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NCT Number: NCT06778083

STI Prophylaxis and Emergence of Antimicrobial Resistance

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.

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Key information

Conditions

Sexually Transmitted Infection (STI) Prevention Antibiotic Prophylaxis Antibiotic Resistance, Bacterial Behavior Communicable Diseases Disease Attributes Doxycycline Genital Diseases Homosexuality Infections Microbiome Pathologic Processes Pathological Conditions, Signs and Symptoms Sexual Behavior Sexuality Sexually Transmitted Diseases Urogenital Diseases

Age range

18 year and older

Sex eligibility

Male

Study type

Observational

Primary location

Central and North West London NHS Foundation Trust

London, United Kingdom

Location status: Recruiting

Location contact

Manik Kohli

CONTACT

[email protected]

Manik Kohli

PRINCIPAL_INVESTIGATOR

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Aged ≥ 18 years.
  • Identifies as a man (cis or trans).
  • Has sex with men.
  • Able to provide informed consent.

Exclusion criteria

  • Use of an antibiotic other than doxycycline in the 3 months prior to enrolment
  • Currently being treated for an STI with doxycycline
  • Use of doxycycline within the prior 3 months for an indication other than STI treatment or STI prevention.

Treatment and study plan

Primary outcomes

  1. Detection of antimicrobial resistance genes of interest and characterisation of microbiome

    Time frame: From enrolment to 12 months

    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.

Secondary outcomes

  1. 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

  2. Detection of differences in microbiome between people using and not using antibiotic STI prophylaxis.

    Time frame: From enrolment to 12 months

  3. 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

  4. Change over time in microbiome between people using and not using antibiotic STI prophylaxis.

    Time frame: From enrolment to 12 months

Study contacts

Contact information is provided by the study sponsor or research team.

Manik Kohli, MBChB MSc

CONTACT

[email protected]

+4420276794466

Sponsors and collaborators

Lead sponsor

University College, London

Other

Collaborators

  • University of Oxford

Registry information

Acronym: SPEAR

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Jan 16, 2025
Registry last updated
Mar 27, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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