METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) IN FRESH AND FERMENTED MILK IN ZARIA AND KADUNA, NIGERIA

Methicillin-resistant Staphylococcus aureus (MRSA) is of public health and veterinary concern globally and mastitic milk is one of the sources. In this study, 372 milk samples comprising of raw milk, bulk milk, yogurt and ‘kindirmo’ (locally fermented milk) obtained from Kaduna and Zaria, Nigeria were examined for the prevalence of MRSA and their antibiotic resistance profile. Out of the 372 milk samples examined, 195 staphylococci were isolated and out of which 47 (12.6%) were coagulase positive and 18 (4.8%) were methicillin resistant. There was no significant difference (P > 0.05) between the occurrence of both coagulase positive S. aureus and MRSA in Kaduna (13.4% and 5.1%) and Zaria (11.4% and 4.5%). The occurrence of coagulase positive S. aureus was significantly higher (P 0.05) exists between the occurrences of MRSA among the study variables. No coagulase positive S. aureus and MRSA was detected in any of the yogurt samples examined. A decrease in the prevalence was observed from raw milk to the final yogurt and ‘kindirmo’ products indicating that pasteurization and fermentation eliminated the organisms. Very high percentages of the MRSA isolates were resistant to oxacillin (100.0%), penicillin (100.0%), tetracycline (55.6%), and vancomycin (44.6%) while sulfamethoxazole/trimethoprim and gentamicin recorded the least levels of (11.1%) and (5.6%) respectively. The mec A was detected by polymerase chain reaction in 4 of the 18 MRSA isolates (3 in raw milk and 1 in ‘kindirmo’ samples). The study recommends proper pasteurization and fermentation of milk to eliminate MRSA before human consumption. Keywords Prevalence, Methicillin-resistant Staphylococcus aureus (MRSA), Fresh milk, Fermented milk, Antimicrobial resistance.