2: Comparison of three methods for diagnosis of trichomonas vaginalis infections

Diagnostic accuracy of an antigen-based point-of-care test versus nucleic acid amplification testing for genital trichomoniasis among pregnant women attending antenatal care facilities in Zambia

BACKGROUND

Infection with Trichomonas vaginalis (TV) is the most prevalent curable sexually transmitted infection (STI) globally and is associated with prelabour rupture of membranes, preterm delivery, and low birthweight. Point-of-care (POC) testing for TV during pregnancy may facilitate rapid antenatal case detection and treatment. This study, part of the World Health Organization's global ProSPeRo study, aimed to evaluate the performance of OSOM® Trichomonas Rapid Test, an antigen-based POC test, against a reference nucleic acid amplification test (NAAT) among pregnant women in Zambia. We also assessed the operational characteristics and patient acceptability of the POC test, within the context of WHO's target product profiles for STI POC tests.

METHODS

We enrolled pregnant women attending four health centres in Nchelenge, Zambia, for antenatal care between 15 February and 26 May 2023. Vaginal swabs for the TV POC test and a reference NAAT (Aptima® Trichomonas vaginalis assay) were obtained. POC test results were read independently by two study staff members. Study staff filled a questionnaire on the operational characteristics of the POC test, and participants were asked about their willingness to wait for results.

RESULTS

Paired POC and reference test samples were collected from 1,015 participants. Overall, 23.0% (233/1015) tested positive for TV by NAAT, and 15.3% (155/1015) tested positive by the POC test, with three inconclusive results. The overall sensitivity and specificity of the POC test were 66.4% (95% confidence intervals [CI] 57.7-74.1%) and 99.6% (95% CI: 98.8-99.9%), respectively. Sensitivity was higher among those with TV-associated symptoms compared to those without (83.6% versus 60.4%, relative ratio 1.39, 95% CI 1.14-1.68). Inter-rater agreement was 99.7% (Cohen's Kappa 0.989). The study staff (n = 14) found the test easy to use and interpret, with most staff (12/14) reporting results were available within 25 min.

CONCLUSION

Overall, the TV POC test showed lower sensitivity than WHO's 85% target, but exceeded the 99% specificity target. Among symptomatic pregnant women, sensitivity nearly reached the WHO target. The assay was user-friendly, required minimal training, and delivered results quickly. Further studies are needed to determine the optimal antenatal settings for this technology.

TRIAL REGISTRATION

PACTR202302766902029.

Actin Gene-Based Molecular Typing of Trichomonas vaginalis Clinical Isolates from the North of Iran

AIM

The aim of the current study is to evaluate the prevalence of trichomoniasis in men and women in the north of Iran and to find genotypes in the positive clinical specimens based on T. vaginalis actin gene.

MATERIALS AND METHODS

Women's genital (n = 500) and men's urine (n = 1500) samples were collected from the participants referred to clinics in Mazandaran Province, northern Iran, during 2006-2018. In addition, 1500 Pap smear specimens, archived in the Bu Ali Hospital, Sari City, Mazandaran Province, northern Iran, were examined. The specimens were examined based on parasitological methods, nested polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism, and phylogenetic analysis.

RESULTS

Overall, 17 (0.48%) of 3500 specimens were positive by PCR. Total prevalence was 0.55% (n = 2000) for women, of which 500 (1.4%; n = 7) specimens were collected freshly, and 1500 (0.26%; n = 4) were Pap smears. Moreover, six (0.4%) out of 1500 men urine specimens were positive. Overall, genotypes G, E, and I were detected with the prevalence of seven (0.2%), seven (0.2%), and three (0.08%), respectively. There was no significant statistical difference among the prevalence of the detected genotypes (P > 0.05).

CONCLUSION

As a whole, the prevalence of trichomoniasis was low in the studied area in the north of Iran and, most importantly, the genotypes of E, G, and I were distributed among men and women in the province.