Abstract
Shiga toxigenic strains of E. coli (STEC) known to be etiological agents for diarrhea were screened for their incidence/occurrence in selected abattoirs sources in Osogbo metropolis of Osun State, Nigeria using a randomized block design. Samples were plated directly on selective and differential media and E. coli isolates. Multiplex PCR analysis was used to screen for the presence of specific virulence factors. These were confirmed serologically as non-O157 STEC using latex agglutination serotyping kit. Sequence analysis of PCR products was performed on a representative isolate showing the highest combination of virulence genes using the 16S gene for identification purposes only. Results showed that the average cfu/cm2 was significantly lower in the samples collected at Sekona-2 slaughter slab compared with those collected at Al-maleek batch abattoir and Sekona-1 slaughter slab in ascending order at P = 0.03. Moreover, the average cfu/cm2E. coli in samples collected from butchering knife was significantly lower when compared with that of the workers’ hand (P = 0.047) and slaughtering floor (P = 0.047) but not with the slaughter table (P = 0.98) and effluent water from the abattoir house (P = 0.39). These data suggest that the abattoir type may not be as important in the prevalence and spread of STEC as the hygiene practices of the workers. Sequence analysis of a representative isolate showed 100% coverage and 96.46% percentage identity with Escherichia coli O113:H21 (GenBank Accession number: CP031892.1) strain from Canada. This sequence was subsequently submitted to GenBank with accession number MW463885. 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.
Highlights
Shiga toxigenic strains of E. coli (STEC) are widely recognized as major pathogens for public health problems in developing countries and represent the leading etiological agent of d iarrhea[1,2]
The present study investigated the prevalence of Shiga-toxigenic E. coli from selected beef abattoirs in Osun State
The results revealed that the average colony count of distinct isolates of E. coli was significantly lower in the samples collected at Sekona-2 slaughter slab when compared with those collected at Almaleek and Sekona-1 slaughter slab type abattoir in ascending order (Fig. 1D)
Summary
Shiga toxigenic strains of E. coli (STEC) are widely recognized as major pathogens for public health problems in developing countries and represent the leading etiological agent of d iarrhea[1,2]. E. coli strains producing Shiga toxin type 2 (stx[2], encoded by stx2) appear to be more commonly responsible for serious complications such as HUS than. Those producing only Shiga toxin type 1 5. While meat is usually consumed well-done in Nigeria, thereby limiting infections from meat consumption, contamination of water bodies from abattoir waste constitutes significant environmental and public health h azards[6,7,8]. Shiga toxigenic E. coli infections have been reported for most parts of the world, including a number of African countries[4], specific incidence data are not always collected or readily available in most sub-saharan African countries, especially in Nigeria
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