Inflammatory modulation and outer membrane vesicles (OMV) production associated to Bacteroides fragilis response to subinhibitory concentrations of metronidazole during experimental infection

•Studies on drug-bacteria are based on in vitro observations, the extent of in vivo interactions are still to be elucidated.•A massive production and release of OMV was observed after treatment with metronidazole in an animal infection model.•Along with histological evidences, OMV release may be involved in bacterial pathogenicity facing antimicrobial challenge.•This is the first report in which registry of OMV overproduction after metronidazole treatment is shown.