Discipline: Public Health
The aim of this research was to isolate, identify and determine tetO resistance genes in tetracycline-resistant Streptococcus agalactiae isolated from cows with subclinical mastitis in Surabaya and surrounding areas of Indonesia. Milk samples from cows with subclinical mastitis in six dairy farms were collected. S. agalactiae was isolated and antibiotic resistance was determined. Results showed that out of 173 samples analyzed, 131 (75.7%) were positive for California Mastitis Test. S. agalactiae was isolated in 36 out of the 131 CMT-positive samples. Antibiotic sensitivity test revealed that out of 36 S. agalactiae samples, nine were resistant to tetracycline. PCR analysis showed that six of the nine tetracycline resistant S. agalactiae isolates were positive for the tetO resistance genes.