Methods for Genotyping Verotoxin‐Producing Escherichia coli

• Published in: Zoonoses and public health 2010-12, Vol.57 (7), p.447-462
• Main Authors: Karama, M, Gyles, C.L
• Format: Article
• Language: English
• Subjects: Bacterial Typing Techniques; disease outbreaks; disease surveillance; E coli; Electrophoresis, Gel, Pulsed-Field; Epidemiology; Escherichia coli; Escherichia coli Infections - epidemiology; Escherichia coli Infections - microbiology; Escherichia coli O157 - classification; Escherichia coli O157 - genetics; Escherichia coli O157 - metabolism; Evolution; Food contamination & poisoning; foodborne illness; Genes, Bacterial - genetics; Genetic Variation - genetics; Genotype; Genotype & phenotype; genotyping methods; Humans; literature reviews; loci; methodology; Microarray Analysis; microarray technology; microbial genetics; Minisatellite Repeats; Molecular Epidemiology; molecular sequence data; multiple-locus variable-number tandem-repeats analysis; Polymerase Chain Reaction; pulsed-field gel electrophoresis; Research methodology; Shiga toxin; Shiga Toxins - genetics; Shiga Toxins - metabolism; Shiga-Toxigenic Escherichia coli - classification; Shiga-Toxigenic Escherichia coli - genetics; Shiga-Toxigenic Escherichia coli - isolation & purification; subtyping; tandem repeat sequences; Verotoxin; verotoxins; zoonoses
• ISSN: 1863-1959; 1863-2378
• DOI: 10.1111/j.1863-2378.2009.01259.x

Verotoxin‐producing Escherichia coli (VTEC) is annually incriminated in more than 100 000 cases of enteric foodborne human disease and in losses amounting to $US 2.5 billion every year. A number of genotyping methods have been developed to track VTEC infections and determine diversity and evolutionary relationships among these microorganisms. These methods have facilitated monitoring and surveillance of foodborne VTEC outbreaks and early identification of outbreaks or clusters of outbreaks. Pulsed‐field gel electrophoresis (PFGE) has been used extensively to track and differentiate VTEC because of its high discriminatory power, reproducibility and ease of standardization. Multiple‐locus variable‐number tandem‐repeats analysis (MLVA) and microarrays are the latest genotyping methods that have been applied to discriminate VTEC. MLVA, a simpler and less expensive method, is proving to have a discriminatory power comparable to that of PFGE. Microarrays are successfully being applied to differentiate VTEC and make inferences on genome diversification. Novel methods that are being evaluated for subtyping VTEC include the detection of single nucleotide polymorphisms and optical mapping. This review discusses the principles, applications, advantages and disadvantages of genotyping methods that have been used to differentiate VTEC strains. These methods have been mainly used to differentiate strains of O157:H7 VTEC and to a lesser extent non‐O157 VTEC.