Case Report: The effect of intravenous and oral antibiotics on the gut microbiome and breath volatile organic compounds over one year

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Background: Antimicrobial resistance (AMR) is a global concern and
better understanding of the gut microbiome, a known ‘amplifier’ of
AMR, may allow future clinicians to tailor therapy to minimise this risk
and offer a personalised medicine approach. To examine the gut
microbiome, patients are required to provide faecal samples; more
convenient and cheaper solutions need to be found.
Methods: As part of a pilot study looking at how routes of
administration affect the gut microbiome in NHS patients undergoing
routine clinical management for infections, we hypothesised that
effects on the gut microbiome varied with the route and metabolism
of antibiotic used, and these changes may be reflected in breath
metabolites. We present a case report of a patient with an unusual
clinical history, alongside breath metabolite and gut microbiome data
taken before, during and after antibiotic therapy over a period of one
Results: We noted a shift in the dominant Bacteroides strain in the
patient’s gut microbiome between pre- and post-therapy samples,
along with an alteration in the composition of breath metabolites.
Conclusions: This study provides a framework for similar future work
and highlights the need for further research on the relationships
between changes in microbial gut communities and antimicrobial
exposure, patient clinical status, and the metabolites of human
Original languageEnglish
Number of pages21
Publication statusPublished - 10 Jun 2022


  • microbiome
  • Volatile organic compounds
  • antibiotics
  • breath
  • metabolites
  • resistance
  • antimicrobials

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