Variability in the Pre-Analytical Stages Influences Microbiome Laboratory Analyses

Area of Science:

• Microbiology
• Genomics
• Bioinformatics

Background:

• Pre-analytical variables significantly impact gut microbial composition analysis.
• Inconsistent DNA extraction methods compromise data reproducibility in microbiome studies.

Purpose of the Study:

• To compare the efficacy of two distinct DNA extraction techniques on gut microbial composition.
• To identify variations in bacterial abundance and taxonomic profiles resulting from different DNA isolation procedures.

Main Methods:

• DNA was extracted from 20 fecal samples using two methods: (A) chemical/enzymatic heat lysis and (B) mechanical and chemical/enzymatic heat lysis.
• Gut microbiota was analyzed via 16S rRNA gene sequencing (V3−V9) using targeted DNA probes.
• Bacterial abundance and microbiome deviations were compared between the two extraction methods.

Main Results:

• The combined mechanical and heat lysis technique (B) resulted in a higher yield of bacterial species compared to method (A).
• Significant variations in bacterial abundance were observed between the two DNA extraction methods.
• Predominant bacteria identified included Bacteroidota, Prevotella, Bacillota, Lachnospiraceae, Veillonella, and Clostridioides, with notable differences in abundance influenced by the extraction method.

Conclusions:

• The choice of DNA extraction method significantly influences gut microbiome profiling.
• Standardization of pre-analytical DNA isolation procedures is essential for robust and reproducible microbiome research.
• An international consensus on optimal sampling and DNA isolation is needed as commercial microbiome testing becomes more accessible.