Aim: The present 
study was undertaken to ascertain the prevalence and drug sensitivity pattern of 
causative agents of mastitis in and around Namakkal, Tamilnadu, India. 
 
Materials and Methods: A total of 74 milk samples were collected and 
bacterial isolates from 72 samples were obtained and subjected to in-vitro 
chemotherapeutic sensitivity test. 
 Results: Out of 72 samples, 32 
(44.44%) were found positive for Staphylococci species, 4 (5.5%) for 
Streptococci species, 30 (41.66%) for E.coli and 6 (8.33%) for Klebsiella 
species. The drug sensitivity test performed irrespective of isolates, revealed 
sensitivity of organisms to various antibiotics and none of the isolates were 
found to be sensitive to penicillin G. 
 Conclusion: Enrofloxacin was found 
to be more effective antibiotic among all the tested antibiotics. 
 Keywords:
antibiogram, bacterial isolates, mastitic milk.