Molecular Surveillance of Shiga Toxigenic Escherichia coli in selected beef abattoirs in Osun State Nigeria

Abstract Shiga toxigenic strains of E. coli (STEC) known to be etiological agents for diarrhea were screened for their incidence/ occurrence in selected abattoirs and retail meat sources in Osogbo metropolis of Osun State, Nigeria using a randomized block design. Samples were plated directly on selective and differential media and confirmed serologically using latex agglutination serotyping kit, then, multiplex PCR analysis was used to screen for the presence of specific virulence factors. The results showed a percent occurrence of STEC at the sampled sites ranging from 25.8- 46.3%. None of the strains showed any visible agglutination with the O157 latex reagent. Sequence analysis of PCR products was performed on a representative isolate showing the highest combination of virulence genes. This sequence was subsequently submitted to GenBank with accession number MW463885. The sequence showed 100% coverage and 96.46% percentage identity with Escherichia coli O113:H21 (GenBank Accession number: CP031892.1) strain from Canada. From evolutionary analyses, the strain from Nigeria, sequenced in this study, is evolutionarily distant when compared with the publicly available sequences from Nigeria. Although no case of E. coli O157 was found within the study area, percent occurrence of non-O157 STEC as high as 46.3% at some of the sampled sites is worrisome and requires regulatory interventions in ensuring hygienic practices at the abattoirs within the study area.