Molecular typing of based on coagulase gene.

Aim: This study was conducted to study the coagulase gene-based genetic diversity of , isolated from different samples of cattle using restriction fragment length polymorphism (RFLP) and their sequence-based phylogenetic analysis.

Materials And Methods: A total of 192 different samples from mastitic milk, nasal cavity, and pus from skin wounds of cattle from Military Dairy Farm, Jammu, India, were screened for the presence of . The presumptive isolates were confirmed by gene-based polymerase chain reaction (PCR). The confirmed isolates were subjected to coagulase () gene PCR. Different genotypes observed were subjected to RFLP using restriction enzymes and , to obtain the different restriction patterns. One isolate from each restriction pattern was sequenced. These sequences were aligned for maximum homology using the Bioedit softwareandsimilarity in the sequences was inferred with the help of sequence identity matrix.

Results: Of 192 different samples,39 (20.31%) isolates of were confirmed by targeting gene using PCR. Of 39 isolates, 25 (64.10%) isolates carried gene. Four different genotypes of gene, i.e., 514 bp, 595 bp, 757 bp, and 802 bp were obtained. Two genotypes, 595 bp (15 isolates) and 802 bp (4 isolates), were observed in mastitic milk. 514 bp (2 isolates) and 757 bp (4 isolates) genotypes were observed from nasal cavity and pus from skin wounds, respectively. On RFLP using both restriction enzymes, four different restriction patterns P1, P2, P3, and P4 were observed. On sequencing, four different sequences having unique restriction patterns were obtained. The most identical sequences with the value of 0.810 were found between isolate 514 (nasal cavity) and 595 (mastitic milk), and thus, they are most closely related. While as the most distant sequences with the value of 0.483 were found between 514 and 802 isolates.

Conclusion: The study, being localized to only one farm, yielded different RFLP patterns as observed from different sampling sites, which indicates that different . coagulase typeshave a site-specific predilection. Two patterns were observed in mastitic milk indicating multiple origins of infection, with 595 bp genotype being predominant in mastitic milk. The genotypes and their restriction patterns observed in the present study are novel, not published earlier. 514 and 595 variants of are genetically most related.