IDENTIFICATION OF AQUATIC BURKHOLDERIA (PSEUDOMONAS) CEPACIA BY HYBRIDIZATION WITH SPECIES-SPECIFIC RIBOSOMAL-RNA GENE PROBES

Burkholderia (Pseudomonas) cepacia is a common environmental bacterium which can be pathogenic for plants and humans. In this study, four st rategies were used to identify aquatic isolates: APL test strips, hybr idization with species-specific DNA probes for the 16S and 23S rRNA ge nes, fatty acid methyl ester (FAME) profiles, and growth on selective medium (TB-T agar [C. Hagedorn, W. D. Gould, T. R. Bardinelli, and D. R. Gustarson, Appl. Environ. Microbiol. 53:2265-2268, 1987]). Only 59% of the isolates identified as B. cepacia with the API test strips wer e confirmed as B. cepacia by using fatty acid profiles. The 23S rRNA p robe generated a few false-positive results but dramatically underesti mated the number of B. cepacia isolates (i.e., 40% of the colonies tha t did not hybridize to the probe were B. cepacia, as determined by FAM E). The 16S rRNA probe generated more false-positive results than the 23S rRNA probe but was effective in identifying the majority of the B. cepacia isolates. The selective medium was only partially successful in recovering B. cepacia. Use of the B. cepacia-specific 16S rRNA prob e was the most efficient and accurate way of identifying B. cepacia.