Prevalence of E. coli O157:H7 strains in irrigation water and agricultural soil in two district municipalities in South Africa

Abstract

We assessed the prevalence of E. coli O157:H7 in irrigation water and agricultural soil samples in two District Municipalities in South Africa using standard culture-based and molecular techniques. Presumptive E. coli O157:H7 counts in irrigation water and agricultural soil samples ranged from 1.00 Log10 CFU/100 ml to 4.11 Log10 CFU/100 ml and 2.20 Log10 CFU/g to 4.21 Log10 CFU/g respectively (P ≤ 0.05). Thirteen (28%) of the confirmed isolates (n = 46) were Shiga toxigenic and 33 (72%) were Shiga toxin negative. The presence of Shiga toxigenic E. coli O157:H7 strain in irrigation water and agricultural soil samples reported by this study suggests potential risk to food safety and population health.