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Microbiological surveys conducted by the U.S. Environmental Protection Agency (USEPA) of finished drinking water utilities fromfour states, during 2000 / 2001, yielded 205 Aeromonas isolates. A Polymerase Chain based(PCR) based genetic characterization of these isolates determined the presence of six virulencefactor genes: elastase (ahyB), lipase (pla), the flagella A and B genes (fla) and three enterotoxins(alt, act and ast). Primer sets were designed for all the target genes, except for act, which hadbeen published previously. PCR was performed in three duplex assays using the followingprimer sets together: elastase (ahyB) and lipase (pla); fla and alt ; act and ast. pla was presentin 86%, act in 69%, fla in 55%, ahyB in 40% and alt and ast in 45% and 30% of the strains,respectively. Only one isolate had all six virulence genes. Multiple species were isolated frommost of the utilities and different combinations of virulence factors were observed, sometimeseven in different strains of the same species. However, a dominant strain having the same set ofvirulence factors, was usually isolated from different rounds of sampling from a single tap.These results suggest the importance of examining as many Aeromonas isolates as possible froma water sample. The results indicate Aeromonas strains isolated from water utilities have thepotential to be pathogenic, although additional hitherto uncharacterized virulence factors may beneeded to cause actual disease. Includes 34 references, tables, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 11File Size: 1 file , 2.2 MB