Specific detection of bacterial species in the gut of domestic animals with in situ hybridization and epifluorescent microscopy

Bacterial cells belonging to the species Prevotella bryantii were specifically detected in rumen samples from a black and white Frisian cow using a narrowly specific rRNA probe PBB14 and in situ hybridization combined with epifluorescent microscopy. Bacterial cells from the phylogenetic group cytophaga-flexibacter-bacteroides were also specifically detected with the broad rRNA probe PREBAC. Both probes, labelled with tertramethylrodamine isothiocyanate (TRITC) proved to be highly specific and give strong and clear signal without any or very little of nonspecific fluorescence. The positively identified cells were 2–3 times smaller, when compared to the cells of the laboratory strain P. bryantii B14, but they do exhibit a similar intensity of the signal.