Daily sampling reveals rapid microbiota alterations and antimicrobial resistance gene acquisition during intercontinental travel

Abstract With increasing global travel, individuals are frequently exposed to new diets, environments, and microbial communities that may influence gut microbiota dynamics and facilitate the acquisition of antimicrobial resistance genes (ARGs). At present, studies characterising day-to-day microbiota and ARGs dynamics during travel are lacking. This study aimed to elucidate the short-term effects of travel on gut microbiota dynamics and ARG acquisition using a high-frequency sampling approach. A cohort of eleven Dutch travellers to Asia self-collected 254 fecal swabs before, during, and after travel for microbiota and resistome profiling. Samples were analysed using qPCR targeting clinically relevant ARGs ( qnrB, qnrS and bla CTX-M ) and profiled by 16S rRNA gene amplicon sequencing. Longitudinal analyses revealed pronounced inter- and intra-individual variation, with rapid shifts in microbiota composition observed within the first days of travel. An increase in Enterobacterales and a decline in commensal taxa were detected during early travel, coinciding with swift ARG acquisition. These findings underscore the key role of travel in global ARG dissemination.