GENOTYPIC DIVERSITY AMONG AEROMONAS ISOLATES RECOVERED FROM DRINKING-WATER PRODUCTION PLANTS AS REVEALED BY AFLP(TM) ANALYSIS

A novel DNA fingerprinting method, named AFLP(TM), was used to determi ne the genotypic diversity among 168 Aeromonas isolates originating fr om five drinking water production plants in Flanders, Belgium, The AFL P(TM) technique determines the genomic similarity between bacterial st rains through numerical analysis of banding patterns generated by the electrophoretic separation of selectively amplified restriction fragme nts. Using an identification library (AER094) comprising AFLP fingerpr ints of 107 well-characterized Aeromonas strains, a total of 144 isola tes (86%) could be allocated to one of the 14 DNA hybridization groups (HGs) so far recognized in the genus Aeromonas. The majority of these strains belonged to Aeromonas hydrophila HGs 2 and 3, Aeromonas cavia e HGs 5A and 5B, Aeromonas sobria HG 7, and Aeromonas veronii HG8/10. Cluster analysis of individual banding patterns revealed that eight is olates identified as Aeromonas eucrenophila HG6 were dispersed over tw o well-separated AFLP clusters, suggesting the existence of a genotypi c subdivision within this species. The remaining 24 unidentified isola tes constituted a homogeneous AFLP cluster which was found to be most closely related to HG2. Possibly, these strains may represent a curren tly unknown HG within the A. hydrophila complex. In conclusion, this s tudy clearly elucidates the taxonomic value of the AER094 database for the identification and classification of unknown aeromonads and furth er demonstrates the general applicability of AFLP-based libraries to d etermine genotypic relationships in other bacterial genera.