ANTIMICROBIAL SUSCEPTIBILITY PROFILE OF METHICILLIN RESISTANT AND METHICILLIN SENSITIVE STAPHYLOCOCCUS AUREUS FROM BOVINE MILK IN THE STATE OF HARYANA, INDIA

Bovine mastitis is the principal leading cause of monetary losses to dairy farmers. This disease impacts the udder health as well as the quantitative and qualitative parameters of milk. The disease is multi-etiological, but Staphylococcus aureus (S. aureus) contributing to intramammary infections is the principal cause. Our work intended to go through the sensitivity pattern of S. aureus obtained from milk samples of bovines. The samples used in the study were received at College Central Laboratory, LUVAS, Hisar. The bovine milk samples were inoculated on blood agar to obtain bacterial isolates, followed by morphological and biochemical characterization. S. aureus was confirmed by phenotypic as well as molecular assays. Ninety-five staphylococci were preliminarily isolated from 381 quarter milk samples based on morphological features of a bacterial colony, Gram stain, catalase reaction, oxidase test, and HiStaph latexTM kit from bovines. Out of these, 86 S. aureus isolates were confirmed based on phenotypic (mannitol salt agar) as well as a molecular test (23S rRNA PCR). All these isolates were used for sensitivity profiling by Kirby Bauer disc diffusion method. Maximum sensitivity was observed for chloramphenicol and doxycycline, least against cloxacillin and methicillin. From 86 isolates, 62.79% were found to be multidrug-resistant (MDR). From MDR isolates, 11.11% were extensively drug-resistant (XDR) and none were pan-drug-resistant (PDR). The presence of a high percentage of MDR phenotypes among S. aureus isolates in this study draws our attention that treatment of animals must be carried out after the identification of pathogens, followed by patterns of sensitivity to antimicrobials.