Isolation and Molecular Identification of Staphylococcus Species in Cow’s Milk Distributed in Khartoum State

Abstract

The aim of this study was to identify and evaluate the bacteria load and the level of Staphylococcus Species and Staphylococcus aureus contamination in raw cow´s milk distributed in Khartoum state. One hundred and eighty samples were taken from Khartoum, Omdurman and Khartoum North, 60 samples of raw milk from healthy apparently cows in farms, 60 samples of raw milk vended by donkeys, 60 samples of raw milk vended by cars. Total Viable Bacterial count was done using standard plate count. The samples were detected for the presence of Staphylococcus Species using conventional methods, cultured in Baird-Parker and Mannitol agar, Gram Stain, biochemical tests were done. The TVBC showed that the highest bacterial load was detected in the raw milk vended by Donkey (6.90±.03 log10 cfu/ml) vended by cars (6.78±0.12 log10 cfu/ml) then the lowest bacterial load detected in the milk collected from farm (6.63±0.07 log10 cfu/ml). Out of 180 samples of raw milk studied, 130 showed contamination by Staphylococcus species corresponding to 72.2% of the samples being contaminated and out of 180 samples of raw cow´s milk 80 was contaminated with staphylococcus aureus corresponding to 44.4% of the samples.The isolated Staphylococcus species was confirmed further by using the Polymerase Chain Reaction (PCR) targeting the partial sequence of 16s rRNA gene. Sequencing identified Staphylococcus aureus, staphylococcus epidermidis, Staphylococcus hominies and Staphylococcus simulans. The results showed a high level of contamination by Staphylococcus Spp. and staphylococcus aureus in raw cow´s milk that distributed in Khartoum state.