Screening and in-vitro antibiogram pattern of antibiotics against enterotoxic bacteria staphylococcus aureus from the milk samples

Staphylococcus aureus is a leading cause of food poisoning resulting from the consumption of contaminated food with Staphylococcal enterotoxins. Different food can act as a good medium for S. aureus such as milk and milk products. In the present study differential conventional methods were used to detect the S. aureus isolates from 30 samples of milk were collected from different regions of Tamil Nadu. Among that 23 samples showed positive results and 7 samples showed negative results for S. aureus. The bacterial isolates were tested with gram staining, motility test, indole test, catalase test, oxidase test, methyl red test, Voges-proskauer test, urease test etc. The S. aureus isolates were found different kind of antibiotic resistant against the antibiotics like Clindamicin, Methicillin, Nitrofurantoin, Pencillin and Tobramycin. The S. aureus isolates were analyzed by biofilm formation and coagulase negative test. Among the 23 isolates 52.1% showed positive result on biofilm formation and 39% showed coagulase negative. Based on the biofilm formation, methicillin susceptability, coagulase negative tests the 23 isolated were classified as A, B, C, D, E and F. The highest isolates was observed in biotype A (21.8%), followed by D (17.4%), G (13.04%) B, C, E, F (8.7%) respectively. Among these 13.04% of isolates were not comes under any one of these category. Our study result indicates that samples of examined raw milk contained S. aureus. The presence of S. aureus in milk represents a public health threat. Hence, there is an urgent need for more strict and hygienic preventive measures to reduce the bacterial contamination, so as to increase the wholesomeness and quality of these milk and milk based products for the good health of all consumers. It is essential to prevent risks of contamination of S. aureus from the point of production to the point of consumption of milk.