Simultaneous enumeration of viable Enterobacteriaceae and Pseudomonas spp.  within three hours by multicolor fluorescence in situ hybridization with vital staining. 
A new means of rapidly and simultaneously counting viable phylogenetically different bacteria was developed.  The cyanine dimer dye, BOBO-3 that selectively stains bacteria with damaged membranes were used to evaluate bacterial viability based on membrane integrity.  Viable Enterobacteriaceae and Pseudomonas spp.  could be selectively detected within three hours using multicolor fluorescence in situ hybridization (FISH) following BOBO-3 staining (BOBO3-FISH).