Purpose: This study determined the prevalence, antibiotic susceptibility patterns and biofilm forming abilities of E. coli O157:H7 from feces and milk of slaughtered cattle and abattoir water samples during two climatic seasons at the Bodija municipal abattoir, Ibadan, Nigeria.
Methods: A total number of 196 fecal, 34 milk and 61 water samples were assessed and isolation was made using standard cultural and serological methods. Susceptibility to eight antimicrobials was tested using disc diffusion method. Biofilm was assayed on microtiter plates in two media (Tryptose soy broth and Tryptone soy broth + 2% glucose) at 37°C for 48, 96 and 144 h incubation and quantified using the crystal violet binding assay.
Results: A total prevalence rate of 20.6%, 6.6% and 4.9% were recorded for milk, fecal and water samples, respectively. Prevalence of E. coli O157:H7 was significantly higher during wet than in the dry season (P < 0.05). All isolates were resistant to one or multiple antibiotics, but highest resistance (95.7%) was to Augmentin and Amoxicillin (87%) while Ofloxacin (87%) and Gentamycin (78.3%) were the most sensitive. The strains produced higher biofilm masses after 48 h incubation especially with glucose (0.45 ± 0.02 to 0.46 ± 0.07).
Significance: These results indicate that feces and milk of slaughtered cattle and water used for processing in the abattoir may be important sources of E. coli O157:H7 contamination of beef, especially during the rainy season if strict decontamination strategies are not taken. Presence of glucose sources would increase their biofilm forming abilities.