Detection of type 1 fimbrial genes in fish pathogenic and non-pathogenic Edwardsiella tarda strains by PCR

Presence of fimbrial genes among fish pathogenic and non-pathogenic strains of Edwardsiella tarda was investigated by polymerase chain reaction (PCR). Four primer sets for PCR were designed to detect the four genes (etfA, etfB, etfC, etfD) of the type 1 fimbrial gene cluster of E. tarda. All the four genes were successfully amplified with the four primer sets in all the pathogenic strains. On the other hand, any of etfA, etfB and etfC were not detected in 13 of 14 non-pathogenic strains. The results suggest that fimbriae play a role in the pathogenicity of E. tarda and that detection of etfA, etfB and etfC by PCR is useful to distinguish between pathogenic and non-pathogenic strains of E. tarda.