Year: 2021 | Month: April | Volume 11 | Issue 2

Antimicrobial Resistance and Biofilm Production Potential of Staphylococci from Bovine Mastitis in Andhra Pradesh

Bhavana R.N. Chaitanya R.K. Vinod Kumar N. Sreedevi B.


Bovine mastitis is a frequent cause of economic loss to dairy farmers. This study is aimed at investigating the biofilm formation ability and antimicrobial resistance of Staphylococci from bovine mastitis. Among a total of 125 Staphylococcal isolates obtained from cows and she buffaloes with clinical and subclinical mastitis, 45 were coagulase positive (CPS) and 80 were identified as coagulase negative (CoNS) by tube coagulase test. Considerably high proportion of Staphylococcal isolates (56/125, 45%) formed biofilms on Congo red agar and when these isolates were screened for biofilm genes (icaA, bap, icaAB, aap), only four (7.2%) were found to possess bap gene. The icaA, icaAB and aap genes were not detected in any of the isolates. Majority of the CPS and CoNS isolates from our study (around 96%) were susceptible to ciprofloxacin and ceftriaxone, but most of them were resistant to gentamicin (100% of CPS and 92.5% of CoNS). The isolates (49/125, 39.2%) that showed resistance to cefoxitin were phenotypically identified as methicillin resistant, out of which 10 were MRSA and 39 were CoNS. In PCR for mecA and mecC genes, only eight isolates (8/125, 6.4%) of Staphylococci were found to possess mecA gene. None of the isolates carried mecC gene. The results suggest that the CoNS isolates (44.8%) from bovine mastitis had the potential to form biofilms and has considerably high (49%) methicillin resistant phenotype though only 6.25 per cent of them carried mecA gene and could be confirmed as MRCoNS.


  • Only 6.4% of the Staphylococcal isolates possessed ‘mecA’ gene that confers methicillin resistance.
  • 44.8% of the CoNS isolates showed biofilm production ability on Congo red agar.
  • Only in 7.2% of the Staphylococcal isolates ‘bap’ gene was detected.

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@ Journal of Animal Research | In Association with Association of Mastitis

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