Diagnosis and molecular characterization of Trichomonas vaginalis in sex workers in the Philippines

Trichomonas vaginalis: comparison of primers for implementation as an in-house PCR in rural Vellore, South India

BACKGROUND

Trichomonas vaginalis (TV) accounts for the highest burden of curable, non-viral sexually transmitted infections worldwide. Prevalence in India ranges from 0.4 to 27.4% in women and 0.0-5.6% in men. In 2015, the prevalence of TV among pregnant women of rural Vellore was 3.11% using Sekisui OSOM® Trichomonas test and culture methods. Molecular methods are the most sensitive, rapid diagnostic tool for Sexually Transmitted Infection's (STI) albeit cost hinders implementation of commercial platforms. To determine a sensitive, sustainable molecular method, we compared three targets (Adhesin AP65, cytoskeleton Beta-tubulin BTUB 9/2 and TVK 3/7) with the highest published diagnostic accuracy against microscopy, culture and Real Time PCR (RT- PCR).

MATERIALS & METHODS

Six-hundred adult, sexually active women attending the Obstetrics-Gynaecology rural out-patient clinic the Rural Unit for Health and Social Affairs (RUHSA) from July 2020 - February 2021 were enrolled. A vaginal lateral and posterior fornix specimen was inoculated, onsite, into Biomed InPouch® TV culture and smeared onto a slide for fluorescence microscopy using Acridine orange. A flocked nylon swab specimen for PCR was used to determine the sensitivities of the Adhesin AP65, cytoskeleton Beta-tubulin BTUB 9/2 and TVK 3/7 gene targets. Seegene Allplex™ STI Essential Assay, S.Korea was used to confirm TV positives.

RESULTS

Nine specimens (9/600, 1.5%) were positive for TV. There was a 100% correlation between Biomed InPouch TV® culture, PCR with TVK 3/7 and RT-PCR while a correlation of 66.6% with BTUB 9/2 and AP65 gene targets. Clinically, 77.7% (n = 7) presented with white-greenish discharge per vagina, 11% (n = 1) with infertility, 22.2% (n = 2) were asymptomatic. Eight of nine patients (88.9%) had co-infections with other bacterial STIs. Prevalence of TV coinfection with Neisseria gonorrhoea was 1.1%.

CONCLUSION

Current hospital-based prevalence of TV in rural Vellore was 1.5%. Repetitive DNA target TVK 3/7 was more sensitive than AP65 and BTUB 9/2 primers.

Comparison of diagnostic methods and analysis of socio-demographic factors associated with Trichomonas vaginalis infection in Sri Lanka

BACKGROUND

Trichomonas vaginalis infection is underreported due to nonspecific clinical presentation and the nonavailability of sensitive laboratory diagnostic tests at the clinical setup. Hence, this study was designed to compare the sensitivity and specificity of microscopy and culture methods with polymerase chain reaction (PCR). The socio-demographic factors associated with the infection were explored.

METHODS

The study was carried out at the National Sexually Transmitted Diseases and Acquired Immuno Deficiency Syndrome Control Programme in Colombo and Sexually Transmitted Diseases and Acquired Immuno Deficiency Syndrome Control Programme in Kandy. Samples were collected from a total of 385 patients including, 272 females (70.7%) and 113 males (29.3%), and tested using microscopy (wet mount and Giemsa staining), culture, and PCR. Genus-specific primer set (TFR1/TFR2) that amplifies 5.8S rRNA and species-specific primer sets (TV16Sf-2/TV16Sr-2 and TVK3/7) that amplifies 18S rRNA and repetitive DNA, respectively, were used. Patient's socio-demographic and sexual behaviour data were obtained using a standard interviewer-administered questionnaire. Data were analyzed with R statistical software Version 3.6.3.

RESULTS

The overall prevalence of trichomoniasis was 4.4% (17/385). Of these, six (1.6%) were positive for microscopic examination, 7 (1.8%) were positive for culture, and 13 (3.4%) for TVK3/7, 15 (3.9%) for TV16Sf/r, and TFR1/2 17 (4.4%) were positive for PCR. Sensitivities of PCR using TFR1/2, TV16Sf/r, and TVK3/7 primer sets were 100%, 88.20%, and 76.50%, respectively, against the expanded gold standard. Trichomoniasis was associated with age above 36 (p = 0.033), not using condoms in last three months (p = 0.016), multiple sex partners (p = 0.001), reason for attendance (p = 0.027), symptomatic nature (p = 0.015), and the presence of other sexually transmitted diseases (p = 0.001).

CONCLUSIONS

The study highlighted that age over 36 years, multiple sex partners, not using condoms, reason for attendance, symptomatic nature, and having other sexually transmitted diseases can increase the risk of acquiring trichomoniasis. Furthermore, this study confirmed PCR as highly sensitive and specific diagnostic test for the diagnosis of trichomoniasis in comparison to microscopy and culture methods.

Trichomonas Vaginalis Infection in Men with High-Risk Sexual Behaviors

Background:

Trichomonas vaginalis is a protozoan pathogen of the human genitourinary tract, which is the cause of trichomoniasis. The disease is one of the most important non-viral sexually transmitted infections in the world. Many studies have been performed on the molecular identification of Trichomonas in men in different parts of the world, but in Iran, such a study has been very limited. We aimed to detect T. vaginalis in urine of men with unusual sexual behavior by wet mount microscopic observation, culturing in TYM-33 and molecular method in Tehran, Iran.

Methods:

Totally, 47 urine samples were collected from men with high-risk sexual behaviors referred to Health Care Centers in South of Tehran, Iran during 2017–2018. After urine centrifugation and wet mount sediment preparation, the samples were cultured in TYM-33 medium and examined microscopically. Then DNA was extracted from urine sediment samples and finally the 18srRNA gene was amplified by PCR.

Results:

Thirty-one (65.95%) urine samples were positive for T. vaginalis by PCR. Of these, only 6 (12.76%) were detected positive by wet mount method and 25 (53.19%) by culture and successive passages.

Conclusion:

The high prevalence of trichomoniasis among men with high-risk sexual behavior in Tehran indicates a potent health risk condition for families. Of course, this percentage is not the real infection rate in ordinary men in Tehran. This situation could be controlled by promoting concurrent diagnosis and treatment of T. vaginalis infection in men and women, as well as strengthening religious beliefs and health education in the individuals.

Correlates of trichomoniasis among female sex workers who inject drugs in two Mexico-US border cities

This paper evaluates correlates of trichomoniasis among female sex workers who inject drugs (FSWIDs) in two Mexico-US border cities. HIV-negative FSWIDs aged 18 years or older were enrolled in a study between 2008 and 2010 in Tijuana and Ciudad Juarez (Cd.), Mexico. All participants underwent a baseline interviewer-administered survey and did a rapid test for trichomoniasis. Using regression to estimate prevalence ratios, we examined sociodemographics, sex work characteristics, sexual health and behavior, substance use, and police and violence exposures as potential correlates of trichomoniasis. Of 584 women (284 in Tijuana, 300 in Cd. Juarez), prevalence of trichomoniasis was 33.6%. Factors associated with trichomoniasis in multivariable analysis were having money stolen by police in the past six months (adjusted prevalence ratio [aPR] =1.448, 95% confidence interval [CI] = 1.152-1.821), recent methamphetamine use (aPR = 1.432, CI = 1.055-1.944), lifetime syphilis infection (aPR = 1.360, CI = 1.061-1.743), ever use of a home remedy to treat vaginal symptoms (aPR = 1.301, CI = 1.027-1.649), and number of regular clients in the past month (aPR = 1.006 per client, CI = 1.004-1.009), while controlling for age and city of interview. Alongside the need for trichomoniasis surveillance and treatment programs, findings indicate that both structural and behavioral factors serve as primary correlates of trichomoniasis among FSWIDs in these cities.

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.

Prevalence and correlates of Trichomonas vaginalis infection among female sex workers in a city in Yunnan Province, China

Sexual transmission is the fastest growing route of HIV transmission in China, and Trichomonas vaginalis(TV) can facilitate HIV transmission and acquisition. Our goal was to determine the prevalence and correlates of TV infection among female sex workers (FSWs). This cross-sectional study was conducted in a city of Yunnan Province in southern China, with confidential face-to-face interviews and laboratory tests for TV (wet mount) and other sexually transmitted infections. A total of 734 FSWs participated in the study. The prevalence of TV was 9.0% (95% confidence interval [CI] 7.02-11.30). In multivariate analyses, adjusted odds ratios of TV infection were 3.0 (95% CI 1.47-6.01) for herpes simplex virus type 2 seropositive, 2.4 (95% CI 1.37-4.14) for Chlamydia trachomatis infection, 2.6 (95% CI 1.30-5.31) for genital ulcer, 1.9 (95% CI 1.11-3.30) for starting age in commercial sex <20 years, and 0.5 (95% CI 0.27-0.87) for vaginal douching. We found a relatively high prevalence of TV infection among FSWs in Yunnan Province. A range of control strategies that include TV screening are recommended among FSWs, which could contribute significantly to the disruption of transmission by the provision of immediate treatment.

Development of a loop-mediated isothermal amplification assay for detection of Trichomonas vaginalis

A loop-mediated isothermal amplification (LAMP) assay targeting the 2-kbp repeated DNA species-specific sequence was developed for detection of Trichomonas vaginalis, the causative agent of trichomoniasis. The analytical sensitivity and specificity of the LAMP assay were evaluated using pooled genital swab and urine specimens, respectively, spiked with T. vaginalis trophozoites. Genital secretion and urine did not inhibit the detection of the parasite. The sensitivity of the LAMP was 10-1000 times higher than the PCR performed. The detection limit of LAMP was 1 trichomonad for both spiked genital swab and urine specimens. Also, LAMP did not exhibit cross-reactivity with closely-related trichomonads, Trichomonas tenax and Pentatrichomonas hominis, and other enteric and urogenital microorganisms, Entamoeba histolytica, Candida albicans, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. This is the first report of a LAMP assay for the detection of T. vaginalis and has prospective application for rapid diagnosis and control of trichomoniasis.