HIGH-RESOLUTION DIFFERENTIATION OF AEROMONADS

During a 9-month period water samples were collected monthly from 6 dr inking water production plants located in Flanders. Of 249 presumptive aeromonads isolated on ampicilline dextrin agar, 228 isolates were cl assified in the genus Aeromonas by gasliquid chromatography of cellula r fatty acid methyl esters (FAME) using a commercial database. To iden tify these isolates at the species level, we created a new and more ex tended database of FAME profiles using 70 Aeromonas reference and type strains of known hybridization groups (HGs). Our database allowed ide ntification of 186 Aeromonas isolates at phenospecies level and 125 is olates were further allocated to an existing HG. These data showed tha t A. hydrophila and A. caviae were predominant in the collected water samples. We also investigated the usefulness of a new genomic fingerpr inting technique, Amplified Fragment Length Polymorphism (AFLP). Altho ugh we observed HG-specific AFLP-patterns enabling us to characterize strains of one particular HG, strains within the same HG could be clea rly differentiated from each other. In general, identification of isol ates by the AFLP technique corresponded well with the results obtained by FAME analysis.