Antibiotic sensitivity patterns in Staphylococcus spp. isolated from goat milk in association with molecular detection of antibiotic resistance genes

Document Type : Short paper


Department of Veterinary Microbiology, College of Veterinary Sciences, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana-141004, Punjab, India



Background: Microbes become unresponsive to the drugs used to cure their infections due to their ability to develop resistance to them. Aim: The present research work was carried out to study the patterns of phenotypic and genotypic antimicrobial resistance in Staphylococcus spp. isolated from goat milk. Methods: A total of 200 milk samples from mastitic and healthy goats from Punjab state, India were processed and Staphylococcus spp. isolates obtained were identified biochemically and by PCR.  Antibiotic sensitivity test was conducted using 15 different antibiotics. Molecular detection ofantibiotic resistance genes was done using PCR. Statistical analysis using chi-square test was done to study association between genotypic and phenotypic resistance patterns among the isolates. Results and Conclusion: A total of 47 isolates of Staphylococcus spp. were obtained of which 33 were coagulase positive and 14 were coagulase negative spp. Highest phenotypic resistance in isolates was observed to Penicillin G (91.4%). MRSA was found to be 56.25%. Amongst the antibiotic resistance genes, the most isolated genes were found to be associated with tetK (87.23%), followed by blaZ (85.10%), mecA (48.93%) and tetM (14.89%). Statistical analysis revealed that the genotypic and phenotypic resistance patterns were significantly associated in case of penicillin and methicillin resistance. Presence of antibiotic resistant Staphylococcus spp. in goat milk is of concern and needs to be addressed.


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