Antibiotic resistance and virulence genes in Streptococcus agalactiae isolated from cases of bovine subclinical mastitis.

Twenty-seven Twenty-seven S. agalactiae S. agalactiae isolates obtained after screening 89 cows for subclinical mastitis were studied isolates obtained after screening 89 cows for subclinical mastitis were studied for antibiotic resistance and virulence genes.The highest resistance was found by Disc diffusion method for for antibiotic resistance and virulence genes.The highest resistance was found by Disc diffusion method for Streptomycin (85.1%) whereas the lowest resistance was found for Gentamicin (3.7%).Resistance against Streptomycin (85.1%) whereas the lowest resistance was found for Gentamicin (3.7%).Resistance against Tetracycline, Erythromycin, Co-trimoxazole, Ampicillin and Enrofl oxacin was 55.5%, 33.3%, 11.1%, 11.1%, Tetracycline, Erythromycin, Co-trimoxazole, Ampicillin and Enrofl oxacin was 55.5%, 33.3%, 11.1%, 11.1%, and 7.4% respectively.PCR based detection revealed three isolates carrying the and 7.4% respectively.PCR based detection revealed three isolates carrying the tet tetO gene associated with O gene associated with Tetracycline resistance and seven isolates carrying the Tetracycline resistance and seven isolates carrying the Erm ErmB gene associated with Erythromycin resistance.B gene associated with Erythromycin resistance.Molecular detection of virulence associated genes revealed that out of 27 isolates of Molecular detection of virulence associated genes revealed that out of 27 isolates of S. agalactiae, S. agalactiae, none none was carrying the was carrying the bca bca gene, while 6, 7, 8 and 6 isolates were positive for gene, while 6, 7, 8 and 6 isolates were positive for Scp ScpB, B, rib rib, , lmb lmb and and cyl cylE genes E genes respectively.respectively.