title: A Cross Sectional Analysis of Gonococcal and Chlamydial Infections among Men-Who-Have-Sex-with-Men in Cape Town, South Africa.
abstract: BACKGROUND
  Men-who-have-sex-with-men (MSM) are at high risk of HIV and sexually transmitted infection (STI) transmission. Asymptomatic STIs are common in MSM and remain undiagnosed and untreated where syndromic management is advocated. Untreated STIs could be contributing to high HIV rates. This study investigated symptomatic (SSTI) and asymptomatic STIs (ASTIs) in MSM in Cape Town.
  
  
  METHODS
  MSM, 18 years and above, were enrolled into this study. Participants underwent clinical and microbiological screening for STIs. Urine, oro-pharyngeal and anal swab specimens were collected for STI analysis, and blood for HIV and syphilis screening. A psychosocial and sexual questionnaire was completed. STI specimens were analysed for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) infection.
  
  
  RESULTS
  200 MSM were recruited with a median age of 32 years (IQR 26-39.5). Their median number of sex partners within the last year was 5 (IQR 2-20). 155/200 (78%) reported only male sex partners while 45/200 (23%) reported sex with men and women. 77/200 (39%) reported transactional sex. At enrolment, 88/200 (44%) were HIV positive and 8/112 (7%) initially HIV-negative participants seroconverted during the study. Overall, 47/200 (24%) screened positive for either NG or CT. There were 32 MSM (16%) infected with NG and 7 (3.5%) of these men had NG infections at two anatomical sites (39 NG positive results in total). Likewise, there were 23 MSM (12%) infected with CT and all these men had infections at only one site. Eight of the 47 men (17%) were infected with both NG and CT. ASTI was more common than SSTI irrespective of anatomical site, 38 /200 (19%) versus 9/200 (5%) respectively (p<0.001). The anus was most commonly affected, followed by the oro-pharynx and then urethra. Asymptomatic infection was associated with transgender identity (OR 4.09 CI 1.60-5.62), ≥5 male sex partners in the last year (OR 2.50 CI 1.16-5.62) and transactional sex (OR 2.33 CI 1.13-4.79) but not with HIV infection.
  
  
  CONCLUSIONS
  Asymptomatic STI was common and would not have been detected using a syndromic management approach. Although molecular screening for NG/CT is costly, in our study only four MSM needed to be screened to detect one case. This supports dual NG/CT molecular screening for MSM, which, in the case of confirmed NG infections, may trigger further culture-based investigations to determine gonococcal antimicrobial susceptibility in the current era of multi-drug resistant gonorrhoea.
authors.affiliation: Anova Health Institute, Johannesburg and Cape Town, South Africa; University of Cape Town, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Cape Town, South Africa.
authors.forename: Kevin
authors.initials: K
authors.lastname: Rebe
authors.affiliation: Centre for HIV and Sexually Transmitted Infections, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa; Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa; Western Sydney Sexual Health Centre, Parramatta, Australia; Centre for Infectious Diseases and Microbiology & Marie Bashir Institute for Infectious Diseases and Biosecurity, Westmead Clinical School, University of Sydney, Sydney, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Lewis
authors.affiliation: Division of Epidemiology & Biostatistics, School of Public & Family Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Landon
authors.initials: L
authors.lastname: Myer
authors.affiliation: Anova Health Institute, Johannesburg and Cape Town, South Africa.
authors.forename: Glenn
authors.initials: G
authors.lastname: de Swardt
authors.affiliation: Anova Health Institute, Johannesburg and Cape Town, South Africa; University of Cape Town, Division of Infectious Diseases and HIV Medicine, Department of Medicine, Cape Town, South Africa.
authors.forename: Helen
authors.initials: H
authors.lastname: Struthers
authors.affiliation: Division of Epidemiology & Biostatistics, School of Public & Family Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Monika
authors.initials: M
authors.lastname: Kamkuemah
authors.affiliation: Anova Health Institute, Johannesburg and Cape Town, South Africa; Division of Epidemiology & Biostatistics, School of Public & Family Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: James
authors.initials: J
authors.lastname: McIntyre
mesh_terms: D000328:Adult; D001003:Anal Canal / Q000382:microbiology; D002690:Chlamydia Infections / Q000453:epidemiology* / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000302:isolation & purification; D003430:Cross-Sectional Studies; D024901:Drug Resistance, Multiple, Bacterial; D006069:Gonorrhea / Q000453:epidemiology* / Q000382:microbiology; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008403:Mass Screening; D009344:Neisseria gonorrhoeae / Q000302:isolation & purification; D009960:Oropharynx / Q000382:microbiology; D013019:South Africa; D011795:Surveys and Questionnaires; D014521:Urethra / Q000382:microbiology