Identification of genital chlamydia strains from Female Sex Workers attending the Sex Workers Outreach Program City Clinic in Nairobi, Kenya

Abstract

Genital chlamydia, caused by diverse C. trachomatis strains, is largely asymptomatic but can also present with pelvic discharge, itchy vulva or lower abdominal pain. We aimed to identify genital chlamydia strains amongst Female Sex Workers attending the Sex Workers Outreach Program City Clinic in Nairobi, Kenya. This cross-sectional study was conducted between April 2017 and March 2021. A total of 348 Female Sex Workers, attending the Sex Workers Outreach Program City Clinic in Nairobi, and who met the study eligibility criteria and provided informed written consent were recruited to participate in the study. The participant characteristics and genitourinary complaints of the study participants were documented using structured questionnaires. Thereafter, endocervical swabs were collected from all the study participants for laboratory analysis. C. trachomatis plasmid DNA was extracted from the swabs, amplified using PCR and sequenced. Data from the questionnaires was transferred into an excel database and analysed using Stata/MP Version 13 for Windows. Quantitative data on participant characteristics and genitourinary complaints were summarized using descriptive statistics. Pearson Chi square tests of independence were performed to examine the relationship between participant characteristics, clinical presentation and genital chlamydia positivity. The level of significance was set at p≤ 0.05. For the resultant DNA sequences, consensus sequences were generated using BioEdit software v7.2. The consensus sequences were aligned with reference sequences using open-source BLAST program to determine the C. trachomatis strains. A total of 348 participants were successfully recruited, examined, endocervical swabs collected and tested for C. trachomatis. Of these, 46 (13.2%) tested positive while 302 (86.7%) tested negative for C. trachomatis. Majority (297, 85.3%) of the participants presented with pelvic discharge with or without other symptoms. Fifteen (15, 4.3%) had abdominal pain and 3 (0.9%) had an itchy vulva xv only. Another 3 (0.9%) presented with bleeding from the cervix, genital wounds and rashes in the mons pubis. No statistically significant relationship was observed between clinical presentation and genital chlamydia. DNA from 23 samples were successfully sequenced. Each sequence was at least 90% identical to each of the 13 reference C. trachomatis strains A, B, C, D, E, F, G, Ia, J, L1, L2, L2b and L3. This study findings suggest that genital chlamydia is prevalent amongst Female Sex Workers seeking medical services at the Sex Workers Outreach Programme City Clinic in Nairobi. The findings also suggest that despite there being a relationship between individual genitourinary complaints and genital chlamydia infection, this relationship was not statistically significant. Lastly, the C. trachomatis strains circulating amongst Female Sex Workers in Nairobi appear to be related to genotypes A, B, C, D, E, F, G, Ia, J, L1, L2, L2b and L3. This study corroborates the presence of genital chlamydia infection and the circulating C. trachomatis strains amongst Female Sex Workers within Nairobi, Kenya. Since genital chlamydia is managed syndromically, knowledge of C. trachomatis strains and their virulence factors may improve genital chlamydia infection management strategies