Full-Assembly Genome Screening Detects More Antibiotic-Resistance Genes Than Chromosome-Only Methods
A bioRxiv preprint found that screening only chromosome-level bacterial genomes misses a significant portion of mobile antibiotic-resistance genes (ARGs), particularly those carried on plasmids. Researchers compared 50 reference genomes — 25 probiotic-associated and 25 pathogen/comparator strains — using both full-assembly and chromosome-only screening methods. The findings matter because standard genome-based safety assessments for probiotic bacteria may systematically underestimate mobile resistance cargo, though the study found high-risk loci only in pathogen genomes, not probiotic-associated ones.
Researchers screened 50 bacterial reference genomes using a reproducible bioinformatics workflow to compare full-assembly versus chromosome-only antibiotic-resistance gene (ARG) detection. Full-assembly screening identified 373 ARG loci compared to 338 in chromosome-only mode, and increased 'High-risk' mobile-context calls from 4 to 15, while recovering 32 plasmid replicons that were entirely absent from chromosome-only results. All 15 high-risk loci were found exclusively in pathogen or comparator genomes; none appeared in probiotic-associated genomes. Pathogen genomes also carried a substantially higher per-strain ARG burden on average (12.32 loci versus 0.52 for probiotic-associated strains), a difference that was statistically significant. The authors used multiple external tools — including AMRFinderPlus, ResFinder, and MOB-suite — to cross-validate findings, retaining discordant calls as flagged records for transparency. The study explicitly cautions that its results reflect in silico reference-genome-level analysis and should not be interpreted as evidence about commercial probiotic products or actual genetic transfer events.
What's missing
The study is a preprint and has not yet undergone peer review, which limits confidence in its methods and conclusions. The in silico mobile-context risk categories are predictive rather than experimentally validated — no conjugation or transfer experiments were performed to confirm actual mobility of identified ARGs.
What different sources said
- bioRxivCenter
Full-assembly screening reveals mobile antibiotic-resistance cargo missed by chromosome-only genomes
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