Detection of pathogenic Escherichia coli in samples collected at an abattoir in Zaria, Nigeria and at different points in the surrounding environment.

Pathogenic Escherichia coli can be released with the wastes coming from slaughterhouses into the environment, where they can persist. We investigated the presence of diarrheagenic E. coli in specimens taken at an abattoir located in the Zaria region, Nigeria, in samples of water from the river Koreye, where the effluent from the abattoir spills in, and vegetable specimens taken at a nearby farm. All the isolated E. coli were assayed for the production of Shiga toxins (Stx) by using the Ridascreen verotoxin Immunoassay and by PCR amplification of genes associated with the diarrheagenic E. coli. Three strains from the rectal content of two slaughtered animals and a cabbage were positive for the presence of the Stx-coding genes. Additionally we have isolated one Enteroaggregative E. coli (EAggEC) from the abattoir effluent and two Subtilase-producing E. coli from the slaughterhouse's effluent and a sample of carrots. Our results provide evidence that pathogenic E. coli can contaminate the environment as a result of the discharge into the environment of untreated abattoir effluent, representing a reservoir for STEC and other diarrheagenic E. coli favouring their spread to crops.