Short- and long-term effects of oral vancomycin on the human intestinal microbiota.
Level 4 - case-series / case-control
Prospective longitudinal observational study with an accompanying mouse model and no reported human control group.
PubMed 27707993 · doi:10.1093/jac/dkw383
What was done
High-throughput sequencing was performed on human fecal samples during oral vancomycin therapy and up to 22 weeks post-cessation to track short- and long-term changes in gut microbiota composition. A complementary mouse model was utilized to evaluate how vancomycin-induced microbiota disruptions affect susceptibility to colonization by an antibiotic-resistant pathogen.
What was found
During vancomycin treatment, most intestinal microbiota genera and operational taxonomic units (OTUs) were depleted in all subjects, including all baseline OTUs from the phylum Bacteroidetes. Concurrently, infection-associated genera such as Klebsiella and Escherichia/Shigella expanded. After antibiotic cessation, microbiota resilience differed markedly: while some individuals recovered close to baseline composition, others lost up to 89% of previously abundant OTUs. In mice, vancomycin induced comparable shifts, markedly increasing susceptibility to pathogen colonization during treatment and persisting in mice with less-resilient microbiota after treatment stopped.
Why it matters
This study shows that oral vancomycin causes profound, prolonged, and highly variable gut dysbiosis that can impair colonization resistance against opportunistic pathogens long after treatment ends.
Limits
The abstract does not state the human sample size, clinical indication, dosing details, or participant demographics. No untreated human control cohort is reported, and the functional link between poor microbiota recovery and increased pathogen colonization susceptibility was directly tested in mice rather than humans.
Cited by
- contradicts Following antibiotic use, the gut microbiome shifts but generally bounces back to its baseline composition after cessation of the antibiotic.