title: Evaluation of multiple-locus variable number of tandem-repeats analysis (MLVA) as a method for identification of clonal groups among enteropathogenic, enterohaemorrhagic and avirulent Escherichia coli O26 strains.
abstract: A published multiple-locus variable number of tandem-repeats analysis (MLVA) scheme was compared with pulsed-field gel electrophoresis (PFGE) for genotyping of 62 Escherichia coli O26 strains from humans, animals and food. The strains were isolated between 1947 and 2006 in eight countries on three continents and divided into 23 enterohaemorrhagic E. coli (EHEC), 33 enteropathogenic E. coli (EPEC), one enterotoxigenic E. coli (ETEC) and five avirulent strains. ETEC and avirulent E. coli serotyped as O26:H32. EHEC and EPEC O26 strains shared flagellar type H11 and the eae-beta gene, and divided into two clonal lineages by their arcA gene sequence and fermentation of rhamnose and dulcitol. The rhamnose/dulcitol-nonfermenting (RDF-), 'arcA allele 1' type comprised 22 EHEC and 15 EPEC strains. The rhamnose/dulcitol-fermenting (RDF+), 'arcA allele 2' type encompassed 17 EPEC and one EHEC strain. PFGE typing of the 62 O26 strains revealed 54 distinct patterns, whereas 29 profiles were obtained by MLVA. Like PFGE, MLVA divided RDF- and RDF+ O26:[H11] strains into two distinct clusters of related strains. The O26:H32 strains formed a separate PFGE cluster and two clusters by MLVA. MLVA was found as suitable, but more rapid and easier to standardize than PFGE for identifying genetically related E. coli O26 strains.
authors.affiliation: National Reference Laboratory for E. coli (NRL-E.coli ), Federal Institute for Risk Assessment (BfR), Berlin, Germany.
authors.forename: Angelika
authors.initials: A
authors.lastname: Miko
authors.forename: Bjørn-Arne
authors.initials: BA
authors.lastname: Lindstedt
authors.forename: Lin T
authors.initials: LT
authors.lastname: Brandal
authors.forename: Inger
authors.initials: I
authors.lastname: Løbersli
authors.forename: Lothar
authors.initials: L
authors.lastname: Beutin
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques / Q000379:methods*; D016000:Cluster Analysis; D016172:DNA Fingerprinting / Q000379:methods*; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D029968:Escherichia coli Proteins / Q000235:genetics; D005516:Food Microbiology; D005838:Genotype; D006801:Humans; D018598:Minisatellite Repeats; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D012703:Serotyping; D037521:Virulence Factors / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors