Determination of antibiotic resistance profiles of Lactococcus garivieae isolated from rainbow trout (Oncorhynchus mykiss) farms in Muğla, Turkey

Abstract

This study was aimed to determine the current antibiotic resistance of Lactococcus garvieae, which causes significant economic losses in rainbow trout (Oncorhynchus mykiss) farms. For the study, three farms located around a stream were visited in two consecutive disease outbreaks. Bacteria were isolated from the diseased fish and all bacterial isolates were identified using conventional and molecular methods. Then, they were examined for 5 different antibiotic resistance genes and their antibiotic susceptibility profiles were determined using the disc diffusion technique. The results of the study revealed that all 16 isolates had a different antibiotic resistance profile and each should be considered as a separate strain. Additionally, they showed that there may be different L. garvieae strains within and between farms, using the same water source. Comparison of the results with previous studies from the region and different regions of the country revealed that antibiotic resistance is increasing in L. garvieae, and screenings on a limited number of isolates may not give an accurate picture of the final status of antibiotic resistance. These outcomes of the study are discussed in terms of treatment strategies that trout farms in the region should follow when treating lactococcosis.

Characterization of Lactococcus garvieae and Streptococcus agalactiae in cultured red tilapia Oreochromis sp. in Thailand

“…Our results for Thai isolates of L. garvieae that were resistant to norfloxacin, oxolinic acid, and flumequine but highly susceptible to ampicillin and amoxicillin agreed with results for Rainbow Trout L. garvieae isolates from Turkey (Sezgin et al. 2023). Differences in the degree of susceptibility of L. garvieae to enrofloxacin, sulfamethoxazole/trimethoprim, oxytetracycline, ampicillin, and flumequine have been reported in Rainbow Trout from diverse geographic origins (Chang et al.…”

“…The L. garvieae and S. agalactiae isolates from this study showed either resistance or developing resistance to quinolones, including norfloxacin, oxolinic acid, flumequine, and enrofloxacin, while revealing susceptibility to other antimicrobial classes, such as βlactams, tetracyclines, and folate pathway antagonists. Our results for Thai isolates of L. garvieae that were resistant to norfloxacin, oxolinic acid, and flumequine but highly susceptible to ampicillin and amoxicillin agreed with results for Rainbow Trout L. garvieae isolates from Turkey (Sezgin et al 2023). Differences in the degree of susceptibility of L. garvieae to enrofloxacin, sulfamethoxazole/trimethoprim, oxytetracycline, ampicillin, and flumequine have been reported in Rainbow Trout from diverse geographic origins (Chang et al 2002;Didinen et al 2014;Balta and Balta 2019;Karami et al 2019).…”

Antibiotic susceptibility and resistance genes profiles of Vagococcus salmoninarum in a rainbow trout (Oncorhyncus mykiss, Walbaum) farm

“…The methodology employed in tests for antibiotic susceptibility can have an impact on the outcomes ( Sezgin et al, 2023 ). In accordance with the most recent CLSI recommendations ( CLSI, 2021 ), we employed 5% sheep blood-added MHA (SB-MHA) to assess the antibiotic susceptibility of the microorganisms.…”

“…A digital caliper was used to measure the diameter of the inhibition zones that formed around the antibiotic discs at the end of the incubation period. Based on this measurement and related references ( Sezgin et al, 2023 ), the isolates were categorized as susceptible, moderately susceptible, and resistant.…”

Lactococcus garvieae–associated septicemia in a central bearded dragon

“…Treatment of L. garvieae infection in the human literature has included the use of ceftazidime or other third-generation cephalosporins including ceftriaxone; however, recent antimicrobial susceptibility tests have not included ceftazidime among the other cephalosporins tested. 3,8,22,24 Given the zoonotic concerns surrounding L. garvieae and the popularity of bearded dragons as pets, the isolation of this pathogen from the species is important. Future studies to determine the prevalence, ecology, and epidemiology of L. garvieae in the reptile pet trade are indicated.…”