A new method to detect viable bacteria in natural seawater using 16SrRNA oligonucleotide probe

Abstract

Fluorescent oligonucleotide probes were used to detectVibrio cholerae directly under epifluorescence microscope. The probe which is complementary to the specific 16SrRNA sequence ofVibrio cholerae was labelled with Texas-Red, whereas the universal probe was labelled with Fluorescein. These probes allowed the distinctionVibrio cholerae from other eubacteria under the same microscopic field. In order to detect and enumerate specific bacteria in natural seawater, this method was combined with the direct viable count (DVC) technique. The combined method increased intracellular rRNA levels in the sample, and made it possible to detect the target bacteria with the specific gene probe. The applicability of this new method was confirmed both for the laboratory mixed culture system and natural seawater.