Detection of staphylococci in street-vended ready-to-eat meat in Nsukka and its environs

Abstract

Ready-to-eat (RTE) street-vended meat in Nsukka and its environs were investigated for the presence of staphylococci. The samples were pre-enriched in peptone water for 24 hours at 37^oC and subsequently streaked on mannitol salt agar plates and incubated at 37^oC for 24 hours. The staphylococcal isolates were identified to species level by sequencing of sodA and 16S rDNA genes. Genes coding for TSST-1 (tst), ETA (eta), ETB (etb), and ETD (etd) were investigated by PCR. Phenotypic determination of resistance to 17 antimicrobial agents was carried out using the disc diffusion method, while genes coding for resistance to methicillin (mecA), aminoglycosides (aph(2)-aac(6), ant(4), aph(3)-III), erythromycin (ermA, ermB, ermC, ermT, mphC, msrA, and msrB) and tetracycline (tet(M), tet(O), tet(K), and tet(L) were determined by PCR amplification using their specific primers. Twenty-eight (11.0%) of the R-T-E meat samples contained staphylococci. Twenty-four of the Staphylococcus strains were identified to species level and they belonged to 6 species, namely S. scuiri (54.1%), S. lentus (16.6%), S. saprophyticus (12.5%), S. carnosus (8.4%), S. piscifermentans (4.2%) and S. epidermidis (4.2%). Four (16.7%) of the Staphylococcus species harboured the eta gene. Resistance genes detected in the Staphylococcus species were: mecA (25%), tetK (25%), mphC (12.5%), ermT (8.3%), and ermC (4.2%).