Aeromonas belongs to the family Aeromonadaceae, which are commonly found in aquatic environments. They are opportunist pathogens and causes infections due to the possession of various virulence gene. We isolated and molecularly characterized Aeromonas spp. from different water samples (surface water, waste water, and portable water) in the North-East of Tamaulipas. The isolates were molecularly identified by the sequencing of the gyrB gene. The potential pathogenicity of the isolates was investigated by the PCR amplification of the hemolysin virulence genes (aerA and hlyA) commonly found in Aeromonas species. Three Aeromonas species consisting of 123 strains were identified in this study. The species include A. veronii (43.75%), A. hydrophila (43.75%) and A. caviae (12.50%). The amplification of the virulent genes in the isolates revealed that 89 strains possess the aerA hemolytic gene while 31 strains possess the hlyA gene. The strains which possess aerA gene include, 39 from surfac, 49 wastewater and 1 from portable water. On the other hand, none from portable water possess the hylA gene while 12 from surface water and 19 from wastewater has the hylA genes. The recovery of Aeromonas spp. from different water samples particularly portable water supply make portable water potential source through which Aeromonas infection can be transferred and thus must be properly treated before public distribution. This observation also emphasizes the need for adequate public hygiene.

Keywords : Aeromonas, Virulence, Infections, Genes, Water.