Use of repetitive DNA sequences to determine the persistence of enteropathogenic Escherichia coli in vegetables and in soil grown in fields treated with contaminated irrigation water

Abstract

Aims: Fresh fruits and vegetables are increasingly recognized as vectors for food-borne illness. On farm contamination through contaminated irrigation water is considered likely source of the pathogen for several outbreaks. The purpose of this study is to investigate the possible similarity of strains of Escherichia coli isolated from the soil and vegetables irrigated by treated wastewater. Methods and Results: Seventy-five strains of enteropathogenic Escherichia coli isolated from vegetables, soil and irrigation water were tested for sensitivity to antibiotics and shown to be sensitive. The result of enterobacterial repetitive intergenic consensus (ERIC)-PCR shows similarities between analysed strains isolated from the three different samples. Moreover strains of E. coli isolated from vegetables over different periods of time have the same ERIC-PCR profile. Conclusions: The isolated strains of enteropathogenic E. coli can persist in soil and in vegetables growing in fields treated with contaminated irrigation water for an extended period of time. Significance and Impact of the Study: Contaminated irrigation water can transport pathogenic bacteria, which persists in the soil for a long period of time and contaminates the vegetables growing in the field irrigated by this contaminated water. © 2006 The Authors.