EVALUATION OF THE FLOURESCENCE IN SITU HYBRIDIZATION TECHNIQUE FOR DETECTION OF EUBACTERIA AND SULFATE-REDUCING BACTERIA FROM SAMPLES OF WATER IN OIL FIELDS

The detection, identification and confirmation of microorganisms from cultures and environmental samples of waters from oil fields representing the population of its habitat can be achieved with greater confidence with FISH than with other techniques. In this work we describe our experience in the use of FISH to evaluate the microbial composition of sulfate-reducing bacteria (SRB) cultures and direct samples of waters from oil fields. Composition of the microbial community by DAPI and Fluorescent in situ hybridization (FISH) for 16S rRNA with probes EUB338, for general Eubacteria, SRB-385, group specific for SRB and major species of delta-Proteobacteria, DSV-698, Desulfovibrio-specific and, DSB-129 (SRB-129), Desulfobacteriaceae-specific revealed that 98% of total cells stained with 4', 6-diamidino-2-phenylindole (DAPI), within these 61, 51 and 0% respectively bound to the probes. This indicated that SRB and, especially Desulfovibrio, were the dominant Eubacteria in the whole community of water samples from oil fields. Modifications made to the formamide, NaCl and probe concentrations for hybridization, represented refinements of the experimental conditions utilized by previous investigators.