Dense Sexual Networks, Prior Antimicrobial Exposure Raise Antimicrobial Resistance and Gonorrhea Risk

Antimicrobial resistance in Neisseria gonorrhoeae infections is highly prevalent in communities that feature dense sexual connectivity networks and high rates of antimicrobial exposure, such as men who have sex with men (MSM), according to a study published in Emerging Infectious Diseases. Screening and containment of the infection, as well as education on the importance of reducing the number of sexual partners, represent the best methods for eradicating the infection in these communities.

“In our study, we reviewed various lines of evidence which suggest that the frequent screening for Chlamydia trachomatis and N gonorrhoeae in MSM is contributing to the emergence of antimicrobial resistance in this population,” Chris Kenyon, PhD, of the Institute of Tropical Medicine Antwerp told Contagion^®.

The rise of antimicrobial resistance as well as N gonorrhoeae in MSM has several possible explanations, including the higher prevalence of antimicrobial drug use in this population compared with men who have sex with women. Additionally, MSM who have HIV are also more likely to demonstrate antimicrobial resistance compared with patients without the infection. Higher sexual connectivity, or densely connected sexual networks, may also partially explain the association between MSM and N gonorrhoeae antimicrobial resistance.

According to the authors, the prevalence of sexually transmitted infections (STIs) is a function of sexual network connectivity. Considering homosexual men generally report more sexual partners per unit of time compared with heterosexual men, the higher prevalence of these infections in the MSM population reflect the effect of dense sexual networks. Antimicrobial selection pressure, which is potentially caused by extensive antimicrobial drug use, may lead to N gonorrhoeae AMR in MSM individuals. Of the 4 pathways which have been proposed to describe the antimicrobial drug-induced selection of AMR, high sexual network connectivity with exposure to antimicrobials represents an additional hypothesis proposed by the authors of this study.

Although a global screen-and-treat strategy may help eradicate N gonorrhoeae, a local screen-and-treat strategy may also be helpful in reducing the prevalence of infection in instances where the global approach falls short. For sexually-active MSM patients, the US Centers for Disease Control and Prevention (CDC) recommends N gonorrhoeae screening to take place every 3 to 12 months. Screening high-prevalence populations may be the best strategy to mitigate the spread of the infection, according to the researchers’ connectivity-antimicrobial resistance hypothesis. Both the screening and containment of the infection may prevent further proliferation in the community, resulting in a greater likelihood of eliminating its presence in this community.

Currently, there is conflicting evidence suggesting that, although screening may reduce N gonorrhoeae prevalence, it may also increase the rate of antimicrobial use. In turn, this may increase the risk of antimicrobial resistance in a highly vulnerable patient population. The authors suggest that modeling studies should assess the potential of the emergence of antimicrobial resistance with individual-based models that can include antimicrobial resistance via horizontal gene transfer. “These models could assess if the combination of high connectivity and antimicrobial exposure [is] more likely to produce and disseminate antimicrobial resistance than the combination of low connectivity and high antimicrobial exposure or of high connectivity and low antimicrobial exposure,” the authors noted.

“Randomized controlled trials are urgently called for to assess whether we are doing more harm than good with gonorrhea/chlamydia screening programs in MSM,” Dr. Kenyon concluded. Furthermore, the authors of the paper suggest that STI prevention and control strategies should be focused on minimizing the risk for antimicrobial resistance selection in instances where STI reduction strategies “are unable to attain the level of screen-and-treat coverage required to eradicate STIs (or make negligible the risk for reinfection during the period of posttreatment resistome alteration).” Approaches might include attempting to reduce the number of sexual partners as well as introduce other non-antimicrobial therapies for STIs, including antiseptics and bacteriophages.