Antibiogram of mastitis pathogens in the milk of crossbred cows in Namakkal district, Tamil Nadu

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. [Vet World 2013; 6(6.000): 354-356

Isolation, biochemical and molecular identification, and in-vitro antimicrobial resistance patterns of bacteria isolated from bubaline subclinical mastitis in South India

Buffaloes are the second largest source of milk. Mastitis is a major impediment for milk production, but not much information is available about bubaline mastitis, especially subclinical mastitis. The aim of this study was to (a) investigate the application of various tests for the diagnosis of bubaline subclinical mastitis, (b) identify the major bacteria associated with it, and (c) evaluate the antibiotic resistance pattern of the bacteria. To this end, 190 quarter milk samples were collected from 57 domesticated dairy buffaloes from organized (64 samples) and unorganized (126 samples) sectors. Of these, 48.4%, 40.0%, 45.8%, 61.1%, and 61.6% were positive for subclinical mastitis by somatic cell count, electrical conductivity, California mastitis test, bromothymol blue test, and N-acetyl glucosaminidase test, respectively. As compared to the gold standard of somatic cell count, California mastitis test performed the best. However, a combination of the two methods was found to be the best option. Microbiological evaluation, both by biochemical methods as well as by monoplex and multiplex polymerase chain reaction, revealed that coagulase-negative staphylococci were the most predominant (64.8%) bacteria, followed by streptococci (18.1%), Escherichia coli (9.8%) and Staphylococcus aureus (7.3%). Most of the pathogens were resistant to multiple antibiotics, especially to β-lactam antibiotics. We propose that California mastitis test be combined with somatic cell count for diagnosis of subclinical mastitis in domestic dairy buffaloes. Further, our results reveal high resistance of the associated bacteria to the β-lactam class of antibiotics, and a possible major role of coagulase-negative staphylococci in causing the disease in India