Abstract
Although the clinical significance of Aeromonas spp. in extra-intestinal disease is unequivocal (Altwegg, 1999), evidence for their exact causative role in gastrointestinal disorders is still not conclusive (Johnson et al., 1985). Several previous studies have attempted to determine enteric virulence factors in Aeromonas spp., but none has identified any definitive virulence determinant (González-Serrano et al., 2002; Trower et al., 2000). A more recent study in Canada detecting three haemolysin genes, ahh1, asa1 and aerA, in 121 clinical and 7 reference isolates of Aeromonas demonstrated that genotype 1 (ahh1; n=46) and genotype 4 (ahh1-aerA; n=48) were the most common. Genotype 4 isolates were also shown statistically to be more cytotoxic to Vero cell cultures (Wang et al., 2003).