Antibiotic use in the past 8 years and gut microbiota composition

BACKGROUNDDisruptions in gut microbiota have been implicated in cardiometabolic disorders and other health outcomes. Antibiotics are known gut microbiota disruptors, but their long-term consequences on taxonomic composition of the gut microbiome remain underexplored. MO_SCPLOWETHODSC_SCPLOWWe investigated associations between register-based oral antibiotic use over 8 years and gut microbiota composition assessed with fecal shotgun metagenomics in 15,131 adults from the Swedish population-based studies SCAPIS, MOS, and SIMPLER. We applied multivariable regression models with the number of prescriptions in three pre-specified periods before fecal sampling (<1 year, 1-4, 4-8 years) as the main exposures and adjusted for sociodemographics, lifestyle, and comorbidities. Secondary analyses included participants with only one antibiotic course or none. RO_SCPLOWESULTSC_SCPLOWAntibiotic use <1 year before fecal sampling was associated with the greatest reduction in gut microbiota species diversity; however, antibiotic use 1-4 years and 4-8 years earlier was also associated with decreased diversity. Clindamycin, fluoroquinolones, and flucloxacillin accounted for most of the associations between antibiotic use and the abundance of individual species across all periods. Use of these three antibiotics 4-8 years earlier was associated with altered abundance of 10-14% of the species studied; use of penicillin V, extended-spectrum penicillins, and nitrofurantoin were associated with altered abundance of only a few species. Similar results were found when comparing one antibiotic course 4-8 years before sampling vs. none in the past 8 years. CONCLUSIONCommonly prescribed antibiotics like clindamycin, fluoroquinolones, and the narrow-spectrum flucloxacillin appear to have long-lasting consequences for the gut microbiota.