Genetic variability of Escherichia coli 0157:H7.

Abstract

Escherichia coli 0157:H7 is recognized as an important food-borne pathogen, being implicated in over 2,500 deaths worldwide. Various genetic typing methods have been investigated in studying possible outbreak strains, including pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPO), and enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) . These genetic methods yield information on the genetic diversity of organisms, but make no attempt to identify specific virulence genes. In this study, we present a modified RAPO which targets specific virulence genes under low stringency conditions and also yields information on the diversity of the organism in question. Plasmid profiling, ERIC-I peR, and RAPO were also used to determine genetic heterogeneity for comparison. Our results indicate the modified RAPO may be a better tool for investigating the genetic relationships of organisms.