Applicability of DiversiLab Repetitive Sequence-Based PCR Method in Epidemiological Typing of EnterohemorrhagicEscherichia coli(EHEC)

Abstract

Enterohemorrhagic Escherichia coli (EHEC) causes diarrhea, often with severe complications. Rapid and discriminatory typing of EHEC using advanced molecular methods is needed for determination of the genetic relatedness of clones responsible for foodborne outbreaks and for finding out the transmission sources of the outbreaks. This study evaluated the potential of DiversiLab, a semiautomated repetitive sequence-based polymerase chain reaction method for the genotyping of EHEC strains. A set of 52 EHEC strains belonging to 15 O:H serotypes was clustered into 10 DiversiLab groups. All of the O157 strains and one O55 strain were classified into the same group based on a 90% similarity threshold. The other serotypes were classified to their own DiversiLab group, with the exception of one R:H(-) strain that was grouped with O5:H(-) strains. In addition, O26 and O111 strains were grouped together but ultimately subdivided according to their O-serotypes based on a 95% similarity threshold. The O104 strain, which was associated with a major outbreak of hemolytic uremic syndrome in Germany in May 2011, was also classified independently. The DiversiLab performed well in identifying isolates, but the discriminatory power of the repetitive sequence-based polymerase chain reaction method was lower than that of pulsed-field gel electrophoresis. Analysis of 15 enteropathogenic E. coli (EPEC) strains revealed that some EPEC strains clustered together with EHEC strains. Therefore, the DiversiLab system cannot be used to discriminate between these pathogroups. In conclusion, DiversiLab is a rapid and easy system for the primary exclusion of unrelated EHEC strains based on their serotypes, but more discriminatory methods, such as pulsed-field gel electrophoresis, are needed for accurate typing of the EHEC strains.

Identification of Shiga toxin-producing (STEC) and enteropathogenic (EPEC) Escherichia coli in diarrhoeic calves and comparative genomics of O5 bovine and human STEC

“…The presence of the stx1a gene variant in all 16 isolates and of the b variant of the gene encoding the intimin adhesin (eae gene) is identical to the report in the literature for O5 AE-STEC isolates from adult cattle (Monaghan et al, 2012;Lukinmaa-Aberg et al, 2013). Conversely, the stx2 gene was present in only two isolates and was identified to the stx2a and stx2d variants respectively, according to the Virulence Finder server database v1.2 of the CGE (Joensen et al, 2014).…”

A one-year survey of Microsporum audouinii infections in Belgium: epidemiological and genotypic characterization

“…This study has allowed the gathering of epidemiological data and the collection and characterization of the circulating strains. The technology chosen for the differentiation of the strains was the Diversilab system, a rep-PCR-based system that has been used as a typing method for bacterial strains isolated during epidemics [24][25][26]. However, the system has rarely been applied to the mycology field.…”