Prevalence of antibiotic resistant Staphylococcus aureus from raw milk samples collected from the local vendors in the region of Tirupathi, India.

Aim: The study was carried out with the aim to identify the suitability of the milk for consumer use with special reference to Staphylococcus aureus from milk samples collected from various local vendors and determine the antibiotic susceptibility pattern of those positive isolates.

Materials And Methods: A total of 110 milk samples were collected from the local milk vendors in and around Tirupathi region of India. All the samples were enriched with buffered peptone water in 9:1 ratio and the then inoculated on baird parker agar medium with added 2% egg yolk tellurite emulsion as selective medium for S. aureus and confirmed with mannitol salt agar, Gram's staining and biochemical tests. The typical cultural characters with coagulase-positive samples were taken as positive samples the positive samples were tested for antibiotic susceptibility with 10 different antibiotics by employing disc diffusion method.

Results: Prevalence of coagulase-positive S. aureus was 39.09% (43/110) from the milk samples. The antibiotic susceptibility test of positive isolates showed high resistant toward penicillin G 37/43 (86.04%) and ampicillin 32/43 (74.42%), and also showed resistant to methicillin 6/43 (13.95%), cephalothin 6/43 (13.95%), tetracycline 6/43 (13.95%), ciprofloxacin 4/43 (9.30%), enrofloxacin 3/43 (6.97%), cefoxitin 2/43 (4.65%), gentamicin 2/43 (4.65%), and co-trimoxazole 2/43 (4.65%). Many individual isolates showed resistant against two or more antibiotics in our study.

Conclusion: The above study results show that the milk samples collected from local vendor having S. aureus, which can induce disease condition as well as antibiotic resistant to the humans particularly young children and old age peoples by means of consumption of raw milk and its products. This is the public health issue, which needs to be solved by educating the local vendors regarding health problems related to unhygienic milk supply and make the awareness among the consumers about this hazards and preventive measures.