Screening of Milk Borne Staphylococcus aureus for Resistance against Beta Lactam Antibiotics

DOI: 10.18805/ag.D-5123    | Article Id: D-5123 | Page : 113-115
Citation :- Screening of Milk Borne Staphylococcus aureus for Resistance against Beta Lactam Antibiotics.Agricultural Science Digest.2021.(41):113-115
B. Anurag, T. Ramasamy, S. Ramesh, K.S. Sriraam, L. Kalaiselvi, S.J. Deepak, R. Gokula Kannan, C.S. Arunaman
Address : Madras Veterinary College, Tamil Nadu Veterinary and Animal Sciences University, Chennai-600 007, Tamil Nadu, India.
Submitted Date : 2-01-2020
Accepted Date : 9-07-2020


Background: A study was carried out to screen milk borne Staphylococcus aureus for resistance against Beta lactam antibiotics. 
Methods: A total of 45 milk samples were collected over a period of three months from large animal outpatient unit of Madras Veterinary College Hospital, Chennai. Upon collection of samples, ABST followed by its growth in Mannitol Salt Agar was carried out as part of the phenotypic screening. Genotypic screening for Staphylococcus screening was done with the help of PCR by using nuc  and mec A primers. MIC for ceftriaxone and cloxacillin was carried out with the samples that were found positive for Staphylococcus aureus. The antibiotic sensitivity pattern is presented: Fluoroquinolones (87.5% sensitive), aminoglycosides (72.5% sensitive), Amoxicillin-Clavulanic acid (Amoxyclave) (72.5% sensitive). The MSA positive samples were subjected to molecular identification with the help of PCR. 
Result: The results revealed 10 samples positive for Staphylococcus aureus and 5 among them positive for mecA gene. The MIC results were as follows: MIC50-10.95µg/ml and MIC90- 87.510.95µg/ml for ceftriaxone and MIC50- 43.75 µg/ml and MIC90- 87.5µg/ml for cloxacillin, indicating emergence of resistance. However, further studies are required in a larger sample size that can help us to attain more conclusive results.


ABST Ceftriaxone Cloxacillin MIC PCR


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