A genomic perspective on the near-term impact of doxycycline post-exposure prophylaxis on antimicrobial resistance.

Post-exposure prophylaxis with doxycycline (doxyPEP) is being introduced to prevent bacterial sexually transmitted infections (STIs). Pre-existing tetracycline resistance in limits doxyPEP effectiveness against gonorrhea, and selection for tetracycline resistant lineages may influence prevalence of resistance to other antimicrobials via selection for multi-drug resistant strains. Using genomic and antimicrobial susceptibility data from 5,644 clinical isolates of , we assessed the near-term impact of doxyPEP on antimicrobial resistance. We found that the impact on antimicrobial resistance is likely to be influenced by the strength of selection for plasmid-encoded and chromosomally-encoded tetracycline resistance, as isolates with high-level, plasmid-encoded resistance had lower minimum inhibitory concentrations to other antimicrobials compared to isolates with low-level tetracycline resistance. The impact of doxyPEP may differ across demographic groups and geographic regions within the United States due to variation in pre-existing tetracycline resistance.