Prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) in Cattle Milk from dairy Herds in Oyo State, Nigeria

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) has received a lot of attention in recent years as a zoonotic organism of global concern. Contaminated milk, especially those from mastitic cows, serve as reservoirs for humans in the epidemiology of antibiotic resistant MRSA. This study was designed to determine the level of contamination of bulk fresh milk from dairy cattle herds with MRSA in Ibarapa, Oyo and Oke-Ogun areas of Oyo State and the antibiotic resistance profile of the isolates. One hundred and sixty-five (165) milk samples were obtained from the study areas and used for the study. Staphylococcus aureus was isolated from the samples using bacterial culture and biochemical tests. Methicillin-resistant Staphylococcus aureus was identified using cefoxitin disk diffusion method. All the S. aureus isolates were subjected to microbial susceptibility test. Ninety (54.5%) milk samples were positive for Staphylococcus spp. out of which 52 (31.5%) were Staphylococcus aureus and 13 (7.9%) yielded MRSA. Antibiogram of S. aureus indicated highest resistance to Cloxacillin (88.5%) followed by (Augmentin 67.3%) and Ceftrazidine (67.3%). Ten out of the 13 MRSA isolates were multidrug resistance while all the isolates were 100% susceptible to ofloxacin. The results of this study showed that milk produced from dairy cattle in Oyo State was contaminated with MRSA. This portends serious food safety and public health risk among the consumers of such milk especially in raw or improperly pasteurized form. Proper dairy herd health management and prudent use of antibiotics and hygienic milking procedures are hereby recommended to prevent contamination of milk and subsequent spread of the organism to humans.