Impact of doxycycline post-exposure prophylaxis for sexually transmitted infections on the gut microbiome and antimicrobial resistome

Doxycycline post-exposure prophylaxis (doxy-PEP) is a randomized clinical trial that aims to reduce bacterial sexually transmitted infections among men who have sex with men and transgender women. However, the impact of doxy-PEP on antimicrobial resistance remains a concern. A study comparing doxy-PEP use to standard of care revealed that tetracycline ARGs were detected in all day-0 DNA-seq samples and in 85% of day-0 RNA-seq samples. The proportional mass of tetracycline ARGs in the resistome increased between day-0 and month-6 in DP participants, but no statistically significant increases in other ARG classes were observed. Exposure to a higher number of doxycycline doses correlated with proportional enrichment of tetracycline ARGs in the metagenome and metatranscriptome.