Introduction

The Unit of Sexually Transmitted Infections was established in January 2012. Its research focuses on improving the detection and management of STIs and preventing the emergence of antimicrobial resistance (AMR) in STIs.

Key activities

• Evaluating the efficacy of novel STI prevention interventions in the Belgian context, such as doxycycline post-exposure prophylaxis
• Developing novel treatment strategies for resistant STIs, such as gonorrhoeae and M. genitalium:
  • Ecological studies on the association between network connectivity and antimicrobial consumption versus AMR
  • Observational studies of changes in antimicrobial consumption in high network connectivity populations and subsequent changes in AMR
  • Preventing the emergence of resistance in gonorrhoea (PReGO Study). We assess whether the cumulative incidence of gonorrhoea, chlamydia and syphilis can be reduced through the use of a commercially available mouthwash product.
  • Conducting a trial of three-site, three-monthly screening for gonorrhoeae and C. trachomatis versus no screening in higher-risk men who have sex with men (Gonoscreen RCT)
  • Comparing ceftriaxone versus ceftriaxone and azithromycin for the management of  gonorrhoeae infections (ResistAZM RCT)
  • In-vitro testing of the theory in an gonorrhoea morbidostat
  • Developing a mathematical (STERGM) model of gonorrhoeae transmission that includes the probability of the emergence of AMR depending on screening and treatment strategies. This model is used to optimise STI screening and treatment strategies to minimise the risk of AMR emergence.
• Developing a surveillance system using commensal Neisseria species as an early warning system for excessive antimicrobial consumption in key populations
• Evaluating the lowest concentrations of various antimicrobials that can select for AMR in a range of bacterial species (minimum selection concentrations – MSC). Results indicate that residual antimicrobial concentrations in food could select for AMR.
• Testing the pharmacoecological theory of AMR. This theory suggests that AMR in organisms such as Neisseria gonorrhoeae frequently emerges in core groups, such as sex workers and MSM, due to a combination of dense sexual networks and high consumption rates of antimicrobials. The high network connectivity leads to a high prevalence of STIs, and antimicrobial consumption then creates selection pressure for AMR emergence. This theory is being tested through the following strategies:
  • Evaluating alternative antibiotic combinations and screening policies on the emergence of resistance in Neisseria gonorrhoeae.
  • Investigating the utility of various bacteriocins to treat gonorrhoeae and other pathogens
  • Developing a Galleria mellonellamodel of  gonorrhoeae infection to test treatment combinations
  • Searching for a Treponema pallidum antigen test (SeTPAT), using MS/MS and MRM to detect the presence of various pallidum antigens in the sera of 120 patients with a new diagnosis of syphilis. We aim to develop an ELISA that can detect T. pallidum antigen via this approach.