Quantification of Different Eubacteriumspp. in Human Fecal Samples with Species-Specific 16S rRNA-Targeted Oligonucleotide Probes
ABSTRACTSpecies-specific 16S rRNA-targeted, Cy3 (indocarbocyanine)-labeled oligonucleotide probes were designed and validated to quantify differentEubacteriumspecies in human fecal samples. Probes were directed atEubacterium barkeri,E. biforme,E. contortum,E. cylindroides(two probes),E. dolichum,E. hadrum,E. lentum,E. limosum,E. moniliforme, andE. ventriosum. The specificity of the probes was tested with the type strains and a range of common intestinal bacteria. With one exception, none of the probes showed cross-hybridization under stringent conditions. The species-specific probes were applied to fecal samples obtained from 12 healthy volunteers.E. biforme,E. cylindroides,E. hadrum,E. lentum, andE. ventriosumcould be determined. All otherEubacteriumspecies for which probes had been designed were under the detection limit of 107cells g (dry weight) of feces−1. The cell counts obtained are essentially in accordance with the literature data, which are based on colony counts. This shows that whole-cell in situ hybridization with species-specific probes is a valuable tool for the enumeration ofEubacteriumspecies in feces.