Antibiotic susceptibility of Lactococcus garvieae isolated from rainbow trout (<i>Oncorhynchus mykiss<i>) in Iran fish farms

Abstract

The rates of antibiotic susceptibility and resistance were investigated in Lactococcus garvieae isolates obtained from diseased rainbow trout. A total of 250 clinically suspected fishes were obtained from 10 rainbow trout fish farms in Chaharmahal and Bakhtyari Provinces Iran which is a major trout producing area. L. garvieae strains were isolated from fish tissues such as kidney, spleen and heart, and were identified by biochemical tests and polymerase chain reaction (PCR). All the isolates were found to be resistant to commonly used antibiotics. Resistance to different antibiotics ranged from 25 to 100% of all 52 isolates. These findings revealed a high rate of antibiotic resistance among the strains of L. garvieae which can be transferred to other bacteria.

Key words: Antibiotic susceptibility and resistance, Lactococcus garvieae, rainbow trout.