Vol. 10, Special Issue 8 (2021)

Author(s):
Ritu Sharma, Rajani Joshi, Deepika Dhuriya, Manohar Sain, Devendra Kumar and Chandani Jawa

Abstract:
The research work was conducted to isolate, identify and characterize Staphylococcus aureus in raw milk sold in Bikaner. Detection of S. aureus was performed on the basis of isolation, culture and colony characterization. Further, characterized by Polymerase Chain Reaction (PCR) by 23s rRNA ribotyping. One hundred milk samples were collected from various sources like dairy farms (n=30), milk pooling booths (n=30), and local milk vendors (n=40) in Bikaner, Rajasthan. Isolation of S. aureus was done on selective media mannitol salt agar (MSA) and identification of S. aureus was done by colony characteristics, Gram's staining and for biochemical tests HiStaph^TM commercial kits were used. Out of 100 raw milk samples analysed, 65 samples (16 from dairy farms, 20 from pooled milk and 29 from local vendors) were found positive for S. aureus. The prevalence of S. aureus was 53.33%, 66.67% and 72.5% for raw milk collected from dairy farms, pooled milk and local vendors, respectively. 59 out of 65 isolates of S. aureus tested were found coagulase positive. All the 65 isolates of S. aureus were subjected for molecular characterization by using species-specific primer targeting 23s rRNA gene and all were found positive for 23s rRNA gene. The value of chi square test was found 2.82 and P= 0.244 revealed that there is no significant (P>.05) association between sources of milk samples and presence of S. aureus.