Commensal Neisseria and Antimicrobial-Resistant Gonorrhea

Alongside the crisis of antimicrobial-resistant gonorrhea is the threat of bystander selection on commensal Neisseria. As Neisseria species are permissive to gene flow across lineages, their evolutionary fates are irrevocably intertwined. Horizontal gene transfer (HGT) within the genus occurs through transformation and exchange of plasmids through conjugation. Both mechanisms of HGT threaten the long-term efficacy of antimicrobial treatments, with resistance passed between commensals and pathogens multiple times (e.g., mosaic penA and mtr alleles). Here, we underscore the importance of commensal Neisseria as a bubbling cauldron of adaptive solutions for pathogenic Neisseria, review the mechanisms of resistance harbored by commensals and transferred to the gonococcus, and discuss the impact of contemporary selective pressures on the future evolutionary trajectory of the genus. Ultimately, we believe that predicting the future efficacy of antimicrobials for the treatment of gonorrhea will only be successful if the commensal Neisseria are also considered.