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Liu E, Prinzi AM, Borjan J, Aitken SL, Bradford PA, Wright WF. #AMRrounds: a systematic educational approach for navigating bench to bedside antimicrobial resistance. JAC Antimicrob Resist 2023; 5:dlad097. [PMID: 37583473 PMCID: PMC10424884 DOI: 10.1093/jacamr/dlad097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023] Open
Abstract
Antimicrobial resistance (AMR) continues to serve as a major global health crisis. Clinicians practising in this modern era are faced with ongoing challenges in the therapeutic management of patients suffering from antimicrobial-resistant infections. A strong educational understanding and synergistic application of clinical microbiology, infectious disease and pharmacological concepts can assist the adventuring clinician in the navigation of such cases. Important items include mobilizing laboratory testing for pathogen identification and susceptibility data, harnessing an understanding of intrinsic pathogen resistance, acknowledging epidemiological resistance trends, recognizing acquired AMR mechanisms, and consolidating these considerations when constructing an ideal pharmacological plan. In this article, we outline a novel framework by which to systematically approach clinical AMR, encourage AMR-related education and optimize therapeutic decision-making in AMR-related illnesses.
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Affiliation(s)
- Elaine Liu
- Division of Pharmacy and Division of Infectious Diseases, The Johns Hopkins Bayview Medical Center, 5200 Eastern Avenue, Baltimore, MD, USA
| | - Andrea M Prinzi
- US Medical Affairs, bioMérieux, Salt Lake City, UT 84104, USA
| | - Jovan Borjan
- Division of Pharmacy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Samuel L Aitken
- Department of Pharmacy, Michigan Medicine, Ann Arbor, MI, USA
| | | | - William F Wright
- Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, 733 North Broadway, Baltimore, MD, USA
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Antimicrobial resistance and genetic background of non-typhoidal Salmonella enterica strains isolated from human infections in São Paulo, Brazil (2000-2019). Braz J Microbiol 2022; 53:1249-1262. [PMID: 35446010 PMCID: PMC9433476 DOI: 10.1007/s42770-022-00748-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 03/30/2022] [Indexed: 11/02/2022] Open
Abstract
Salmonella enterica causes Salmonellosis, an important infection in humans and other animals. The number of multidrug-resistant (MDR) phenotypes associated with Salmonella spp. isolates is increasing worldwide, causing public health concern. Here, we aim to characterize the antimicrobial-resistant phenotype of 789 non-typhoidal S. enterica strains isolated from human infections in the state of São Paulo, Brazil, along 20 years (2000-2019). Among the non-susceptible isolates, 31.55, 14.06, and 13.18% were resistant to aminoglycosides, tetracycline, and β-lactams, respectively. Moreover, 68 and 11 isolates were considered MDR and Extended Spectrum β-Lactamase (ESBL) producers, respectively, whereas one isolate was colistin-resistant. We selected four strains to obtain a draft of the Genome Sequence; one S. Infantis (ST32), one S. Enteritidis (ST11), one S. I 4,[5],12:i:- (ST19), and one S. Typhimurium (ST313). Among them, three presented at least one of the following antimicrobial resistance genes (AMR) linked to mobile DNA: blaTEM-1B, dfrA1, tetA, sul1, floR, aac(6')-laa, and qnrE1. This is the first description of the plasmid-mediated quinolone resistance (PMQR) gene qnrE1 in a clinical isolate of S. I 4,[5],12:i:-. The S. Typhimurium is a colistin-resistant isolate, but did not harbor mcr genes, but it presented mutations within the mgrB, pmrB, and pmrC regions that might be linked to the colistin-resistant phenotype. The virulence pattern of the four isolates resembled the virulence pattern of the highly pathogenic S. Typhimurium UK-1 reference strain in assays involving the in vivo Galleria mellonella model. In conclusion, most isolates studied here are susceptible, but a small percentage present an MDR or ESBL-producer and pathogenic phenotype. Sequence analyses revealed plasmid-encoded AMR genes, such as β-lactam and fluoroquinolone resistance genes, indicating that these characteristics can be potentially disseminated among other bacterial strains.
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Dolatyar Dehkharghani A, Haghighat S, Rahnamaye Farzami M, Rahbar M, Douraghi M. Clonal Relationship and Resistance Profiles Among ESBL-Producing Escherichia coli. Front Cell Infect Microbiol 2021; 11:560622. [PMID: 34249771 PMCID: PMC8261245 DOI: 10.3389/fcimb.2021.560622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 05/19/2021] [Indexed: 11/13/2022] Open
Abstract
AmpC β-lactamases hydrolyze all β-lactams except cefepime and carbapenems. The study of AmpC-producing E. coli has high priority for the infection control committee. This research is aimed to investigate the resistant urinary AmpC-generating E. coli isolates and identify their genetic variety. Some 230 E. coli isolates from patients suffering urinary tract infection symptoms were studied in 2017-2018 to assess their susceptibility toward antimicrobial agents. AmpC gene was evaluated by PCR and molecular typing using the 10-loci MLVA method. MLVA images were examined by BioNumerics 6.6 software through the use of the UPGMA algorithms. Thirty-eight AmpC-generating E. coli isolates were detected. The most abundant determinant was blaCIT and blaEBC , blaFOX , and blaDHA had the next ranks, respectively. Six major clusters and a singleton were identified by MLVA. AmpC beta-lactamases in urinary isolates of E. coli in the hospital under study and high rate of additional resistance to gentamicin, cotrimoxazole and ciprofloxacin. The most frequent gene determinant of AmpC beta-lactamase was blaCIT and vary depending on time and geographical location.
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Affiliation(s)
- Alireza Dolatyar Dehkharghani
- Department of Microbiology, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Setareh Haghighat
- Department of Microbiology, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Marjan Rahnamaye Farzami
- Department of Microbiology, Research Center of Reference Health Laboratory, Ministry of Health and Medical Education, Tehran, Iran
| | - Mohammad Rahbar
- Department of Microbiology, Research Center of Reference Health Laboratory, Ministry of Health and Medical Education, Tehran, Iran
| | - Masoumeh Douraghi
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Deng S, Wu J, Zhang K, Li Y, Yang L, Hu D, Jin Y, Hao Y, Wang X, Liu Y, Liu H, Chen Y, Xie M. Fluorescence Resonance Energy Transfer-Mediated Immunosensor Based on Design and Synthesis of the Substrate of Amp Cephalosporinase for Biosensing. Anal Chem 2019; 91:11316-11323. [DOI: 10.1021/acs.analchem.9b02427] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Suimin Deng
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Jing Wu
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Kaina Zhang
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Yike Li
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Lina Yang
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Dehua Hu
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Yuhao Jin
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Yun Hao
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Xiangfeng Wang
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Yuan Liu
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Hailing Liu
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
| | - Yiping Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei China
| | - Mengxia Xie
- Analytical and Testing Center of Beijing Normal University, Beijing 100875, China
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Sakanashi D, Miyazaki N, Kawamoto Y, Ohno T, Yamada A, Koita I, Suematsu H, Hagihara M, Asai N, Koizumi Y, Yamagishi Y, Mikamo H. A novel disk-based detection method with superior sensitivity for β-lactamase production in third-generation cephalosporin-resistant Enterobacteriaceae. J Infect Chemother 2019; 25:330-336. [PMID: 30797690 DOI: 10.1016/j.jiac.2018.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Current phenotypic methods for extended-spectrum β-lactamase (ESBL), AmpC β-lactamase (AmpC), and carbapenemases fail to detect isolates that co-produce other classes of β-lactamases. In this study, we have developed a novel assay (Applied Multiplex Disk Method: AMU-DM) for the phenotypic detection and identification of β-lactamases produced by Enterobacteriaceae. METHODS We evaluated the performance of the method by comparison with PCR results for 78 Enterobacteriaceae clinical isolates that were positive by the ESBL screening test and negative by the ESBL confirmation test. Additionally, one NCTC strain and four ATCC strains were also included in the test population for the study as reference. RESULTS For 79/83 (95%) isolates tested, the AMU-DM results matched those obtained by PCR. The concordance rates were 31/31 (100%), 11/11 (100%), 3/3 (100%), 0/1 (0%), 15/15 (100%), 16/19 (84%), and 3/3 (100%) for AmpC, ESBL and AmpC co-production, Klebsiella pneumoniae carbapenemase (KPC), KPC and ESBL co-production, metallo β-lactamase (MBL), MBL and ESBL co-production, and MBL and AmpC co-production, respectively. CONCLUSION The AMU-DM is convenient to perform, economical, and highly sensitive in identifying ESBLs, AmpCs, and carbapenemases. Our method may be useful in clinical settings for the implementation of relevant infection control measures and for surveillance purposes.
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Affiliation(s)
- Daisuke Sakanashi
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan
| | - Narimi Miyazaki
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan
| | - Yuzuka Kawamoto
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan
| | - Tomoko Ohno
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan
| | - Atsuko Yamada
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan
| | - Isao Koita
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan
| | - Hiroyuki Suematsu
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan
| | - Mao Hagihara
- Department of Molecular Epidemiology and Biomedical Sciences, Aichi Medical University, Japan
| | - Nobuhiro Asai
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan; Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Japan
| | - Yusuke Koizumi
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan; Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Japan
| | - Yuka Yamagishi
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan; Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Japan
| | - Hiroshige Mikamo
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan; Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Japan.
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Zorgani A, Daw H, Sufya N, Bashein A, Elahmer O, Chouchani C. Co-Occurrence of Plasmid-Mediated AmpC β-Lactamase Activity Among Klebsiella pneumoniae and Escherichia Coli. Open Microbiol J 2017; 11:195-202. [PMID: 29151996 PMCID: PMC5678236 DOI: 10.2174/1874285801711010195] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/17/2017] [Accepted: 08/13/2017] [Indexed: 11/22/2022] Open
Abstract
Introduction: Extended-spectrum β-lactamases (ESBLs), including the AmpC type, are important mechanisms of resistance among Klebsiella pneumoniae and Escherichia coli isolates. Objective: The aim of the study was to investigate the occurrence of AmpC-type β-lactamase producers isolated from two hospitals in Tripoli, Libya. Methods: All clinical isolates (76 K. pneumoniae and 75 E. coli) collected over two years (2013-2014) were evaluated for susceptibility to a panel of antimicrobials and were analyzed phenotypically for the ESBL and AmpC phenotype using E-test and ESBL and AmpC screen disc test. Both ESBL and AmpC-positive isolates were then screened for the presence of genes encoding plasmid-mediated AmpC β-lactamases by polymerase chain reaction (PCR). Results: Of the K. pneumoniae and E. coli tested, 75% and 16% were resistant to gentamicin, 74% and 1.3% to imipenem, 71% and 12% to cefoxitin, 80% and 12% to cefepime, 69% and 22.6% to ciprofloxacin, respectively. None of the E. coli isolates were multidrug resistant compared with K. pneumoniae (65.8%). K. pneumoniae ESBL producers were significantly higher (85.5%) compared with (17.3%) E. coli isolates (P <0.0001, OR=4.93). Plasmid-mediated AmpC genes were detected in 7.9% of K. pneumoniae, and 4% E. coli isolates. There was low agreement between phenotypic and genotypic methods, phenotypic testing underestimated detection of AmpC enzyme and did not correlate well with molecular results. The gene encoding CMY enzyme was the most prevalent (66.6%) of AmpC positive isolates followed by MOX, DHA and EBC. Only one AmpC gene was detected in 5/9 isolates, i.e, blaCMY (n=3), blaMOX (n=1), blaDHA (n=1). However, co-occurrence of AmpC genes were evident in 3/9 isolates with the following distribution:
blaCMY and blaEBC (n=1), and blaCMY and blaMOX (n=2). Neither blaFOX nor blaACC was detected in all tested isolates. All AmpC positive strains were resistant to cefoxitin and isolated from patients admitted to intensive care units. Conclusion: Further studies are needed for detection of other AmpC variant enzyme production among such isolates. Continued surveillance and judicious antibiotic usage together with the implementation of efficient infection control measures are absolutely required.
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Affiliation(s)
- Abdulaziz Zorgani
- Medical Microbiology and Immunology Department, Faculty of Medicine, University of Tripoli, Tripoli, Libya.,National Centre for Disease Control, Tripoli, Libya
| | - Hiyam Daw
- Medical Microbiology and Immunology Department, Faculty of Pharmacy, University of Tripoli, Tripoli, Libya
| | - Najib Sufya
- Medical Microbiology and Immunology Department, Faculty of Pharmacy, University of Tripoli, Tripoli, Libya
| | - Abdullah Bashein
- Biochemistry Department, Faculty of Medicine, University of Tripoli, Tripoli, Libya.,National Centre for Disease Control, Tripoli, Libya
| | - Omar Elahmer
- National Centre for Disease Control, Tripoli, Libya.,Faculty of Medical Technology, University of Tripoli, Tripoli, Libya
| | - Chedly Chouchani
- Laboratoire de Microorganismes et Biomolécules Actives Faculté des Sciences de Tunis, Université de Tunis El-Manar, 2098 El-Manar II, Tunisie.,Laboratoire de Recherche Sciences et Technologies de l'Environnement, Institut Supérieur des Sciences et Technologies de l'Environnement de Borj-Cedria, Université de Carthage, Technopôle de Borj-Cedria, BP-1003, Hammam-Lif 2050, Tunisie
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Yanat B, Dali Yahia R, Yazi L, Machuca J, Díaz-De-Alba P, Touati A, Pascual Á, Rodríguez-Martínez JM. Occurrence of the Plasmid-Mediated Fluoroquinolone Resistance qepA1 Gene in Two Clonal Clinical Isolates of CTX-M-15-Producing Escherichia coli from Algeria. Microb Drug Resist 2016; 23:497-499. [PMID: 27736309 DOI: 10.1089/mdr.2016.0135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
QepA is a plasmid-mediated quinolone resistance determinant of low prevalence described worldwide, mainly in Enterobacteriaceae. This study describes, for the first time in Algeria, two clonally related, QepA-producing Escherichia coli clinical isolates positive for CTX-M-15. The clonal spread of these multidrug-resistant isolates is a major public health concern.
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Affiliation(s)
- Betitera Yanat
- 1 Laboratoire d'Ecologie Microbienne, FSNV, Université de Bejaia , Bejaia, Algeria .,2 Department of Microbiology, University of Seville , Seville, Spain
| | - Radia Dali Yahia
- 3 Service de Bactériologie Etablissement Hospitalier et Universitaire d'Oran, Université d'Oran Faculté de Médecine , Oran, Algeria
| | - Leila Yazi
- 3 Service de Bactériologie Etablissement Hospitalier et Universitaire d'Oran, Université d'Oran Faculté de Médecine , Oran, Algeria
| | - Jesús Machuca
- 2 Department of Microbiology, University of Seville , Seville, Spain .,4 Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III , Madrid, Spain .,5 Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena , Sevilla, Spain
| | - Paula Díaz-De-Alba
- 5 Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena , Sevilla, Spain
| | - Abdelaziz Touati
- 1 Laboratoire d'Ecologie Microbienne, FSNV, Université de Bejaia , Bejaia, Algeria
| | - Álvaro Pascual
- 2 Department of Microbiology, University of Seville , Seville, Spain .,4 Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III , Madrid, Spain .,5 Unidad Intercentros de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena , Sevilla, Spain
| | - José-Manuel Rodríguez-Martínez
- 2 Department of Microbiology, University of Seville , Seville, Spain .,4 Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III , Madrid, Spain
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Rocha DAC, Campos JC, Passadore LF, Sampaio SCF, Nicodemo AC, Sampaio JLM. Frequency of Plasmid-Mediated AmpC β-Lactamases in Escherichia coli Isolates from Urine Samples in São Paulo, Brazil. Microb Drug Resist 2015; 22:321-7. [PMID: 26670152 DOI: 10.1089/mdr.2015.0190] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Plasmid-mediated AmpC β-lactamases (PMACBLs) in Enterobacteriaceae encode resistance to third-generation cephalosporins, and these can mediate carbapenem resistance when associated with porin loss. However, no standardized phenotypic method is available for detecting these enzymes in the clinical microbiology laboratory. Limited data are available concerning the frequency of PMACBLs in Enterobacteriaceae in Brazil. This study was conducted in response to an increased cefoxitin (CFO) resistance rate of 3.7% in Escherichia coli isolates from urine samples from patients with suspected urinary tract infections during 2010. We collected 2,266 E. coli isolates prospectively during January 2012. A total of 109 (4.8%) isolates were nonsusceptible to CFO. These strains were further examined using multiplex PCR for the presence of genes encoding PMACBLs and using inhibitor assays with CFO and ceftazidime (CAZ) disks with and without phenylboronic acid. Pulsed-field gel electrophoresis was used to evaluate clonal dissemination. Genes encoding PMACBLs were detected in 1.8% of the isolates from inpatients and 0.46% of isolates from outpatients. The most prevalent gene was blaCMY-2 and blaCMY-4 was also detected. The phenotypic analysis showed 100% sensitivity and specificity for CMY-2 and CMY-4 when CFO-resistant isolates with a minimum zone diameter difference of 5 mm for CAZ or CAZ and CFO were considered positive. Although most of the isolates were nonclonal, one clonal group with two isolates was observed. Thus, the most frequent PMACBL in E. coli from São Paulo, Brazil is CMY-2, and both clonal and plasmid-mediated dissemination occur.
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Affiliation(s)
- Darlan Augusto Costa Rocha
- 1 Clinical Analysis and Toxicology Department, School of Pharmacy, University of São Paulo , São Paulo, Brazil
| | - Juliana Coutinho Campos
- 1 Clinical Analysis and Toxicology Department, School of Pharmacy, University of São Paulo , São Paulo, Brazil
| | | | | | - Antonio Carlos Nicodemo
- 4 Department of Infectious and Parasitic Diseases, University of São Paulo , Medical School, São Paulo, Brazil
| | - Jorge Luiz Mello Sampaio
- 1 Clinical Analysis and Toxicology Department, School of Pharmacy, University of São Paulo , São Paulo, Brazil .,5 Fleury Diagnostic Medicine-Microbiology Section , São Paulo, Brazil
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Al-Bayssari C, Dabboussi F, Hamze M, Rolain JM. Detection of expanded-spectrum β-lactamases in Gram-negative bacteria in the 21st century. Expert Rev Anti Infect Ther 2015; 13:1139-58. [PMID: 26162631 DOI: 10.1586/14787210.2015.1066247] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Emerging β-lactamase-producing-bacteria (ESBL, AmpC and carbapenemases) have become a serious problem in our community due to their startling spread worldwide and their ability to cause infections which are difficult to treat. Diagnosis of these β-lactamases is of clinical and epidemiological interest. Over the past 10 years, several methods have been developed aiming to rapidly detect these emerging enzymes, thus preventing their rapid spread. In this review, we describe the range of screening and detection methods (phenotypic, molecular and other) for detecting these β-lactamases but also whole genome sequencing as a tool for detecting the genes encoding these enzymes.
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Affiliation(s)
- Charbel Al-Bayssari
- Laboratoire Microbiologie Santé et Environnement (LMSE), Centre Azm pour la Recherche en Biotechnologie et ses Applications, Ecole Doctorale de Sciences et de Technologie, Université Libanaise, Tripoli, Liban
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10
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How to detect carbapenemase producers? A literature review of phenotypic and molecular methods. J Microbiol Methods 2014; 107:106-18. [DOI: 10.1016/j.mimet.2014.09.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 01/04/2023]
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Phenotypic and molecular characterization of plasmid mediated AmpC β-lactamases among Escherichia coli, Klebsiella spp., and Proteus mirabilis isolated from urinary tract infections in Egyptian hospitals. BIOMED RESEARCH INTERNATIONAL 2014; 2014:171548. [PMID: 25003107 PMCID: PMC4070535 DOI: 10.1155/2014/171548] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/16/2014] [Accepted: 05/18/2014] [Indexed: 11/21/2022]
Abstract
The incidence of resistance by Enterobacteriaceae to β-lactam/β-lactamase inhibitors combination is increasing in Egypt. Three phenotypic techniques, comprising AmpC disk diffusion and inhibition dependent methods using phenylboronic acid (PBA) and cloxacillin, were compared to PCR based method for detection of plasmid mediated AmpC β-lactamase in common urinary tract isolates. A total of 143 isolates, including E. coli, Klebsiella pneumonia, and Proteus mirabilis, were collected from urinary tract infections cases in Egyptian hospitals. Plasmid encoded AmpC genes were detected by PCR in 88.46% of cefoxitin resistant isolates. The most prevalent AmpC gene family was CIT including CMY-2, CMY-4, and two CMY-2 variants. The second prevalent gene was DHA-1 which was detected in E. coli and Klebsiella pneumonia. The genes EBC, FOX, and MOX were also detected but in small percentage. Some isolates were identified as having more than one pAmpC gene. The overall sensitivity and specificity of phenotypic tests for detection of AmpC β-lactamase showed that AmpC disk diffusion and inhibition dependent method by cloxacillin were the most sensitive and the most specific disk tests. PCR remains the gold standard for detection of AmpC β-lactamases. This study represents the first report of CMY-2 variants of CMY-42 and CMY-102 β-lactamase-producing E. coli, Klebsiella pneumonia, and Proteus mirabilis isolates in Egypt.
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Maraskolhe D, Deotale V, Mendiratta D, Narang P. Comparision of Three Laboratory Tests for Detection of AmpC β Lactamases in Klebsiella Species and E. Coli. J Clin Diagn Res 2014; 8:DC05-8. [PMID: 25120977 PMCID: PMC4129299 DOI: 10.7860/jcdr/2014/8256.4432] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 04/19/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND OBJECTIVE AmpC β lactamases are one of the important causes of drug resistance in gram negative bacteria. Failure to detect these enzymes in the laboratory has contributed to therapeutic failures but there are till date no standard guideline available. This study was therefore undertaken to evaluate three phenotypic laboratory tests and the inhibitors used in two of the tests to detect AmpC β lactamases produced by E. coli and Klebsiella species as they are most commonly isolated organisms. METHODS E. coli and Klebsiella isolates from different clinical samples were tested for ESBLs production as per CLSI guidelines and excluded from the study. The non-ESBLs isolates were then screened for AmpC β lactamases production, by cefoxitin and then confirmed by three different methods, i.e., Disc Potentiation Test (DPT) , Double Disc Synergy Test (DDST) and Modified Three Dimensional Test (M3DT) which in the absence of molecular methods, was taken as the gold standard. Boronic acid and cloxacillin were used as inhibitory agents in the Disc Potentiation and Double Disc synergy Tests. RESULTS A total of 2,933 isolates were tested out of which 165 isolates were detected as non ESBLs producers,135 (81.82%) when screened for AmpC β lactamases based on resistance to cefoxitin were labelled as positive. 30 (18.18%) cefoxitin sensitive isolates were labelled as probably non AmpC producers . M3DT, in addition to detecting all the 135 (100%) cefoxitin resistant isolates, also detected 5 (16.67%) cefoxitin sensitive isolates as AmpC producers. Other phenotypic tests, DPT and DDST with different inhibitors like boronic acid and cloxacillin in different potencies were all found to be less sensitive. The best results among these two methods were obtained with DDST using cloxacillin 500μg. CONCLUSION In the absence of recommended guidelines for AmpC detection, the study reports, among the tests performed, M3DT as the best phenotypic method for AmpC confirmation, as it is not only the most sensitive but also specific test for AmpC as it rules out the resistance due to other mechanisms like the porin channel.
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Affiliation(s)
- D.L. Maraskolhe
- Assistant Professor, Department of Microbiology,MGIMS, Sevagram, India
| | - V.S. Deotale
- Professor, Department of Microbiology,MGIMS, Sevagram, India
| | - D.K. Mendiratta
- Professor and Head, Department of Microbiology,MGIMS, Sevagram, India
| | - P. Narang
- Director and Professor, Department of Microbiology,MGIMS, Sevagram, India
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Wassef M, Behiry I, Younan M, El Guindy N, Mostafa S, Abada E. Genotypic Identification of AmpC β-Lactamases Production in Gram-Negative Bacilli Isolates. Jundishapur J Microbiol 2014; 7:e8556. [PMID: 25147649 PMCID: PMC4138665 DOI: 10.5812/jjm.8556] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 03/09/2013] [Accepted: 03/17/2013] [Indexed: 11/16/2022] Open
Abstract
Background: AmpC type β-lactamases are commonly isolated from extended-spectrum Cephalosporin-resistant Gram-negative bacteria. Also, resistance appeared in bacterial species not naturally producing AmpC enzymes. Therefore, a standard test for the detection of the plasmid-mediated AmpC enzyme and new breakpoints for extended spectrum Cephalosporins are urgently necessary. Objectives: To detect plasmid and chromosomal mediated AmpC-β-lactamases in Gram negative bacteria in community and hospital acquired infections. Materials and Methods: 1073 Gram negative clinical isolates were identified by the conventional methods and were screened for AmpC production using Cefoxitin discs. Confirmatory phenotypic identifications were done for the Cefoxitin-resistant isolates using Boronic Acid for combined and double disc synergy tests, Cloxacillin based double disc synergy test, and induction tests. The genotypic identification of plasmid-mediated AmpC was done using multiplex PCR. ESBL production was also screened by discs of Ceftazidime and Cefotaxime with and without Clavulanic Acid (10 μg). Results: The AmpC-producing isolates among all identified Gram negative bacilli were 5.8% (62/1073) as detected by screening disc diffusion methods, where 72% were positive for AmpC by combined disc method (Cefotetan and Boronic Acid), 56.5% were positive by each of Boronic Acid and Cloxacillin double disc synergy tests, 35.5% were positive by the induction test, and 25.8% were plasmid-mediated AmpC β-lactamase producers by the multiplex PCR. Plasmid-mediated AmpC genes retrieved, belonged to the families (MOX, FOX, EBC and CIT). ESBL producers were found in 26 (41.9%) isolates, 15 (57%) of which also produced AmpC. Isolates caused hospital acquired infections were (53/62); of which (39/62) were AmpC producers. While only (8/62) of the isolates caused community-acquired infections, were AmpC producers, and (1.6%) (1/62) were non AmpC producer. Conclusions: The AmpC β-lactamases detection tests had to be included in the routine microbiology workup of Gram negative bacteria, namely Cefoxitin as a screening test, combined Boronic Acid disc test with Cefotetan, followed by synergy tests and finally by the induction test for phenotypic identifications. Multiplex PCR can successfully detect the plasmid AmpC genes.
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Affiliation(s)
- Mona Wassef
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Giza, Egypt
| | - Iman Behiry
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Giza, Egypt
| | - Mariam Younan
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Giza, Egypt
| | - Nancy El Guindy
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Giza, Egypt
| | - Sally Mostafa
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Giza, Egypt
| | - Emad Abada
- Department of Botany and Microbiology, Faculty of science, Helwan University, Cairo, Egypt
- Department of Biology, Faculty of Science, Jazan University, Jazan, KSA
- Corresponding author: Emad Abada, Department of Botany and Microbiology, Faculty of Science, Helwan University, Ain Helwan, Cairo, Egypt. Tel:+20-225552468, Fax:+20-225552468, E-mail:
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A conserved virulence plasmidic region contributes to the virulence of the multiresistant Escherichia coli meningitis strain S286 belonging to phylogenetic group C. PLoS One 2013; 8:e74423. [PMID: 24086343 PMCID: PMC3784414 DOI: 10.1371/journal.pone.0074423] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 08/01/2013] [Indexed: 12/31/2022] Open
Abstract
Recent isolation of the non-K1 Escherichia coli neonatal meningitis strain S286, belonging to phylogroup C, which is closely related to major group B1, and producing an extended-spectrum beta-lactamase, encouraged us to seek the genetic determinants responsible for its virulence. We show that S286 belongs to the sequence O type ST23O78 and harbors 4 large plasmids. The largest one, pS286colV (~120 kb), not related to resistance, contains genes characteristic of a Conserved Virulence Plasmidic (CVP) region initially identified in B2 extra-intestinal avian pathogenic E. coli (APEC) strains and in the B2 neonatal meningitis E. coli strain S88. The sequence of this CVP region has a strong homology (98%) with that of the recently sequenced plasmid pChi7122-1 of the O78 APEC strain Chi7122. A CVP plasmid-cured variant of S286 was less virulent than the wild type strain in a neonatal rat sepsis model with a significant lower level of bacteremia at 24 h (4.1 ± 1.41 versus 2.60 ± 0.16 log CFU/ml, p = 0.001) and mortality. However, the mortality in the model of adult mice was comparable between wild type and variant indicating that pS286colV is not sufficient by itself to fully explain the virulence of S286. Gene expression analysis of pS286colV in iron depleted environment was very close to that of pS88, suggesting that genes of CVP region may be expressed similarly in two very different genetic backgrounds (group C versus group B2). Screening a collection of 178 human A/B1 extraintestinal pathogenic E. coli (ExPEC) strains revealed that the CVP region is highly prevalent (23%) and MLST analysis indicated that these CVP positive strains belong to several clusters and mostly to phylogroup C. The virulence of S286 is explained in part by the presence of CVP region and this region has spread in different clusters of human A/B1 ExPEC, especially in group C.
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Detection of β-lactamase residues in milk by sandwich ELISA. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:2688-98. [PMID: 23812026 PMCID: PMC3734450 DOI: 10.3390/ijerph10072688] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/09/2013] [Accepted: 06/17/2013] [Indexed: 01/08/2023]
Abstract
β-Lactamase residues in milk represent a public health risk. The cylinder plate detection method, which is based on bacterial growth, is laborious and time consuming. In this study, 15 monoclonal antibodies (mAbs) were selected against Temoneira (TEM) 1 β-lactamase. A sandwich enzyme-linked immunosorbent assay (ELISA) based on an optimum mAb pair was developed and validated for the detection of β-lactamase. The limit of detection and linear dynamic range of the method were 4.17 ng/mL and 5.5–100 ng/mL, respectively. β-Lactamase recovery in pure milk was 96.82–103.13%. The intra- and inter-assay coefficients of variation were 6.21–7.38% and 12.96–13.74%, respectively. Our developed sandwich ELISA can be used as a rapid detection method of β-lactamase in milk.
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Rawat V, Singhai M, Kumar A, Jha PK, Goyal R. Bacteriological and resistance profile in isolates from diabetic patients. NORTH AMERICAN JOURNAL OF MEDICAL SCIENCES 2012; 4:563-8. [PMID: 23181227 PMCID: PMC3503374 DOI: 10.4103/1947-2714.103315] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Diabetes mellitus has become a global epidemic illness and poses a threat for development of resistant bacterial infections. AIM This study was aimed to know the bacteriological and resistance profile of isolates obtained from diabetic patients. MATERIALS AND METHODS The bacterial isolates obtained from various samples of diabetic patients admitted in medicine department in 6-month period were identified and tested for antibiotic susceptibility. The extended spectrum beta-lactamases (ESβL), AmpC, and metallo-beta-lactamases (MβL) enzymes were detected in gram-negative bacilli. Methicillin, macrolide-lincosamide-streptogramin (MLS), and linezolid resistance in Staphylococcus spp. were detected. High-level aminoglycoside resistance (HLAR) in Enterococcus spp. was also tested. RESULTS In all, 38 of 125 diabetic patients (30.4%) had bacterial infection, 18 patients had wound infections, 18 had urinary tract infections (UTIs), and 2 had respiratory tract infections. Escherichia coli among gram-negative bacteria and Staphylococcus aureus among gram-positive bacteria were the predominant pathogens. 32.5% gram-negative bacilli were AmpC producers, 37.5% were MβL producers, and 40% were ESβL producers. Methicillin and MLS resistance was found in 50% and 33.3% isolates of Staphylococcus spp., respectively. HLAR resistance was alarming in Enterococcus spp. Polymyxin among gram-negative bacteria and vancomycin for gram-positive bacteria were the last resort with highest susceptibility rates to treat infections among diabetic patients. CONCLUSION Resistant bacterial infections in diabetic patients are common. The presence of various resistance mechanisms in isolates of our study shows that therapeutic failure can occur if empirical prescription is unsubstantiated.
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Affiliation(s)
- Vinita Rawat
- Department of Microbiology, Government Medical College, Haldwani, Uttarakhand, India
| | - Monil Singhai
- Department of Microbiology, Government Medical College, Haldwani, Uttarakhand, India
| | - Ashok Kumar
- Department of Medicine, Government Medical College, Haldwani, Uttarakhand, India
| | - Pawan Kumar Jha
- Department of Surgery, Government Medical College, Haldwani, Uttarakhand, India
| | - Rajeev Goyal
- Department of Biochemistry, Government Medical College, Haldwani, Uttarakhand, India
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Ben Aissa M, Herteg Fernea A, Bouraoui H, Ben Aissa R, Mercuri PS, Manai M. Molecular characterization of plasmid-encoded ACC-1a4 β-lactamase produced by Salmonella strains isolated from water in a Tunisian hospital. ANN MICROBIOL 2012. [DOI: 10.1007/s13213-011-0221-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Detection of AmpC beta-lactamase in Escherichia coli: comparison of three phenotypic confirmation assays and genetic analysis. J Clin Microbiol 2011; 49:2924-32. [PMID: 21653764 DOI: 10.1128/jcm.00091-11] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two mechanisms account for AmpC activity in Escherichia coli, namely, mutations in the ampC promoter and attenuator regions resulting in ampC overexpression and acquisition of plasmid-carried ampC genes. In this study, we analyzed 51 clinical E. coli isolates with reduced susceptibility to amoxicillin-clavulanic acid, piperacillin-tazobactam, or extended-spectrum cephalosporins for the presence of AmpC production. Three phenotypic AmpC confirmation assays (cefoxitin-cloxacillin disk diffusion test, cefoxitin-EDTA disk diffusion test, and AmpC Etest) were compared for the detection of AmpC activity. All 51 isolates were characterized genetically by mutational analysis of the chromosomal ampC promoter/attenuator region and by PCR detection of plasmid-carried ampC genes. Altogether, 21/51 (41%) E. coli isolates were considered true AmpC producers. AmpC activity due to chromosomal ampC promoter/attenuator mutations was found in 12/21 strains, and plasmid-carried ampC genes were detected in 8/21 isolates. One strain contained both ampC promoter mutations and a plasmid-carried ampC gene. All three phenotypic tests were able to detect the majority (>90%) of AmpC-positive strains correctly. Cefoxitin resistance was found to be a discriminative parameter, detecting 20/21 AmpC-producing strains. Susceptibility to extended-spectrum cephalosporins, e.g., ceftriaxone, ceftazidime, and cefotaxime, was found in 9 of the 21 AmpC-positive strains. Considering the elevated zone diameter breakpoints of the 2010 CLSI guidelines, 2/21 AmpC-positive strains were categorized as susceptible to extended-spectrum cephalosporins.
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Practical approach for reliable detection of AmpC beta-lactamase-producing Enterobacteriaceae. J Clin Microbiol 2011; 49:2798-803. [PMID: 21632895 DOI: 10.1128/jcm.00404-11] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this prospective study all Enterobacteriaceae isolates (n = 2,129) recovered in the clinical microbiology laboratory during October 2009 to April 2010 were analyzed for AmpC production. Clinical and Laboratory Standards Institute (CLSI) cefoxitin and cefotetan susceptibility breakpoints and CLSI critical ESBL diameters were used to screen for potential AmpC producers. In total, 305 isolates (211 potential AmpC producers and 94 AmpC screen-negative isolates as a control group) were further analyzed by multiplex PCR for the detection of plasmid-encoded ampC beta-lactamase genes and by ampC promoter sequence analysis (considered as the gold standard). Cefoxitin and cefotetan were assessed as primary screening markers. The sensitivities of cefoxitin and cefotetan for the detection of AmpC production were 97.4 and 52.6%, respectively, and the specificities were 78.7 and 99.3%, respectively. As a phenotypic confirmation test, the Etest AmpC and the cefoxitin-cloxacillin double-disk synergy method (CC-DDS) were compared. The sensitivities for the Etest AmpC and the CC-DDS method were 77.4 and 97.2%, respectively, and the specificity was 100% for both methods. The results of the Etest AmpC were inconclusive for 10 isolates. With the CC-DDS method 2 inconclusive results were observed. Based on this study, we propose a comprehensive diagnostic flow chart for the detection of AmpC production consisting of a simple phenotypic screening and a single phenotypic confirmation test with inconclusive results being resolved by molecular analysis. For the proposed flow chart using (i) cefoxitin as a screening marker for AmpC production, (ii) the CC-DDS method as phenotypic confirmation, and (iii) molecular methods in case of inconclusive results, the sensitivity and specificity for AmpC detection would have been 97.4 and 100%, respectively, with respect to the studied isolates. The phenotypic methods used in the AmpC algorithm are simple to perform and easy to implement in the diagnostic laboratory.
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CMY-2, CMY-8b, and DHA-1 plasmid-mediated AmpC β-lactamases among clinical isolates of Escherichia coli and Klebsiella pneumoniae from a university hospital, Thailand. Diagn Microbiol Infect Dis 2010; 68:271-7. [DOI: 10.1016/j.diagmicrobio.2010.06.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 06/02/2010] [Accepted: 06/25/2010] [Indexed: 11/21/2022]
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Pitout J, Le P, Moore K, Church D, Gregson D. Detection of AmpC β-lactamases in Escherichia coli, Klebsiella spp., Salmonella spp. and Proteus mirabilis in a regional clinical microbiology laboratory. Clin Microbiol Infect 2010; 16:165-70. [DOI: 10.1111/j.1469-0691.2009.02756.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Källman O, Giske CG, Samuelsen Ø, Wretlind B, Kalin M, Olsson-Liljequist B. Interplay of Efflux, Impermeability, and AmpC Activity Contributes to Cefuroxime Resistance in Clinical, Non-ESBL-Producing Isolates ofEscherichia coli. Microb Drug Resist 2009; 15:91-5. [DOI: 10.1089/mdr.2009.0883] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Owe Källman
- Clinical Microbiology, MTC, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Christian G. Giske
- Clinical Microbiology, MTC, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Ørjan Samuelsen
- Department of Microbiology and Infection Control, Reference Centre for Detection of Antimicrobial Resistance, University Hospital of North Norway, Tromsø, Norway
| | - Bengt Wretlind
- Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
| | - Mats Kalin
- Unit of Infectious Diseases, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Barbro Olsson-Liljequist
- Division of Antibiotics and Infection Control, Department of Bacteriology, Swedish Institute for Infectious Disease Control, Solna, Sweden
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The plasmid of Escherichia coli strain S88 (O45:K1:H7) that causes neonatal meningitis is closely related to avian pathogenic E. coli plasmids and is associated with high-level bacteremia in a neonatal rat meningitis model. Infect Immun 2009; 77:2272-84. [PMID: 19307211 DOI: 10.1128/iai.01333-08] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A new Escherichia coli virulent clonal group, O45:K1, belonging to the highly virulent subgroup B2(1) was recently identified in France, where it accounts for one-third of E. coli neonatal meningitis cases. Here we describe the sequence, epidemiology and function of the large plasmid harbored by strain S88, which is representative of the O45:K1 clonal group. Plasmid pS88 is 133,853 bp long and contains 144 protein-coding genes. It harbors three different iron uptake systems (aerobactin, salmochelin, and the sitABCD genes) and other putative virulence genes (iss, etsABC, ompT(P), and hlyF). The pS88 sequence is composed of several gene blocks homologous to avian pathogenic E. coli plasmids pAPEC-O2-ColV and pAPEC-O1-ColBM. PCR amplification of 11 open reading frames scattered throughout the plasmid was used to investigate the distribution of pS88 and showed that a pS88-like plasmid is present in other meningitis clonal groups such as O18:K1, O1:K1, and O83:K1. A pS88-like plasmid was also found in avian pathogenic strains and human urosepsis strains belonging to subgroup B2(1). A variant of S88 cured of its plasmid displayed a marked loss of virulence relative to the wild-type strain in a neonatal rat model, with bacteremia more than 2 log CFU/ml lower. The salmochelin siderophore, a known meningovirulence factor, could not alone explain the plasmid's contribution to virulence, as a salmochelin mutant displayed only a minor fall in bacteremia (0.9 log CFU/ml). Thus, pS88 is a major virulence determinant related to avian pathogenic plasmids that has spread not only through meningitis clonal groups but also human urosepsis and avian pathogenic strains.
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Abstract
SUMMARY AmpC beta-lactamases are clinically important cephalosporinases encoded on the chromosomes of many of the Enterobacteriaceae and a few other organisms, where they mediate resistance to cephalothin, cefazolin, cefoxitin, most penicillins, and beta-lactamase inhibitor-beta-lactam combinations. In many bacteria, AmpC enzymes are inducible and can be expressed at high levels by mutation. Overexpression confers resistance to broad-spectrum cephalosporins including cefotaxime, ceftazidime, and ceftriaxone and is a problem especially in infections due to Enterobacter aerogenes and Enterobacter cloacae, where an isolate initially susceptible to these agents may become resistant upon therapy. Transmissible plasmids have acquired genes for AmpC enzymes, which consequently can now appear in bacteria lacking or poorly expressing a chromosomal bla(AmpC) gene, such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. Resistance due to plasmid-mediated AmpC enzymes is less common than extended-spectrum beta-lactamase production in most parts of the world but may be both harder to detect and broader in spectrum. AmpC enzymes encoded by both chromosomal and plasmid genes are also evolving to hydrolyze broad-spectrum cephalosporins more efficiently. Techniques to identify AmpC beta-lactamase-producing isolates are available but are still evolving and are not yet optimized for the clinical laboratory, which probably now underestimates this resistance mechanism. Carbapenems can usually be used to treat infections due to AmpC-producing bacteria, but carbapenem resistance can arise in some organisms by mutations that reduce influx (outer membrane porin loss) or enhance efflux (efflux pump activation).
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Giske CG, Sundsfjord AS, Kahlmeter G, Woodford N, Nordmann P, Paterson DL, Cantón R, Walsh TR. Redefining extended-spectrum beta-lactamases: balancing science and clinical need. J Antimicrob Chemother 2008; 63:1-4. [PMID: 18957393 DOI: 10.1093/jac/dkn444] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The current beta-lactamase classifications have reached a high level of complexity, making them less accessible to clinicians, infection control professionals, hospital management and politicians. From the clinical perspective, a revised comprehensible nomenclature scheme is therefore needed. The term extended-spectrum beta-lactamases (ESBLs) has reached a broader audience over time, but is currently restricted to functional class 2be/molecular class A, clavulanic acid inhibited enzymes with activity against extended-spectrum cephalosporins. The proposed new classification expands the definition of ESBL to other clinically important acquired beta-lactamases with activity against extended-spectrum cephalosporins and/or carbapenems. The classical class A ESBLs have been designated ESBLA in this classification, whereas plasmid-mediated AmpC and OXA-ESBLs are classed as miscellaneous ESBLs (ESBLM). Lastly, the carbapenemases have been designated ESBLCARBA, ESBLs with hydrolytic activity against carbapenems. We believe that this simplified classification may encourage new groups of healthcare professionals to engage in the effort to prevent the spread of acquired beta-lactamases.
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Affiliation(s)
- Christian G Giske
- Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.
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Evaluation of screening methods to detect plasmid-mediated AmpC in Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. Antimicrob Agents Chemother 2008; 53:146-9. [PMID: 18955528 DOI: 10.1128/aac.00862-08] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There are currently no standardized phenotypic methods for the screening and detection of AmpC enzymes. This study aimed to evaluate different methods to detect AmpC enzymes in Escherichia coli, Klebsiella spp., and Proteus spp., comparing the results from two disk-based methods and an agar dilution method. AmpC activity was determined for 255 clinical isolates by use of a three-dimensional enzyme assay combined with a multiplex PCR assay for plasmid-borne ampC genes. These results were compared against a disk-based inhibitor assay using various combinations of cefpodoxime and cefoxitin as antibiotic substrates and boronic acid or cloxacillin as an AmpC inhibitor. The presence of enzyme induction by disk approximation was evaluated using imipenem, cefoxitin, and amoxicillin-clavulanate as inducing agents against ceftazidime. Finally, an agar dilution assay was performed, using cefoxitin with and without added cloxacillin. AmpC activity was present in 49.8% of test isolates, 93.7% of which were positive for plasmid-borne ampC genes. CIT-like enzymes were predominant in E. coli, and DHA-like enzymes were predominant in Klebsiella spp. The disk-based inhibitor tests performed better than the agar dilution assay, while detection of AmpC by disk induction had a poor sensitivity. The cefoxitin-cloxacillin disk combination provided the best overall performance, with a sensitivity and specificity of 95%. This study confirmed the accuracy of disk-based inhibitor screening for AmpC enzymes, which proved reliable at detecting CIT- and DHA-like plasmid-borne ampC genes. The methods are simple enough for introduction into clinical microbiology laboratories.
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Risk of misidentification of Enterobacter aerogenes inducible cephalosporinases. J Infect 2008; 57:416-8. [PMID: 18835042 DOI: 10.1016/j.jinf.2008.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 08/19/2008] [Accepted: 08/23/2008] [Indexed: 11/23/2022]
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30
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Ko KS, Lee MY, Song JH, Lee H, Jung DS, Jung SI, Kim SW, Chang HH, Yeom JS, Kim YS, Ki HK, Chung DR, Kwon KT, Peck KR, Lee NY. Prevalence and characterization of extended-spectrum β-lactamase–producing Enterobacteriaceae isolated in Korean hospitals. Diagn Microbiol Infect Dis 2008; 61:453-9. [DOI: 10.1016/j.diagmicrobio.2008.03.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 03/14/2008] [Accepted: 03/18/2008] [Indexed: 10/22/2022]
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Whole-genome pyrosequencing of an epidemic multidrug-resistant Acinetobacter baumannii strain belonging to the European clone II group. Antimicrob Agents Chemother 2008; 52:2616-25. [PMID: 18411315 DOI: 10.1128/aac.01643-07] [Citation(s) in RCA: 211] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The whole-genome sequence of an epidemic, multidrug-resistant Acinetobacter baumannii strain (strain ACICU) belonging to the European clone II group and carrying the plasmid-mediated bla(OXA)(-)(58) carbapenem resistance gene was determined. The A. baumannii ACICU genome was compared with the genomes of A. baumannii ATCC 17978 and Acinetobacter baylyi ADP1, with the aim of identifying novel genes related to virulence and drug resistance. A. baumannii ACICU has a single chromosome of 3,904,116 bp (which is predicted to contain 3,758 genes) and two plasmids, pACICU1 and pACICU2, of 28,279 and 64,366 bp, respectively. Genome comparison showed 86.4% synteny with A. baumannii ATCC 17978 and 14.8% synteny with A. baylyi ADP1. A conspicuous number of transporters belonging to different superfamilies was predicted for A. baumannii ACICU. The relative number of transporters was much higher in ACICU than in ATCC 17978 and ADP1 (76.2, 57.2, and 62.5 transporters per Mb of genome, respectively). An antibiotic resistance island, AbaR2, was identified in ACICU and had plausibly evolved by reductive evolution from the AbaR1 island previously described in multiresistant strain A. baumannii AYE. Moreover, 36 putative alien islands (pAs) were detected in the ACICU genome; 24 of these had previously been described in the ATCC 17978 genome, 4 are proposed here for the first time and are present in both ATCC 17978 and ACICU, and 8 are unique to the ACICU genome. Fifteen of the pAs in the ACICU genome encode genes related to drug resistance, including membrane transporters and ex novo acquired resistance genes. These findings provide novel insight into the genetic basis of A. baumannii resistance.
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