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Muñoz-Gutiérrez I, Cantu L, Shanahan J, Girguis M, de la Cruz M, Mota-Bravo L. Cryptic environmental conjugative plasmid recruits a novel hybrid transposon resulting in a new plasmid with higher dispersion potential. mSphere 2024; 9:e0025224. [PMID: 38771049 DOI: 10.1128/msphere.00252-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Accepted: 04/11/2024] [Indexed: 05/22/2024] Open
Abstract
Cryptic conjugative plasmids lack antibiotic-resistance genes (ARGs). These plasmids can capture ARGs from the vast pool of the environmental metagenome, but the mechanism to recruit ARGs remains to be elucidated. To investigate the recruitment of ARGs by a cryptic plasmid, we sequenced and conducted mating experiments with Escherichia coli SW4848 (collected from a lake) that has a cryptic IncX (IncX4) plasmid and an IncF (IncFII/IncFIIB) plasmid with five genes that confer resistance to aminoglycosides (strA and strB), sulfonamides (sul2), tetracycline [tet(A)], and trimethoprim (dfrA5). In a conjugation experiment, a novel hybrid Tn21/Tn1721 transposon of 22,570 bp (designated Tn7714) carrying the five ARG mobilized spontaneously from the IncF plasmid to the cryptic IncX plasmid. The IncF plasmid was found to be conjugative when it was electroporated into E. coli DH10B (without the IncX plasmid). Two parallel conjugations with the IncF and the new IncX (carrying the novel Tn7714 transposon) plasmids in two separate E. coli DH10B as donors and E. coli J53 as the recipient revealed that the conjugation rate of the new IncX plasmid (with the novel Tn7714 transposon and five ARGs) is more than two orders of magnitude larger than the IncF plasmid. For the first time, this study shows experimental evidence that cryptic environmental plasmids can capture and transfer transposons with ARGs to other bacteria, creating novel multidrug-resistant conjugative plasmids with higher dispersion potential. IMPORTANCE Cryptic conjugative plasmids are extrachromosomal DNA molecules without antibiotic-resistance genes (ARGs). Environmental bacteria carrying cryptic plasmids with a high conjugation rate threaten public health because they can capture clinically relevant ARGs and rapidly spread them to pathogenic bacteria. However, the mechanism to recruit ARG by cryptic conjugative plasmids in environmental bacteria has not been observed experimentally. Here, we document the first translocation of a transposon with multiple clinically relevant ARGs to a cryptic environmental conjugative plasmid. The new multidrug-resistant conjugative plasmid has a conjugation rate that is two orders of magnitude higher than the original plasmid that carries the ARG (i.e., the new plasmid from the environment can spread ARG more than two orders of magnitude faster). Our work illustrates the importance of studying the mobilization of ARGs in environmental bacteria. It sheds light on how cryptic conjugative plasmids recruit ARGs, a phenomenon at the root of the antibiotic crisis.
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Affiliation(s)
- Iván Muñoz-Gutiérrez
- School of Biological Sciences, University of California, Irvine, California, USA
| | - Luis Cantu
- School of Biological Sciences, University of California, Irvine, California, USA
| | - Jack Shanahan
- School of Biological Sciences, University of California, Irvine, California, USA
| | - Miray Girguis
- School of Biological Sciences, University of California, Irvine, California, USA
| | - Marlene de la Cruz
- School of Biological Sciences, University of California, Irvine, California, USA
| | - Luis Mota-Bravo
- School of Biological Sciences, University of California, Irvine, California, USA
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2
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Chowdhury AR, Mukherjee D, Chatterjee R, Chakravortty D. Defying the odds: Determinants of the antimicrobial response of Salmonella Typhi and their interplay. Mol Microbiol 2024; 121:213-229. [PMID: 38071466 DOI: 10.1111/mmi.15209] [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: 07/31/2023] [Revised: 11/12/2023] [Accepted: 11/27/2023] [Indexed: 02/12/2024]
Abstract
Salmonella Typhi, the invasive serovar of S. enterica subspecies enterica, causes typhoid fever in healthy human hosts. The emergence of antibiotic-resistant strains has consistently challenged the successful treatment of typhoid fever with conventional antibiotics. Antimicrobial resistance (AMR) in Salmonella is acquired either by mutations in the genomic DNA or by acquiring extrachromosomal DNA via horizontal gene transfer. In addition, Salmonella can form a subpopulation of antibiotic persistent (AP) cells that can survive at high concentrations of antibiotics. These have reduced the effectiveness of the first and second lines of antibiotics used to treat Salmonella infection. The recurrent and chronic carriage of S. Typhi in human hosts further complicates the treatment process, as a remarkable shift in the immune response from pro-inflammatory Th1 to anti-inflammatory Th2 is observed. Recent studies have also highlighted the overlap between AP, persistent infection (PI) and AMR. These incidents have revealed several areas of research. In this review, we have put forward a timeline for the evolution of antibiotic resistance in Salmonella and discussed the different mechanisms of the same availed by the pathogen at the genotypic and phenotypic levels. Further, we have presented a detailed discussion on Salmonella antibiotic persistence (AP), PI, the host and bacterial virulence factors that can influence PI, and how both AP and PI can lead to AMR.
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Affiliation(s)
- Atish Roy Chowdhury
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Debapriya Mukherjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Ritika Chatterjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, India
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Zhou J, Wang W, Liang M, Yu Q, Cai S, Lei T, Jiang Y, Du X, Zhou Z, Yu Y. A Novel CMY Variant Confers Transferable High-Level Resistance to Ceftazidime-Avibactam in Multidrug-Resistant Escherichia coli. Microbiol Spectr 2023; 11:e0334922. [PMID: 36786629 PMCID: PMC10100771 DOI: 10.1128/spectrum.03349-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/21/2023] [Indexed: 02/15/2023] Open
Abstract
Here, our objective was to explore the molecular mechanism underlying ceftazidime-avibactam resistance in a novel CMY-178 variant produced by the clinical Escherichia coli strain AR13438. The antibiotic susceptibility of the clinical isolate, its transconjugants, and its transformants harboring transferable blaCMY were determined by the agar dilution method. S1-PFGE, cloning experiments, and whole-genome sequencing (WGS) were performed to investigate the molecular characteristics of ceftazidime-avibactam resistance genes. Kinetic parameters were compared among the purified CMY variants. Structural modeling and molecular docking were performed to assess the affinity between the CMYs and drugs. The horizontal transferability of the plasmid was evaluated by a conjugation experiment. The fitness cost of the plasmid was analyzed by determining the maximal growth rate, the maximum optical density at 600 nm (OD600), and the duration of the lag phase. AR13438, a sequence type 457 E. coli strain, was resistant to multiple cephalosporins, piperacillin-tazobactam, and ceftazidime-avibactam at high levels and was susceptible to carbapenems. WGS and cloning experiments indicated that a novel CMY gene, blaCMY-178, was responsible for ceftazidime-avibactam resistance. Compared with the closely related CMY-172, CMY-178 had a nonsynonymous amino acid substitution at position 70 (Asn70Thr). CMY-178 increased the MICs of multiple cephalosporins and ceftazidime-avibactam compared with CMY-172. The kinetic constant Ki values of CMY-172 and CMY-178 against tazobactam were 2.12 ± 0.34 and 2.49 ± 0.51 μM, respectively. Structural modeling and molecular docking indicated a narrowing of the CMY-178 ligand-binding pocket and its entrance and a stronger positive charge at the pocket entrance compared with those observed with CMY-172. blaCMY-178 was located in a 96.9-kb IncI1-type plasmid, designated pAR13438_2, which exhibited high transfer frequency without a significant fitness cost. In conclusion, CMY-178 is a novel CMY variant that mediates high-level resistance to ceftazidime-avibactam by enhancing the ability to hydrolyze ceftazidime and reducing the affinity for avibactam. Notably, blaCMY-178 could be transferred horizontally at high frequency without fitness costs. IMPORTANCE Ceftazidime-avibactam is a novel β-lactam-β-lactamase inhibitor (BLBLI) combination with powerful activity against Enterobacterales isolates producing AmpC, such as CMY-like cephalosporinase. However, in recent years, CMY variants have been reported to confer ceftazidime-avibactam resistance. We reported a novel CMY variant, CMY-178, that confers high-level ceftazidime-avibactam resistance with potent transferability. Therefore, this resistance gene is a tremendous potential menace to public health and needs attention of clinicians.
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Affiliation(s)
- Junxin Zhou
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Weiping Wang
- Department of Clinical Laboratory, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Min Liang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qian Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shiqi Cai
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Tailong Lei
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Jiang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoxing Du
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhihui Zhou
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Li L, Olsen RH, Xiao J, Liang M, Meng H, Peng S. Characterization of extended-spectrum cephalosporins and fluoroquinolone resistance of a Salmonella enterica serovar Thompson isolate from ready-to-eat pork product in China. Front Microbiol 2022; 13:964009. [PMID: 36187962 PMCID: PMC9521377 DOI: 10.3389/fmicb.2022.964009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/24/2022] [Indexed: 12/02/2022] Open
Abstract
Salmonella is a leading cause of foodborne illness worldwide and is a common concern in food safety. Salmonella enterica displaying resistance to extended-spectrum cephalosporins (ESCs) and fluoroquinolone (FQs) has been deemed a high-priority pathogen by the World Health Organization. Co-resistance to ESCs and FQs has been reported in S. enterica serovar Thompson (S. Thompson). However, the genetic context of ESCs and FQs resistance genes in S. Thompson lacks sufficient characterization. In this study, we characterized a multi-drug resistant (MDR) S. Thompson isolate recovered from a retail ready-to-eat (RTE) pork product in China. Short- and long-read sequencing (HiSeq and MinION) of the genome identified the presence of blaCMY−2, qnrS1, and qepA8, along with 11 additional acquired antimicrobial resistance genes, residing on a 152,940 bp IncA/C plasmid. Specifically, the blaCMY−2, qnrS1, and qepA8 genes were located in insertion sequences (ISs) and integron mediated mobile genetic structure, sugE-blc-blaCMY−2-ISEc9, IS26-orf6-qnrS1-orf5-ISKpn19, and intl1-qepA8-orf10-IS91-orf1-dfrA12-orf11-aadA2-qacEΔ1-sul1, respectively. Each gene was identified in various bacteria species, indicating their high transfer ability. The plasmid was found to be transferable to Escherichia coli J53 by conjugation and resulted in the acquiring of multiple resistances in the transconjugants. The plasmid is closely related to plasmids from two human S. Thompson strains isolated in different regions and years in China. Moreover, core-genome Multi Locus Sequence Typing (cgMLST) and phylogenetic analysis based on global 1,868 S. Saintpaul isolates showed that the S. Thompson isolate was highly epidemiologically linked to a human isolate in China. Our findings suggest that Chinese RTE pork products are a possible source of human pathogenic ESCs and FQs co-resistant S. Thompson. Furthermore, the results underline the important role of conjugative plasmids in acquiring and transmission of ESCs and FQs resistance in S. Thompson isolates, which need continuous investigation.
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Affiliation(s)
- Lili Li
- Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Rikke Heidemann Olsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Jian Xiao
- Guangzhou Food Inspection Institute, Guangzhou, China
| | - Meidan Liang
- Guangzhou Food Inspection Institute, Guangzhou, China
| | - Hecheng Meng
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- *Correspondence: Hecheng Meng
| | - Shifu Peng
- Department of Environment and Health, Jiangsu Center for Disease Control and Prevention, Nanjing, China
- Shifu Peng
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Baquero F, Martínez JL, F. Lanza V, Rodríguez-Beltrán J, Galán JC, San Millán A, Cantón R, Coque TM. Evolutionary Pathways and Trajectories in Antibiotic Resistance. Clin Microbiol Rev 2021; 34:e0005019. [PMID: 34190572 PMCID: PMC8404696 DOI: 10.1128/cmr.00050-19] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Evolution is the hallmark of life. Descriptions of the evolution of microorganisms have provided a wealth of information, but knowledge regarding "what happened" has precluded a deeper understanding of "how" evolution has proceeded, as in the case of antimicrobial resistance. The difficulty in answering the "how" question lies in the multihierarchical dimensions of evolutionary processes, nested in complex networks, encompassing all units of selection, from genes to communities and ecosystems. At the simplest ontological level (as resistance genes), evolution proceeds by random (mutation and drift) and directional (natural selection) processes; however, sequential pathways of adaptive variation can occasionally be observed, and under fixed circumstances (particular fitness landscapes), evolution is predictable. At the highest level (such as that of plasmids, clones, species, microbiotas), the systems' degrees of freedom increase dramatically, related to the variable dispersal, fragmentation, relatedness, or coalescence of bacterial populations, depending on heterogeneous and changing niches and selective gradients in complex environments. Evolutionary trajectories of antibiotic resistance find their way in these changing landscapes subjected to random variations, becoming highly entropic and therefore unpredictable. However, experimental, phylogenetic, and ecogenetic analyses reveal preferential frequented paths (highways) where antibiotic resistance flows and propagates, allowing some understanding of evolutionary dynamics, modeling and designing interventions. Studies on antibiotic resistance have an applied aspect in improving individual health, One Health, and Global Health, as well as an academic value for understanding evolution. Most importantly, they have a heuristic significance as a model to reduce the negative influence of anthropogenic effects on the environment.
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Affiliation(s)
- F. Baquero
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Network Center for Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - J. L. Martínez
- National Center for Biotechnology (CNB-CSIC), Madrid, Spain
| | - V. F. Lanza
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Network Center for Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Central Bioinformatics Unit, Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain
| | - J. Rodríguez-Beltrán
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Network Center for Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - J. C. Galán
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Network Center for Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - A. San Millán
- National Center for Biotechnology (CNB-CSIC), Madrid, Spain
| | - R. Cantón
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Network Center for Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - T. M. Coque
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Network Center for Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain
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Sia CM, Baines SL, Valcanis M, Lee DYJ, Gonçalves da Silva A, Ballard SA, Easton M, Seemann T, Howden BP, Ingle DJ, Williamson DA. Genomic diversity of antimicrobial resistance in non-typhoidal Salmonella in Victoria, Australia. Microb Genom 2021; 7:000725. [PMID: 34907895 PMCID: PMC8767345 DOI: 10.1099/mgen.0.000725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Non-typhoidal Salmonella (NTS) is the second most common cause of foodborne bacterial gastroenteritis in Australia with antimicrobial resistance (AMR) increasing in recent years. Whole-genome sequencing (WGS) provides opportunities for in silico detection of AMR determinants. The objectives of this study were two-fold: (1) establish the utility of WGS analyses for inferring phenotypic resistance in NTS, and (2) explore clinically relevant genotypic AMR profiles to third generation cephalosporins (3GC) in NTS lineages. The concordance of 2490 NTS isolates with matched WGS and phenotypic susceptibility data against 13 clinically relevant antimicrobials was explored. In silico serovar prediction and typing was performed on assembled reads and interrogated for known AMR determinants. The surrounding genomic context, plasmid determinants and co-occurring AMR patterns were further investigated for multidrug resistant serovars harbouring blaCMY-2, blaCTX-M-55 or blaCTX-M-65. Our data demonstrated a high correlation between WGS and phenotypic susceptibility testing. Phenotypic-genotypic concordance was observed between 2440/2490 (98.0 %) isolates, with overall sensitivity and specificity rates >98 % and positive and negative predictive values >97 %. The most common AMR determinants were blaTEM-1, sul2, tet(A), strA-strB and floR. Phenotypic resistance to cefotaxime and azithromycin was low and observed in 6.2 % (151/2486) and 0.9 % (16/1834) of the isolates, respectively. Several multi-drug resistant NTS lineages were resistant to 3GC due to different genetic mechanisms including blaCMY-2, blaCTX-M-55 or blaCTX-M-65. This study shows WGS can enhance existing AMR surveillance in NTS datasets routinely produced in public health laboratories to identify emerging AMR in NTS. These approaches will be critical for developing capacity to detect emerging public health threats such as resistance to 3GC.
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Affiliation(s)
- Cheryll M. Sia
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia,*Correspondence: Cheryll M. Sia,
| | - Sarah L. Baines
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Mary Valcanis
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Darren Y. J. Lee
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Anders Gonçalves da Silva
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Susan A. Ballard
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | | | - Torsten Seemann
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Benjamin P. Howden
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia,Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Danielle J. Ingle
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia,National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia,*Correspondence: Danielle J. Ingle,
| | - Deborah A. Williamson
- Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia,Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology & Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia,Department of Microbiology, Royal Melbourne Hospital, Melbourne, Australia,*Correspondence: Deborah A. Williamson,
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Xu M, Zhao J, Xu L, Yang Q, Xu H, Kong H, Zhou J, Fu Y. Emergence of transferable ceftazidime-avibactam resistance in KPC-producing Klebsiella pneumoniae due to a novel CMY AmpC β-lactamase in China. Clin Microbiol Infect 2021; 28:136.e1-136.e6. [PMID: 34044150 DOI: 10.1016/j.cmi.2021.05.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 12/26/2022]
Abstract
OBJECTIVES To evaluate the molecular mechanisms of ceftazidime/avibactam (CAZ/AVI) resistance in six Klebsiella pneumoniae strains that co-produce K. pneumoniae carbapenemase (KPC)-2 and a novel variant of CMY cephalosporinase in a Chinese hospital. METHODS Antimicrobial susceptibility was determined by broth microdilution. Whole-genome sequencing (WGS) was performed to investigate potential resistance determinants. Plasmid conjugation, electroporation, S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) hybridization and cloning experiment were carried out to investigate the resistance plasmids and genes. RESULTS A high level of CAZ/AVI resistance was observed in six KPC-Kp strains (MIC 128 mg/L). Five strains were isolated in 2015 and one in 2016, before the approval of CAZ/AVI in China. Sequence analysis indicated that all the strains belonged to sequence type (ST) 11 and uniformly carried a novel CMY AmpC β-lactamase gene, designated blaCMY-172. When compared with CMY-2, CMY-172 has a deletion of three consecutive amino acids (K290, V291 and A292) in the R2-loop region and a non-synonymous amino acid substitution at position 346 (N346I). The blaCMY-172-bearing plasmid, pKPCZA02_4, was 93.3 Kb, IncI1-I type, and conjugative; blaCMY-172 was located in an IS1294-mediated transposon. Plasmid conjugation and DNA fragment cloning proved that blaCMY-172 was responsible for CAZ/AVI resistance. CONCLUSIONS Our study identified conjugative plasmid-mediated blaCMY-172 as a new mechanism for CAZ/AVI resistance in clinical KPC-Kp strains. Careful monitoring of CAZ/AVI susceptibility is imperative for preventing the spread of the resistance gene.
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Affiliation(s)
- Min Xu
- Department of Laboratory Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jun Zhao
- Department of Respiratory Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Li Xu
- Department of Clinical Laboratory, Yangzhou Centre for Disease Control and Prevention, Yangzhou, China
| | - Qing Yang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Centre for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Hao Xu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Centre for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Haishen Kong
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Centre for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianying Zhou
- Department of Respiratory Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| | - Yiqi Fu
- Department of Respiratory Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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Incompatibility Group I1 (IncI1) Plasmids: Their Genetics, Biology, and Public Health Relevance. Microbiol Mol Biol Rev 2021; 85:85/2/e00031-20. [PMID: 33910982 DOI: 10.1128/mmbr.00031-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bacterial plasmids are extrachromosomal genetic elements that often carry antimicrobial resistance (AMR) genes and genes encoding increased virulence and can be transmissible among bacteria by conjugation. One key group of plasmids is the incompatibility group I1 (IncI1) plasmids, which have been isolated from multiple Enterobacteriaceae of food animal origin and clinically ill human patients. The IncI group of plasmids were initially characterized due to their sensitivity to the filamentous bacteriophage If1. Two prototypical IncI1 plasmids, R64 and pColIb-P9, have been extensively studied, and the plasmids consist of unique regions associated with plasmid replication, plasmid stability/maintenance, transfer machinery apparatus, single-stranded DNA transfer, and antimicrobial resistance. IncI1 plasmids are somewhat unique in that they encode two types of sex pili, a thick, rigid pilus necessary for mating and a thin, flexible pilus that helps stabilize bacteria for plasmid transfer in liquid environments. A key public health concern with IncI1 plasmids is their ability to carry antimicrobial resistance genes, including those associated with critically important antimicrobials used to treat severe cases of enteric infections, including the third-generation cephalosporins. Because of the potential importance of these plasmids, this review focuses on the distribution of the plasmids, their phenotypic characteristics associated with antimicrobial resistance and virulence, and their replication, maintenance, and transfer.
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Liu J, Zhu Y, Jay-Russell M, Lemay DG, Mills DA. Reservoirs of antimicrobial resistance genes in retail raw milk. MICROBIOME 2020; 8:99. [PMID: 32591006 PMCID: PMC7320593 DOI: 10.1186/s40168-020-00861-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 05/11/2020] [Indexed: 05/16/2023]
Abstract
BACKGROUND It has been estimated that at least 3% of the USA population consumes unpasteurized (raw) milk from animal sources, and the demand to legalize raw milk sales continues to increase. However, consumption of raw milk can cause foodborne illness and be a source of bacteria containing transferrable antimicrobial resistance genes (ARGs). To obtain a comprehensive understanding of the microbiome and antibiotic resistome in both raw and processed milk, we systematically analyzed 2034 retail milk samples including unpasteurized milk and pasteurized milk via vat pasteurization, high-temperature-short-time pasteurization, and ultra-pasteurization from the United States using complementary culture-based, 16S rRNA gene, and metagenomic sequencing techniques. RESULTS Raw milk samples had the highest prevalence of viable bacteria which were measured as all aerobic bacteria, coliform, and Escherichia coli counts, and their microbiota was distinct from other types of milk. 16S rRNA gene sequencing revealed that Pseudomonadaceae dominated raw milk with limited levels of lactic acid bacteria. Among all milk samples, the microbiota remained stable with constant bacterial populations when stored at 4 °C. In contrast, storage at room temperature dramatically enriched the bacterial populations present in raw milk samples and, in parallel, significantly increased the richness and abundance of ARGs. Metagenomic sequencing indicated raw milk possessed dramatically more ARGs than pasteurized milk, and a conjugation assay documented the active transfer of blaCMY-2, one ceftazidime resistance gene present in raw milk-borne E. coli, across bacterial species. The room temperature-enriched resistome differed in raw milk from distinct geographic locations, a difference likely associated with regionally distinct milk microbiota. CONCLUSION Despite advertised "probiotic" effects, our results indicate that raw milk microbiota has minimal lactic acid bacteria. In addition, retail raw milk serves as a reservoir of ARGs, populations of which are readily amplified by spontaneous fermentation. There is an increased need to understand potential food safety risks from improper transportation and storage of raw milk with regard to ARGs. Video Abstract.
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Affiliation(s)
- Jinxin Liu
- Department of Food Science and Technology, Robert Mondavi Institute for Wine and Food Science, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
- Foods for Health Institute, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| | - Yuanting Zhu
- Department of Food Science and Technology, Robert Mondavi Institute for Wine and Food Science, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
- Foods for Health Institute, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| | - Michele Jay-Russell
- Western Center for Food Safety, University of California, Davis, Davis, CA, 95616, USA
| | - Danielle G Lemay
- USDA ARS Western Human Nutrition Research Center, 430 West Health Sciences Dr, Davis, CA, 95616, USA
- Genome Center, University of California, 451 Health Sciences Dr., Davis, California, 95616, USA
- Department of Nutrition, University of California, Davis, One Shields Ave., Davis, CA, 95616, USA
| | - David A Mills
- Department of Food Science and Technology, Robert Mondavi Institute for Wine and Food Science, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA.
- Foods for Health Institute, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA.
- Department of Viticulture and Enology, Robert Mondavi Institute for Wine and Food Science, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA.
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Lallement C, Pasternak C, Ploy MC, Jové T. The Role of IS CR1-Borne P OUT Promoters in the Expression of Antibiotic Resistance Genes. Front Microbiol 2018; 9:2579. [PMID: 30425694 PMCID: PMC6218425 DOI: 10.3389/fmicb.2018.02579] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/09/2018] [Indexed: 11/13/2022] Open
Abstract
The ISCR1 (Insertion sequence Common Region) element is the most widespread member of the ISCR family, and is frequently present within γ-proteobacteria that occur in clinical settings. ISCR1 is always associated with the 3'Conserved Segment (3'CS) of class 1 integrons. ISCR1 contains outward-oriented promoters POUT, that may contribute to the expression of downstream genes. In ISCR1, there are two POUT promoters named PCR1-1 and PCR1-2. We performed an in silico analysis of all publically available ISCR1 sequences and identified numerous downstream genes that mainly encode antibiotic resistance genes and that are oriented in the same direction as the POUT promoters. Here, we showed that both PCR1-1 and PCR1-2 significantly increase the expression of the downstream genes bla CTX-M-9 and dfrA19. Our data highlight the role of ISCR1 in the expression of antibiotic resistance genes, which may explain why ISCR1 is so frequent in clinical settings.
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Affiliation(s)
- Claire Lallement
- INSERM, CHU Limoges, RESINFIT, U1092, University of Limoges, Limoges, France
| | - Cécile Pasternak
- INSERM, CHU Limoges, RESINFIT, U1092, University of Limoges, Limoges, France
| | - Marie-Cécile Ploy
- INSERM, CHU Limoges, RESINFIT, U1092, University of Limoges, Limoges, France
| | - Thomas Jové
- INSERM, CHU Limoges, RESINFIT, U1092, University of Limoges, Limoges, France
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11
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Partridge SR, Kwong SM, Firth N, Jensen SO. Mobile Genetic Elements Associated with Antimicrobial Resistance. Clin Microbiol Rev 2018; 31:e00088-17. [PMID: 30068738 PMCID: PMC6148190 DOI: 10.1128/cmr.00088-17] [Citation(s) in RCA: 1139] [Impact Index Per Article: 189.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Strains of bacteria resistant to antibiotics, particularly those that are multiresistant, are an increasing major health care problem around the world. It is now abundantly clear that both Gram-negative and Gram-positive bacteria are able to meet the evolutionary challenge of combating antimicrobial chemotherapy, often by acquiring preexisting resistance determinants from the bacterial gene pool. This is achieved through the concerted activities of mobile genetic elements able to move within or between DNA molecules, which include insertion sequences, transposons, and gene cassettes/integrons, and those that are able to transfer between bacterial cells, such as plasmids and integrative conjugative elements. Together these elements play a central role in facilitating horizontal genetic exchange and therefore promote the acquisition and spread of resistance genes. This review aims to outline the characteristics of the major types of mobile genetic elements involved in acquisition and spread of antibiotic resistance in both Gram-negative and Gram-positive bacteria, focusing on the so-called ESKAPEE group of organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli), which have become the most problematic hospital pathogens.
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Affiliation(s)
- Sally R Partridge
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, New South Wales, Australia
| | - Stephen M Kwong
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Neville Firth
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Slade O Jensen
- Microbiology and Infectious Diseases, School of Medicine, Western Sydney University, Sydney, New South Wales, Australia
- Antibiotic Resistance & Mobile Elements Group, Ingham Institute for Applied Medical Research, Sydney, New South Wales, Australia
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12
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Zhou K, Luo Q, Wang Q, Huang C, Lu H, Rossen JWA, Xiao Y, Li L. Silent transmission of an IS1294b-deactivated mcr-1 gene with inducible colistin resistance. Int J Antimicrob Agents 2018; 51:822-828. [PMID: 29339296 DOI: 10.1016/j.ijantimicag.2018.01.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/04/2018] [Accepted: 01/06/2018] [Indexed: 10/18/2022]
Abstract
Global dissemination of the mobile colistin resistance mcr-1 is of particular concern as colistin is one of the last-resort antibiotics for the treatment of severe infections caused by carbapenem-resistant Gram-negative bacteria. In this study, an inactive form of mcr-1 in a fluoroquinolone-resistant and colistin-susceptible uropathogenic Escherichia coli isolate (ECO3347) was characterised. The mcr-1 gene was deactivated by insertion of a 1.7-kb IS1294b element flanked by two tetramers (GTTC) and located on a 62-kb pHNSHP45-like plasmid (p3347-mcr-1). Single-step and multistep selections were used to induce colistin resistance in vitro in ECO3347. ECO3347 acquired colistin resistance (MIC = 16-32 mg/L) only after a serial passage selection with increasing concentrations of colistin (2-8 mg/L). Deactivated mcr-1 was re-activated by loss of IS1294b without any remnants in most colistin-resistant mutants. In addition, a novel amino acid variant (Leu105Pro) in the CheY homologous receiver domain of PmrA was detected in one colistin-resistant mutant. Plasmid p3347-mcr-1+ carrying the re-activated mcr-1 gene is transferrable to E. coli J53 recipient with a high conjugation rate (ca. 10-1 cells per recipient cell). Transconjugants showed an identical growth status to J53, suggesting lack of a fitness cost after acquiring p3347-mcr-1+. These results highlight that the disrupted mcr-1 gene has the potential for wide silent dissemination with the help of pHNSHP45-like epidemic plasmids. Inducible colistin resistance may likely compromise the success of clinical treatment and infection control. Continuous monitoring of mcr-1 is imperative for understanding and tackling its dissemination in different forms.
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Affiliation(s)
- Kai Zhou
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou 310003, China; Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Qixia Luo
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou 310003, China
| | - Qin Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou 310003, China
| | - Chen Huang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou 310003, China
| | - Haifeng Lu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou 310003, China
| | - John W A Rossen
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Yonghong Xiao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou 310003, China.
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Medicine School, Zhejiang University, Hangzhou 310003, China
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Gratia JP. Genetic recombinational events in prokaryotes and their viruses: insight into the study of evolution and biodiversity. Antonie van Leeuwenhoek 2017; 110:1493-1514. [DOI: 10.1007/s10482-017-0916-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/20/2017] [Indexed: 01/21/2023]
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A Novel Hybrid Plasmid Carrying Multiple Antimicrobial Resistance and Virulence Genes in Salmonella enterica Serovar Dublin. Antimicrob Agents Chemother 2017; 61:AAC.02601-16. [PMID: 28320711 DOI: 10.1128/aac.02601-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/28/2017] [Indexed: 11/20/2022] Open
Abstract
Virulence plasmids and antibiotic resistance plasmids are usually maintained separately in Salmonella spp.; however, we report an instance of a hybrid plasmid (pN13-01125) in Salmonella enterica serovar Dublin. Review of the complete sequence of the 172,265-bp plasmid suggests that pN13-01125 is comprised of the previously described pSDVr and pSH696_135 plasmids and that the mechanism of hybridization likely involves IS6 (IS26) insertion sequence elements. The plasmid has a low conjugation frequency, confers resistance to six classes of antimicrobials, and contains a complete spv virulence operon.
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15
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Jahanbakhsh S, Letellier A, Fairbrother JM. Circulating of CMY-2 β-lactamase gene in weaned pigs and their environment in a commercial farm and the effect of feed supplementation with a clay mineral. J Appl Microbiol 2017; 121:136-48. [PMID: 27138244 DOI: 10.1111/jam.13166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 04/02/2016] [Accepted: 04/27/2016] [Indexed: 12/30/2022]
Abstract
AIMS To investigate the mechanisms leading to an increase in the prevalence of blaCMY -2 conferring resistance to ceftiofur in pigs receiving a feed medicated with chlortetracycline and penicillin, and to examine the effect of supplementation with a clay mineral on this phenomenon. METHODS AND RESULTS In 138 blaCMY -2 -positive Escherichia coli isolates from faeces of pigs receiving feed supplemented or not with 2% clinoptilolite, from day 2 to day 28 after weaning, isolates from the two groups differed significantly with respect to their phylogenetic group: phylotype A predominated in the supplemented group, whereas phylotypes B1 and D predominated in the control group, as determined by PCR. In 36 representative isolates, pulsed-field gel electrophoresis and antimicrobial susceptibility testing revealed that the blaCMY -2 -positive E. coli isolates were polyclonal with diverse antimicrobial resistance patterns and blaCMY -2 -carrying plasmids of incompatibility (Inc) groups, A/C, I1 and ColE were observed in transformants as detected by PCR. Enterobacter cloacae possessing blaCMY -2 -carrying IncA/C plasmids were found in the pens before introduction of this batch of pigs. The blaCMY -2 -positive E. coli isolates were more clonally diverse in the control group than the supplemented group. CONCLUSIONS The blaCMY -2 gene appears to have spread both horizontally and clonally in this batch of pigs and may have spread from previous batches of pigs via plasmids carried by Ent. cloacae and expanded in animals of the present batch in the presence of the selection pressure due to administration of chlortetracycline and penicillin in the feed. Feed supplementation may have an effect on clonal diversity of blaCMY -2 -positive isolates. SIGNIFICANCE AND IMPACT OF THE STUDY Implementation of improved hygiene measures, decreased administration of certain antimicrobials on farm and feed supplementation with certain ingredients may limit antimicrobial resistance spread between and within batches of animals.
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Affiliation(s)
- S Jahanbakhsh
- OIE Reference Laboratory for Escherichia coli (EcL), Faculté de médecine vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire (CRIPA), Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - A Letellier
- NSERC Industrial Research Chair in Meat Safety, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - J M Fairbrother
- OIE Reference Laboratory for Escherichia coli (EcL), Faculté de médecine vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire (CRIPA), Université de Montréal, Saint-Hyacinthe, QC, Canada
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16
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Chen W, Fang T, Zhou X, Zhang D, Shi X, Shi C. IncHI2 Plasmids Are Predominant in Antibiotic-Resistant Salmonella Isolates. Front Microbiol 2016; 7:1566. [PMID: 27746775 PMCID: PMC5043248 DOI: 10.3389/fmicb.2016.01566] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/20/2016] [Indexed: 01/07/2023] Open
Abstract
The wide usage of antibiotics contributes to the increase in the prevalence of antibiotic-resistant Salmonella. Plasmids play a critical role in horizontal transfer of antibiotic resistance markers in Salmonella. This study aimed to screen and characterize plasmid profiles responsible for antibiotic resistance in Salmonella and ultimately to clarify the molecular mechanism of transferable plasmid-mediated antibiotic resistance. A total of 226 Salmonella isolates were examined for antimicrobial susceptibility by a disk diffusion method. Thirty-two isolates (14.2%) were resistant to at least one antibiotic. The presence of plasmid-mediated quinolone resistance (PMQR) genes and β-lactamase genes were established by PCR amplification. PCR-based replicon typing revealed that these 32 isolates represented seven plasmid incompatibility groups (IncP, HI2, A/C, FIIs, FIA, FIB, and I1), and the IncHI2 (59.4%) was predominant. Antibiotic resistance markers located on plasmids were identified through plasmid curing. Fifteen phenotypic variants were obtained with the curing efficiency of 46.9% (15/32). The cured plasmids mainly belong to the HI2 incompatibility group. The elimination of IncHI2 plasmids correlated with the loss of β-lactamase genes (blaOXA-1 and blaTEM-1) and PMQR genes (qnrA and aac(6')-Ib-cr). Both IncHI2 and IncI1 plasmids in a S. enterica serovar Indiana isolate SJTUF 10584 were lost by curing. The blaCMY -2-carrying plasmid pS10584 from SJTUF 10584 was fully sequenced. Sequence analysis revealed that it possessed a plasmid scaffold typical for IncI1 plasmids with the unique genetic arrangement of IS1294-ΔISEcp1-blaCMY -2-blc-sugE-ΔecnR inserted into the colicin gene cia. These data suggested that IncHI2 was the major plasmid lineage contributing to the dissemination of antibiotic resistance in Salmonella and the activity of multiple mobile genetic elements may contribute to antibiotic resistance evolution and dissemination between different plasmid replicons.
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Affiliation(s)
| | | | | | | | | | - Chunlei Shi
- Ministry of Science and Technology–United States Department of Agriculture Joint Research Center for Food Safety, School of Agriculture and Biology, Shanghai Jiao Tong UniversityShanghai, China
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Host-Specific Patterns of Genetic Diversity among IncI1-Iγ and IncK Plasmids Encoding CMY-2 β-Lactamase in Escherichia coli Isolates from Humans, Poultry Meat, Poultry, and Dogs in Denmark. Appl Environ Microbiol 2016; 82:4705-14. [PMID: 27235431 DOI: 10.1128/aem.00495-16] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/19/2016] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED CMY-2 is the most common plasmid-mediated AmpC β-lactamase in Escherichia coli isolates of human and animal origin. The aim of this study was to elucidate the epidemiology of CMY-2-producing E. coli in Denmark. Strain and plasmid relatedness was studied in 93 CMY-2-producing clinical and commensal E. coli isolates collected from 2006 to 2012 from humans, retail poultry meat, broilers, and dogs. Multilocus sequence typing (MLST), antimicrobial susceptibility testing, and conjugation were performed in conjunction with plasmid replicon typing, plasmid multilocus sequence typing (pMLST), restriction fragment length polymorphism (RFLP), and sequencing of selected blaCMY-2-harboring plasmids. MLST revealed high strain diversity, with few E. coli lineages occurring in multiple host species and sample types. blaCMY-2 was detected on plasmids in 83 (89%) isolates. Most (75%) of the plasmids were conjugative and did not (96%) cotransfer resistance to antimicrobials other than cephalosporins. The main replicon types identified were IncI1-Iγ (55%) and IncK (39%). Isolates from different host species mainly carried distinct plasmid subtypes. Seven of the 18 human isolates harbored IncI1-Iγ/sequence type 2 (ST2), IncI1-Iγ/ST12, or IncK plasmids highly similar to those found among animal isolates, even though highly related human and animal plasmids differed by nonsynonymous single nucleotide polymorphisms (SNPs) or insertion sequence elements. This study clearly demonstrates that the epidemiology of CMY-2 can be understood only by thorough plasmid characterization. To date, the spread of this β-lactam resistance determinant in Denmark is mainly associated with IncK and IncI1-Iγ plasmids that are generally distributed according to host-specific patterns. These baseline data will be useful to assess the consequences of the increasing human exposure to CMY-2-producing E. coli via animal sources. IMPORTANCE CMY-2 is the most common plasmid-mediated AmpC β-lactamase in Escherichia coli This β-lactamase is poorly inhibited by clavulanic acid and confers resistance to cephamycins, third-generation cephalosporins, and aztreonam. Furthermore, resistance to carbapenems has been reported in E. coli as a result of production of plasmid-encoded CMY-2 β-lactamase in combination with decreased outer membrane permeability. The gene encoding CMY-2 generally resides on transferable plasmids belonging to different incompatibility groups. The prevalence of CMY-2-mediated cephalosporin resistance in E. coli varies significantly depending on the geographical region and host. This study demonstrates that the epidemiology of CMY-2 can be understood only by thorough plasmid characterization. To date, the spread of this β-lactam resistance determinant in Denmark is mainly associated with IncK and IncI1-Iγ plasmids, which are generally distributed according to host-specific patterns. These data will be useful to assess the consequences of the increasing human exposure to CMY-2-producing E. coli via animal sources.
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A Helitron transposon reconstructed from bats reveals a novel mechanism of genome shuffling in eukaryotes. Nat Commun 2016; 7:10716. [PMID: 26931494 PMCID: PMC4778049 DOI: 10.1038/ncomms10716] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/14/2016] [Indexed: 02/08/2023] Open
Abstract
Helitron transposons capture and mobilize gene fragments in eukaryotes, but experimental evidence for their transposition is lacking in the absence of an isolated active element. Here we reconstruct Helraiser, an ancient element from the bat genome, and use this transposon as an experimental tool to unravel the mechanism of Helitron transposition. A hairpin close to the 3′-end of the transposon functions as a transposition terminator. However, the 3′-end can be bypassed by the transposase, resulting in transduction of flanking sequences to new genomic locations. Helraiser transposition generates covalently closed circular intermediates, suggestive of a replicative transposition mechanism, which provides a powerful means to disseminate captured transcriptional regulatory signals across the genome. Indeed, we document the generation of novel transcripts by Helitron promoter capture both experimentally and by transcriptome analysis in bats. Our results provide mechanistic insight into Helitron transposition, and its impact on diversification of gene function by genome shuffling. Helitron elements are proposed rolling-circle transposons in eukaryotic genomes, but experimental evidence for their transposition has been lacking. Here, Grabundzija et al. reconstruct an active Helitron from bats which they name Helraiser, and characterize its mechanism of transposition in cell-free reactions and in human cell cultures in vitro.
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Dominguez JE, Gutkind GO, Di Conza JA, Mercado EC. Occurrence of plasmidic AmpC β-lactamase in a Salmonella Typhimurium isolate of equine origin: First report of CMY-2 in animals in Argentina. J Glob Antimicrob Resist 2015; 3:315-316. [PMID: 27842885 DOI: 10.1016/j.jgar.2015.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 09/23/2015] [Accepted: 09/25/2015] [Indexed: 11/29/2022] Open
Affiliation(s)
- Johana E Dominguez
- Instituto de Patobiología, Centro de Investigación en Ciencias Veterinarias y Agronómicas, Instituto Nacional de Tecnología Agropecuaria, Nicolás Repetto y de los Reseros s/n, 1686 Hurlingham, provincia de Buenos Aires, Argentina
| | - Gabriel O Gutkind
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina
| | - José A Di Conza
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina
| | - Elsa C Mercado
- Instituto de Patobiología, Centro de Investigación en Ciencias Veterinarias y Agronómicas, Instituto Nacional de Tecnología Agropecuaria, Nicolás Repetto y de los Reseros s/n, 1686 Hurlingham, provincia de Buenos Aires, Argentina.
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