This study was conducted to identify Shiga toxin producing Escherichia coli (STEC) isolated from slaughtered cattle and effluents at Zaria Abattoir, Nigeria. A total of 800 samples comprising of 400 samples each from faeces of slaughtered cattle and effluent wastes were collected. Out of the 800 samples 438 (54.8%) were positive for E. coli using Eosin Methylene Blue agar (EMB). Biochemical characterization of E. coli isolates yielded 253 (31.6%). Confirmation of the E. coli isolates was done using MicrobactTM 24E identification kits which revealed prevalence rate of 34 (4.3%).To detect E. coli O157:H7, the isolates were further tested in Cefixime and Potassium Tellurite Sorbitol MacConkey Agar (CT-SMAC) which yielded isolation rate of 25(3.1%). Serotyping to confirm E. coli O157:H7 serotypes was done using Wellcolex TM kits and that showed that 17(2.1%) were positive for E. coli O157:H7 serotypes. To identify STEC O157:H7, Vero Cell Assay was used and this yielded 13(1.6%) STEC isolates, in which 8(2.0%) and 5(1.3%) were from faeces of cattle and effluent samples respectively. Detection of STEC from slaughtered cattle feaces and effluent is novel and indicates that good hygienic practices are necessary to be adopted in our abattoirs in order to curb the menace of this disease.

Keywords: Shiga toxin, abattoir, effluent, vero cell assay, serotypes