ABSTRACT
On monthly intervals and over a period of 14 months (November, 1993-December, 1994) biofilm samples from sediments taken at the Szentendre Island on the Danube were culturel and the isolated organisms were examined macromorphologically and micromorphogically and tested for oxidase and catalase production and their ability to oxidise and ferment glucose. The majority (85%) of the strains isolated were catalase positive. 43% were oxidase positive, 38% were glucose oxidisers and only 19% fermented glucose. In the sediment upmost biofilm layers Gram-negatives dominate (10 samples out of 14). A representative set strains has been subjected to complete identification using the Biolog automated identification system. The coryneform bacteria (e.g. Arthrobacter spp.) and members of the genus Rhodococcus dominated the Gram-positive bacteria while the dominant Gram-negative bacteria were facultative H2 autotrophs, methylotrophs (e.g. Xanthobacter flavus, Hydrogenophaga spp.) and different Aeromonas, Enterobacter and Pseudomonas species. Because the water supply of Budapest (the capital of Hungary) comes from bankwall filtred Danube water resources, the presence of clinically important microorganisms (i.e. Aeromonas, Enterobacter, Pseudomonas and Rhodococcus spp) in the Danube-sediments may pose a public health problem to the users (in particular the immunocompromised) of such water supplies.
