Variations of Bacterial Populations in Human Feces Measured by Fluorescent In Situ Hybridization with Group-Specific 16S rRNA-Targeted Oligonucleotide Probes
Longitudinal study reveals baseline bacterial fluctuations in human feces, indicating that natural variations must be considered when evaluating flora-modulating agents.
Key Points
To design, validate, and apply group-specific 16S rRNA-targeted oligonucleotide probes using fluorescent in situ hybridization to quantify predominant anaerobic bacteria in human fecal samples.
Designed six oligonucleotide probes targeting specific anaerobic bacterial groups, validating dissociation temperatures and specificity using dot blot hybridization and fluorescent in situ hybridization (FISH).
Conducted longitudinal FISH profiling to monitor fecal microbial composition across nine volunteers over an eight-month follow-up period.
The Clostridium coccoides-Eubacterium rectale and Bacteroides-specific probes detected the highest bacterial abundances, averaging 7.2 × 10¹⁰ and 5.4 × 10¹⁰ cells per gram of dry feces, respectively.
Probes targeting Clostridium histolyticum, Clostridium lituseburense, and Streptococcus-Lactococcus groups measured lower abundances, ranging from 1 × 10⁷ to 7 × 10⁸ cells per gram of dry feces.
The multi-probe combination successfully enumerated at least two-thirds of the total fecal flora and demonstrated notable natural baseline variation over eight months.