Multiple-locus variable-number tandem repeats analysis typing of Shiga toxin-producing Escherichia coli isolates

Objective To evaluate the performance of multiple-locus variable number tandem repeats analysis (MLVA) in typing of Shiga toxin producing Escherichia coli (STEC) isolates, and understand the molecular epidemiological characteristics of the stains. Methods Totally 70 STEC isolates were typed by MLVA using 7 VNTR loci. A dendrogram was constructed using BioNumerics based on allele numbers. Results Using the MLVA protocol, 46 MLVA types were obtained from 70 STEC isolates. O157 and non-O157 isolates were divided into A and B groups. Isolates of different sources, serotypes or Shiga toxin gene types are well divided with some exceptions. Conclusion Though it needs to be improved, the MLVA protocol based on 7 VNTR loci is useful to differentiate STEC isolates, to trace the source of outbreak and so on.