Prevalence of four sexually transmitted pathogens and risk factors related to oral, vaginal, or anal intercourse among informal female sex workers from Tshwane, South Africa, 2022

Background: Female sex workers (FSWs) are at high risk for sexually transmitted infections (STIs). This study estimated the prevalence of STIs caused by Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), Mycoplasma genitalium (MG), and Trichomonas vaginalis (TV) and identified factors related to oral, vaginal, or anal intercourse among FSWs in informal settings in Tshwane, South Africa. Methods: Samples were collected from 200 FSWs aged 18 and older in Pretoria who engaged in transactional sex. Participants completed a questionnaire on demographics, sexual history, and HIV testing. Three swabs (rectal, oral, and endocervical) from each participant were tested for NG, CT, MG, and TV. Results: Of the 200 participants, 53 (26.5%) had at least one infection. Of these infections, the most common site of infection was genital (100 %), followed by the rectum (45.3 %), and pharynx (20.8 %). CT and TV were detected in 24 (12.0%) participants, while NG and MG were found in 20 (10.0%) participants. Most of the infected FSWs (32/53) had one sexually transmitted pathogen, while 21 (40%) had multiple STIs. Substance use was significantly associated with the presence of an STI. Conclusion: This study reveals a high burden of STIs among FSWs, highlighting pathogen prevalence at genital and extragenital sites. These findings underscore the need for targeted STI control interventions for high-risk groups like FSWs in South Africa.