Yersinia enterocolitica as a cause of septicemia in crucian carp (Carassius carassius)

Yersinia enterocolitica is an important pathogen to animals and humans. Thirteen strains of Y. enterocolitica were isolated from diseased fish. The partial ۱۶SrDNA gene, five virulence genes, pathogenicity, and drug resistance of Y. enterocolitica strain G۶۰۲۹ were studied using molecular biological technology and toxicological method. Results showed that the length of amplified ۱۶SrDNA sequence was ۱۴۴۸bp, and revealed ۹۹% homology with Y. enterocolitica. Its GenBank accession number was JX۸۵۵۱۳۵. Five virulence genes (ail, ystB, yadA, virF and HPIint) were detected, and only yadA gene was not seen. Twenty-eight crucian carps that were injected with strain G۶۰۲۹ died within a week, and the mortality was ۹۳.۳%, indicating highly pathogenic attribute of this strain. In addition, the strain G۶۰۲۹ was resistant to four antibiotics (sulfafurazole, furazolidone, enrofloxacin and norfloxacin), but it was susceptible to six antibiotics (florfenicol, vibramycin, cefaloridine, ciprofloxacin, streptomycin, and ampicillin). Further study of pathogenicity of Y. enterocolitica in teleost fish is suggested.

Keywords:

Yersinia enterocolitica , Virulence gene , Pathogenicity , Carassius auratus