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High prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae infections among HIV-1 negative men who have sex with men in coastal Kenya
  1. Eduard J Sanders1,2,
  2. Alexander N Thiong'o1,
  3. Haile Selassie Okuku1,
  4. John Mwambi1,
  5. Frances Priddy3,
  6. Juma Shafi4,
  7. Henry de Vries5,6,
  8. R Scott McClelland4,7,
  9. Susan M Graham1,7
  1. 1Centre for Geographic Medicine Research ─ Coast, Kenya Medical Research Institute (KEMRI) ─ Kilifi, Kilifi, Kenya
  2. 2Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Headington, UK
  3. 3International AIDS Vaccine Initiative, New York, USA
  4. 4Department of Medicine, University of Nairobi, Nairobi, Kenya
  5. 5STI Outpatient Clinic, Public Health Service of Amsterdam (GGD Amsterdam), Amsterdam, The Netherlands
  6. 6Department of Dermatology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
  7. 7Department of Medicine, University of Washington, Seattle, Washington, USA
  1. Correspondence to Dr Eduard J Sanders, Kenya Medical Research Institute, Centre for Geographic Medicine Research – Coast, PO Box 230, Kilifi, Kenya; esanders{at}kilifi.kemri-wellcome.org

Abstract

Objectives To assess the burden of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) in high-risk HIV-1 negative men who have sex with men (MSM) in Africa.

Methods Before the start of a pre-exposure prophylaxis trial, HIV-1 negative volunteers were screened for sexually transmitted infection (STI) including CT and NG, using a highly sensitive and specific nucleic acid amplification test. Samples positive for CT by Aptima testing, were evaluated for the presence of lymphogranuloma venereum (LGV) serovars using an in-house PCR assay. All men were asked to submit a urine specimen, and all had a rectal swab collected by a clinician. Men were asked if they had dysuria, urethral or rectal discharge, or rectal pain.

Results 43 HIV-1 negative MSM were screened, of whom 13 reported sex with men only; the majority (27/43) reported sex work. One volunteer had dysuria and another, rectal pain. Eleven MSM (26%, 95% CI 14% to 41%) had infections with either or both pathogens. Homosexual men had a higher prevalence of any infection than bisexual men (46% vs 17%, p=0.04), and all cases of rectal infections, including one with CT, two with NG and two with CT/NG co-infection. All patients with CT were negative for LGV. One patient with a rectal NG infection reported rectal pain.

Conclusions A remarkably high burden of STI infection was found among HIV-1 negative MSM. Most (12/13) infections, including three of four rectal NG infections, were subclinical. These findings suggest that high-risk MSM will benefit from effective STI screening in Kenya.

  • MSM
  • RAI
  • rectal STI
  • LGV
  • PrEP screening
  • Africa
  • anogenital
  • anorectal
  • men
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Introduction

Men who have sex with men (MSM) in Africa are at high risk for HIV-1 infection.1 Results from HIV-1 testing among MSM in Coastal Kenya showed a 21% seroprevalence, and HIV-1 incidence among MSM sex workers has been estimated at 9.9 per 100 person-years (95% CI 7.2 to 13.6).2 Unprotected receptive anal intercourse is common and greatly increases HIV risk in this group,3 but far less is known about the risk of other sexually transmitted infections (STIs) in this population.

Methods

Before the initiation of a small trial of pre-exposure prophylaxis,4 we screened HIV-1 negative volunteers for STIs, including Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG), using a highly sensitive and specific nucleic acid amplification test (GenProbe Aptima Combo 2 assay, San Diego, USA). Men were recruited from a previously described at-risk cohort, in which volunteers received monthly or quarterly risk reduction counselling and HIV testing, had a medical history and physical examination at each scheduled visit.3

All men submitted a urine specimen, and had a rectal swab collected by a clinician.5 Men were asked if they had dysuria, urethral or rectal discharge, or rectal pain. Each sample was tested for CT and NG by the Aptima assay.6 Samples positive for CT were re-examined for CT by Aptima testing, and evaluated for the presence of lymphogranuloma venereum serovars using an in-house PCR assay.7 Routinely, volunteers who reported rectal anal intercourse (RAI) were offered proctoscopy. Syndromic STI treatment was given to symptomatic volunteers.8 Data were tabulated by sexual partner preference (ie, sex with men only or with both men and women), and differences tested by the χ2 test.

Results

Forty-three MSM were screened: 13 of whom reported sex with men only (MSM-only), and 30 of whom had sex with both men and women (MSMW). The median age was 27 years (IQR 22–32). MSM-only reported more transactional sex than MSMW (85% vs 53%, p=0.05). None of the 43 men reported urethral or rectal discharge, but one man had dysuria and another had rectal pain. Overall, 11 MSM (26%) had CT, NG, or both (table 1). Six men had an infection of the urethra (five CT, one NG); and five men an infection of the rectum (one CT, two with NG, and two with CT/NG co-infection). One patient with a rectal NG infection reported rectal pain. All CT cases were confirmed and negative for lymphogranuloma venereum. MSM-only had a higher prevalence of any infection than MSMW (46% vs 17%, p=0.04), and all rectal infections. Sixteen (78%) of 21 men who reported RAI refused proctoscopy, including two men with rectal CT/NG co-infection and one men with rectal CT. All 11 cases were traced and received appropriate STI treatment.

Table 1

Prevalence of Chlamydia and gonorrhoea in HIV-1 negative MSM, by sexual orientation of MSM, Coastal Kenya

Discussion

We documented a high burden of anogenital CT and NG infections in a small sample of HIV-1 negative MSM. The absence of urethral or rectal discharge and low acceptance of proctoscopy presents challenges for clinical diagnosis of proctitis in Africa.9 That almost half of MSM-only in this study had proctitis despite regular HIV testing and counselling is a great concern.

Potential study limitations include pre-exposure prophylaxis trial selection, small sample size, and the possibility that these men may represent a sexual network in which CT and NG were circulating at the time of this study. These results suggest that Kenyan high-risk MSM, particularly those involved in sex work and practising unprotected RAI, would benefit from regular screening for both rectal and urethral infections with a sample collection method they find acceptable. Nucleic acid amplification test testing, however, is expensive and further work is needed to determine the optimal approach to STI screening in this high-risk population.

Key messages

  • Little is known about the burden of anogenital sexually transmitted infection (STI) in men who have sex with men (MSM) in Africa.

  • Highly sensitive and specific nucleic acid amplification tests will detect asymptomatic STI and should be considered for screening high-risk MSM in Kenya.

Acknowledgments

We thank the staff at International AIDS Vaccine Initiative for regulatory support and trial monitoring. This report was published with permission from the Kenya Medical Research Institute.

References

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Footnotes

  • Funding International AIDS Vaccine Initiative.

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval This study was conducted with the approval of the National Ethical Review Committee of the Kenya Medical Research Institute.

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

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