PhD project

Neisseria gonorrhoeae is a WHO priority pathogen as the incidence of gonococcal disease and the extent of antimicrobial resistance (AMR) is increasing. This host adapted pathogen has a limited repertoire plasmids, with two conferring AMR. These plasmids are of particular public health importance, as the implementation by UKHSA in 2025 of doxycycline prophylaxis (Doxy-PEP) to protect individuals having unprotected intercourse from bacterial sexually transmitted infection is likely to drive the prevalence and spread of these plasmids; one of the gonococcal plasmids, pConj, confers resistance against doxycycline and the incidence of infections caused by plasmid-containing strains.

We will examine the factors in the gonococcus that promote the success of these plasmids in this bacterium; the plasmids are largely restricted to certain lineages of N. gonorrhoeae and are not commonly found in other species. This will be achieved by combining molecular epidemiological and genetic approaches, together with modelling. Results will inform approaches for controlling the spread of AMR plasmids in the gonococcal population and for vaccine design/implementation.

1. https://www.bashh.org/resources/141/doxycycline_postexposure_prophylaxis_2025
2. Yee W-X, Elsener T, Cehovin A, Maiden MCJ, Tang CM. Evolution and exchange of plasmids in pathogenic Neisseria. mSphere. 2023 Dec 20;8(6):e0044123. doi: 10.1128/msphere.00441-23.PMID: 37850911; PMCID: PMC10732060.
3. Elsener TA, Cehovin A, Philp C, Fortney K, Spinola SM, Maiden MCJ, et al. (2025) Origin, evolution, and success of pbla, the gonococcal beta-lactamase plasmid, and implications for public health. PLoS Pathog 21(5): e1013151. https://doi.org/10.1371/journal.ppat.1013151