Isolation, Molecular Identification and Multidrug Resistance Profiling of Bacteria Causing Clinical Mastitis in Cows

Abstract

Background: Mastitis, the inflammation of parenchyma of mammary gland is frequently considered to be costliest and complex disease prevalent in India. Mastitis is caused by pathogens like Staphylococcus spp., Streptococcus spp., Mycoplasma bovis, E. coli, Klebsiella spp., Citrobacter spp., Enterobacter spp. and Entercoccus. The treatment of mastitis in animals is carried out using antibiotics. Treatment failure in mastitis is due to increased antibiotic resistance of mastitis pathogens and also due to indiscriminate use of antibiotics without testing in vitro antibiotic sensitivity test against causal organisms. In comparison to cultural method, PCR assays takes less time for detection of bacteria from the mastitis milk samples. Present research work was carried out regarding isolation, identification and multiple drug resistance profile of clinical bovine mastitis associated pathogens using conventional as well as molecular approach. Methods: In the present study, 73 mastitis milk samples were collected from Anand and Panchmahal district of Gujarat. The milk samples were subjected for cultural isolation and DNA extraction for identification of bacteria by cultural and PCR method. Antimicrobial sensitivity pattern of the isolates were carried by disc diffusion method and isolates were categorized in multiple drug resistant. Result: In the present study, Out of 73 mastitis milk samples collected from cows 48 (65.75%) cows were positive for bacterial isolation and S. aureus was the most predominant bacterial species. PCR from the mastitis milk additionally detected bacteria in culturally negative milk samples. Most sensitive drug was gentamicin and most of the isolates (90.19%) showed the multiple drug resistance for the two to nine drugs with 0.1 to 0.6 multiple antibiotic resistance index.