Background The aim of this study was to detect Trichomonas vaginalis infection in HIV positive women receiving anti-retroviral therapy in Pretoria, South Africa.
Methods Self-collected vaginal swab specimens from 95 consecutive patients attending the anti-retroviral clinic (Tshwane District Hospital) were analysed. Trichomonas vaginalis was diagnosed by wet mount microscopy, culture using InPouch and a commercial PCR assay targeting the DNA repeat units. Trichomoniasis was diagnosed if any test was positive.
Results Five (5.3%) of the 95 specimens were positive by wet mount microscopy, 21 (22.1%) were culture positive and 28 (29.5%) were detected by PCR. All culture and wet mount positive specimens were PCR positive. The sensitivity and specificity of wet mount microscopy compared to culture were 23.8% and 98.7% respectively. PCR detected seven additional positive specimens than culture. The specificity of PCR compared to culture was 100%, with a sensitivity of 90.5%. The prevalence of T vaginalis was found to be 29.5% in this study.
Conclusions Previous studies in South Africa focused on the prevalence of trichomoniasis in pregnant women and women without HIV status and from lower socio-economic groups. This is the first report in HIV positive women receiving ARV treatment. There was a high prevalence (29.5%) of T vaginalis in this group. This is similar to that reported from Nigeria (24.4%) and Ivory Coast (27.0%), whilst the rate reported in Congolese (18.6%) HIV positive women was lower. Using microscopy alone for the diagnosis of trichomoniasis as is the current practice in most laboratories in South Africa is inadequate and leads to missed infections.