The mastitis caused by Streptococcus spp. in bovines is a major global issue for dairy farmers due to reduced milk production and high treatment costs. This study was designed to evaluate the molecular prevalence of Streptococcus spp. associated subclinical mastitis (SCM) along with risk factors analysis. The study also focused on the antimicrobial resistance profiling, resistance modulation strategy, and phylogenetic analysis of Streptococcus spp. A total of 384 milk samples were collected from bovines along with associated risk factor data. Streptococcus spp. isolates were phenotypically identified on the basis of hemolysis, catalase test, and esculin test on Edward’s media. Genotypic confirmation was performed by PCR targeting the 16S rRNA gene. Antimicrobial resistance profiling and drug modulation were performed to evaluate the efficacy of antibiotics with non-antibiotics compounds. A total of 157 (40.89%) animals were positive for SCM, with Streptococcus spp. phenotypically confirmed in 32 (20.38%) milk isolates. Genotypic identification revealed that 31 (19.75%) isolates were positive for Streptococcus spp. The phylogenetic analysis revealed closer resemblance of study isolates to each other and with the isolates of other countries. Antibiotic resistance profiling showed high resistance against gentamicin and trimethoprim + sulfamethoxazole, while vancomycin and penicillin showed highest efficacy against streptococci isolates. Moreover, modulation therapy revealed a synergistic effect of gentamicin with flunixin meglumine and ketoprofen. However, trimethoprim + sulfamethoxazole and oxytetracycline exhibited synergism with ketoprofen and meloxicam, respectively. This study provided the key data regarding Streptococcus spp. associated with SCM and a better therapeutic regime against the rising issue of AMR in Streptococcus spp.

To Cite This Article: Shah MH, Ijaz M, Ahmed A and Awan F, 2026. Molecular epidemiology, antibiogram profiling, and antimicrobial resistance modulation of Streptococcus spp. isolated from bovine subclinical mastitis. Pak Vet J. http://dx.doi.org/10.29261/pakvetj/2026.157