The prevalence of plasmid-mediated quinolone resistance genes in Chryseobacterium aquaticum isolated from farmed salmonids in Turkey

Satıcıoğlu İ. B. , Duman M., Altun S.

19th International Conference on Diseases of Fish and Shellfish, Porto, Portugal, 9 - 12 September 2019, pp.108

  • Publication Type: Conference Paper / Summary Text
  • City: Porto
  • Country: Portugal
  • Page Numbers: pp.108


Introduction: The aquatic environment can serve both as a natural reservoir of antibiotic resistance

genes and the spreading of bacteria and antimicrobial resistance genes to environment.

Plasmid-mediated quinolone resistance (PMQR) genes represent an important challenge to the

effectiveness of quinolones in the treatment of human and animal infections. In this study, 70

Chrysobacterium aquaticum isolates recovered from farmed salmonids in Turkey were analyzed

for PMQR genes.

Methodology: C. aquaticum strains were recovered from farmed salmonids in Turkey, 2013-

2017 and identified with 16S rRNA sequence analysis. Quinolone susceptibility among the

strains was determined using minimum inhibitory concentration method against oxolinic acid,

and the frequency of PMQR genes (qnrA, qnrB, qnrS) was investigated by PCR.

Results: The isolates recovered from farmed rainbow trout exhibiting clinical signs such as

darkening of skin color, exophthalmia, and caudal fin root were identified as C. aquaticum.

The rates of reduced susceptibility in phenotypically were determined for oxolinic acid (89%).

Of the 70 isolates, 28 (40%) isolates harbored qnrA, 23 isolates (32%) harbored qnrS and 17

isolates (24%) have both qnrA and qnrS. None of the isolates harbored qnrB.

Conclusion: This is the first report of C. aquaticum recovered from rainbow trout in Turkey.

Its pathogenicity was not assessed previously. Further research is needed for determining the

virulence mechanisms and pathogenesis of C. aquaticum. Our findings showed high rates of

quinolone resistance (89%) and qnr genes, underlining the importance of aquatic environment

as reservoirs for the dissemination of potentially possible C. aquaticum and horizontal gene

transfer between other waterborne bacterial species. Other possible mechanisms of resistance

should also be investigated for better characterization of quinolone-resistant C. aquaticum


Keywords: Chrysobacterium aquaticum, antimicrobial resistance, rainbow trout, plasmid-mediated

quinolone resistance genes

Funding: The Research Fund of Erciyes University, project number TCD-2018-8586.