Chlamydia trachomatis infection in fertile and subfertile women in Rwanda: prevalence and diagnostic significance of IgG and IgA antibodies testing.

BACKGROUND: In many developing countries, little is known about the prevalence of genital Chlamydia trachomatis infections and complications, such as infertility, thus preventing any policy from being formulated regarding screening for C. trachomatis of patients at risk for infertility. The objective of the present study was to determine the prevalence of C. trachomatis and evaluate the diagnostic utility of serological markers namely anti-C. trachomatis IgG and IgA antibodies in women attending an infertility clinic.
METHODS: Serum and vaginal swab specimens of 303 women presenting with infertility to the infertility clinic of the Kigali University Teaching Hospital and 312 fertile controls who recently delivered were investigated. Two commercial species-specific ELISA were used to determine serum IgG and IgA antibodies to C. trachomatis and vaginal swabs specimens were tested by PCR. Hysterosalpingography (HSG) was performed in subfertile women.
RESULTS: The PCR prevalence of C. trachomatis infection was relatively low and did not differ significantly among subfertile and fertile women (3.3 versus 3.8%). Similarly, no significant differences in overall prevalence rates of C. trachomatis IgG and IgA among both groups were observed. The only factor associated with C. trachomatis infection in our study population was age <25 years. The seroprevalence of IgG in both assays (86.4% for ANILabsystems and 90.9% for Vircell) was significantly higher in the group of PCR C. trachomatis-positive women compared with that of PCR-negative women. Evidence of tubal pathology identified by HSG was found in 185 patients in the subfertile group (67.8%). All the serological markers measured in this study had very low sensitivities and negative predictive values in predicting tubal pathology. The specificities for ANILabsystems IgG, Vircell IgG, Anilabsystem IgA and positive C. trachomatis DNA to predict tubal pathology were 84, 86, 95 and 98%, respectively, whereas their respective positive predictive values were 73, 76, 81 and 80%.
CONCLUSIONS: The prevalence of C. trachomatis in our study population in Rwanda appears to be low and women aged <25 years are more likely to have genital infection with C. trachomatis. Since serological testing for Chlamydia shows an excellent negative predictive value for lower genital tract infection, specific peptide-based serological assays may be of use for screening in low prevalence settings. Our data suggest that C. trachomatis is not the primary pathogen responsible for tubal pathology in Rwandan women.