Study on the pathogenicity and ERIC- PCR fingerprinting of 27 strains of Aeromonas hydrophila

27 strains of Aeromonas hydrophila were isolated from cultured fish in Fujian Province．Based on the 16S rDNA gene sequence and aerolysin gene sequence of A. hydrophila，the synthetic oligonucleotide primers were designed and used to perform duplex PCR amplification of the two conservative genes fragments．The resuts showed that 18 strains were pathogenic A. hydrophila，Its was 66.67% Of the strains isolated. Enterobacterial repetitive intergenic consensus sequence PCR(ERIC-PCR) was used to genotype 27 strains of A. hydrophila, By the similarity 54.00%，two special genotypes (Ⅰand Ⅱ)from the 27 isolated were identified. However,All the strains could be divided into eleven groups by the similarity 76.00%.There was a tendency that the strains from the same area could be clustered into one group. The results showed Its likely a correlation between the genotype and isolating regional among A. hydrophila strains. And ERIC-PCR was of a great significance for Molecular epidemiological investigation of A. hydrophila．