Optimization of Trichomonas vaginalis Diagnosis during Pregnancy at a University Hospital, Argentina

Construction a novel detection method for Trichomonas vaginalis based on recombinant enzyme polymerase amplification targeting the Actin gene

Trichomoniasis is a common and curable sexually transmitted disease worldwide. The rapid, convenient, and accurate diagnosis of trichomoniasis is an important link in the prevention and treatment of the disease. The current detection methods of Trichomonas vaginalis are mainly wet mount microscopy, culture, nested PCR, and loop-mediated isothermal amplification. However, these detection methods have some shortcomings. In this study, a recombinant enzyme polymerase amplification (RPA) assay had been conducted to detect T. vaginalis. The target gene and the corresponding primers were screened, and the reaction system and conditions were optimized in the assay of RPA. The sensitivity and specificity of this detection method were analyzed. The detection efficiency of wet mount microscopy, culture, nested PCR, and RPA was compared by testing 53 clinical samples from vaginal secretions. By screening, the actin gene of T. vaginalis could be used as a target gene for RPA detection of T. vaginalis, and the optimum reaction condition to amplify the actin gene by RPA was at 39°C for 30 min. The detection limit of T. vaginalis DNA using RPA was 1 pg, corresponding to a sensitivity of approximately five trophozoites. The RPA assay demonstrated high specificity for T. vaginalis, and there was no cross-reactivity with Giardia lamblia, Escherichia coli, Lactobacillus, Toxoplasma gondii, Staphylococcus aureus, and Candida albicans. Of the 53 clinical samples, the positive rates of T. vaginalis detected by wet mount microscopy, culture, nested PCR and RPA were 50.9 4% (27/53), 71.7% (38/53), 71.7% (38/53), and 69.81% (37/53), respectively. Compared with culture which was used as the gold standard for diagnosing trichomoniasis, testing clinical samples by wet mount microscopy showed 71.05% sensitivity, 100% specificity, and moderate diagnostic agreement with the culture (K = 0.581, Z = 4.661, p < 0.001). The nested PCR showed 100% sensitivity, 100% specificity, and excellent diagnostic agreement (K = 1, Z = 7.28, p < 0.001), while RPA displayed 97.37% sensitivity, 100% specificity, and excellent diagnostic agreement (K = 0.954, Z = 6.956, p < 0.001). At the present study, rapid amplification of actin gene by RPA could be used as a tool for detection of T. vaginalis. The detection method of RPA was more sensitive than wet mount microscopy and displayed excellent specificity. Moreover, RPA amplification of actin gene did not require a PCR instrument and the amplification time was shorter than that of ordinary PCR. Therefore, the RPA assay was proposed in this study as a point-of-care examination and a diagnostic method of T. vaginalis infection, which exhibited the potential value in the treatment and prevention of trichomoniasis.

The International Society for the Study of Vulvovaginal Disease Vaginal Wet Mount Microscopy Guidelines: How to Perform, Applications, and Interpretation

OBJECTIVES

The aims of the study were to assess the available literature concerning the indications, performance, technique, and classification of wet mount microscopy (WMM) and to establish evidence-based recommendations.

METHODS

Literature review from the main scientific databases was performed by the ad hoc "Vaginitis and Microbiome Committee" of the International Society for the Study of Vulvovaginal Disease. The document was approved by the executive council and membership of the International Society for the Study of Vulvovaginal Disease.

RESULTS

Available data are limited and usually of low level of evidence. Nevertheless, it shows that WMM is capable of reducing misdiagnosis, overtreatment, and undertreatment of vaginal conditions. It has an excellent performance for the diagnosis of bacterial vaginosis and variable performance for trichomoniasis and candidiasis. It is the gold standard for aerobic vaginitis/desquamative inflammatory vaginitis. Currently, there is no recommendation to use WMM in the screening of asymptomatic women.The use of phase contrast is recommended to improve performance and reproducibility. Sampling location, devices, and technique have an impact on the results.Available scoring and classification scores have significant limitations.

CONCLUSIONS

Wet mount microscopy is a point-of-care, inexpensive, and fast technique that, with practice, can be mastered by office clinicians. It should be considered a basic skill in the curricula of gynecology and obstetrics residencies. Recommendations are provided on sampling, reading, and scoring.

Development of a convenient detection method for Trichomonas vaginalis based on loop-mediated isothermal amplification targeting adhesion protein 65

BACKGROUND

Trichomoniasis resulting from Trichomonas vaginalis (T. vaginalis) has been considered as a commonly seen disease with the transmission way of sex. At present, the detection methods of T. vaginalis mainly include wet mount microscopy, culture, PCR, immunofluorescence and ELISA. However, all of these detection methods exist shortcomings.

METHODS

In this study, a loop-mediated isothermal amplification (LAMP) assay that targeted the species-specific sequence of adhesion protein 65 (AP65) gene had been conducted to detect T. vaginalis. The optimum reaction system and conditions were optimized in this rapid detection method.

RESULTS

The results of sensitivity analysis showed that the LAMP assay targeting the AP65 gene was 1000 times more sensitive than the nested PCR targeting the actin gene commonly used for detection of T. vaginalis, and the detecting limitation of the former was 10 trichomonad. Moreover, the amplification of the target gene AP65 by LAMP assay exhibited high specificity and the product was exclusively from T. vaginalis. The detection technique of LAMP did not exhibit cross-reactivity with the common pathogens of Trichinella spiralis, Toxoplasma gondii, Escherichia coli, Candida albicans, Staphylococcus aureus, Haemophilus.

CONCLUSIONS

According to the present study, the LAMP assay with the target of AP65 gene, was suitable for the early diagnosis of T. vaginalis infections. Consequently, the LAMP assay was proposed by the current study as a point-of-care examination and an alternative molecular tool which exhibited the potential value in the treatment, control and prevention of trichomoniasis transmission and relevant complication.

Chlamydia, gonorrhoea, trichomoniasis and syphilis: global prevalence and incidence estimates, 2016

OBJECTIVE

To generate estimates of the global prevalence and incidence of urogenital infection with chlamydia, gonorrhoea, trichomoniasis and syphilis in women and men, aged 15-49 years, in 2016.

METHODS

For chlamydia, gonorrhoea and trichomoniasis, we systematically searched for studies conducted between 2009 and 2016 reporting prevalence. We also consulted regional experts. To generate estimates, we used Bayesian meta-analysis. For syphilis, we aggregated the national estimates generated by using Spectrum-STI.

FINDINGS

For chlamydia, gonorrhoea and/or trichomoniasis, 130 studies were eligible. For syphilis, the Spectrum-STI database contained 978 data points for the same period. The 2016 global prevalence estimates in women were: chlamydia 3.8% (95% uncertainty interval, UI: 3.3-4.5); gonorrhoea 0.9% (95% UI: 0.7-1.1); trichomoniasis 5.3% (95% UI:4.0-7.2); and syphilis 0.5% (95% UI: 0.4-0.6). In men prevalence estimates were: chlamydia 2.7% (95% UI: 1.9-3.7); gonorrhoea 0.7% (95% UI: 0.5-1.1); trichomoniasis 0.6% (95% UI: 0.4-0.9); and syphilis 0.5% (95% UI: 0.4-0.6). Total estimated incident cases were 376.4 million: 127.2 million (95% UI: 95.1-165.9 million) chlamydia cases; 86.9 million (95% UI: 58.6-123.4 million) gonorrhoea cases; 156.0 million (95% UI: 103.4-231.2 million) trichomoniasis cases; and 6.3 million (95% UI: 5.5-7.1 million) syphilis cases.

CONCLUSION

Global estimates of prevalence and incidence of these four curable sexually transmitted infections remain high. The study highlights the need to expand data collection efforts at country level and provides an initial baseline for monitoring progress of the World Health Organization global health sector strategy on sexually transmitted infections 2016-2021.

[Microbiological analysis of the maternal genital tract and umbilical cord blood and its association with neonatal damage]

The etiology leading to neonatal damage is multifactorial, being genital infections one of the causes. The objective of the study was to identify microorganisms of the maternal genital tract that are associated with neonatal damage, in order to prevent future perinatal complications. Seven hundred and eleven pregnant patients attended their prenatal control during the period January 2010-July 2013. Ureaplasma urealyticum and Mycoplasma hominis presence was investigated in umbilical cord blood by metabolic substrates (Micofast-Biomerieux) and that of T.vaginalis, by PCR using specific primers. The microbiological study of the vaginal contents of 288 pregnant patients at weeks 35 to 37 was performed by conventional methods, adding the modified thioglycolate culture for T.vaginalis. GroupB streptococcus (GBS) was investigated in anorectal and vaginal introitus swabs, using selective broth enrichment and subsequent isolation in chromogenic medium. The χ² Yates test and Fisher's test were used for independent samples. A p value <0.05 was considered statistically significant. The pathogens significantly related to neonatal damage were M.hominis (p=0.03), T.vaginalis (p=0.03), and BV (p=0.02). Main complications were preterm birth, premature rupture of membranes (PRM), low weight and Apgar score ≤7. U.urealyticum (p=0.35), Candidaspp. (p=0.94) and GBS (p=0.18) were not related to neonatal damage. Since different microorganisms of the maternal genital tract were related to neonatal damage, it is very important to perform the microbiological study of vaginal contents during pregnancy to prevent possible maternal and perinatal complications.

Very low sensitivity of wet mount microscopy compared to PCR against culture in the diagnosis of vaginal trichomoniasis in Uganda: a cross sectional study

BACKGROUND

Trichomonas vaginalis (TV) causes the Trichomoniasis Syndrome composed of vaginitis in women, urethritis in men and tube infection in both sexes. This infection is strongly associated with premature rupture of membranes, preterm delivery, low birth weight, promoting HIV sexual transmission and infertility. Prevention of these complications requires accurate early detection and effective treatment of infected individuals. In the resource limited settings, the wet mount microscopy (WMM) is often the only available test for laboratory detection of TV, but its accuracy and that of polymerase chain reaction (PCR) tools in Uganda remain poorly studied. The aim of this cross-sectional study was to compare the diagnostic accuracy of the WMM and PCR against culture as reference standard for the direct diagnosis of TV among symptomatic women. Three high vaginal swabs were collected from each of one hundred fifty women presenting with symptoms suggestive of active vaginal trichomoniasis at the sexually transmitted diseases clinic of Mulago National Referral Hospital Kampala, Uganda. The swabs were tested for TV with WMM, in-house PCR and TV culture. Results were analysed using excel 2007, SPSS v16, and Meta-disc software to determine the diagnostic accuracy of the tests.

RESULTS

The sensitivity, specificity and kappa agreement of the WMM was 25% (95% CI 5.5-57.2%), 100% (95% CI 97-100) and 0.38, respectively. Corresponding values for the PCR were 91.7% (95% CI 61.5-99.8), 99.3% (95% CI 96-100) and 0.91, respectively.

CONCLUSION

Among the TV symptomatic women, the sensitivity of the WMM was very low, with two-thirds of the patients missing a diagnosis while the in-house PCR was highly sensitive and specific. Feasibility studies aimed at incorporating PCR tools in algorithms for diagnosis of TV infection in resource-limited settings are recommended.