Vol. 11, Issue 8 (2022)

Author(s):
M Latha Mala Priyadharshini, S Manoharan, K Viswanathan, K Porteen, B Samuel Masilamoni Ronald and G Dhinakar Raj

Abstract:
In this report, the biofilm forming character of the Staphylococcus spp isolates were characterized based on bacteriological and molecular techniques. For this study, initially milk samples were collected from lactating cows, both apparently normal and clinically affected by mastitis. Totally 110 mastitis milk samples was collected and cultured in Tryptic Soy Broth. Among this 93 samples (84.5%) showed turbidity and we found only 76 (81.7%) samples produced viable pathogens by isolation. Based on cultural morphology many types of bacterial isolates were obtained like Micrococcus spp (12); Escherichia coli (3), Klebsiella spp (2), Pseudomonas spp (5) and Bacillus spp. (7). So other viable bacterial species accounted for was 29 (26.4%) and along with Staphylococcus spp viable bacterial isolates was 110. The Staphylococcus spp. isolates obtained were 81 (87.1%) from 93 samples. Out of this 81 isolates 69 (85.2%) were from sub-clinical milk and remaining (14.8%) from clinical mastitis milk. The Antibiotic susceptibility test (AST) was done using 12 antibiotics for all isolates along with PCR typing of the bio-film forming genes in iCAD operon. The result showed that specific bio-film forming genes was present in Staphylococcus spp. and if they got amplified for at least 2 out of the 4 genes screened for the iCAD operon it had a positive correlation by exhibiting drug resistance to more than two antibiotics. Based on the amplifications of biofilm genes in Staphylococcus spp. 10 were positive for ica-A gene, 25 for ICA-D gene, 30 for ica-D gene and only 2 for ICA-A gene. The study results concluded that, the presence of biofilm gene indicates the tendency for increased resistance to antibiotics that are used in regular mastitis treatment and thereby cause recurrence.