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Environmental contamination by Chlamydia trachomatis and Neisseria gonorrhoeae: is it time to change our infection control practices? Results of a regional study
  1. Sophie Ramsden1,
  2. Katie Ovens2,
  3. James Griffiths3,
  4. Peter Muir4,
  5. Ann Steele-Nicholson1,
  6. Paddy J Horner1,5,6
  1. 1 Unity Sexual Health, University Hospitals Bristol NHS Trust, Bristol, UK
  2. 2 Sexual Health in Plymouth (SHiP), University Hospitals Plymouth NHS Trust, Plymouth, UK
  3. 3 Clinical Microbiology, Royal Cornwall Hospitals NHS Trust, Truro, UK
  4. 4 Public Health Laboratory Bristol, National Infection Service, Public Health England, Bristol, UK
  5. 5 Population Health Sciences, University of Bristol, Bristol, UK
  6. 6 National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Behavioural Science and Evaluation, Bristol, UK
  1. Correspondence to Dr Katie Ovens, Sexual Health in Plymouth, University Hospitals Plymouth NHS Trust, Plymouth, UK; katie.ovens{at}


Objectives Nucleic acid amplification tests (NAATs) are highly sensitive for the detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) DNA/ribosomal RNA (rRNA). Previous studies have demonstrated contamination of surfaces in sexual health clinics (SHCs) with CT/NG. False positive results can occur if patient samples are contaminated by environmental DNA/rRNA. This can have a dramatic impact on patients’ lives and relationships. Previous attempts to reduce contamination, through staff training alone, have been unsuccessful. We aimed to investigate environmental contamination levels in SHCs and to assess a two-armed intervention aimed at reducing surface contamination.

Methods Questionnaires were sent to 10 SHCs. Six clinics, with differing characteristics, were selected to participate in sample collection. Each clinic followed standardised instructions to sample surfaces using a CT/NG NAAT swab. Clinics were invited to introduce the two-armed intervention. The first arm was cleaning with a chlorine-based cleaning solution once daily. The second arm involved introducing clinic-specific changes to reduce contamination.

Results 7/10 (70%) clinics completed the questionnaire. Overall, 88/263 (33%) swabs were positive for CT/NG. Clinics 1, 3 and 4 had high levels of contamination, with 28/64 (44%), 17/33 (52%) and 30/52 (58%) swabs testing positive, respectively. Clinics 2 and 6 had lower levels of contamination, with 7/46 (15%) and 6/35 (17%), respectively. 0/33 (0%) of swabs were positive at clinic 5 and this was the only clinic already using a chlorine-based solution to clean all surfaces and delivering twice-yearly clinic-specific infection control training. Following both intervention arms at clinic 1, 2/50 (4%, p<0.0001) swabs tested positive for CT/NG. Clinic 4 introduced each arm separately. After the first intervention, 13/52 (25%, p=0.003) swabs tested positive and following the second arm 4/50 (8%, p<0.0001) swabs were positive.

Conclusions Environmental contamination is a concern in SHCs. We recommend that all SHCs monitor contamination levels and, if necessary, consider using chlorine-based cleaning products and introduce clinic-specific changes to address environmental contamination.

  • Chalmydia trachomatis
  • nucleic acid amplification techniques
  • Neisseria gonorrhoeae
  • specimen handling
  • diagnostic techniques and procedures

Data availability statement

All data relevant to the study are included in the article or uploaded as supplemental information. Not applicable.

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Data availability statement

All data relevant to the study are included in the article or uploaded as supplemental information. Not applicable.

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  • Handling editor Jason J Ong

  • Contributors KO and SR conceived the original study, were involved in obtaining samples and wrote the first draft of the manuscript. KO and SR are joint first authors and are both guarantors. KO, SR, PJH, AS-N and PM were involved in the study design and planning sample collection. PM and JG supervised CT/NG NAAT testing for specimens collected at their local clinic. KO, SR and PJH analysed the data. All authors were involved in data interpretation and revising the first draft of the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Disclaimer The views expressed are those of the author and not necessarily those of the NIHR, the Department of Health and Social Care or PHE.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.