Clinical performance of the Solana® Point-of-Care Trichomonas Assay from clinician-collected vaginal swabs and urine specimens from symptomatic and asymptomatic women

On The Horizon: Novel Approaches to Sexually Transmitted Infection Prevention

Rates of sexually transmitted infections (STIs), especially cases of infectious and congenital syphilis, are increasing in the United States. Novel strategies for STI prevention are being explored and include doxycycline post-exposure prophylaxis and the potential utility of vaccines against gonorrhea. Self-collection of samples and point of care testing for STI are increasingly being employed in a variety of settings. Both can improve uptake of screening and lead to earlier detection and treatment of incident STI in target populations. Overcoming existing regulatory issues and optimizing implementation of current evidence-based strategies will be key to maximizing future STI prevention efforts. Here we provide an update for primary care providers on selected new strategies for STI prevention either currently available or under development for possible future use.

The Past, Present, and Future in the Diagnosis of a Neglected Sexually Transmitted Infection: Trichomoniasis

More than one million curable sexually transmitted infections occur every day. Trichomonas vaginalis is one of the main infections responsible for these epidemiological data; however, the diagnosis of this protozoan is still mainly based on microscopic and culture identification. The commercialization of immunological tests and the development of molecular techniques have improved the sensitivity of classical methods. Nevertheless, the fact that trichomoniasis is a neglected parasitic infection hinders the development of novel techniques and their implementation in routine diagnosis. This review article shows the different methods developed to identify T. vaginalis in population and the difficulties in diagnosing male and asymptomatic patients. The importance of including this parasite in routine gynecological screening, especially in pregnant women, and the importance of considering T. vaginalis as an indicator of high-risk sexual behavior are also discussed.

Isothermal nucleic acid amplification and its uses in modern diagnostic technologies

Nucleic acids are prominent biomarkers for diagnosing infectious pathogens using nucleic acid amplification techniques (NAATs). PCR, a gold standard technique for amplifying nucleic acids, is widely used in scientific research and diagnosis. Efficient pathogen detection is a key to adequate food safety and hygiene. However, using bulky thermal cyclers and costly laboratory setup limits its uses in developing countries, including India. The isothermal amplification methods are exploited to develop miniaturized sensors against viruses, bacteria, fungi and other pathogenic organisms and have been applied for in situ diagnosis. Isothermal amplification techniques have been found suitable for POC techniques and follow WHO's ASSURED criteria. LAMP, NASBA, SDA, RCA and RPA are some of the isothermal amplification techniques which are preferable for POC diagnostics. Furthermore, methods such as WGA, CPA, HDA, EXPAR, SMART, SPIA and DAMP were introduced for even more accuracy and robustness. Using recombinant polymerases and other nucleic acid-modifying enzymes has dramatically broadened the detection range of target pathogens under the scanner. The coupling of isothermal amplification methods with advanced technologies such as CRISPR/Cas systems, fluorescence-based chemistries, microfluidics and paper-based sensors has significantly influenced the biosensing and diagnosis field. This review comprehensively analyzed isothermal nucleic acid amplification methods, emphasizing their advantages, disadvantages and limitations.

Advances in Diagnostics of Sexually Transmitted Infections

Sexually transmitted infections (STIs) are caused by various pathogens, many of which have common symptoms. Diagnostic tests are critical to supporting clinical evaluations in making patient management decisions. Molecular diagnostics are the preferred test type when available, especially in asymptomatic patients for many STIs. However, for some infections, serology offers the best insight into infectious status. Clinicians should be aware of the performance characteristics of the available STI diagnostic tests and understand how to use them. Point-of-care tests are helpful to implement rapid and accurate treatment responses, which are particularly helpful in certain at-risk populations.

Trichomoniasis

Trichomoniasis is the most common nonviral sexually transmitted infection worldwide. It has been associated with a variety of adverse sexual and reproductive health outcomes for both men and women. In this review, the authors discuss updates in its epidemiology, pathophysiology, clinical significance, diagnosis, and treatment.

Meta-analysis of the correlation between vaginal microenvironment and HPV infection

PURPOSE

To study the correlation between the vaginal microenvironment and human papillomavirus (HPV) infection by meta-analysis.

METHODS

Databases including the Chinese Journal Full-text Database, China Science and Technology Journal, Wanfang, PubMed, Embase, Cochrane, and Web of Science were used to comprehensively retrieve published clinical studies on the correlation between the vaginal microenvironment and HPV infection. The retrieval was performed according to the inclusion and exclusion criteria, then qualified clinical studies were included for quality evaluation and data extraction. Revman 5.3 software was used for meta-analysis. The correlation between the vaginal microenvironment and HPV infection was assessed. The statistical results were shown by forest plots. Publication bias was tested by funnel plot.

RESULTS

Ten independent studies were included in this study, involving 11,649 patients. The meta-analysis results showed that compared with the HPV-negative group, the HPV-positive group had a significant increase in the aerobic vaginitis (OR = 1.73, 95% CI: 1.19-2.50, P = 0.004), bacterial vaginosis (OR = 2.52, 95% CI: 1.78-3.57, P < 0.001) and trichomonal vaginitis (OR = 1.60, 95% CI: 1.27-2.02, P < 0.001) infection rates, while there was no substantial difference in the vulvovaginal candidiasis infection rate between two groups (OR = 1.48, 95% CI: 0.99-2.23, P = 0.06).

CONCLUSION

The vaginal microenvironment is closely related to HPV infection, especially aerobic vaginitis, bacterial vaginosis and trichomonal vaginitis are high-risk factors for HPV infection.

Diagnosis and Management of Trichomonas vaginalis: Summary of Evidence Reviewed for the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infections Treatment Guidelines

Trichomonas vaginalis is likely the most prevalent nonviral sexually transmitted infection, affecting an estimated 3.7 million women and men in the United States. Health disparities are prominent in the epidemiology of trichomoniasis, as African Americans are >4 times more likely to be infected than persons of other races. Since publication of the 2015 Centers for Disease Control and Prevention sexually transmitted diseases treatment guidelines, additional data have bolstered the importance of T. vaginalis infection sequelae in women, including increased risk of human immunodeficiency virus (HIV) acquisition, cervical cancer, preterm birth, and other adverse pregnancy outcomes. Less is known about the clinical significance of infection in men. Newly available diagnostic methods, including point-of-care assays and multiple nucleic acid amplification tests, can be performed on a variety of genital specimens in women and men, including urine, allowing more accurate and convenient testing and screening of those at risk for infection. Repeat and persistent infections are common in women; thus, rescreening at 3 months after treatment is recommended. In vitro antibiotic resistance to 5-nitroimidazole in T. vaginalis remains low (4.3%) but should be monitored. High rates of T. vaginalis among sexual partners of infected persons suggest a role for expedited partner treatment. A randomized controlled trial in HIV-uninfected women demonstrated that multidose metronidazole 500 mg twice daily for 7 days reduced the proportion of women with Trichomonas infection at 1 month test of cure compared with women receiving single-dose therapy (2 g). The 2-g single-dose oral metronidazole regimen remains the preferred treatment in men.

Bridging the gap between development of point-of-care nucleic acid testing and patient care for sexually transmitted infections

The incidence rates of sexually transmitted infections (STIs), including the four major curable STIs - chlamydia, gonorrhea, trichomoniasis and, syphilis - continue to increase globally, causing medical cost burden and morbidity especially in low and middle-income countries (LMIC). There have seen significant advances in diagnostic testing, but commercial antigen-based point-of-care tests (POCTs) are often insufficiently sensitive and specific, while near-point-of-care (POC) instruments that can perform sensitive and specific nucleic acid amplification tests (NAATs) are technically complex and expensive, especially for LMIC. Thus, there remains a critical need for NAAT-based STI POCTs that can improve diagnosis and curb the ongoing epidemic. Unfortunately, the development of such POCTs has been challenging due to the gap between researchers developing new technologies and healthcare providers using these technologies. This review aims to bridge this gap. We first present a short introduction of the four major STIs, followed by a discussion on the current landscape of commercial near-POC instruments for the detection of these STIs. We present relevant research toward addressing the gaps in developing NAAT-based STI POCT technologies and supplement this discussion with technologies for HIV and other infectious diseases, which may be adapted for STIs. Additionally, as case studies, we highlight the developmental trajectory of two different POCT technologies, including one approved by the United States Food and Drug Administration (FDA). Finally, we offer our perspectives on future development of NAAT-based STI POCT technologies.

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.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Isothermal amplifications - a comprehensive review on current methods

The introduction of nucleic acid amplification techniques has revolutionized the field of medical diagnostics in the last decade. The advent of PCR catalyzed the increasing application of DNA, not just for molecular cloning but also for molecular based diagnostics. Since the introduction of PCR, a deeper understanding of molecular mechanisms and enzymes involved in DNA/RNA replication has spurred the development of novel methods devoid of temperature cycling. Isothermal amplification methods have since been introduced utilizing different mechanisms, enzymes, and conditions. The ease with which isothermal amplification methods have allowed nucleic acid amplification to be carried out has had a profound impact on the way molecular diagnostics are being designed after the turn of the millennium. With all the advantages isothermal amplification brings, the issues or complications surrounding each method are heterogeneous making it difficult to identify the best approach for an end-user. This review pays special attention to the various isothermal amplification methods by classifying them based on the mechanistic characteristics which include reaction formats, amplification information, promoter, strand break, and refolding mechanisms. We would also compare the efficiencies and usefulness of each method while highlighting the potential applications and detection methods involved. This review will serve as an overall outlook on the journey and development of isothermal amplification methods as a whole.

Point-of-Care Testing for Sexually Transmitted Infections: A Review of Recent Developments

CONTEXT.—

Sexually transmitted infections (STIs) are among the most common communicable diseases globally and are associated with significant morbidity and mortality worldwide. Point-of-care tests have the potential to revolutionize the prevention and control of STIs by enabling rapid diagnosis and early treatment of infections, thus interrupting transmission and preventing the sequelae of untreated infections. Currently, there are several point-of-care (POC) tests available for the diagnosis of Treponema pallidum, Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis infections, although these tests differ with regard to their performance, turnaround time, and cost.

OBJECTIVE.—

To provide an updated review of the POC tests available and under development for the diagnosis of T pallidum, C trachomatis, N gonorrhoeae, and T vaginalis infections, to discuss the context for which these tests might be used, and to highlight future directions for test development.

DATA SOURCES.—

We reviewed the literature pertaining to the recent development and performance evaluations of POC tests for the diagnosis of syphilis, chlamydia, gonorrhea, and trichomonas.

CONCLUSIONS.—

Recently, there has been rapid development of new POC tests for STIs. Although there are inexpensive, rapid, and accurate POC tests available for syphilis, there are few such tests available for the diagnosis of chlamydia, gonorrhea, or trichomonas, and currently none with the ability to detect antimicrobial resistance in N gonorrhoeae. Research evaluating implementation strategies for the currently available tests and the development of additional POC tests that are rapid, accurate, and affordable are urgently needed to address the rising number of STIs worldwide.

Update on the Diagnosis of Sexually Transmitted Infections

Sexually transmitted infections (STIs) are one of the most frequent and universal Public Health problems. Health professionals should be aware of the possibility of STIs due to their high morbidity and the presence of sequelae. The delay in the diagnosis is one of the factors that justifies the difficulty to infections control. Diagnostic tests allow the introduction of aetiological treatment and also lead to treating symptomatic and asymptomatic patients more effectively, as well as to interrupt the epidemiological transmission chain without delay. In this review we have made an update of the main existing diagnostic methods for the more important STIs.

Optimal Timing for Trichomonas vaginalis Test of Cure Using Nucleic Acid Amplification Testing

BACKGROUND

The optimal timing for nucleic acid amplification testing (NAAT) posttreatment for Trichomonas vaginalis has not been fully established. Testing too soon posttreatment may detect remnant nucleic acid that is not from viable organisms, falsely misclassifying person as infected. The purpose of this study was to examine how long T. vaginalis nucleic acid is detectable postmetronidazole (MTZ) treatment.

METHODS

Women diagnosed with T. vaginalis treated with MTZ (2 g single-dose or 500 mg twice daily for 7 days multidose) self-collected a vaginal swab for NAAT at baseline and each week postcompletion of treatment through test of cure (TOC) at week 4, when a culture was also performed. Women who reported interim sexual exposure or who were culture positive at 4 weeks were excluded. Time to first negative NAAT was examined using Kaplan Meier analysis.

RESULTS

All women receiving multidose metronidazole were NAAT-negative by 21 days and those receiving single dose by 28 days postcompletion of treatment. Though over half (60.7%) of the cohort reinitiated sex during follow-up¸ all reported using condoms during sex or that they and their partner were treated before sex. Six (6.7%) of 89 had a positive NAAT following their first negative NAAT.

CONCLUSIONS

The optimal timing for T. vaginalis retesting after completion of treatment is 3 weeks for those receiving multidose MTZ and 4 weeks for those receiving single-dose, though sexual reexposure and false negatives should be considered.

Current and Future Perspectives on Isothermal Nucleic Acid Amplification Technologies for Diagnosing Infections

Nucleic acid amplification technology (NAAT) has assumed a critical position in disease diagnosis in recent times and contributed significantly to healthcare. Application of these methods has resulted in a more sensitive, accurate and rapid diagnosis of infectious diseases than older traditional methods like culture-based identification. NAAT such as the polymerase chain reaction (PCR) is widely applied but seldom available to resource-limited settings. Isothermal amplification (IA) methods provide a rapid, sensitive, specific, simpler and less expensive procedure for detecting nucleic acid from samples. However, not all of these IA techniques find regular applications in infectious diseases diagnosis. Disease diagnosis and treatment could be improved, and the rapidly increasing problem of antimicrobial resistance reduced, with improvement, adaptation, and application of isothermal amplification methods in clinical settings, especially in developing countries. This review centres on some isothermal techniques that have found documented applications in infectious diseases diagnosis, highlighting their principles, development, strengths, setbacks and imminent potentials for use at points of care.

Recent advances in the epidemiology, diagnosis, and management of Trichomonas vaginalis infection

Trichomonas vaginalis is the most common, curable non-viral sexually transmitted infection (STI) worldwide. Despite this burden of disease, it is not currently a reportable disease in the United States. Recent advances in the epidemiology, diagnosis, and management of T. vaginalis infection are described in this article. This includes updated global and U.S. prevalence data in women and men as well as recent epidemiological data in HIV-infected individuals and pregnant women. Advances in molecular diagnostics are also reviewed, as are data from recent clinical trials regarding the treatment of trichomonas in women.

Strategies for Prevention and Treatment of Trichomonas vaginalis Infections

The last estimated annual incidence of Trichomonas vaginalis worldwide exceeds that of chlamydia and gonorrhea combined. This critical review updates the state of the art on advances in T. vaginalis diagnostics and strategies for treatment and prevention of trichomoniasis. In particular, new data on treatment outcomes for topical administration of formulations are reviewed and discussed.

Helicase-dependent isothermal amplification: a novel tool in the development of molecular-based analytical systems for rapid pathogen detection

Highly sensitive testing of nucleic acids is essential to improve the detection of pathogens, which pose a major threat for public health worldwide. Currently available molecular assays, mainly based on PCR, have a limited utility in point-of-need control or resource-limited settings. Consequently, there is a strong interest in developing cost-effective, robust, and portable platforms for early detection of these harmful microorganisms. Since its description in 2004, isothermal helicase-dependent amplification (HDA) has been successfully applied in the development of novel molecular-based technologies for rapid, sensitive, and selective detection of viruses and bacteria. In this review, we highlight relevant analytical systems using this simple nucleic acid amplification methodology that takes place at a constant temperature and that is readily compatible with microfluidic technologies. Different strategies for monitoring HDA amplification products are described. In addition, we present technological advances for integrating sample preparation, HDA amplification, and detection. Future perspectives and challenges toward point-of-need use not only for clinical diagnosis but also in food safety testing and environmental monitoring are also discussed.

Graphical Abstract

Rapid and point-of-care tests for the diagnosis of Trichomonas vaginalis in women and men

BACKGROUND

Trichomonasvaginalis (TV) is a highly prevalent parasitic infection worldwide. It is associated with many adverse reproductive health outcomes. Many infections are asymptomatic and syndromic management leads to underdetection of TV. Traditional methods of TV detection such as wet preparation are insensitive. New rapid, point-of-care (POC) tests can enhance the diagnosis of trichomoniasis.

METHODS

The authors reviewed the literature and discuss older POC tests for TV detection, as well as the OSOM lateral flow test, the AmpliVue test, the Solana test and the GeneXpert test as well as the limitations of wet preparation and culture for detection of TV.

RESULTS

The OSOM test is easy to perform, compared with other POC tests, and is Clinical Laboratory Improvement Amendments (CLIA)-waived, equipment-free, has sensitivities of 83%-86% compared with nucleic acid amplification tests (NAATs) and can be performed in 15 min. The AmpliVue and the Solana tests are not CLIA waived and require small pieces of equipment. They are molecular amplified assays and can be completed in <1 hour. AmpliVue demonstrated a sensitivity for vaginal swabs of 100% compared with wet preparation/culture and 90.7% compared with NAATs. Solana demonstrated a sensitivity of 98.6%-100% for vaginal swabs and 92.9%-98% for female urines, compared with wet preparation/culture. Compared with other NAATs, the sensitivity for Solana was 89.7% for swabs and 100% for urine. The GeneXpert TV test for women and men is a moderately complex test, requires a small platform and can be performed in <1 hour. The sensitivity compared with wet preparation/culture for self-collected vaginal swabs was 96.4%, 98.9% for endocervical specimens and 98.4% for female urine. For men, sensitivity for urines was excellent (97.2%). The specificity for all assays was excellent.

CONCLUSIONS

Several rapid POC tests have the potential to rapidly diagnose trichomoniasis in women and one is available for detection of TV in men.