Quantification of bacterial groups within human fecal flora by oligonucleotide probe hybridization

To investigate the population structure of the predominant phylogenetic gro ups within the human adult fecal microbiota, a new oligonucleotide probe de signated S-G-Clept-1240-a-A-18 was designed, validated, and used with a set of five 16S rRNA-targeted oligonucleotide probes. Application of the six p robes to fecal samples from 27 human adults showed additivity of 70% of the total 16S rRNA detected by the bacterial domain probe. The Bacteroides gro up-specific probe accounted for 37% +/- 16% of the total rRNA, while the en teric group probe accounted for less than 1%. Clostridium leptum subgroup a nd Clostridium coccoides group-specific probes accounted for 16% +/- 7% and 14% +/- 6%, respectively, while Bifidobacterium and Lactobacillus groups m ade up less than 2%.