pathogens. These facts must be carefully considered in order to design future resistance-preventive strategies.
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Affiliation(s)
- Isabel M. Barceló
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Maria Escobar-Salom
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Gabriel Cabot
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Pau Perelló-Bauzà
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
| | - Elena Jordana-Lluch
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Biel Taltavull
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Gabriel Torrens
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Estrella Rojo-Molinero
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Laura Zamorano
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Astrid Pérez
- National Center for Microbiology, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Antonio Oliver
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Carlos Juan
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
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Carson DV, Juarez RJ, Do T, Yang Z, James Link A. Antimicrobial Lasso Peptide Cloacaenodin Utilizes a Unique TonB-Dependent Transporter to Access Susceptible Bacteria. ACS Chem Biol 2024; 19:981-991. [PMID: 38527226 PMCID: PMC11031277 DOI: 10.1021/acschembio.4c00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
The development of new antimicrobial agents effective against Gram-negative bacteria remains a major challenge in drug discovery. The lasso peptide cloacaenodin has potent antimicrobial activity against multiple strains in the Enterobacter genus, one of the ESKAPE pathogens. Here, we show that cloacaenodin uses a previously uncharacterized TonB-dependent transporter, which we name CloU, to cross the outer membrane (OM) of susceptible bacteria. Inner membrane transport is mediated by the protein SbmA. CloU is distinct from the known OM transporters (FhuA and PupB) utilized by other antimicrobial lasso peptides and thus offers important insight into the spectrum of activity of cloacaenodin. Using knowledge of the transport pathway to predict other cloacaenodin-susceptible strains, we demonstrate the activity of cloacaenodin against clinical isolates of Enterobacter and of a Kluyvera strain. Further, we use molecular dynamics simulations and mutagenesis of CloU to explain the variation in cloacaenodin susceptibility observed across different strains of Enterobacter. This work expands the currently limited understanding of lasso peptide uptake and advances the potential of cloacaenodin as an antibiotic.
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Affiliation(s)
- Drew V. Carson
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Reecan J. Juarez
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Truc Do
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Zhongyue Yang
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
- Data Science Institute, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - A. James Link
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
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3
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Lazarus JE, Wang Y, Waldor MK, Hooper DC. Divergent genetic landscapes drive lower levels of AmpC induction and stable de-repression in Serratia marcescens compared to Enterobacter cloacae. Antimicrob Agents Chemother 2024; 68:e0119323. [PMID: 38084952 PMCID: PMC10777825 DOI: 10.1128/aac.01193-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/21/2023] [Indexed: 01/11/2024] Open
Abstract
The chromosomally encoded AmpC beta-lactamase is widely distributed throughout the Enterobacterales. When expressed at high levels through transient induction or stable de-repression, resistance to ceftriaxone, a commonly used antibiotic, can develop. Recent clinical guidance suggests, based on limited evidence, that resistance may be less likely to develop in Serratia marcescens compared to the better-studied Enterobacter cloacae and recommends that ceftriaxone may be used if the clinical isolate tests susceptible. We sought to generate additional data relevant to this recommendation. AmpC de-repression occurs predominantly because of mutation in the ampD peptidoglycan amidohydrolase. We find that, in contrast to E. cloacae, where deletion of ampD results in high-level ceftriaxone resistance (with ceftriaxone MIC = 96 µg/mL), in S. marcescens deletion of two amidohydrolases (ampD and amiD2) is necessary for AmpC de-repression, and the resulting ceftriaxone MIC is 1 µg/mL. Two mechanisms for this difference were identified. We find both a higher relative increase in ampC transcript level in E. cloacae ΔampD compared to S. marcescens ΔampDΔamiD2, as well as higher in vivo efficiency of ceftriaxone hydrolysis by the E. cloacae AmpC enzyme compared to the S. marcescens AmpC enzyme. We also observed higher relative levels of transient AmpC induction in E. cloacae vs S. marcescens when exposed to ceftriaxone. In time-kill curves, this difference translates into the survival of E. cloacae but not S. marcescens at clinically relevant ceftriaxone concentrations. In summary, our findings can explain the decreased propensity for on-treatment ceftriaxone resistance development in S. marcescens, thereby supporting recently issued clinical guidance.
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Affiliation(s)
- Jacob E. Lazarus
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yin Wang
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew K. Waldor
- Department of Medicine, Division of Infectious Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
| | - David C. Hooper
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Barceló IM, Escobar-Salom M, Jordana-Lluch E, Torrens G, Oliver A, Juan C. Filling knowledge gaps related to AmpC-dependent β-lactam resistance in Enterobacter cloacae. Sci Rep 2024; 14:189. [PMID: 38167986 PMCID: PMC10762043 DOI: 10.1038/s41598-023-50685-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 12/22/2023] [Indexed: 01/05/2024] Open
Abstract
Enterobacter cloacae starred different pioneer studies that enabled the development of a widely accepted model for the peptidoglycan metabolism-linked regulation of intrinsic class C cephalosporinases, highly conserved in different Gram-negatives. However, some mechanistic and fitness/virulence-related aspects of E. cloacae choromosomal AmpC-dependent resistance are not completely understood. The present study including knockout mutants, β-lactamase cloning, gene expression analysis, characterization of resistance phenotypes, and the Galleria mellonella infection model fills these gaps demonstrating that: (i) AmpC enzyme does not show any collateral activity impacting fitness/virulence; (ii) AmpC hyperproduction mediated by ampD inactivation does not entail any biological cost; (iii) alteration of peptidoglycan recycling alone or combined with AmpC hyperproduction causes no attenuation of E. cloacae virulence in contrast to other species; (iv) derepression of E. cloacae AmpC does not follow a stepwise dynamics linked to the sequential inactivation of AmpD amidase homologues as happens in Pseudomonas aeruginosa; (v) the enigmatic additional putative AmpC-type β-lactamase generally present in E. cloacae does not contribute to the classical cephalosporinase hyperproduction-based resistance, having a negligible impact on phenotypes even when hyperproduced from multicopy vector. This study reveals interesting particularities in the chromosomal AmpC-related behavior of E. cloacae that complete the knowledge on this top resistance mechanism.
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Affiliation(s)
- Isabel M Barceló
- Health Research Institute of the Balearic Islands (IdISBa), 07010, Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), 07010, Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - María Escobar-Salom
- Health Research Institute of the Balearic Islands (IdISBa), 07010, Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), 07010, Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Elena Jordana-Lluch
- Health Research Institute of the Balearic Islands (IdISBa), 07010, Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), 07010, Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Gabriel Torrens
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, 901 87, Umeå, Sweden
| | - Antonio Oliver
- Health Research Institute of the Balearic Islands (IdISBa), 07010, Palma, Spain
- Microbiology Department, University Hospital Son Espases (HUSE), 07010, Palma, Spain
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Carlos Juan
- Health Research Institute of the Balearic Islands (IdISBa), 07010, Palma, Spain.
- Microbiology Department, University Hospital Son Espases (HUSE), 07010, Palma, Spain.
- Centro de Investigación Biomédica en Red, Área Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029, Madrid, Spain.
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Gupta R, Singh M, Pathania R. Chemical genetic approaches for the discovery of bacterial cell wall inhibitors. RSC Med Chem 2023; 14:2125-2154. [PMID: 37974958 PMCID: PMC10650376 DOI: 10.1039/d3md00143a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 08/10/2023] [Indexed: 11/19/2023] Open
Abstract
Antimicrobial resistance (AMR) in bacterial pathogens is a worldwide health issue. The innovation gap in discovering new antibiotics has remained a significant hurdle in combating the AMR problem. Currently, antibiotics target various vital components of the bacterial cell envelope, nucleic acid and protein biosynthesis machinery and metabolic pathways essential for bacterial survival. The critical role of the bacterial cell envelope in cell morphogenesis and integrity makes it an attractive drug target. While a significant number of in-clinic antibiotics target peptidoglycan biosynthesis, several components of the bacterial cell envelope have been overlooked. This review focuses on various antibacterial targets in the bacterial cell wall and the strategies employed to find their novel inhibitors. This review will further elaborate on combining forward and reverse chemical genetic approaches to discover antibacterials that target the bacterial cell envelope.
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Affiliation(s)
- Rinki Gupta
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee Roorkee - 247 667 Uttarakhand India
| | - Mangal Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee Roorkee - 247 667 Uttarakhand India
| | - Ranjana Pathania
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee Roorkee - 247 667 Uttarakhand India
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Ding L, Sun Y, Zhang Y, Shen S, Hu F. In Vivo Development of Aztreonam Resistance in Meropenem-Resistant Pseudomonas aeruginosa Owing to Overexpression of the blaPDC-16. Microbiol Spectr 2023; 11:e0308022. [PMID: 37070974 PMCID: PMC10269455 DOI: 10.1128/spectrum.03080-22] [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: 08/06/2022] [Accepted: 03/30/2023] [Indexed: 04/19/2023] Open
Abstract
The rapid acquisition of antibiotic resistance of Pseudomonas aeruginosa has been a complex problem in clinics. Two meropenem-resistant P. aeruginosa isolates were collected from the same patient on May 24, 2021, and June 4, 2021, respectively. The first was susceptible to aztreonam, while the second displayed resistance. This study aimed to identify the genetic differences between two P. aeruginosa isolates and uncover alterations formed by the within-host bacterial evolution leading to aztreonam resistance during therapy. Strains were subjected to antimicrobial susceptibility testing using the broth microdilution method. Genomic DNAs were obtained to identify their genetic differences. The relative mRNA levels of β-lactam-resistance genes were determined by real-time PCR. Both isolates belonged to ST 773 high-risk clones with the same antibiotic resistance genes, eliminating the possibility of horizontally obtaining resistance genes. Reverse transcription (RT)-PCR results showed that the blaPDC-16 mRNA level in the second one was about 1,500 times higher than that in the first one. When 3-aminophenyl boronic acid was added, the second strain recovered its susceptibility to aztreonam, which confirmed that the overexpression of blaPDC-16 was the main reason for the isolate's resistance to aztreonam. Compared to the first strain, the second showed a single amino acid substitution in AmpR located upstream of blaPDC-16, which may contribute to the upregulation of blaPDC-16 and lead to aztreonam resistance. AmpR plays an essential role in regulating antibiotic resistance in P. aeruginosa, and there is a need to be alert to clinical treatment failures associated with mutations in ampR. IMPORTANCE Pseudomonas aeruginosa is notorious for being highly resistant to antimicrobial agents. In this study, two P. aeruginosa strains isolated from the same patient with different susceptibility to aztreonam were used to illustrate the within-host resistance evolution process of P. aeruginosa. Both isolates, which belonged to a ST773 high-risk clone, had the same β-lactam resistance genes (blaPDC-16, blaIMP-45, blaOXA-1, and blaOXA-395), which means the second isolate might have been derived from the first isolate by gaining aztreonam resistance via mutations associated with aztreonam resistance relative genes. Subsequently, we found that mutation in ampR may be the cause of aztreonam resistance in the second isolate. Mutation in ampR leads to its loss of control over blaPDC-16, allowing overexpression of blaPDC-16 and further resistance to aztreonam. This study revealed that ampR plays an essential role in regulating antibiotic resistance in P. aeruginosa. There is a need to be alert to clinical treatment failures associated with mutations in ampR.
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Affiliation(s)
- Li Ding
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
- Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, People’s Republic of China
| | - Yue Sun
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
- Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, People’s Republic of China
| | - Yizhuo Zhang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
- Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, People’s Republic of China
| | - Siquan Shen
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
- Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, People’s Republic of China
| | - Fupin Hu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People’s Republic of China
- Key Laboratory of Clinical Pharmacology of Antibiotics, Ministry of Health, Shanghai, People’s Republic of China
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Guérin F, Gravey F, Reissier S, Penven M, Michaux C, Le Hello S, Cattoir V. Temocillin Resistance in the Enterobacter cloacae Complex Is Conferred by a Single Point Mutation in BaeS, Leading to Overexpression of the AcrD Efflux Pump. Antimicrob Agents Chemother 2023; 67:e0035823. [PMID: 37195180 PMCID: PMC10269110 DOI: 10.1128/aac.00358-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/24/2023] [Indexed: 05/18/2023] Open
Abstract
The Enterobacter cloacae complex (ECC) has become a major opportunistic pathogen with antimicrobial resistance issues. Temocillin, an "old" carboxypenicillin that is remarkably stable toward β-lactamases, has been used as an alternative for the treatment of multidrug-resistant ECC infections. Here, we aimed at deciphering the never-investigated mechanisms of temocillin resistance acquisition in Enterobacterales. By comparative genomic analysis of two clonally related ECC clinical isolates, one susceptible (Temo_S [MIC of 4 mg/L]) and the other resistant (Temo_R [MIC of 32 mg/L]), we found that they differed by only 14 single-nucleotide polymorphisms, including one nonsynonymous mutation (Thr175Pro) in the two-component system (TCS) sensor histidine kinase BaeS. By site-directed mutagenesis in Escherichia coli CFT073, we demonstrated that this unique change in BaeS was responsible for a significant (16-fold) increase in temocillin MIC. Since the BaeSR TCS regulates the expression of two resistance-nodulation-cell division (RND)-type efflux pumps (namely, AcrD and MdtABCD) in E. coli and Salmonella, we demonstrated by quantitative reverse transcription-PCR that mdtB, baeS, and acrD genes were significantly overexpressed (15-, 11-, and 3-fold, respectively) in Temo_R. To confirm the role of each efflux pump in this mechanism, multicopy plasmids harboring mdtABCD or acrD were introduced into either Temo_S or the reference strain E. cloacae subsp. cloacae ATCC 13047. Interestingly, only the overexpression of acrD conferred a significant increase (from 8- to 16-fold) of the temocillin MIC. Altogether, we have shown that temocillin resistance in the ECC can result from a single BaeS alteration, likely resulting in the permanent phosphorylation of BaeR and leading to AcrD overexpression and temocillin resistance through enhanced active efflux.
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Affiliation(s)
- François Guérin
- Department of Clinical Microbiology, Rennes University Hospital, Rennes, France
- University of Rennes, INSERM UMR 1230 BRM, Rennes, France
| | - François Gravey
- Normandie Université, UNICAEN, UNIROUEN, INSERM UMR 1311 DYNAMICURE, Caen, France
- Microbiology Department, CHU Caen, Caen, France
| | - Sophie Reissier
- Department of Clinical Microbiology, Rennes University Hospital, Rennes, France
- University of Rennes, INSERM UMR 1230 BRM, Rennes, France
| | - Malo Penven
- Department of Clinical Microbiology, Rennes University Hospital, Rennes, France
- University of Rennes, INSERM UMR 1230 BRM, Rennes, France
| | | | - Simon Le Hello
- Normandie Université, UNICAEN, UNIROUEN, INSERM UMR 1311 DYNAMICURE, Caen, France
- Microbiology Department, CHU Caen, Caen, France
| | - Vincent Cattoir
- Department of Clinical Microbiology, Rennes University Hospital, Rennes, France
- University of Rennes, INSERM UMR 1230 BRM, Rennes, France
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8
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Complete Genome Sequence of Enterobacter roggenkampii RX.G5M56, a C1-Metabolizing Strain from a Freshwater Stream in Hong Kong. Microbiol Resour Announc 2023; 12:e0001523. [PMID: 36920231 PMCID: PMC10112238 DOI: 10.1128/mra.00015-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
The C1-metabolizing strain Enterobacter roggenkampii RX.G5M56 was isolated from a freshwater stream in Hong Kong. Its complete genome, a single chromosome of 4,772,201 bp (GC content of 56.05%), was established through hybrid assembly.
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Sethuvel DPM, Bakthavatchalam YD, Karthik M, Irulappan M, Shrivastava R, Periasamy H, Veeraraghavan B. β-Lactam Resistance in ESKAPE Pathogens Mediated Through Modifications in Penicillin-Binding Proteins: An Overview. Infect Dis Ther 2023; 12:829-841. [PMID: 36877435 PMCID: PMC10017896 DOI: 10.1007/s40121-023-00771-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 01/30/2023] [Indexed: 03/07/2023] Open
Abstract
Bacteria acquire β-lactam resistance through a multitude of mechanisms among which production of β-lactamases (enzymes that hydrolyze β-lactams) is the most common, especially in Gram-negatives. Structural changes in the high-molecular-weight, essential penicillin-binding proteins (PBPs) are widespread in Gram-positives and increasingly reported in Gram-negatives. PBP-mediated resistance is largely achieved by accumulation of mutation(s) resulting in reduced binding affinities of β-lactams. Herein, we discuss PBP-mediated resistance among ESKAPE pathogens that cause diverse hospital- and community-acquired infections globally.
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Affiliation(s)
| | | | - Maruthan Karthik
- Department of Clinical Microbiology, Christian Medical College, Vellore, 632004, India
| | - Madhumathi Irulappan
- Department of Clinical Microbiology, Christian Medical College, Vellore, 632004, India
| | | | | | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, 632004, India.
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Narayanasamy S, Thankappan S, Kumaravel S, Ragupathi S, Uthandi S. Complete genome sequence analysis of a plant growth-promoting phylloplane Bacillus altitudinis FD48 offers mechanistic insights into priming drought stress tolerance in rice. Genomics 2023; 115:110550. [PMID: 36565792 DOI: 10.1016/j.ygeno.2022.110550] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/08/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
Bacillus altitudinis FD48 is a multifunctional plant growth-promoting bacterium isolated from the phylloplane of rice and survives at --10 bars of osmotic potential (--1.0 MPa). It also serves as an ideal PGPM against drought stress by triggering antioxidant defense mechanisms in rice. To further unravel the genetic determinants of osmotic stress tolerance and plant growth-promoting traits, the whole genome sequence of FD48 was compared with its related strains. The whole genome analysis revealed a single chromosome with a total length of 3,752,533 bp (3.7 Mb) and an average G + C ratio of 41.19%. A total of 4029 genes were predicted, of which 3964 (98.4%) were protein-encoding genes (PEGs) and 65 (1.6%) were non-protein-coding genes. The interaction of FD48 with the host plants is associated with many chemotactic and motility-related genes. The ability of FD48 to colonize plants and maintain plant growth under adverse environmental conditions was evidenced by the presence of genes for plant nutrient acquisition, phytohormone synthesis, trehalose, choline, and glycine betaine biosynthesis, microbial volatile organic compounds (acetoin synthesis), heat and cold shock chaperones, translation elongation factor TU (Ef-Tu), siderophore production, DEAD/DEAH boxes, and non- ribosomal peptide synthase clusters (bacilysin, fengycin, and bacitracin). This study sheds light on the drought stress-resilient mechanism, metabolic pathways and potential activity, and plant growth-promoting traits of B. altitudinis FD48 at the genetic level.
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Affiliation(s)
- Shobana Narayanasamy
- Biocatalysts Laboratory, Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641 003, India
| | - Sugitha Thankappan
- Biocatalysts Laboratory, Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641 003, India
| | - Sowmya Kumaravel
- Biocatalysts Laboratory, Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641 003, India
| | - Sridar Ragupathi
- Biocatalysts Laboratory, Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641 003, India
| | - Sivakumar Uthandi
- Biocatalysts Laboratory, Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641 003, India.
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11
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Yang X, Wang Z, Liu M, Yu X, Zhong Y, Wang F, Xu Y. Cefazolin and imipenem enhance AmpC expression and resistance in NagZ-dependent manner in Enterobacter cloacae complex. BMC Microbiol 2022; 22:284. [PMID: 36443681 PMCID: PMC9706910 DOI: 10.1186/s12866-022-02707-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 11/15/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Enterobacter cloacae complex (ECC) is a common opportunistic pathogen and is responsible for causing various infections in humans. Owing to its inducible chromosomal AmpC β-lactamase (AmpC), ECC is inherently resistant to the 1st- and 2nd- generation cephalosporins. However, whether β-lactams antibiotics enhance ECC resistance remains unclear. RESULTS In this study, we found that subinhibitory concentrations (SICs) of cefazolin (CFZ) and imipenem (IMP) can advance the expression of AmpC and enhance its resistance towards β-lactams through NagZ in Enterobacter cloacae (EC). Further, AmpC manifested a substantial upregulation in EC in response to SICs of CFZ and IMP. In nagZ knockout EC (ΔnagZ), the resistance to β-lactam antibiotics was rather weakened and the effect of CFZ and IMP on AmpC induction was completely abrogated. NagZ ectopic expression can rescue the induction effects of CFZ and IMP on AmpC and increase ΔnagZ resistance. More importantly, CFZ and IMP have the potential to induce the expression of AmpR's target genes in a NagZ-dependent manner. CONCLUSIONS Our findings suggest that NagZ is a critical determinant for CFZ and IMP to promote AmpC expression and resistance and that CFZ and IMP should be used with caution since they may aggravate ECC resistance. At the same time, this study further improves our understanding of resistance mechanisms in ECC.
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Affiliation(s)
- Xianggui Yang
- grid.414880.1Department of Laboratory Medicine, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan China
| | - Zhenguo Wang
- grid.414880.1Department of Stomatology, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan China
| | - Mingquan Liu
- grid.414880.1Department of Laboratory Medicine, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan China
| | - Xuejing Yu
- grid.267313.20000 0000 9482 7121Department of Internal Medicine, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Yuanxiu Zhong
- grid.413856.d0000 0004 1799 3643Department of Biotechnology, Chengdu Medical College, Chengdu, Sichuan China
| | - Fuying Wang
- grid.413856.d0000 0004 1799 3643Department of Biotechnology, Chengdu Medical College, Chengdu, Sichuan China
| | - Ying Xu
- grid.414880.1Department of Laboratory Medicine, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan China
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12
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Shropshire WC, Konovalova A, McDaneld P, Gohel M, Strope B, Sahasrabhojane P, Tran CN, Greenberg D, Kim J, Zhan X, Aitken S, Bhatti M, Savidge TC, Treangen TJ, Hanson BM, Arias CA, Shelburne SA. Systematic Analysis of Mobile Genetic Elements Mediating β-Lactamase Gene Amplification in Noncarbapenemase-Producing Carbapenem-Resistant Enterobacterales Bloodstream Infections. mSystems 2022; 7:e0047622. [PMID: 36036505 PMCID: PMC9601100 DOI: 10.1128/msystems.00476-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/26/2022] [Indexed: 01/25/2023] Open
Abstract
Noncarbapenemase-producing carbapenem-resistant Enterobacterales (non-CP-CRE) are increasingly recognized as important contributors to prevalent carbapenem-resistant Enterobacterales (CRE) infections. However, there is limited understanding of mechanisms underlying non-CP-CRE causing invasive disease. Long- and short-read whole-genome sequencing was used to elucidate carbapenem nonsusceptibility determinants in Enterobacterales bloodstream isolates at MD Anderson Cancer Center in Houston, Texas. We investigated carbapenem nonsusceptible Enterobacterales (CNSE) mechanisms (i.e., isolates with carbapenem intermediate resistance phenotypes or greater) through a combination of phylogenetic analysis, antimicrobial resistance gene detection/copy number quantification, porin assessment, and mobile genetic element (MGE) characterization. Most CNSE isolates sequenced were non-CP-CRE (41/79; 51.9%), whereas 25.3% (20/79) were Enterobacterales with intermediate susceptibility to carbapenems (CIE), and 22.8% (18/79) were carbapenemase-producing Enterobacterales (CPE). Statistically significant copy number variants (CNVs) of extended-spectrum β-lactamase (ESBL) genes (Wilcoxon Test; P-value < 0.001) were present in both non-CP-CR E. coli (median CNV = 2.6×; n = 17) and K. pneumoniae (median CNV = 3.2×, n = 17). All non-CP-CR E. coli and K. pneumoniae had predicted reduced expression of at least one outer membrane porin gene (i.e., ompC/ompF or ompK36/ompK35). Completely resolved CNSE genomes revealed that IS26 and ISEcp1 structures harboring blaCTX-M variants along with other antimicrobial resistance elements were associated with gene amplification, occurring in mostly IncFIB/IncFII plasmid contexts. MGE-mediated β-lactamase gene amplifications resulted in either tandem arrays, primarily mediated by IS26 translocatable units, or segmental duplication, typically due to ISEcp1 transposition units. Non-CP-CRE strains were the most common cause of CRE bacteremia with carbapenem nonsusceptibility driven by concurrent porin loss and MGE-mediated amplification of blaCTX-M genes. IMPORTANCE Carbapenem-resistant Enterobacterales (CRE) are considered urgent antimicrobial resistance (AMR) threats. The vast majority of CRE research has focused on carbapenemase-producing Enterobacterales (CPE) even though noncarbapenemase-producing CRE (non-CP-CRE) comprise 50% or more of isolates in some surveillance studies. Thus, carbapenem resistance mechanisms in non-CP-CRE remain poorly characterized. To address this problem, we applied a combination of short- and long-read sequencing technologies to a cohort of CRE bacteremia isolates and used these data to unravel complex mobile genetic element structures mediating β-lactamase gene amplification. By generating complete genomes of 65 carbapenem nonsusceptible Enterobacterales (CNSE) covering a genetically diverse array of isolates, our findings both generate novel insights into how non-CP-CRE overcome carbapenem treatments and provide researchers scaffolds for characterization of their own non-CP-CRE isolates. Improved recognition of mechanisms driving development of non-CP-CRE could assist with design and implementation of future strategies to mitigate the impact of these increasingly recognized AMR pathogens.
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Affiliation(s)
- W. C. Shropshire
- Department of Infectious Diseases and Infection Control, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - A. Konovalova
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - P. McDaneld
- Division of Pharmacy, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - M. Gohel
- Department of Infectious Diseases and Infection Control, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - B. Strope
- Department of Infectious Diseases and Infection Control, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - P. Sahasrabhojane
- Department of Infectious Diseases and Infection Control, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - C. N. Tran
- Department of Infectious Diseases and Infection Control, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - D. Greenberg
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
- Department of Microbiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - J. Kim
- Department of Bioinformatics, UT Southwestern Medical Center, Dallas, Texas, USA
| | - X. Zhan
- Department of Bioinformatics, UT Southwestern Medical Center, Dallas, Texas, USA
| | - S. Aitken
- Division of Pharmacy, Michigan Medicine at University of Michigan, Ann Arbor, Michigan, USA
| | - M. Bhatti
- Department of Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - T. C. Savidge
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
- Department of Pathology, Texas Children’s Hospital, Houston, Texas, USA
| | - T. J. Treangen
- Department of Computer Science, Rice University, Houston, Texas, USA
| | - B. M. Hanson
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center, Houston, Texas, USA
| | - C. A. Arias
- Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - S. A. Shelburne
- Department of Infectious Diseases and Infection Control, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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13
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Chang CY, Huang PH, Lu PL. The Resistance Mechanisms and Clinical Impact of Resistance to the Third Generation Cephalosporins in Species of Enterobacter cloacae Complex in Taiwan. Antibiotics (Basel) 2022; 11:antibiotics11091153. [PMID: 36139933 PMCID: PMC9494969 DOI: 10.3390/antibiotics11091153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 08/21/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
Enterobacter cloacae complex (ECC) is ubiquitous in the environment and is an important pathogen causing nosocomial infections. Because routine methods used in clinical laboratories cannot identify species within ECC, the clinical significance of each species within ECC is less known. We applied hsp60 gene sequencing to identify the species/clusters of ECC and detected β-lactamase genes and class 1 integrons with PCR for 184 clinical ECC isolates in Taiwan from 2013 to 2014 to investigate the clinical impact of species within ECC. The four most common clusters were E. hormaechei subsp. steigerwaltii (cluster VIII) (29.9%), E. hormaechei subsp. oharae (cluster VI) (20.1%), E. cloacae subsp. cloacae (cluster XI) (12%), and E. kobei (cluster II) (10.3%). E. hormaechei, which consisted of four clusters (clusters III, VI, VII, and VIII), is the predominant species and accounted for 57.1% of the isolates. The ceftazidime resistance rate was 27.2%, and the ceftriaxone resistance rate was 29.3%. Resistance to third generation cephalosporin was associated with a higher 30-day mortality rate. In total, 5 (2.7%), 24 (13.0%), and 1 (0.5%) isolates carried ESBL, AmpC, and carbapenemase genes, respectively. Class 1 integrons were present in 24.5% of the isolates, and most of the cassettes pertain to antibiotic resistance. Resistance to third generation cephalosporins, multidrug resistance, and class 1 integrons were significantly more in E. hormaechei (clusters III, VI, VII, and VIII) than in the other species. The 30-day mortality rate and 100-day mortality did not differ significantly between patients with E. hormaechei and those with infections with the other species. In conclusion, the distribution of third generation cephalosporin resistance, multidrug resistance, and class 1 integrons were uneven among Enterobacter species. The resistance to third generation cephalosporins possessed significant impact on patient outcome.
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Affiliation(s)
- Chung-Yu Chang
- School of Post-Baccalaureate Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Po-Hao Huang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Po-Liang Lu
- School of Post-Baccalaureate Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Center for Liquid Biopsy and Cohort Research, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Biological Science and Technology, College of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- M.Sc. Program in Tropical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Correspondence: ; Tel.: +886-7-3121101 (ext. 5675)
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14
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Xie L, Xu R, Zhu D, Sun J. Emerging resistance to ceftriaxone treatment owing to different ampD mutations in Enterobacter roggenkampii. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 102:105301. [PMID: 35568334 DOI: 10.1016/j.meegid.2022.105301] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/08/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
OBJECTIVES The Enterobacter cloacae complex is responsible for a variety of infections in hospitalized patients and is resistant to β-lactam antibiotics owing to the expression of AmpC β-lactamase. We report emerging resistance in Enterobacter roggenkampii exposed to ceftriaxone and explore the mechanism underlying mutations responsible for this resistance. METHODS Three strains were derived from different samples from one patient (blood and liver abscess fluid). Antimicrobial susceptibility was evaluated by standard broth microdilution, while ampC expression was determined via RT-PCR. Genetic relatedness was evaluated via pulsed-field gel electrophoresis (PFGE). Species identification and comparative genome analysis were performed via genome sequencing. Mutation rate testing and selection of AmpC-derepressed mutants were conducted to explore the mutation mechanism. RESULTS E. roggenkampii F1247 was susceptible to third-generation cephalosporins (3GCs); F95 and F1057, found in blood sample on day 11 and liver abscess drainage fluid on day 25, were resistant. ampC expression was 341- and 642-fold higher in F95 and F1057, respectively, than in F1247. Three isolates were the same PFGE and sequence types (ST1778) and were highly homologous (2 and 4 core genome single nucleotide polymorphism differences). Compared to F1247, F95 possessed a 575 bp deletion, including 537 bp of ampD, whereas F1057 harbored only one amino acid mutation (Leu140Pro in ampD). The mutation rates from F1247 exposure to cefotaxime, ceftazidime, ceftriaxone, piperacillin-tazobactam, and cefepime were (1.90 ± 0.21) × 10-8, (3.18 ± 0.43) × 10-8, (2.00 ± 0.20) × 10-8, (2.92 ± 0.29) × 10-9, and zero, respectively. In vitro-selected mutations responsible for resistance were identified in ampD, ampR, and dacB. CONCLUSIONS E. roggenkampii may develop resistance in vivo and in vitro upon exposure to 3GCs and to a lesser extent to piperacillin-tazobactam. 3GCs should not be used as a monotherapy for E. roggenkampii infections. Therapy using cefepime or carbapenems may be preferred to piperacillin-tazobactam in the treatment of E. roggenkampii, especially if source control is difficult.
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Affiliation(s)
- Lianyan Xie
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Rong Xu
- Department of Clinical Microbiology, Shanghai Center for Clinical Laboratory, Shanghai, China
| | - Dongan Zhu
- Department of Clinical Laboratory, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China.
| | - Jingyong Sun
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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15
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Resistance mechanisms in Gram-negative bacteria. Med Intensiva 2022; 46:392-402. [PMID: 35660283 DOI: 10.1016/j.medine.2022.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/13/2022] [Indexed: 12/24/2022]
Abstract
Enterobacterales resistant to carbapenems or producing extended-spectrum β-lactamases (ESBL) and non-fermenters resistant to carbapenems present resistance to many of the antimicrobials commonly used in clinical practice, and have been recognized by the World Health Organization as a critical priority for the development of new antimicrobials. In this review, the main mechanisms of resistance of Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia to β-lactams, quinolones, aminoglycosides and polymyxins will be addressed. Updated information will be presented on the importance in resistance of antimicrobial modification mechanisms (including class C or extended-spectrum β-lactamases, carbapenemases and aminoglycoside-modifying enzymes), permeability alterations due to porin or lipopolysaccharide expression disorders, production of active efflux pumps, target alterations or protection, and expression of two-component systems.
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16
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Abstract
Class C β-lactamases or cephalosporinases can be classified into two functional groups (1, 1e) with considerable molecular variability (≤20% sequence identity). These enzymes are mostly encoded by chromosomal and inducible genes and are widespread among bacteria, including Proteobacteria in particular. Molecular identification is based principally on three catalytic motifs (64SXSK, 150YXN, 315KTG), but more than 70 conserved amino-acid residues (≥90%) have been identified, many close to these catalytic motifs. Nevertheless, the identification of a tiny, phylogenetically distant cluster (including enzymes from the genera Legionella, Bradyrhizobium, and Parachlamydia) has raised questions about the possible existence of a C2 subclass of β-lactamases, previously identified as serine hydrolases. In a context of the clinical emergence of extended-spectrum AmpC β-lactamases (ESACs), the genetic modifications observed in vivo and in vitro (point mutations, insertions, or deletions) during the evolution of these enzymes have mostly involved the Ω- and H-10/R2-loops, which vary considerably between genera, and, in some cases, the conserved triplet 150YXN. Furthermore, the conserved deletion of several amino-acid residues in opportunistic pathogenic species of Acinetobacter, such as A. baumannii, A. calcoaceticus, A. pittii and A. nosocomialis (deletion of residues 304-306), and in Hafnia alvei and H. paralvei (deletion of residues 289-290), provides support for the notion of natural ESACs. The emergence of higher levels of resistance to β-lactams, including carbapenems, and to inhibitors such as avibactam is a reality, as the enzymes responsible are subject to complex regulation encompassing several other genes (ampR, ampD, ampG, etc.). Combinations of resistance mechanisms may therefore be at work, including overproduction or change in permeability, with the loss of porins and/or activation of efflux systems.
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17
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Lepe J, Martínez-Martínez L. Mecanismos de resistencia en bacterias gramnegativas. Med Intensiva 2022. [DOI: 10.1016/j.medin.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Nakano R, Yamada Y, Nakano A, Suzuki Y, Saito K, Sakata R, Ogawa M, Narita K, Kuga A, Suwabe A, Yano H. The Role of nmcR, ampR, and ampD in the Regulation of the Class A Carbapenemase NmcA in Enterobacter ludwigii. Front Microbiol 2022; 12:794134. [PMID: 35095805 PMCID: PMC8790168 DOI: 10.3389/fmicb.2021.794134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
Various carbapenemases have been identified in the Enterobacteriaceae. However, the induction and corresponding regulator genes of carbapenemase NmcA has rarely been detected in the Enterobacter cloacae complex (ECC). The NmcA-positive isolate ECC NR1491 was first detected in Japan in 2013. It was characterized and its induction system elucidated by evaluating its associated regulator genes nmcR, ampD, and ampR. The isolate was highly resistant to all β-lactams except for third generation cephalosporins (3GC). Whole-genome analysis revealed that blaNmcA was located on a novel 29-kb putatively mobile element called EludIMEX-1 inserted into the chromosome. The inducibility of β-lactamase activity by various agents was evaluated. Cefoxitin was confirmed as a strong concentration-independent β-lactamase inducer. In contrast, carbapenems induced β-lactamase in a concentration-dependent manner. All selected 3GC-mutants harboring substitutions on ampD (as ampR and nmcR were unchanged) were highly resistant to 3GC. The ampD mutant strain NR3901 presented with a 700 × increase in β-lactamase activity with or without induction. Similar upregulation was also observed for ampC and nmcA. NR1491 (pKU412) was obtained by transforming the ampR mutant (135Asn) clone plasmid whose expression increased by ∼100×. Like NR3901, it was highly resistant to 3GC. Overexpression of ampC, rather than nmcA, may have accounted for the higher MIC in NR1491. The ampR mutant repressed nmcA despite induction and it remains unclear how it stimulates nmcA transcription via induction. Future experiments should analyze the roles of nmcR mutant strains.
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Affiliation(s)
- Ryuichi Nakano
- Department of Microbiology and Infectious Diseases, Nara Medical University, Kashihara, Japan
| | - Yuki Yamada
- Division of Central Clinical Laboratory, Iwate Medical University Hospital, Yahaba, Japan
| | - Akiyo Nakano
- Department of Microbiology and Infectious Diseases, Nara Medical University, Kashihara, Japan
| | - Yuki Suzuki
- Department of Microbiology and Infectious Diseases, Nara Medical University, Kashihara, Japan
| | - Kai Saito
- Department of Microbiology and Infectious Diseases, Nara Medical University, Kashihara, Japan
| | - Ryuji Sakata
- Department of Bacteriology, BML Inc., Kawagoe, Japan
| | - Miho Ogawa
- Department of Bacteriology, BML Inc., Kawagoe, Japan
| | - Kazuya Narita
- Division of Central Clinical Laboratory, Iwate Medical University Hospital, Yahaba, Japan
| | - Akio Kuga
- Hamamatsu Pharmaceutical Association, Hamamatsu, Japan
| | - Akira Suwabe
- Department of Laboratory Medicine, Iwate Medical University School of Medicine, Yahaba, Japan
| | - Hisakazu Yano
- Department of Microbiology and Infectious Diseases, Nara Medical University, Kashihara, Japan
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19
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Murtha AN, Kazi MI, Schargel RD, Cross T, Fihn C, Cattoir V, Carlson EE, Boll JM, Dörr T. High-level carbapenem tolerance requires antibiotic-induced outer membrane modifications. PLoS Pathog 2022; 18:e1010307. [PMID: 35130322 PMCID: PMC8853513 DOI: 10.1371/journal.ppat.1010307] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 02/17/2022] [Accepted: 01/26/2022] [Indexed: 12/22/2022] Open
Abstract
Antibiotic tolerance is an understudied potential contributor to antibiotic treatment failure and the emergence of multidrug-resistant bacteria. The molecular mechanisms governing tolerance remain poorly understood. A prominent type of β-lactam tolerance relies on the formation of cell wall-deficient spheroplasts, which maintain structural integrity via their outer membrane (OM), an asymmetric lipid bilayer consisting of phospholipids on the inner leaflet and a lipid-linked polysaccharide (lipopolysaccharide, LPS) enriched in the outer monolayer on the cell surface. How a membrane structure like LPS, with its reliance on mere electrostatic interactions to maintain stability, is capable of countering internal turgor pressure is unknown. Here, we have uncovered a novel role for the PhoPQ two-component system in tolerance to the β-lactam antibiotic meropenem in Enterobacterales. We found that PhoPQ is induced by meropenem treatment and promotes an increase in 4-amino-4-deoxy-L-aminoarabinose [L-Ara4N] modification of lipid A, the membrane anchor of LPS. L-Ara4N modifications likely enhance structural integrity, and consequently tolerance to meropenem, in several Enterobacterales species. Importantly, mutational inactivation of the negative PhoPQ regulator mgrB (commonly selected for during clinical therapy with the last-resort antibiotic colistin, an antimicrobial peptide [AMP]) results in dramatically enhanced tolerance, suggesting that AMPs can collaterally select for meropenem tolerance via stable overactivation of PhoPQ. Lastly, we identify histidine kinase inhibitors (including an FDA-approved drug) that inhibit PhoPQ-dependent LPS modifications and consequently potentiate meropenem to enhance lysis of tolerant cells. In summary, our results suggest that PhoPQ-mediated LPS modifications play a significant role in stabilizing the OM, promoting survival when the primary integrity maintenance structure, the cell wall, is removed. Treating an infection with an antibiotic often fails, resulting in a tremendous public health burden. One understudied likely reason for treatment failure is the development of “antibiotic tolerance”, the ability of bacteria to survive normally lethal exposure to an antibiotic. Here, we describe a molecular mechanism promoting tolerance. A bacterial stress sensor (PhoPQ) is activated in response to antibiotic (meropenem) treatment and consequently strengthens a bacterial protective “shell” to enhance survival. We also identify inhibitors of this mechanism, opening the door to developing compounds that help antibiotics work better against tolerant bacteria.
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Affiliation(s)
- Andrew N. Murtha
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Microbiology, Cornell University, Ithaca, New York, United States of America
| | - Misha I. Kazi
- Department of Biology, University of Texas Arlington, Arlington, Texas, United States of America
| | - Richard D. Schargel
- Department of Biology, University of Texas Arlington, Arlington, Texas, United States of America
| | - Trevor Cross
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Microbiology, Cornell University, Ithaca, New York, United States of America
| | - Conrad Fihn
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Vincent Cattoir
- Department of Clinical Microbiology and National Reference Center for Antimicrobial Resistance (Lab Enterococci), Rennes University Hospital, Rennes, France; Inserm Unit U1230, University of Rennes 1, Rennes, France
| | - Erin E. Carlson
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Molecular Pharmacology and Therapeutics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Joseph M. Boll
- Department of Biology, University of Texas Arlington, Arlington, Texas, United States of America
- * E-mail: (JMB); (TD)
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, United States of America
- Department of Microbiology, Cornell University, Ithaca, New York, United States of America
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York, United States of America
- * E-mail: (JMB); (TD)
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20
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Mallik D, Jain D, Bhakta S, Ghosh AS. Role of AmpC-Inducing Genes in Modulating Other Serine Beta-Lactamases in Escherichia coli. Antibiotics (Basel) 2022; 11:antibiotics11010067. [PMID: 35052944 PMCID: PMC8772759 DOI: 10.3390/antibiotics11010067] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/21/2021] [Accepted: 01/05/2022] [Indexed: 02/04/2023] Open
Abstract
The consistently mutating bacterial genotypes appear to have accelerated the global challenge with antimicrobial resistance (AMR); it is therefore timely to investigate certain less-explored fields of targeting AMR mechanisms in bacterial pathogens. One of such areas is beta-lactamase (BLA) induction that can provide us with a collection of prospective therapeutic targets. The key genes (ampD, ampE and ampG) to which the AmpC induction mechanism is linked are also involved in regulating the production of fragmented muropeptides generated during cell-wall peptidoglycan recycling. Although the involvement of these genes in inducing class C BLAs is apparent, their effect on serine beta-lactamase (serine-BLA) induction is little known. Here, by using ∆ampD and ∆ampE mutants of E. coli, we attempted to elucidate the effects of ampD and ampE on the expression of serine-BLAs originating from Enterobacteriaceae, viz., CTX-M-15, TEM-1 and OXA-2. Results show that cefotaxime is the preferred inducer for CTX-M-15 and amoxicillin for TEM-1, whereas oxacillin for OXA-2. Surprisingly, exogenous BLA expressions are elevated in ∆ampD and ∆ampE mutants but do not always alter their beta-lactam susceptibility. Moreover, the beta-lactam resistance is increased upon in trans expression of ampD, whereas the same is decreased upon ampE expression, indicating a differential effect of ampD and ampE overexpression. In a nutshell, depending on the BLA, AmpD amidase moderately facilitates a varying level of serine-BLA expression whereas AmpE transporter acts likely as a negative regulator of serine-BLA.
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Affiliation(s)
- Dhriti Mallik
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India; (D.M.); (D.J.)
| | - Diamond Jain
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India; (D.M.); (D.J.)
| | - Sanjib Bhakta
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK;
| | - Anindya Sundar Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India; (D.M.); (D.J.)
- Correspondence:
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21
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Laganà P, Visalli G, Facciolà A, Ciarello MP, Laganà A, Iannazzo D, Di Pietro A. Is the Antibacterial Activity of Multi-Walled Carbon Nanotubes (MWCNTs) Related to Antibiotic Resistance? An Assessment in Clinical Isolates. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18179310. [PMID: 34501898 PMCID: PMC8431017 DOI: 10.3390/ijerph18179310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/27/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022]
Abstract
Antimicrobial resistance has spread globally, compromising the treatment of common infections. This feature is particularly harmful for nosocomial pathogens that can survive on hospital surfaces. Research studies have been conducted to evaluate new materials that are able to counteract the microbial growth and the colonization of the hospital environment. In this context, nanotechnologies have showed encouraging applications. We investigated the antibacterial activity of multi-walled carbon nanotubes (MWCNTs), both pristine (p) and functionalized (f), at concentrations of 50 and 100 μg mL−1, against bacterial strains isolated from hospital-acquired infections, and this activity was correlated with the antibiotic susceptibility of the strains. The inhibiting effect of MWCNTs occurred for both types and doses tested. Moreover, f-MWCNTs exerted a greater inhibiting effect, with growth decreases greater than 10% at 24 h and 20% at 48 h compared to p-MWCNTs. Moreover, a lower inhibitory effect of MWCNTs, which was more lasting in Gram-positives resistant to cell wall antibiotics, or temporary in Gram-negatives resistant to nucleic acid and protein synthesis inhibitors, was observed, highlighting the strong relation between antibiotic resistance and MWCNT effect. In conclusion, an antimicrobial activity was observed especially for f-MWCNTs that could therefore be loaded with bioactive antimicrobial molecules. However, this potential application of CNTs presupposes the absence of toxicity and therefore total safety for patients.
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Affiliation(s)
- Pasqualina Laganà
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (G.V.); (A.F.); (M.P.C.); (A.L.); (A.D.P.)
- Correspondence:
| | - Giuseppa Visalli
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (G.V.); (A.F.); (M.P.C.); (A.L.); (A.D.P.)
| | - Alessio Facciolà
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (G.V.); (A.F.); (M.P.C.); (A.L.); (A.D.P.)
| | - Marianna Pruiti Ciarello
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (G.V.); (A.F.); (M.P.C.); (A.L.); (A.D.P.)
| | - Antonio Laganà
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (G.V.); (A.F.); (M.P.C.); (A.L.); (A.D.P.)
| | - Daniela Iannazzo
- Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, 98125 Messina, Italy;
| | - Angela Di Pietro
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy; (G.V.); (A.F.); (M.P.C.); (A.L.); (A.D.P.)
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22
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Hussain HI, Aqib AI, Seleem MN, Shabbir MA, Hao H, Iqbal Z, Kulyar MFEA, Zaheer T, Li K. Genetic basis of molecular mechanisms in β-lactam resistant gram-negative bacteria. Microb Pathog 2021; 158:105040. [PMID: 34119627 PMCID: PMC8445154 DOI: 10.1016/j.micpath.2021.105040] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/25/2021] [Accepted: 06/02/2021] [Indexed: 12/14/2022]
Abstract
Antibiotic-resistant bacteria are considered one of the major global threats to human and animal health. The most harmful among the resistant bacteria are β-lactamase producing Gram-negative species (β-lactamases). β-lactamases constitute a paradigm shift in the evolution of antibiotic resistance. Therefore, it is imperative to present a comprehensive review of the mechanisms responsible for developing antimicrobial resistance. Resistance due to β-lactamases develops through a variety of mechanisms, and the number of resistant genes are involved that can be transferred between bacteria, mostly via plasmids. Over time, these new molecular-based resistance mechanisms have been progressively disclosed. The present review article provides information on the recent findings regarding the molecular mechanisms of resistance to β-lactams in Gram-negative bacteria, including CTX-M-type ESBLs with methylase activity, plasmids harbouring phages with β-lactam resistance genes, the co-presence of β-lactam resistant genes of unique combinations and the presence of β-lactam and non-β-lactam antibiotic-resistant genes in the same bacteria. Keeping in view, the molecular level resistance development, multifactorial and coordinated measures may be taken to counter the challenge of rapidly increasing β-lactam resistance.
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Affiliation(s)
- Hafiz Iftikhar Hussain
- Department of Pathology, Cholistan University of Veterinary and Animal Sciences, Bahawalpur, 63100, Pakistan
| | - Amjad Islam Aqib
- Department of Medicine, Cholistan University of Veterinary and Animal Sciences, Bahawalpur, 63100, Pakistan.
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, USA
| | | | - Haihong Hao
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, 430070, Wuhan, China
| | - Zahid Iqbal
- Department of Pharmacology, International Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China.
| | | | - Tean Zaheer
- Department of Parasitology, University of Agriculture, Faisalabad, 38000, Pakistan
| | - Kun Li
- Institute of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China; MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, PR China.
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23
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Pot M, Reynaud Y, Couvin D, Ducat C, Ferdinand S, Gravey F, Gruel G, Guérin F, Malpote E, Breurec S, Talarmin A, Guyomard-Rabenirina S. Wide Distribution and Specific Resistance Pattern to Third-Generation Cephalosporins of Enterobacter cloacae Complex Members in Humans and in the Environment in Guadeloupe (French West Indies). Front Microbiol 2021; 12:628058. [PMID: 34248862 PMCID: PMC8268024 DOI: 10.3389/fmicb.2021.628058] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 05/31/2021] [Indexed: 11/25/2022] Open
Abstract
Species belonging to Enterobacter cloacae complex have been isolated in numerous environments and samples of various origins. They are also involved in opportunistic infections in plants, animals, and humans. Previous prospection in Guadeloupe (French West Indies) indicated a high frequency of E. cloacae complex strains resistant to third-generation cephalosporins (3GCs) in a local lizard population (Anolis marmoratus), but knowledge of the distribution and resistance of these strains in humans and the environment is limited. The aim of this study was to compare the distribution and antibiotic susceptibility pattern of E. cloacae complex members from different sources in a “one health” approach and to find possible explanations for the high level of resistance in non-human samples. E. cloacae complex strains were collected between January 2017 and the end of 2018 from anoles, farm animals, local fresh produce, water, and clinical human samples. Isolates were characterized by the heat-shock protein 60 gene-fragment typing method, and whole-genome sequencing was conducted on the most frequent clusters (i.e., C-VI and C-VIII). The prevalence of resistance to 3GCs was relatively high (56/346, 16.2%) in non-human samples. The associated resistance mechanism was related to an AmpC overproduction; however, in human samples, most of the resistant strains (40/62) produced an extended-spectrum beta-lactamase. No relation was found between resistance in isolates from wild anoles (35/168) and human activities. Specific core-genome phylogenetic analysis highlighted an important diversity in this bacterial population and no wide circulation among the different compartments. In our setting, the mutations responsible for resistance to 3GCs, especially in ampD, were diverse and not compartment specific. In conclusion, high levels of resistance in non-human E. cloacae complex isolates are probably due to environmental factors that favor the selection of these resistant strains, and this will be explored further.
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Affiliation(s)
- Matthieu Pot
- Transmission, Reservoir and Diversity of Pathogens Unit, Pasteur Institute of Guadeloupe, Les Abymes, France
| | - Yann Reynaud
- Transmission, Reservoir and Diversity of Pathogens Unit, Pasteur Institute of Guadeloupe, Les Abymes, France
| | - David Couvin
- Transmission, Reservoir and Diversity of Pathogens Unit, Pasteur Institute of Guadeloupe, Les Abymes, France
| | - Célia Ducat
- Transmission, Reservoir and Diversity of Pathogens Unit, Pasteur Institute of Guadeloupe, Les Abymes, France
| | - Séverine Ferdinand
- Transmission, Reservoir and Diversity of Pathogens Unit, Pasteur Institute of Guadeloupe, Les Abymes, France
| | - François Gravey
- GRAM 2.0, Normandie University, UNICAEN, UNIROUEN, Caen, France
| | - Gaëlle Gruel
- Transmission, Reservoir and Diversity of Pathogens Unit, Pasteur Institute of Guadeloupe, Les Abymes, France
| | - François Guérin
- GRAM 2.0, Normandie University, UNICAEN, UNIROUEN, Caen, France.,Department of Clinical Microbiology, Caen University Hospital, Caen, France
| | - Edith Malpote
- Laboratory of Clinical Microbiology, University Hospital of Guadeloupe, Pointe-à-Pitre/Les Abymes, France
| | - Sébastien Breurec
- Transmission, Reservoir and Diversity of Pathogens Unit, Pasteur Institute of Guadeloupe, Les Abymes, France.,Faculty of Medicine Hyacinthe Bastaraud, University of the Antilles, Pointe-à-Pitre, France.,Centre for Clinical Investigation 1424, INSERM, Pointe-à-Pitre/Les Abymes, France
| | - Antoine Talarmin
- Transmission, Reservoir and Diversity of Pathogens Unit, Pasteur Institute of Guadeloupe, Les Abymes, France
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24
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Makhlouf J, Merhi G, Salloum T, Abboud E, Tokajian S. Molecular characterization of a carbapenem-resistant Enterobacter hormaechei ssp. xiangfangensis co-harbouring bla NDM-1 and a chromosomally encoded phage-linked bla CTX-M-15 genes. INFECTION GENETICS AND EVOLUTION 2021; 93:104924. [PMID: 34004359 DOI: 10.1016/j.meegid.2021.104924] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/22/2021] [Accepted: 05/13/2021] [Indexed: 10/21/2022]
Abstract
Enterobacter cloacae complex (ECC) members are rapidly emerging as successful nosocomial pathogens, especially, with the emergence of carbapenem-resistant clones. In this study, we performed a comprehensive molecular characterization of a carbapenem-resistant E. hormaechei ssp. xiangfangensis LAU_ENC1. hsp60 and average nucleotide identity (ANI) were used for its identification. The repertoire of resistance genes and phage content were analyzed. Plasmid sequences were extracted and compared to closest references. The isolate LAU_ENC1 was identified as an E. hormaechei ssp. xiangfangensis and belonged to ST-114A sub-cluster. blaNDM-1, blaCTX-M-15, blaOXA-1, and blaACT-16 genes were detected as β-lactam resistance determinants. A chromosomal hybrid intact phage, Enterobacter phage LAU1, with blaCTX-M-15 integrated in its direct vicinity within an ISEcp1 - blaCTX-M-15 - wbuC - ∆Tn2 rare cassette was detected. blaNDM-1 was integrated within a novel IncFII conjugative plasmid, pLAU_ENC1, through an IS3000- ΔISAba125-blaNDM-1-bleMBL-//-Tn5403 cassette. To our knowledge, this is the first report of a multi-drug resistant (MDR) E. hormaechei ssp. xiangfangensis carrying a blaCTX-M-15 integrated within the proximity of a provirus chromosomal region. Treatment options for MDR ECC members are becoming scarce, thus warranting an increased monitoring of the dissemination of these pathogens in clinical settings.
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Affiliation(s)
- Jana Makhlouf
- Department of Natural Sciences, Lebanese American University, Lebanon
| | - Georgi Merhi
- Department of Natural Sciences, Lebanese American University, Lebanon
| | - Tamara Salloum
- Department of Natural Sciences, Lebanese American University, Lebanon
| | - Edmond Abboud
- Laboratory Department, Middle East Institute of Health University Hospital, Lebanon
| | - Sima Tokajian
- Department of Natural Sciences, Lebanese American University, Lebanon.
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25
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Nepal S, Maaß S, Grasso S, Cavallo FM, Bartel J, Becher D, Bathoorn E, van Dijl JM. Proteomic Charting of Imipenem Adaptive Responses in a Highly Carbapenem Resistant Clinical Enterobacter roggenkampii Isolate. Antibiotics (Basel) 2021; 10:antibiotics10050501. [PMID: 33924830 PMCID: PMC8145422 DOI: 10.3390/antibiotics10050501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 11/16/2022] Open
Abstract
Gram-negative bacteria belonging to the Enterobacter cloacae complex are increasingly implicated in difficult-to-treat nosocomial infections, as exemplified by a recently characterized highly carbapenem-resistant clinical Enterobacter roggenkampii isolate with sequence type (ST) 232. While mechanisms of carbapenem resistance are well-understood, little is known about the responses of highly drug-resistant bacteria to these antibiotics. Our present study was therefore aimed at charting the responses of the E. roggenkampii ST232 isolate to the carbapenem imipenem, using a ‘stable isotope labeling of amino acids in cell culture’ approach for quantitative mass spectrometry. This unveiled diverse responses of E. roggenkampii ST232 to imipenem, especially altered levels of proteins for cell wall biogenesis, central carbon metabolism, respiration, iron–sulfur cluster synthesis, and metal homeostasis. These observations suggest a scenario where imipenem-challenged bacteria reduce metabolic activity to save resources otherwise used for cell wall biogenesis, and to limit formation of detrimental reactive oxygen species at the cytoplasmic membrane due to respiration and Fenton chemistry. We consider these observations important, because knowing the adaptive responses of a highly resistant bacterium of the E. cloacae complex to last-resort antibiotics, such as imipenem, provides a ‘sneak preview’ into the future development of antibiotic resistance in this emerging group of pathogens.
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Affiliation(s)
- Suruchi Nepal
- University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands; (S.N.); (S.G.); (F.M.C.); (E.B.)
| | - Sandra Maaß
- Institute for Microbiology, University of Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany; (S.M.); (J.B.); (D.B.)
| | - Stefano Grasso
- University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands; (S.N.); (S.G.); (F.M.C.); (E.B.)
| | - Francis M. Cavallo
- University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands; (S.N.); (S.G.); (F.M.C.); (E.B.)
| | - Jürgen Bartel
- Institute for Microbiology, University of Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany; (S.M.); (J.B.); (D.B.)
| | - Dörte Becher
- Institute for Microbiology, University of Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany; (S.M.); (J.B.); (D.B.)
| | - Erik Bathoorn
- University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands; (S.N.); (S.G.); (F.M.C.); (E.B.)
| | - Jan Maarten van Dijl
- University Medical Center Groningen, Department of Medical Microbiology and Infection Prevention, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands; (S.N.); (S.G.); (F.M.C.); (E.B.)
- Correspondence: ; Tel.: +31-50-3615187
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26
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Hansen GT. Continuous Evolution: Perspective on the Epidemiology of Carbapenemase Resistance Among Enterobacterales and Other Gram-Negative Bacteria. Infect Dis Ther 2021; 10:75-92. [PMID: 33492641 PMCID: PMC7954928 DOI: 10.1007/s40121-020-00395-2] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 12/22/2020] [Indexed: 12/20/2022] Open
Abstract
The global emergence of carbapenemase-producing bacteria capable of hydrolyzing the once effective carbapenem antibiotics is considered a contemporary public health concern. Carbapenemase enzymes, once constrained to isolates of Klebsiella pneumoniae, are now routinely reported in different bacteria within the Enterobacterales order of bacteria, creating the acronym CRE which now defines Carbapenem-Resistant Enterobacterales. CRE harboring different types of enzymes, including the most prevalent types KPC, VIM, IMP, NDM, and OXA-48, are now routinely reported and more importantly, are now frequently present in many infections world-wide. Defining and updating the contemporary epidemiology of both the US and global burden of carbapenem-resistant infections is now more important than ever. This review describes the global distribution and continued evolution of carbapenemases which continue to spread at alarming rates. Informed understanding of the current epidemiology of CRE, coupled with advances in antibiotic options, and the use rapid diagnostics offers the potential for rapid identification and management of carbapenem-resistant infections.
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Affiliation(s)
- Glen T Hansen
- Department of Pathology and Laboratory Medicine, Hennepin County Medical Center, Minneapolis, MN, USA.
- Department of Pathology and Laboratory Medicine, University of Minnesota, School of Medicine, Minneapolis, MN, USA.
- Department of Medicine, Infectious Disease, University of Minnesota, School of Medicine, Minneapolis, MN, USA.
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27
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Custodio MM, Sanchez D, Anderson B, Ryan KL, Walraven C, Mercier RC. Emergence of Resistance in Klebsiella aerogenes to Piperacillin-Tazobactam and Ceftriaxone. Antimicrob Agents Chemother 2021; 65:e01038-20. [PMID: 33139285 PMCID: PMC7848979 DOI: 10.1128/aac.01038-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 10/28/2020] [Indexed: 02/07/2023] Open
Abstract
We examined the effects of piperacillin-tazobactam (TZP) concentration and bacterial inoculum on in vitro killing and the emergence of resistance in Klebsiella aerogenes The MICs for 15 clinical respiratory isolates were determined by broth microdilution for TZP and by Etest for ceftriaxone (CRO) and cefepime (FEP). The presence of resistance in TZP-susceptible isolates (n = 10) was determined by serial passes over increasing concentrations of TZP-containing and CRO-containing agar plates. Isolates with growth on TZP 16/4-μg/ml and CRO 8-μg/ml plates (n = 5) were tested in high-inoculum (HI; 7.0 log10 CFU/ml) and low-inoculum (LI; 5.0 log10 CFU/ml) time-kill studies. Antibiotic concentrations were selected to approximate TZP 3.375 g every 8 h (q8h) via a 4-h prolonged-infusion free peak concentration (40 μg/ml [TZP40]), peak epithelial lining fluid (ELF) concentrations, and average AUC0-24 values for TZP (20 μg/ml [TZP20] and 10 μg/ml [TZP10], respectively), the ELF FEP concentration (14 μg/ml), and the average AUC0-24 CRO concentration (6 μg/ml). For HI, FEP exposure significantly reduced 24-h inocula against all comparators (P ≤ 0.05) with a reduction of 4.93 ± 0.64 log10 CFU/ml. Exposure to TZP40, TZP20, and TZP10 reduced inocula by 0.81 ± 0.43, 0.21 ± 0.18, and 0.05 ± 0.16 log10 CFU/ml, respectively. CRO-exposed isolates demonstrated an increase of 0.42 ± 0.39 log10 CFU/ml compared to the starting inocula, with four of five CRO-exposed isolates demonstrating TZP-nonsusceptibility. At LI after 24 h of exposure to TZP20 and TZP10, the starting inoculum decreased by averages of 2.24 ± 1.98 and 2.91 ± 0.50 log10 CFU/ml, respectively. TZP demonstrated significant inoculum-dependent killing, warranting dose optimization studies.
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Affiliation(s)
- Marco M Custodio
- Department of Pharmacy, University of New Mexico Hospitals, Albuquerque, New Mexico, USA
| | - Daniel Sanchez
- University of New Mexico College of Pharmacy, Albuquerque, New Mexico, USA
| | - Beverly Anderson
- University of New Mexico College of Pharmacy, Albuquerque, New Mexico, USA
| | - Keenan L Ryan
- Department of Pharmacy, University of New Mexico Hospitals, Albuquerque, New Mexico, USA
| | - Carla Walraven
- Department of Pharmacy, University of New Mexico Hospitals, Albuquerque, New Mexico, USA
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28
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Yang X, Zeng J, Zhou Q, Yu X, Zhong Y, Wang F, Du H, Nie F, Pang X, Wang D, Fan Y, Bai T, Xu Y. Elevating NagZ Improves Resistance to β-Lactam Antibiotics via Promoting AmpC β-Lactamase in Enterobacter cloacae. Front Microbiol 2020; 11:586729. [PMID: 33250874 PMCID: PMC7672007 DOI: 10.3389/fmicb.2020.586729] [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: 07/23/2020] [Accepted: 10/02/2020] [Indexed: 11/13/2022] Open
Abstract
Enterobacter cloacae complex (ECC), one of the most common opportunistic pathogens causing multiple infections in human, is resistant to β-lactam antibiotics mainly due to its highly expressed chromosomal AmpC β-lactamase. It seems that regulation of chromosomal AmpC β-lactamase is associated with peptidoglycan recycling. However, underlying mechanisms are still poorly understood. In this study, we confirmed that NagZ, a glycoside hydrolase participating in peptidoglycan recycling in Gram-negative bacteria, plays a crucial role in developing resistance of E. cloacae (EC) to β-lactam antibiotics by promoting expression of chromosomal AmpC β-lactamase. Our data shows that NagZ was significantly up-regulated in resistant EC (resistant to at least one type of the third or fourth generation cephalosporins) compared to susceptible EC (susceptible to all types of the third and fourth generation cephalosporins). Similarly, the expression and β-lactamase activity of ampC were markedly enhanced in resistant EC. Moreover, ectopic expression of nagZ enhanced ampC expression and resistance to β-lactam antibiotics in susceptible EC. To further understand functions of NagZ in β-lactam resistance, nagZ-knockout EC model (ΔnagZ EC) was constructed by homologous recombination. Conversely, ampC mRNA and protein levels were down-regulated, and resistance to β-lactam antibiotics was attenuated in ΔnagZ EC, while specific complementation of nagZ was able to rescue ampC expression and resistance in ΔnagZ EC. More interestingly, NagZ and its hydrolyzates 1,6-anhydromuropeptides (anhMurNAc) could induce the expression of other target genes of AmpR (a global transcriptional factor), which suggested that the promotion of AmpC by NagZ is mediated AmpR activated by anhMurNAc in EC. In conclusion, these findings provide new elements for a better understanding of resistance in EC, which is crucial for the identification of novel potential drug targets.
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Affiliation(s)
- Xianggui Yang
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Jun Zeng
- Division of Pulmonary and Critical Care Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Qin Zhou
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Xuejing Yu
- Department of Cardiothoracic Surgery, University of Utah, Salt Lake City, UT, United States
| | - Yuanxiu Zhong
- Department of Biotechnology, Chengdu Medical College, Chengdu, China
| | - Fuying Wang
- Department of Cardiothoracic Surgery, University of Utah, Salt Lake City, UT, United States
| | - Hongfei Du
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Fang Nie
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Xueli Pang
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Dan Wang
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Yingzi Fan
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Tingting Bai
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Ying Xu
- Department of Laboratory Medicine, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
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ramR Deletion in an Enterobacter hormaechei Isolate as a Consequence of Therapeutic Failure of Key Antibiotics in a Long-Term Hospitalized Patient. Antimicrob Agents Chemother 2020; 64:AAC.00962-20. [PMID: 32778545 DOI: 10.1128/aac.00962-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/22/2020] [Indexed: 11/20/2022] Open
Abstract
Genome changes are central to the adaptation of bacteria, especially under antibiotic pressure. The aim of this study was to report phenotypic and genomic adaptations undergone by an Enterobacter hormaechei clinical strain that became highly resistant to key antimicrobials during a 4-month period in a patient hospitalized in an intensive care unit (ICU). All six clinical E. hormaechei strains isolated in one ICU-hospitalized patient have been studied. MICs regarding 17 antimicrobial molecules have been measured. Single nucleotide polymorphisms (SNPs) were determined on the sequenced genomes. The expression of genes involved in antibiotic resistance among Enterobacter cloacae complex strains were determined by reverse transcription-quantitative PCR (qRT-PCR). All the strains belonged to sequence type 66 and were distant by a maximum of nine SNPs. After 3 months of hospitalization, three strains presented a significant increase in MICs for ceftazidime, cefepime, temocillin, ertapenem, tigecycline, ciprofloxacin, and chloramphenicol. Those resistant strains did not acquire additional antibiotic resistance genes but harbored a 16-bp deletion in the ramR gene. This deletion led to upregulated expression of RamA, AcrA, AcrB, and TolC and downregulated expression of OmpF. The ΔramR mutant harbored the same phenotype as the resistant clinical strains regarding tigecycline, chloramphenicol, and ciprofloxacin. The increased expression of RamA due to partial deletion in the ramR gene led to a cross-resistance phenotype by an increase of antibiotic efflux through the AcrAB-TolC pump and a decrease of antibiotic permeability by porin OmpF. ramR appears to be an important adaptative trait for E. hormaechei strains.
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Tamma PD, Doi Y, Bonomo RA, Johnson JK, Simner PJ. A Primer on AmpC β-Lactamases: Necessary Knowledge for an Increasingly Multidrug-resistant World. Clin Infect Dis 2020; 69:1446-1455. [PMID: 30838380 DOI: 10.1093/cid/ciz173] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 02/26/2019] [Indexed: 12/13/2022] Open
Abstract
Understanding the nuances of AmpC β-lactamase-mediated resistance can be challenging, even for the infectious diseases specialist. AmpC resistance can be classified into 3 categories: (1) inducible chromosomal resistance that emerges in the setting of a β-lactam compound, (2) stable derepression due to mutations in ampC regulatory genes, or (3) the presence of plasmid-mediated ampC genes. This review will mainly focus on inducible AmpC resistance in Enterobacteriaceae. Although several observational studies have explored optimal treatment for AmpC producers, few provide reliable insights into effective management approaches. Heterogeneity within the data and inherent selection bias make inferences on effective β-lactam choices problematic. Most experts agree it is prudent to avoid expanded-spectrum (ie, third-generation) cephalosporins for the treatment of organisms posing the greatest risk of ampC induction, which has best been described in the context of Enterobacter cloacae infections. The role of other broad-spectrum β-lactams and the likelihood of ampC induction by other Enterobacteriaceae are less clear. We will review the mechanisms of resistance and triggers resulting in AmpC expression, the species-specific epidemiology of AmpC production, approaches to the detection of AmpC production, and treatment options for AmpC-producing infections.
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Affiliation(s)
- Pranita D Tamma
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yohei Doi
- Department of Medicine, University of Pittsburgh, School of Medicine, Pennsylvania
| | - Robert A Bonomo
- Department of Medicine, The Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Case Western Reserve University, Ohio
| | - J Kristie Johnson
- Department of Pathology, University of Maryland School of Medicine, Baltimore
| | - Patricia J Simner
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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31
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Guérin F, Lallement C, Goudergues B, Isnard C, Sanguinetti M, Cacaci M, Torelli R, Cattoir V, Giard JC. Landscape of in vivo Fitness-Associated Genes of Enterobacter cloacae Complex. Front Microbiol 2020; 11:1609. [PMID: 32754144 PMCID: PMC7365913 DOI: 10.3389/fmicb.2020.01609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 06/19/2020] [Indexed: 11/13/2022] Open
Abstract
Species of the Enterobacter cloacae complex (ECC) represent an increasing cause of hospital-acquired infections and commonly exhibit multiple antibiotic resistances. In order to identify genes that may play a role in its ability to colonize the host, we used the transposon-sequencing (Tn-seq) approach. To this end, a high-density random transposon insertion library was obtained from E. cloacae subsp. cloacae ATCC 13047, which was used to analyze the fitness of ca. 300,000 mutants in Galleria mellonella colonization model. Following massively parallel sequencing, we identified 624 genes that seemed essential for the optimal growth and/or the fitness within the host. Moreover, 63 genes where mutations resulted in positive selection were found, while 576 genes potentially involved in the in vivo fitness were observed. These findings pointed out the role of some transcriptional regulators, type VI secretion system, and surface-associated proteins in the in vivo fitness of E. cloacae ATCC 13047. We then selected eight genes based on their high positive or negative fold changes (FCs) and tested the corresponding deletion mutants for their virulence and ability to cope with stresses. Thereby, we showed that ECL_02247 (encoding the NAD-dependent epimerase/dehydratase) and ECL_04444 (coding for a surface antigen-like protein) may correspond to new virulence factors, and that the regulator ECL_00056 was involved in in vivo fitness. In addition, bacterial cells lacking the flagellum-specific ATP synthase FliI (ECL_03223) and the hypothetical protein ECL_01421 were affected for mobility and resistance to H2O2, respectively. All these results yield valuable information regarding genes important for infection process and stress response of E. cloacae ATCC 13047 and participate to a better understanding of the opportunistic traits in this bacterial pathogen.
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Affiliation(s)
- François Guérin
- Université de Caen Normandie, EA4655 U2RM (Équipe «Antibio-Résistance»), Caen, France.,CHU de Caen, Service de Microbiologie, Caen, France
| | - Claire Lallement
- Université de Caen Normandie, EA4655 U2RM (Équipe «Antibio-Résistance»), Caen, France
| | - Benoit Goudergues
- Université de Caen Normandie, EA4655 U2RM (Équipe «Antibio-Résistance»), Caen, France
| | - Christophe Isnard
- Université de Caen Normandie, EA4655 U2RM (Équipe «Antibio-Résistance»), Caen, France.,CHU de Caen, Service de Microbiologie, Caen, France
| | - Maurizio Sanguinetti
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Università Cattolica del Sacro Cuore, Rome, Italy.,Dipartimento di Scienze di Laboratorio e Infettivologiche, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Margherita Cacaci
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Università Cattolica del Sacro Cuore, Rome, Italy.,Dipartimento di Scienze di Laboratorio e Infettivologiche, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Riccardo Torelli
- Institute of Microbiology, Catholic University of the Sacred Heart, Rome, Italy
| | - Vincent Cattoir
- Rennes University Hospital, Department of Clinical Microbiology, Rennes, France.,Inserm U1230, University of Rennes 1, Rennes, France
| | - Jean-Christophe Giard
- Université de Caen Normandie, EA4655 U2RM (Équipe «Antibio-Résistance»), Caen, France
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32
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Wand ME, Sutton JM. Mutations in the two component regulator systems PmrAB and PhoPQ give rise to increased colistin resistance in Citrobacter and Enterobacter spp. J Med Microbiol 2020; 69:521-529. [PMID: 32125265 DOI: 10.1099/jmm.0.001173] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Introduction. Colistin is a last resort antibiotic for treating infections caused by carbapenem-resistant isolates. Mechanisms of resistance to colistin have been widely described in Klebsiella pneumoniae and Escherichia coli but have yet to be characterized in Citrobacter and Enterobacter species.Aim. To identify the causative mutations leading to generation of colistin resistance in Citrobacter and Enterobacter spp.Methodology. Colistin resistance was generated by culturing in increasing concentrations of colistin or by direct culture in a lethal (above MIC) concentration. Whole-genome sequencing was used to identify mutations. Fitness of resistant strains was determined by changes in growth rate, and virulence in Galleria mellonella.Results. We were able to generate colistin resistance upon exposure to sub-MIC levels of colistin, in several but not all strains of Citrobacter and Enterobacter resulting in a 16-fold increase in colistin MIC values for both species. The same individual strains also developed resistance to colistin after a single exposure at 10× MIC, with a similar increase in MIC. Genetic analysis revealed that this increased resistance was attributed to mutations in PmrB for Citrobacter and PhoP in Enterobacter, although we were not able to identify causative mutations in all strains. Colistin-resistant mutants showed little difference in growth rate, and virulence in G. mellonella, although there were strain-to-strain differences.Conclusions. Stable colistin resistance may be acquired with no loss of fitness in these species. However, only select strains were able to adapt suggesting that acquisition of colistin resistance is dependent upon individual strain characteristics.
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Affiliation(s)
- Matthew E Wand
- Public Health England, National Infection Service, Porton Down, Salisbury, Wiltshire, SP4 0JG, UK
| | - J Mark Sutton
- Public Health England, National Infection Service, Porton Down, Salisbury, Wiltshire, SP4 0JG, UK
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33
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Mancini S, Röthlin K, Bodendoerfer E, Herren S, Kolesnik-Goldmann N, Courvalin P, Zbinden R, Böttger EC. Tentative breakpoints and areas of technical uncertainty for early reading automated disc diffusion for Enterobacterales. J Antimicrob Chemother 2020; 75:1495-1505. [PMID: 32155259 DOI: 10.1093/jac/dkaa051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/15/2020] [Accepted: 01/28/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Disc diffusion is a reliable, accurate and cost-efficient procedure for antimicrobial susceptibility testing (AST) but requires long (18-24 h) incubation times. Reading of disc diffusion after short incubation times (6-8 h) by automated systems is feasible but should be categorized with time-adapted breakpoints to reduce errors. OBJECTIVES This study systematically compared early readings (6 and 8 h) of disc diffusion using an automated system with that of the standard 18 h EUCAST method. Time-adapted tentative breakpoints were proposed to discriminate susceptible from resistant isolates and areas of technical uncertainty were defined to minimize the risk of errors. METHODS A total of 1106 Enterobacterales isolates with a wide variety of resistance mechanisms and resistance profiles were included. All isolates were analysed for susceptibility to amoxicillin/clavulanic acid, ceftriaxone, cefepime, meropenem, ciprofloxacin and gentamicin using the automated WASPLabTM system. Part of the collection (515 isolates) was also analysed for susceptibility to an additional 10 antibiotics. RESULTS Separation between WT and non-WT populations was poorer at early incubation times than following standard incubation. Editing of rapid automated AST results after 6 and 8 h incubation with time-adapted breakpoints resulted in 84.0% and 88.5% interpretable results with assignment to the resistant or susceptible category. Major error and very major error rates for the 6 h readings were only 0.4% and 0.3%, virtually identical to those of 18 h AST reading. CONCLUSIONS Time-adapted clinical breakpoints in disc diffusion testing for Enterobacterales allow for accurate automated AST interpretation after shortened incubation times for a large number of antibiotics, with the additional possibility of subsequent confirmation after 18 h incubation.
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Affiliation(s)
- Stefano Mancini
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Kim Röthlin
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Elias Bodendoerfer
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Sebastian Herren
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | | | | | - Reinhard Zbinden
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
| | - Erik C Böttger
- Institut für Medizinische Mikrobiologie, Universität Zürich, Zürich, Switzerland
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Complex Response of the CpxAR Two-Component System to β-Lactams on Antibiotic Resistance and Envelope Homeostasis in Enterobacteriaceae. Antimicrob Agents Chemother 2020; 64:AAC.00291-20. [PMID: 32229490 DOI: 10.1128/aac.00291-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/17/2020] [Indexed: 01/17/2023] Open
Abstract
The Cpx stress response is widespread among Enterobacteriaceae We previously reported a mutation in cpxA in a multidrug-resistant strain of Klebsiella aerogenes isolated from a patient treated with imipenem. This mutation yields a single-amino-acid substitution (Y144N) located in the periplasmic sensor domain of CpxA. In this work, we sought to characterize this mutation in Escherichia coli by using genetic and biochemical approaches. Here, we show that cpxAY144N is an activated allele that confers resistance to β-lactams and aminoglycosides in a CpxR-dependent manner, by regulating the expression of the OmpF porin and the AcrD efflux pump, respectively. We also demonstrate the effect of the intimate interconnection between the Cpx system and peptidoglycan integrity on the expression of an exogenous AmpC β-lactamase by using imipenem as a cell wall-active antibiotic or by inactivating penicillin-binding proteins. Moreover, our data indicate that the Y144N substitution abrogates the interaction between CpxA and CpxP and increases phosphotransfer activity on CpxR. Because the addition of a strong AmpC inducer such as imipenem is known to cause abnormal accumulation of muropeptides (disaccharide-pentapeptide and N-acetylglucosamyl-1,6-anhydro-N-acetylmuramyl-l-alanyl-d-glutamy-meso-diaminopimelic-acid-d-alanyl-d-alanine) in the periplasmic space, we propose these molecules activate the Cpx system by displacing CpxP from the sensor domain of CpxA. Altogether, these data could explain why large perturbations to peptidoglycans caused by imipenem lead to mutational activation of the Cpx system and bacterial adaptation through multidrug resistance. These results also validate the Cpx system, in particular, the interaction between CpxA and CpxP, as a promising therapeutic target.
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35
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Eida AA, Bougouffa S, L’Haridon F, Alam I, Weisskopf L, Bajic VB, Saad MM, Hirt H. Genome Insights of the Plant-Growth Promoting Bacterium Cronobacter muytjensii JZ38 With Volatile-Mediated Antagonistic Activity Against Phytophthora infestans. Front Microbiol 2020; 11:369. [PMID: 32218777 PMCID: PMC7078163 DOI: 10.3389/fmicb.2020.00369] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
Salinity stress is a major challenge to agricultural productivity and global food security in light of a dramatic increase of human population and climate change. Plant growth promoting bacteria can be used as an additional solution to traditional crop breeding and genetic engineering. In the present work, the induction of plant salt tolerance by the desert plant endophyte Cronobacter sp. JZ38 was examined on the model plant Arabidopsis thaliana using different inoculation methods. JZ38 promoted plant growth under salinity stress via contact and emission of volatile compounds. Based on the 16S rRNA and whole genome phylogenetic analysis, fatty acid analysis and phenotypic identification, JZ38 was identified as Cronobacter muytjensii and clearly separated and differentiated from the pathogenic C. sakazakii. Full genome sequencing showed that JZ38 is composed of one chromosome and two plasmids. Bioinformatic analysis and bioassays revealed that JZ38 can grow under a range of abiotic stresses. JZ38 interaction with plants is correlated with an extensive set of genes involved in chemotaxis and motility. The presence of genes for plant nutrient acquisition and phytohormone production could explain the ability of JZ38 to colonize plants and sustain plant growth under stress conditions. Gas chromatography-mass spectrometry analysis of volatiles produced by JZ38 revealed the emission of indole and different sulfur volatile compounds that may play a role in contactless plant growth promotion and antagonistic activity against pathogenic microbes. Indeed, JZ38 was able to inhibit the growth of two strains of the phytopathogenic oomycete Phytophthora infestans via volatile emission. Genetic, transcriptomic and metabolomics analyses, combined with more in vitro assays will provide a better understanding the highlighted genes' involvement in JZ38's functional potential and its interaction with plants. Nevertheless, these results provide insight into the bioactivity of C. muytjensii JZ38 as a multi-stress tolerance promoting bacterium with a potential use in agriculture.
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Affiliation(s)
- Abdul Aziz Eida
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Salim Bougouffa
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- BioScience Core Lab, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Intikhab Alam
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Laure Weisskopf
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Vladimir B. Bajic
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Maged M. Saad
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Heribert Hirt
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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36
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Mizrahi A, Delerue T, Morel H, Le Monnier A, Carbonnelle E, Pilmis B, Zahar J. Infections caused by naturally AmpC-producing Enterobacteriaceae: Can we use third-generation cephalosporins? A narrative review. Int J Antimicrob Agents 2020; 55:105834. [DOI: 10.1016/j.ijantimicag.2019.10.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 10/07/2019] [Accepted: 10/20/2019] [Indexed: 12/21/2022]
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The Transcriptional Repressor SmvR Is Important for Decreased Chlorhexidine Susceptibility in Enterobacter cloacae Complex. Antimicrob Agents Chemother 2019; 64:AAC.01845-19. [PMID: 31685460 DOI: 10.1128/aac.01845-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
Major facilitator superfamily (MFS) efflux pumps have been shown to be important for bacterial cells to cope with biocides such as chlorhexidine (CHX), a widely used molecule in hospital settings. In this work, we evaluated the role of two genes, smvA and smvR, in CHX resistance in Enterobacter cloacae complex (ECC). smvA encodes an MFS pump whereas smvR, located upstream of smvA, codes for a TetR-type transcriptional repressor. To this aim, we constructed corresponding deletion mutants from the ATCC 13047 strain (CHX MIC, 2 mg/liter) as well as strains overexpressing smvA or smvR in both ATCC 13047 and three clinical isolates exhibiting elevated CHX MICs (16 to 32 mg/liter). Determination of MICs revealed that smvA played a modest role in CHX resistance, in contrast to smvR that modulated the ability of ECC to survive in the presence of CHX. In clinical isolates, the overexpression of smvR significantly reduced MICs of CHX (2 to 8 mg/liter). Sequence analyses of smvR and promoter regions pointed out substitutions in conserved regions. Moreover, transcriptional studies revealed that SmvR acted as a repressor of smvA expression even if no quantitative correlation between the level of smvA mRNA and MICs of CHX could be observed. On the other hand, overproduction of smvA was able to complement the lack of the major resistance-nodulation-cell division (RND) superfamily efflux pump AcrB and restored resistance to ethidium bromide and acriflavine. Although SmvA could expel biocides such as CHX, other actors, whose expression is under SmvR control, should play a critical role in ECC.
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38
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Kohlmann R, Bähr T, Gatermann SG. Species-specific mutation rates for ampC derepression in Enterobacterales with chromosomally encoded inducible AmpC β-lactamase. J Antimicrob Chemother 2019; 73:1530-1536. [PMID: 29566147 DOI: 10.1093/jac/dky084] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 02/15/2018] [Indexed: 11/13/2022] Open
Abstract
Background AmpC β-lactamases are encoded on the chromosomes of certain Enterobacterales and lead to clinical resistance to various β-lactams in case of high-level expression. In WT bacteria with inducible AmpC, the expression is low, but selection of stably ampC-derepressed mutants may occur during β-lactam therapy. Thus, for Enterobacter spp., Citrobacter freundii complex, Serratia spp. and Morganella morganii that test susceptible in vitro to oxyimino-cephalosporins, the EUCAST expert rules recommend suppressing susceptibility testing results for these agents or noting that their use in monotherapy should be discouraged, owing to the risk of selecting resistance. However, clinical observations suggest that emergence of resistance is not equally common in all species with inducible AmpC. Objectives To determine species-specific mutation rates, which are more accurate and reproducible than previously described mutant frequencies, for ampC derepression in Enterobacterales with inducible AmpC. Methods Mutation rates were determined using a protocol based on Luria-Delbrück fluctuation analyses. Overall, 237 isolates were analysed. Results Mutation rates were high in Enterobacter cloacae complex, Enterobacter aerogenes, C. freundii complex and Hafnia alvei isolates, with a mean mutation rate of 3 × 10-8. In contrast, mean mutation rates were considerably lower in Providencia spp., Serratia spp. and especially M. morganii isolates. Furthermore, we observed species-specific variations in the resistance patterns of ampC-derepressed mutants. Conclusions Our data might help to predict the risk of treatment failure with oxyimino-cephalosporins in infections by different Enterobacterales with inducible AmpC. Moreover, we make a proposal for optimization of the current EUCAST expert rule.
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Affiliation(s)
- Rebekka Kohlmann
- Department of Medical Microbiology, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Tobias Bähr
- Department of Medical Microbiology, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Sören G Gatermann
- Department of Medical Microbiology, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
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Ellington MJ, Heinz E, Wailan AM, Dorman MJ, de Goffau M, Cain AK, Henson SP, Gleadall N, Boinett CJ, Dougan G, Brown NM, Woodford N, Parkhill J, Török ME, Peacock SJ, Thomson NR. Contrasting patterns of longitudinal population dynamics and antimicrobial resistance mechanisms in two priority bacterial pathogens over 7 years in a single center. Genome Biol 2019; 20:184. [PMID: 31477167 PMCID: PMC6717969 DOI: 10.1186/s13059-019-1785-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 08/05/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Two of the most important pathogens contributing to the global rise in antimicrobial resistance (AMR) are Klebsiella pneumoniae and Enterobacter cloacae. Despite this, most of our knowledge about the changing patterns of disease caused by these two pathogens is based on studies with limited timeframes that provide few insights into their population dynamics or the dynamics in AMR elements that they can carry. RESULTS We investigate the population dynamics of two priority AMR pathogens over 7 years between 2007 and 2012 in a major UK hospital, spanning changes made to UK national antimicrobial prescribing policy in 2007. Between 2006 and 2012, K. pneumoniae showed epidemiological cycles of multi-drug-resistant (MDR) lineages being replaced approximately every 2 years. This contrasted E. cloacae where there was no temporally changing pattern, but a continuous presence of the mixed population. CONCLUSIONS The differing patterns of clonal replacement and acquisition of mobile elements shows that the flux in the K. pneumoniae population was linked to the introduction of globally recognized MDR clones carrying drug resistance markers on mobile elements. However, E. cloacae carries a chromosomally encoded ampC conferring resistance to front-line treatments and shows that MDR plasmid acquisition in E. cloacae was not indicative of success in the hospital. This led to markedly different dynamics in the AMR populations of these two pathogens and shows that the mechanism of the resistance and its location in the genome or mobile elements is crucial to predict population dynamics of opportunistic pathogens in clinical settings.
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Affiliation(s)
- Matthew J Ellington
- Public Health England, National Infection Service, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QW, UK.
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
- Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, National Infection Service, Public Health England, 61 Colindale Avenue, London, NW9 5EQ, UK.
- Present address: National Infection Service, Public Health England, 61 Colindale Avenue, London, NW9 5EQ, UK.
| | - Eva Heinz
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Alexander M Wailan
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Matthew J Dorman
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Marcus de Goffau
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Amy K Cain
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Department of Molecular Sciences, Macquarie University, Sydney, 2109, Australia
| | - Sonal P Henson
- KEMRI-Wellcome Trust Research Programme, CGMRC, Kilifi, Kenya
| | - Nicholas Gleadall
- Public Health England, National Infection Service, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QW, UK
| | - Christine J Boinett
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Gordon Dougan
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QW, UK
| | - Nicholas M Brown
- Public Health England, National Infection Service, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QW, UK
- Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge, CB2 0QQ, UK
| | - Neil Woodford
- Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, National Infection Service, Public Health England, 61 Colindale Avenue, London, NW9 5EQ, UK
| | - Julian Parkhill
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - M Estée Török
- Public Health England, National Infection Service, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QW, UK
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QW, UK
- Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge, CB2 0QQ, UK
| | - Sharon J Peacock
- Public Health England, National Infection Service, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QW, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QW, UK
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Nicholas R Thomson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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A New Suite of Allelic-Exchange Vectors for the Scarless Modification of Proteobacterial Genomes. Appl Environ Microbiol 2019; 85:AEM.00990-19. [PMID: 31201277 DOI: 10.1128/aem.00990-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/06/2019] [Indexed: 01/05/2023] Open
Abstract
Despite the advent of new techniques for genetic engineering of bacteria, allelic exchange through homologous recombination remains an important tool for genetic analysis. Currently, sacB-based vector systems are often used for allelic exchange, but counterselection escape, which prevents isolation of cells with the desired mutation, occasionally limits their utility. To circumvent this, we engineered a series of "pTOX" allelic-exchange vectors. Each plasmid encodes one of a set of inducible toxins, chosen for their potential utility in a wide range of medically important proteobacteria. A codon-optimized rhaS transcriptional activator with a strong synthetic ribosome-binding site enables tight toxin induction even in organisms lacking an endogenous rhamnose regulon. Expression of the gene encoding blue AmilCP or magenta TsPurple nonfluorescent chromoprotein facilitates monitoring of successful single- and double-crossover events using these vectors. The versatility of these vectors was demonstrated by deleting genes in Serratia marcescens, Escherichia coli O157:H7, Enterobacter cloacae, and Shigella flexneri Finally, pTOX was used to characterize the impact of disruption of all combinations of the 3 paralogous S. marcescens peptidoglycan amidohydrolases on chromosomal ampC β-lactamase activity and the corresponding β-lactam antibiotic resistance. Mutation of multiple amidohydrolases was necessary for high-level ampC derepression and β-lactam resistance. These data suggest why β-lactam resistance may emerge during treatment less frequently in S. marcescens than in other AmpC-producing pathogens, like E. cloacae Collectively, our findings suggest that the pTOX vectors should be broadly useful for genetic engineering of Gram-negative bacteria.IMPORTANCE Targeted modification of bacterial genomes is critical for genetic analysis of microorganisms. Allelic exchange is a technique that relies on homologous recombination to replace native loci with engineered sequences. However, current allelic-exchange vectors often enable only weak selection for successful homologous recombination. We developed a suite of new allelic-exchange vectors, pTOX, which were validated in several medically important proteobacteria. They encode visible nonfluorescent chromoproteins that enable easy identification of colonies bearing integrated vectors and permit stringent selection for the second step of homologous recombination. We demonstrate the utility of these vectors by using them to investigate the effect of inactivation of Serratia marcescens peptidoglycan amidohydrolases on β-lactam antibiotic resistance.
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Enterobacter spp.: Update on Taxonomy, Clinical Aspects, and Emerging Antimicrobial Resistance. Clin Microbiol Rev 2019; 32:32/4/e00002-19. [PMID: 31315895 DOI: 10.1128/cmr.00002-19] [Citation(s) in RCA: 239] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The genus Enterobacter is a member of the ESKAPE group, which contains the major resistant bacterial pathogens. First described in 1960, this group member has proven to be more complex as a result of the exponential evolution of phenotypic and genotypic methods. Today, 22 species belong to the Enterobacter genus. These species are described in the environment and have been reported as opportunistic pathogens in plants, animals, and humans. The pathogenicity/virulence of this bacterium remains rather unclear due to the limited amount of work performed to date in this field. In contrast, its resistance against antibacterial agents has been extensively studied. In the face of antibiotic treatment, it is able to manage different mechanisms of resistance via various local and global regulator genes and the modulation of the expression of different proteins, including enzymes (β-lactamases, etc.) or membrane transporters, such as porins and efflux pumps. During various hospital outbreaks, the Enterobacter aerogenes and E. cloacae complex exhibited a multidrug-resistant phenotype, which has stimulated questions about the role of cascade regulation in the emergence of these well-adapted clones.
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Overestimation of an Outbreak of Enterobacter cloacae in a Neonatal Intensive Care Unit in Germany, 2015. Pediatr Infect Dis J 2019; 38:631-637. [PMID: 30550512 DOI: 10.1097/inf.0000000000002264] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND In August 2015, 17 neonates with Enterobacter cloacae (E. cloacae) colonization were identified in a neonatal intensive care unit (NICU) in Germany. Two developed severe brain abscesses. Despite temporary NICU closure in September, another infant with E. cloacae colonization was detected in October 2015. METHODS We defined potential cases as inpatients treated in the NICU or any pediatric/maternity ward in 2015 with E. cloacae in any specimen before molecular typing. Cases were at first confirmed by arbitrarily-primed-polymerase-chain-reaction and later by XbaI-macrorestriction/pulsed-field gel electrophoresis and next-generation-sequencing. Enhanced barrier precautions and cohorting were implemented for all potential cases and microbiologic screening was extended from NICU to all pediatric/maternity wards. RESULTS Of 41 potential cases (occurring between 08/04/2015 and 15/11/2015 in 4 wards), the isolates of 23 shared identical arbitrarily-primed-polymerase-chain-reaction patterns; 3 without plausible epidemiologic link. Pulsed-field gel electrophoresis analyses verified only 10 cases (all in the NICU); next-generation-sequencing analysis confirmed these results. In addition 6 cases without isolates available for genotyping were closely linked in place and time. CONCLUSIONS Forty-one suspected patients were cohorted and the NICU was temporarily closed. Further analyses revealed that only 16 cases belonged to the outbreak. Only close interdisciplinary collaboration and highly discriminatory genotyping methods allowed to clearly differentiate between cases and noncases in this E. cloacae outbreak.
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False-Positive Carbapenem-Hydrolyzing Confirmatory Tests Due to ACT-28, a Chromosomally Encoded AmpC with Weak Carbapenemase Activity from Enterobacter kobei. Antimicrob Agents Chemother 2019; 63:AAC.02388-18. [PMID: 30783006 DOI: 10.1128/aac.02388-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 02/12/2019] [Indexed: 11/20/2022] Open
Abstract
In Enterobacter cloacae complex (ECC), the overproduction of the chromosome-encoded cephalosporinase (cAmpC) associated with decreased outer membrane permeability may result in carbapenem resistance. In this study, we have characterized ACT-28, a cAmpC with weak carbapenemase activity, from a single Enterobacter kobei lineage. ECC clinical isolates were characterized by whole-genome sequencing (WGS), susceptibility testing, and MIC, and carbapenemase activity was monitored using diverse carbapenem hydrolysis methods. ACT-28 steady-state kinetic parameters were determined. Among 1,039 non-carbapenemase-producing ECC isolates with decreased susceptibility to carbapenems received in 2016-2017 at the French National Reference Center for antibiotic resistance, only 8 had a positive carbapenemase detection test (Carba NP). These eight ECC isolates were resistant to broad-spectrum cephalosporins due to AmpC derepression, showed decreased susceptibility to carbapenems, and were categorized as carbapenemase-producing Enterobacteriaceae (CPE) according to several carbapenemase detection assays. WGS identified a single clone of E. kobei ST125 expressing only its cAmpC, ACT-28. The bla ACT-28 gene was expressed in a wild-type and in a porin-deficient Escherichia coli background and compared to the bla ACT-1 gene. Detection of carbapenemase activity was positive only for E. coli expressing the bla ACT-28 gene. Kinetic parameters of purified ACT-28 revealed a slightly increased imipenem hydrolysis compared to that of ACT-1. In silico porin analysis revealed the presence of a peculiar OmpC-like protein specific to E. kobei ST125 that could impair carbapenem influx into the periplasm and thus enhance carbapenem-resistance caused by ACT-28. We described a widespread lineage of E. kobei ST125 producing ACT-28, with weak carbapenemase activity that can lead to false-positive detection by several biochemical and phenotypic diagnostic tests.
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44
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Kang KN, Klein DR, Kazi MI, Guérin F, Cattoir V, Brodbelt JS, Boll JM. Colistin heteroresistance in Enterobacter cloacae is regulated by PhoPQ-dependent 4-amino-4-deoxy-l-arabinose addition to lipid A. Mol Microbiol 2019; 111:1604-1616. [PMID: 30873646 DOI: 10.1111/mmi.14240] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2019] [Indexed: 01/01/2023]
Abstract
The Enterobacter cloacae complex (ECC) consists of closely related bacteria commonly associated with the human microbiota. ECC are increasingly isolated from healthcare-associated infections, demonstrating that these Enterobacteriaceae are emerging nosocomial pathogens. ECC can rapidly acquire multidrug resistance to conventional antibiotics. Cationic antimicrobial peptides (CAMPs) have served as therapeutic alternatives because they target the highly conserved lipid A component of the Gram-negative outer membrane. Many Enterobacteriaceae fortify their outer membrane with cationic amine-containing moieties to prevent CAMP binding, which can lead to cell lysis. The PmrAB two-component system (TCS) directly activates 4-amino-4-deoxy-l-arabinose (l-Ara4N) biosynthesis to result in cationic amine moiety addition to lipid A in many Enterobacteriaceae such as E. coli and Salmonella. In contrast, PmrAB is dispensable for CAMP resistance in E. cloacae. Interestingly, some ECC clusters exhibit colistin heteroresistance, where a subpopulation of cells exhibit clinically significant resistance levels compared to the majority population. We demonstrate that E. cloacae lipid A is modified with l-Ara4N to induce CAMP heteroresistance and the regulatory mechanism is independent of the PmrABEcl TCS. Instead, PhoPEcl binds to the arnBEcl promoter to induce l-Ara4N biosynthesis and PmrAB-independent addition to the lipid A disaccharolipid. Therefore, PhoPQEcl contributes to regulation of CAMP heteroresistance in some ECC clusters.
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Affiliation(s)
- Katie N Kang
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Dustin R Klein
- Department of Chemistry, University of Texas at Austin, Austin, TX, USA
| | - Misha I Kazi
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - François Guérin
- Department of Clinical Microbiology, Caen University Hospital, EA4655, University of Caen Normandie, Caen, France
| | - Vincent Cattoir
- Department of Clinical Microbiology and National Reference Center for Antimicrobial Resistance (Lab Enterococci), Rennes University Hospital Inserm Unit U1230, University of Rennes 1, Rennes, France
| | | | - Joseph M Boll
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
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45
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Jiang S, Jiang H, Zhou Y, Jiang S, Zhang G. High-level expression of β-N-Acetylglucosaminidase BsNagZ in Pichia pastoris to obtain GlcNAc. Bioprocess Biosyst Eng 2019; 42:611-619. [DOI: 10.1007/s00449-018-02067-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 12/21/2018] [Indexed: 01/11/2023]
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46
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In Vitro Activity of Ceftolozane-Tazobactam against Enterobacter cloacae Complex Clinical Isolates with Different β-Lactam Resistance Phenotypes. Antimicrob Agents Chemother 2018; 62:AAC.00675-18. [PMID: 29914962 DOI: 10.1128/aac.00675-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 06/14/2018] [Indexed: 02/05/2023] Open
Abstract
The study evaluated the in vitro activity of ceftolozane-tazobactam (C/T) against 94 unique clinical isolates of Enterobacter cloacae complex (ECC). No difference was observed according to the ECC cluster. The in vitro activity greatly varied depending on the β-lactamase-producing profile: 100%, 67%, and 19% of wild-type, extended-spectrum β-lactamase (ESBL)-producing, and AmpC-overproducing strains, respectively, were susceptible to C/T. The use of C/T could be of interest for the treatment of some infections caused by ESBL-producing AmpC-nonoverexpressing ECC isolates.
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47
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Shelburne SA, Kim J, Munita JM, Sahasrabhojane P, Shields RK, Press EG, Li X, Arias CA, Cantarel B, Jiang Y, Kim MS, Aitken SL, Greenberg DE. Whole-Genome Sequencing Accurately Identifies Resistance to Extended-Spectrum β-Lactams for Major Gram-Negative Bacterial Pathogens. Clin Infect Dis 2018; 65:738-745. [PMID: 28472260 DOI: 10.1093/cid/cix417] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/27/2017] [Indexed: 12/16/2022] Open
Abstract
Background There is marked interest in using DNA-based methods to detect antimicrobial resistance (AMR), with targeted polymerase chain reaction (PCR) approaches increasingly being incorporated into clinical care. Whole-genome sequencing (WGS) could offer significant advantages over targeted PCR for AMR detection, particularly for species where mutations are major drivers of AMR. Methods Illumina MiSeq WGS and broth microdilution (BMD) assays were performed on 90 bloodstream isolates of the 4 most common gram-negative bacteria causing bloodstream infections in neutropenic patients. The WGS data, including both gene presence/absence and detection of mutations in an array of AMR-relevant genes, were used to predict resistance to 4 β-lactams commonly used in the empiric treatment of neutropenic fever. The genotypic predictions were then compared to phenotypic resistance as determined by BMD and by commercial methods during routine patient care. Results Of 133 putative instances of resistance to the β-lactams of interest identified by WGS, only 87 (65%) would have been detected by a typical PCR-based approach. The sensitivity, specificity, and positive and negative predictive values for WGS in predicting AMR were 0.87, 0.98, 0.97, and 0.91, respectively. Using BMD as the gold standard, our genotypic resistance prediction approach had a significantly higher positive predictive value compared to minimum inhibitory concentrations generated by commercial methods (0.97 vs 0.92; P = .025). Conclusions These data demonstrate the potential feasibility of using WGS to guide antibiotic treatment decisions for patients with life-threatening infections for an array of medically important pathogens.
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Affiliation(s)
- Samuel A Shelburne
- Department of Infectious Diseases, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America,Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America.,Center for Antimicrobial Resistance and Microbial Genomics, Division of Infectious Diseases, University of Texas McGovern Medical School at Houston
| | - Jiwoong Kim
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas.,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas
| | - Jose M Munita
- Center for Antimicrobial Resistance and Microbial Genomics, Division of Infectious Diseases, University of Texas McGovern Medical School at Houston.,Division of Infectious Diseases, Department of Internal Medicine, University of Texas McGovern Medical School at Houston.,Genomics and Resistant Microbes Group, Clinica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Pranoti Sahasrabhojane
- Department of Infectious Diseases, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Ryan K Shields
- Department of Medicine, University of Pittsburgh, Pennsylvania
| | - Ellen G Press
- Department of Medicine, University of Pittsburgh, Pennsylvania
| | - Xiqi Li
- Graduate Program in Diagnostic Genetics, School of Health Professions, University of Texas MD Anderson Cancer Center
| | - Cesar A Arias
- Center for Antimicrobial Resistance and Microbial Genomics, Division of Infectious Diseases, University of Texas McGovern Medical School at Houston.,Division of Infectious Diseases, Department of Internal Medicine, University of Texas McGovern Medical School at Houston.,Department of Microbiology and Molecular Genetics, University of Texas McGovern Medical School at Houston.,Molecular Genetics and Antimicrobial Resistance Unit, International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia
| | - Brandi Cantarel
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas
| | - Ying Jiang
- Department of Infectious Diseases, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Min S Kim
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas.,Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas
| | - Samuel L Aitken
- Center for Antimicrobial Resistance and Microbial Genomics, Division of Infectious Diseases, University of Texas McGovern Medical School at Houston.,Division of Pharmacy, MD Anderson Cancer Center, Houston
| | - David E Greenberg
- Center for Antimicrobial Resistance and Microbial Genomics, Division of Infectious Diseases, University of Texas McGovern Medical School at Houston.,Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA.,Microbiology, University of Texas Southwestern, Dallas
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Zhuang W, Liu H, Li J, Chen L, Wang G. Regulation of Class A β-Lactamase CzoA by CzoR and IscR in Comamonas testosteroni S44. Front Microbiol 2017; 8:2573. [PMID: 29312251 PMCID: PMC5744064 DOI: 10.3389/fmicb.2017.02573] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 12/11/2017] [Indexed: 11/13/2022] Open
Abstract
A genomic analysis of Comamonas testosteroni S44 revealed a gene that encodes a LysR family transcriptional regulator (here named czoR, czo for cefazolin) located upstream of a putative class A β-lactamase encoding gene (here named czoA). A putative DNA-binding motif of the Fe-S cluster assembly regulator IscR was identified in the czoR-czoA intergenic region. Real-time RT-PCR and lacZ fusion expression assays indicated that transcription of czoA and czoR were induced by multiple β-lactams. CzoA expressed in Escherichia coli was shown to contribute to susceptibility to a wide range of β-lactams judged from minimum inhibitory concentrations. In vitro enzymatic assays showed that CzoA hydrolyzed seven β-lactams, including benzylpenicillin, ampicillin, cefalexin, cefazolin, cefuroxime, ceftriaxone, and cefepime. Deletion of either iscR or czoR increased susceptibility to cefalexin and cefazolin, while complemented strains restored their wild-type susceptibility levels. Electrophoretic mobility shift assays (EMSA) demonstrated that CzoR and IscR bind to different sites of the czoR-czoA intergenic region. Precise CzoR- and IscR-binding sites were confirmed via DNase I footprinting or short fragment EMSA. When cefalexin or cefazolin was added to cultures, czoR deletion completely inhibited czoA expression but did not affect iscR transcription, while iscR deletion decreased the expressions of both czoR and czoA. These results reveal that CzoR positively affects the expression of czoA with its own expression upregulated by IscR.
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Affiliation(s)
- Weiping Zhuang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Hongliang Liu
- Shandong Provincial Research Center for Bioinformatic Engineering and Technique, School of Life Sciences, Shandong University of Technology, Zibo, China
| | - Jingxin Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Lu Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Gejiao Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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Wang S, Xiao SZ, Gu FF, Tang J, Guo XK, Ni YX, Qu JM, Han LZ. Antimicrobial susceptibility and molecular epidemiology of clinical Enterobacter cloacae bloodstream isolates in Shanghai, China. PLoS One 2017; 12:e0189713. [PMID: 29244831 PMCID: PMC5731700 DOI: 10.1371/journal.pone.0189713] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/30/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Enterobacter cloacae is a major nosocomial pathogen causing bloodstream infections. We retrospectively conducted a study to assess antimicrobial susceptibility and phylogenetic relationships of E. cloacae bloodstream isolates in two tertiary university-affiliated hospitals in Shanghai, in order to facilitate managements of E. cloacae bloodstream infections and highlight some unknowns for future prevention. METHODS Fifty-three non-duplicate E. cloacae bloodstream isolates were consecutively collected from 2013 to 2016. Antimicrobial susceptibility was determined by disk diffusion. PCR was performed to detect extended-spectrum β-lactamase (ESBL), carbapenemase and colistin resistance (MCR-1) gene. Plasmid-mediated AmpC β-lactamase (pAmpC) genes were detected using a multiplex PCR assay targeting MIR/ACT gene (closely related to chromosomal EBC family gene) and other plasmid-mediated genes, including DHA, MOX, CMY, ACC, and FOX. eBURST was applied to analyze multi-locus sequence typing (MLST). RESULTS The rates of resistance to all tested antibiotics were <40%. Among 53 E. cloacae isolates, 8(15.1%) were ESBL producers, 3(5.7%) were carbapenemase producers and 18(34.0%) were pAmpC producers. ESBL producers bear significantly higher resistance to cefotaxime (100.0%), ceftazidime (100.0%), aztreonam (100.0%), piperacillin (87.5%), tetracycline (75.0%), and trimethoprim-sulfamethoxazole (62.5%) than non-producers (p<0.05). PAmpC- and non-producers both presented low resistance rates (<40%) to all antibiotics (p>0.05). SHV (6/8, 75.0%) and MIR/ACT (15/18, 83.3%) predominated in ESBL and pAmpC producers respectively. Moreover, 2 isolates co-carried TEM-1, SHV-12, IMP-26 and DHA-1. MLST analysis distinguished the 53 isolates into 51 STs and only ST414 and ST520 were assigned two isolates of each (2/53). CONCLUSION The antimicrobial resistance rates were low among 53 E. cloacae bloodstream isolates in the two hospitals. Multiclonality disclosed no evidence on spread of these isolates in Shanghai. The simultaneous presence of ESBL, carbapenemase and pAmpC detected in 2 isolates was firstly reported in Shanghai, which necessitated active ongoing surveillances and consistent prevention and control of E. cloacae.
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Affiliation(s)
- Su Wang
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shu-Zhen Xiao
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fei-Fei Gu
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jin Tang
- Department of Clinical Laboratory, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
| | - Xiao-Kui Guo
- Department of Medical Microbiology and Parasitology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yu-Xing Ni
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jie-Ming Qu
- Department of Pulmonary Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (LZH); (JMQ)
| | - Li-Zhong Han
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (LZH); (JMQ)
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50
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Tada T, Uechi K, Nakasone I, Miyazato Z, Shinzato T, Shimada K, Tsuchiya M, Kirikae T, Fujita J. A hemin auxotrophic Enterobacter cloacae clinical isolate with increased resistance to carbapenems and aminoglycosides. J Med Microbiol 2017; 67:29-32. [PMID: 29205135 DOI: 10.1099/jmm.0.000655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Small-colony variants (SCVs) were obtained from an Enterobacter cloacae clinical isolate in Okinawa, Japan. One variant showed auxotrophy for hemin with a deletion of 20 365 nucleotides, dosC-ydiK-mmuP-mmuM-tauA-tauB-tauC-tauD-hemB-yaiT-yaiV-ampH-yddQ-sbmA-yaiW-yaiY-yaiZ, including hemB, and was more resistant to aminoglycosides and carbapenems, but more susceptible to aztreonam, than the parent strain.
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Affiliation(s)
- Tatsuya Tada
- Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan.,Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Kohei Uechi
- Division of Clinical Laboratory and Blood Transfusion, University Hospital of the Ryukyus, Okinawa, Japan.,Department of Infectious Diseases, Respiratory, and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Isamu Nakasone
- Control and Prevention of Infectious Disease, University Hospital of the Ryukyus, Okinawa, Japan
| | | | | | - Kayo Shimada
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Mitsuhiro Tsuchiya
- Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Teruo Kirikae
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.,Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Jiro Fujita
- Department of Infectious Diseases, Respiratory, and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
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