The Isolation of Lactococcus garvieae from Eyes of Diseased Rainbow Trout (Oncorhynchus mykiss) with Exopthalmia

Abstract

In this study, fish were sampled from 9 different fish farms in the dam lakes in the Eastern Black Sea Region between January 2016 and September 2018. It was isolated twenty-two bacteria isolates from eyes of diseased rainbow trout (Oncorhynchus mykiss). All isolates identification was carried out by using conventional biochemical tests, api 20 strep tests and PCR tests. ATCC 43921 reference strain was used as a positive control. According to results of the api 20 strep test, it was determined that 20 isolates from 22 bacterial isolates were Lactococcus garvieae. The PZR test was confirmed by using the pLG-1 and pLG-2 reference genes (16S rRNA) specific for the L. garvieae species. As a result of the study, it was confirmed that there were 20 L. garvieae from 22 strains isolated from rainbow trout in the dam lakes fish farms. The antibiotic susceptibility test results showed that L. garvieae isolates were resistant %100 to streptomycin, sulfamethoxazole and sulfamethoxazole+trimethoprim, 94.2% to ampicillin, 72.5% to oxytetracycline, 55.07% to erythromycin and 43.5% to oxolinic acid, 26.09% to enrofloxacin, % 20.3 doxycycline, 8,7% to amoxicillin and florphenicol. The most effective antibiotic was found to be florfenicol, amoxicillin, doxisicline and enrofloxacin.