Multi-locus variable number tandem repeat analysis for Escherichia coli causing extraintestinal infections☆
Introduction
Discriminatory molecular typing methods for non-O157:H7 Escherichia coli are necessary for outbreak investigation, public health surveillance, and molecular epidemiological studies. Pulsed-field gel electrophoresis (PFGE) is the current standard for molecular subtyping, but it is time-consuming, and the results can be difficult to compare across laboratories. Multi-locus variable number tandem repeat analysis (MLVA) has shown promise in differentiating closely related strains of E. coli (Keys et al., 2005, Lindstedt et al., 2004, Noller et al., 2003, Noller et al., 2004). However, these MLVA protocols have been developed specifically for E. coli O157:H7. The objective of this study was to develop a fast and reliable MLVA protocol which could be used alone or in conjunction with other typing methods such as enterobacterial repetitive intergenic consensus 2 (ERIC2) sequence PCR, to genotype large collections of E. coli.
Section snippets
E. coli isolates
E. coli isolates from three sources were included in the study: 417 isolates were from retail chicken, pork, and beef meat that were systematically selected from the Canadian Integrated Program on Antimicrobial Resistance Surveillance (CIPARS) collection; 74 E. coli isolates were from restaurant and ready-to-eat food items collected by the Division de l'inspection des aliments, Ville de Montréal; and 345 E. coli isolates were from human extraintestinal infections. E. coli was grown in
Results and conclusions
An MLVA method was developed to rapidly and unambiguously group diverse E. coli isolates. A total of 803 diverse E. coli and 33 E. coli isolates belonging to known clonal groups were analyzed with the new MLVA method. All 836 isolates were typeable by MLVA. The average call rates for each locus are presented in Table 1. Sequencing results confirmed the presence of tandem repeats at each locus.
Evaluation of the 803 diverse E. coli identified 303 isolates (38%) with unique MLVA profiles and 121
Acknowledgments
We wish to thank members of the surveillance team of the Canadian Integrated Program for Antimicrobial Resistance Surveillance (Lucie Dutil and Danielle Daignault); the Division de l'inspection des aliments, Ville de Montréal (Myrto Mantzavrakos and Annie Laviolette) and the Student Health Services Clinical Technician (Christiaine Lacombe). This study was supported by the Public Health Agency of Canada (A.R.M) and by the Canadian Institutes of Health Research, M.Sc. Award (C.V.).
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Cited by (8)
Comparison of 2 proposed MLVA protocols for subtyping non-O157: H7 verotoxigenic Escherichia coli
2014, Diagnostic Microbiology and Infectious DiseaseCitation Excerpt :MLVA allows differentiating closely related isolates and, at epidemiological level, source tracking during investigation of outbreaks, as well as the interpretation of suspected outbreaks. Several MLVA protocols have been developed for the specific typing of VTEC O157:H7 (Keim et al., 2000; Lindstedt et al., 2004; Noller et al., 2003) and other ones for non-O157:H7 serotypes (Izumiya et al., 2010; Lindstedt et al., 2007; Manges et al., 2009). In previous studies, we implemented a generic E. coli MLVA assay based on the combination of 7 loci with different degrees of polymorphism proposed by Lindstedt et al. (2007), called by us MLVAG7.
An abbreviated MLVA identifies Escherichia coli ST131 as the major extended-spectrum β-lactamase-producing lineage in the Copenhagen area
2013, European Journal of Clinical Microbiology and Infectious Diseases
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Ethics committee approval: The study protocol was approved by the McGill University, Institutional Review Board (A01-M04-05A).