Genotype-Specific Concordance of Chlamydia trachomatis Genital Infection Within Heterosexual Partnerships

Abstract

Background Sexual transmission rates of Chlamydia trachomatis (Ct) cannot be measured directly; however, the study of concordance of Ct infection in sexual partnerships (dyads) can help to illuminate factors influencing Ct transmission. Methods Heterosexual men and women with Ct infection and their sex partners were enrolled and partner-specific coital and behavioral data collected for the prior 30 days. Microbiological data included Ct culture, nucleic acid amplification testing (NAAT), quantitative Ct polymerase chain reaction (qPCR), and ompA genotyping. We measured Ct concordance in dyads, and factors (correlates) associated with concordance. Results 121 women and 125 men formed 128 dyads. Overall, 72.9% of male partners of NAAT-positive women and 68.6% of female partners of NAAT-positive men were Ct-infected. Concordance was more common in dyads with culture-positive members (78.6% of male partners, 77% of female partners). Partners of women and men who were NAAT-positive only had lower concordance (33.3%, 46.4%, respectively). Women in concordant dyads had significantly higher median endocervical qPCR values (3,032) compared with CT-infected women in discordant dyads (1,013 IFU DNA equivalents per ml), p<0.01. Among 54 Ct-concordant dyads with ompA genotype data for both members, 96.2% had identical genotypes. Conclusions Higher organism load appears associated with concordance among women. Same-genotype chlamydial concordance was high in sexual partnerships. No behavioral factors were sufficiently discriminating to guide partner services activities. Findings may help model coitus-specific transmission probabilities.

Prevalence, concordance and reproductive sequelae after Chlamydia trachomatis infection in Mexican infertile couples

“…Regarding the percentages of concordance, they were lower than those reported by -Infante et al, 2005;Quinn et al, 1996;Schillinger et al, 2016;Tait & Hart, 2002).…”

Concordance of chlamydia infections of the rectum and urethra in same-sex male partnerships: a cross-sectional analysis

“…Obviously, in every partnership at least one of the partners must have had sexual contact with a third party who had a chlamydia infection, but we are not able to determine in how many partnerships both partners separately acquired chlamydia from a third party, as this would require testing all third parties for chlamydia and conducting a molecular analysis of chlamydia serovars. A recently-published study of chlamydia concordance in heterosexual partnerships found that in 96.2% (51/53) of chlamydia-concordant partnerships both partners had the same chlamydia genotype (Schillinger et al, [22]). This finding suggests that concordance represents transmission within partnerships, but as described above, we may not be able to extrapolate from heterosexual partnerships to same sex male partnerships.…”

Characterization of the Horizontal and Vertical Sexual Transmission ofChlamydiaGenital Infections in a New Mouse Model

“…The transmission rate increased to 70% (53/76) when nucleic acid methods were used for diagnosis. In a study by Schillinger et al (31), based on culture results, ϳ80% concordance between female and male sexual partners was found. Rank et al (26) infected the meatus urethra of male guinea pigs with 10 7 IFU of C. caviae and caged them with naive females.…”

“…This mouse model bears similarities with horizontal human sexually transmitted C. trachomatis infections. Two concordant studies reported ϳ70 to 80% transmission rates in females from C. trachomatis-positive males (30,31). For example, Quinn et al (30) studied 494 sexual partner couples using urethral and endocervical swabs for the detection of C. trachomatis.…”