An observational study in Sexually Transmitted Infection (STI) Prevention, Antibiotic Prophylaxis and Antibiotic Resistance, Bacterial, sponsored by University College, London. Recruiting at 1 site in United Kingdom. Open to male participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-03-27.
Sponsored by University College, London · Observational
The goal of this observational study is to understand the risk of antibiotic resistance and changes in the human microbiome (bacteria that live inside and on us), if people use antibiotics to prevent sexually transmitted infections (STI prophylaxis, doxycycline post-exposure prophylaxis, or 'doxyPEP'). The study will assess how easy and acceptable it is to find antibiotic resistance and microbiome changes in the throats and guts of men-who-have-sex-with-men (MSM) who use STI prophylaxis.
The study will recruit 108 MSM who are using and not using STI prophylaxis. Participants will visit the clinic every 6 months. At each visit, they will provide a throat swab and stool sample, and complete a questionnaire. DNA of the bacteria from the samples will be analysed to identify the bacteria and look for antibiotic resistance.
424 studies on the registry are indexed under Sexually Transmitted Diseases; 71 are open to participants now.
This study's planned enrollment of 108 is below the median of 513 across 74 observational studies indexed under Sexually Transmitted Diseases.
Browse Sexually Transmitted Diseases studies →University College, London is the lead sponsor of 632 studies on the registry; 145 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 2 (33%) have results posted.
Counted across the registry records on this site, refreshed daily.
Men-who-have-sex-with men aged ≥ 18 years living in the United Kingdom. Target of 108 participants, with minimum 40 participants living with HIV.
Exclusion Criteria:
Previous use of doxycycline post-exposure prophylaxis within 3 months of baseline visit.
Previous use of doxycycline for STI treatment within 3 months of baseline visit. Once enrolled all participants may use doxycycline post-exposure prophylaxis.
No antibiotics within previous 3 months of baseline visit. Once enrolled all participants may use doxycycline post-exposure prophylaxis.
Detection of antimicrobial resistance genes of interest and characterisation of microbiome
The successful detection of antimicrobial resistance genes of interest (tetracycline and other antibiotic classes) and identification of bacterial species (microbiome) and in the oropharynx and gastrointestinal tract.
Time frame: From enrolment to 12 months
Detection of differences in prevalence of antimicrobial resistance genes of interest between people using and not using antibiotic STI prophylaxis.
Time frame: From enrolment to 12 months
Detection of differences in microbiome between people using and not using antibiotic STI prophylaxis.
Time frame: From enrolment to 12 months
Change over time in prevalence of antimicrobial resistance genes of interest between people using and not using antibiotic STI prophylaxis.
Time frame: From enrolment to 12 months
Change over time in microbiome between people using and not using antibiotic STI prophylaxis.
Time frame: From enrolment to 12 months
Documents are hosted by the registry — open the source record to download them.
Plan to share: No
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Sexually Transmitted Diseases→
University College, London