ANTIMICROBIAL RESISTANCE IN Streptococcus agalactiae IN TILAPIA (Oreochromis sp.) FARMING IN NORTHERN VIETNAM

Antimicrobial resistance (AMR) is a threat to animal and human health globally. Antimicrobials are used in aquaculture to control different bacterial diseases. However, inappropriate use of antimicrobials can accelerate the emergence of AMR. This study was conducted to determine antimicrobial resistance in Streptococcus agalactiae, which affects and causes diseases with high mortality in tilapia. A total of 26 S. agalactiae isolates were streaked from kidney/brain/liver samples of diseased farmed tilapia from 2017 to 2021 at Hai Duong, Bac Ninh, Hoa Binh, Yen Bai provinces. The sensitivity of the isolates to 7 antimicrobials was established by disc diffusion (Oxiod). The results showed that levels of resistance vary from S. agalactiae to DOX (34.4%), RIF (64.1%), TET (45.0%), ERY (64.8%), TMPSMX (70%), FLO (35.3%), and AMP (75%). The resistance rate to DOX was significantly different (p