Detection of Verocytotoxigenic Escherichia coli O157 Serotype in Dairy Products in Abuja, Nigeria

Abstract

Ruminants are recognized as healthy carriers of Verocytotoxigenic Escherichia Coli (VTEC) organisms and as such most dairy products may provide these bacteria with favourable conditions for their growth. A cross sectional study was conducted to detect the occurrence of VTEC O157 in dairy products in the Federal Capital Territory, Abuja, Nigeria. Raw milk, Nunu and yoghurt were analyzed using standard cultural and biochemical procedures to isolate typical E. coli. Isolated E. coli samples were sub-cultured into plates of sorbitol MacConkey and Cefixime Tellurite-Sorbitol MacConkey agar. Isolates that are sorbitol negative were further characterized using commercially procured latex agglutination test kits. A total of 367 samples were analyzed out of which 3 tested positive for VTEC O157 (108 of raw milk - 1 (0.93%); 127 of Nunu - 2 (1.57%) and 132 of yoghurt - none). There was no significant association (p > 0.05) between season and infection with VTEC O157 in dairy products. Dairy products remained a potential vehicle for VTEC O157 infection.