Determination of Aeromonas Virulences Genes by Multiplex PCR Method
Aeromonas is recognized as an opportunistic pathogen that can affect immunocompromised people. The major virulence factors correlate with Aeromonas infection include some critical exotoxins which are important causes of bacterial pathogenesis. However the distribution of exotoxin genes are expectedly diverse across Aeromonas. To effectively identify the exotoxin genes of Aeromonas, a multiplex PCR was developed to detect the genes that encode the four important putative exotoxin genes including alt, ast, aerA and hlyA. The pathogenic potentials of thirty clinical and thirty environmental isolates were tested by using cytotoxicity and hemolysis assays. In general, a higher number of exotoxin genes were found in the clinical isolates compared with those of the environmental isolates. Through cytotoxic analysis, we found that the isolates with four exotoxin genes had higher cytotoxicity and stronger hemolysis capacity than those carrying only one gene. Our results showed that this method can effectively identify strains with virulence, and strains with more exotoxin genes were highly correlated with bacterial cytotoxicity.