Absolute quantification of microbial taxon abundances.

Area of Science:

• Microbiology
• Molecular Biology
• Ecology

Background:

• High-throughput amplicon sequencing (e.g., 16S rRNA gene) is standard for microbial community profiling.
• Microbiome surveys aim to link bacterial taxon shifts to environmental factors.
• Current sequencing methods yield semi-quantitative data, potentially misrepresenting actual taxon densities.

Purpose of the Study:

• To combine 16S rRNA gene sequencing with flow cytometry for absolute microbial taxon abundance quantification.
• To analyze longitudinal changes in absolute abundances for clearer microbial community profiling.
• To investigate the relationship between relative and absolute taxon abundance changes.

Main Methods:

• Utilized high-throughput 16S rRNA gene amplicon sequencing.
• Employed robust single-cell enumeration via flow cytometry.
• Conducted detailed longitudinal analysis of absolute taxon abundances.

Main Results:

• Absolute abundance profiling provided less ambiguous and directly comparable data across studies.
• Demonstrated that increased relative abundance (enrichment) does not always correlate with increased absolute abundance (outgrowth).
• Distinct abundance profiles were observed when analyzing absolute rather than relative abundances.

Conclusions:

• Absolute taxon abundance quantification is crucial for accurate microbiome survey interpretation.
• Relying solely on relative abundances can lead to misinterpretations of microbial community dynamics.
• Integrating absolute and relative abundance data provides a more comprehensive understanding of microbial ecology.