Antimicrobial profiles determination of Lactococcus garvieae strains isolated from diseased rainbow trout (Oncorhynchus mykiss)

In this study, fish were sampled from 12 different fish farms in Eastern Black Sea Region between January 2014 and September 2017. It was isolated hundred bacteria isolates from diseased rainbow trout (Oncorhynchus mykiss). All isolates identification were carryed out using conventional 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 65 isolates from 100 bacterial isolates were Lactococcus garvieae. The PCR assay was determined using the reference genes pLG-1 and pLG-2 (16S rRNA) specific for the L. garvieae species. As a result of the study, it was confirmed that there were 68 L. garvieae from 100 strains isolated from rainbow trout. 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. According to the antibiogram test results, one of the most effective antibiotics florfenicol, amoxycline and doxycycline was recommended to the fish farmers for the treatment of the disease.