Genotyping of Chlamydia trachomatis from vaginal swabs by restriction analysis of the outer membrane protein gene

Abstract

Background: Chlamydia trachomatis (C. trachomatis) is a common cause of bacterial sexually transmitted infections (STIs). The genetic characterisation of C. trachomatis serovars reveals significant genetic diversity in this organism. This study investigated the diversity of C. trachomatis serovars in human immunodeficiency virus (HIV)-infected pregnant women in South Africa.
Methods: For this study, 385 vaginal swab samples were tested for the presence of C. trachomatis. The swabs were collected from HIVinfected pregnant women at the King Edward VIII Hospital in Durban, South Africa. The outer membrane protein (omp1) gene from C. trachomatis was amplified and positive amplicons were digested with restriction enzymes AluI, DdeI and HinfI for the assignment of serovars.
Results: The prevalence of C. trachomatis in the study population was 12.2% (47/385). Serovar E (46.5%) was the most frequent serovar in our study population, followed by serovars F (20.9%), G (14.0%) and D (11.6%). Serovar I (4.7%), which was detected in two samples, was the least frequent. Risk factors for C. trachomatis include having a low level of education, being unemployed, being unmarried, not cohabitating, early age of first sex, high number of lifetime sex partners, a partner having other partners, lack of condom use, lacking symptoms of STIs, and lacking treatment for STIs.
Conclusion: Five different serovars were observed among the participants. The high genetic diversity observed in this study contributes to the challenges regarding future vaccine design and the development of antigen-based rapid diagnostic tests for Chlamydia.