Introduction Antimicrobial resistant (AMR) gonorrhoea is a global public health threat. In London, diagnoses in men who have sex with men (MSM) have more than quadrupled from 2010 to 2015. Importantly, our last-line treatment (ceftriaxone) is used in first-line dual therapy. However, over half of tested isolates are still sensitive to older drugs, e.g. ciprofloxacin. Discriminatory point-of-care tests (POCT) to detect drug sensitivity are under development, enabling individualised treatment decisions.
Methods We developed an individual-based transmission model of gonorrhoea infection in MSM, incorporating ciprofloxacin-sensitive and resistant strains. The cumulative contact network is captured by periodically restricting active connexions to reflect the transience of high degree contacts. We explored different strategies to improve treatment selection including a) discriminatory POCT, and b) selecting partner treatment based on index case susceptibility. Outcomes included population prevalence and percentage reduction in ceftriaxone doses. Additional sensitivity analyses simulated the impact of reducing delays in the patient pathways on gonorrhoea prevalence.
Results The flexible model structure enabled us to efficiently explore a large region of parameter space, and credibly simulate London gonorrhoea transmission dynamics - assuming 2%–10% prevalence and 10–50 daily diagnoses per 100,000 MSM. Initial simulations show that a) using POCT to detect ciprofloxacin sensitive infections resulted in a 66% decrease in ceftriaxone doses, and b) using index case sensitivity profile to direct treatment of partners could reduce ceftriaxone use by 25%.
Conclusion POCT are likely to dramatically reduce reliance on ceftriaxone. In the meantime, we could use existing data more informatively. If lab turnaround times are fast enough, index case sensitivity profiles could be used to select effective treatments for partners. This new framework addresses limitations of previous models and provides a flexible platform for exploring control options for AMR gonorrhoea.