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: 
An individual-based transmission model of gonorrhoea infection in MSM was developed, incorporating ciprofloxacin-sensitive and resistant strains, using novel heuristic approach to capture partnership dynamics. We explored different strategies to improve treatment selection including a) discriminatory POCT, b) partner treatment based on index case susceptibility, and c) variably delayed positivity testing prior to treatment (pre-screening).

Results: 
The flexible model structure enabled us to credibly simulate London gonorrhoea transmission dynamics - assuming 2-10% prevalence and 10-50 daily diagnoses per 100,000 MSM. Simulations show that a) using POCT to detect ciprofloxacin sensitive infections resulted in a ~70% decrease in ceftriaxone doses, and b) using index case sensitivity profile to direct treatment of partners could reduce ceftriaxone use by ~27%.

Discussion: 
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

Assessing the impact of individualised treatment: an individual-based mathematical modelling study of antimicrobial resistant Neisseria gonorrhoeae transmission, diagnosis and treatment in men who have sex with men

The Joint Annual Conference of the British Association for Sexual Health and HIV & the Society for the Study of Sexually Transmitted Diseases in Ireland