Molecular surveillance of non-O157 Shiga toxigenic Escherichia coli in selected chicken abattoirs and retail outlets in Osogbo, Osun State, Nigeria

Three selected chicken abattoirs and two retail locations were studied to determine the frequency of occurrence and profile for Shiga toxin-producing Escherichia coli (STEC) strains present in abattoirs and retail (frozen) chicken carcasses in Osun state, Nigeria. Samples were plated on Eosin Methylene Blue agar for the presence of E. coli. Furthermore, the isolates were confirmed serologically as non-O157 STEC using latex agglutination serotyping kit. Multiplex PCR was used to check for specific virulence factors in the isolated E. coli strains. The mean colony count results showed that effluent water samples from the Ikirun slaughter slab type abattoir were the highest at 25 cfu/ml. A post hoc comparison showed that this value was significantly higher than that of the slaughtering table at Oluode-1 (P = 0.04) and retail chicken meat samples at Igbona (P = 0.01). The results show that chicken abattoirs are poor reservoirs of STEC. Moreover, the results from this study showing that the stx2-producing strains that are more prone to cause hemolytic uremic syndrome is the predominant strain in the study area is worrisome. These results underscore the improper hygiene practices of the abattoir workers combined with inadequate waste management and biological waste disposal systems. It is recommended that regulatory bodies in this locality should focus on ensuring the upgrade of biological waste disposal from these abattoirs in order to limit spread of potentially virulent pathogens into the runoff and ground water.