In Vitro Study of the Susceptibility of Clinical Isolates of Trichomonas vaginalis to Metronidazole and Secnidazole

Evaluation of the impact of tragacanth/xanthan gum interpolymer complexation with chitosan on pharmaceutical performance of gels with secnidazole as potential periodontal treatment

Periodontitis consists a group of dental disorders that affect about 70 % of the world population. The therapy mainly relies on mechanical removing bacterial biofilm, nevertheless, local or systemic antibacterial agents play a key role in treating the acute conditions. Secnidazole is a newer derivative of commonly used metronidazole with high safety profile and broad spectrum of antimicrobial activity. The aim of the study was to evaluate the applicability of polyelectrolyte complex-based hydrogels composed of anionic tragacanth with addition of xanthan gum and cationic chitosan as carriers for buccal/intra pocket delivery of secnidazole. Prepared hydrogels with 5 % and 10 % (w/w) drug content were evaluated pharmaceutically towards inter alia physicomechanical, rheological and thermal properties, drug release kinetics, swelling behavior or antimicrobial activity. Cytotoxicity against human primary umbilical vein endothelial cells was also assessed with two independent method. Stable compositions with secnidazole were obtained, however, various miscibility of the drug with the polymers was noted. By adding chitosan, antibacterial activity and swelling performance of the gels were improved, nevertheless, drop of the mucoadhesiveness was also recorded. Hydrogels with 5 % secnidazole were selected as effective antimicrobial compositions with the highest cytocompatibility. They might be considered as promising for oromucosal application with special attention given to SEC as an alternative locally administered antimicrobial agent.

Identification of Trichomonas vaginalis 5-Nitroimidazole Resistance Targets

Trichomonas vaginalis is the most common non-viral sexually transmitted infection. 5-nitroimidazoles are the only FDA-approved medications for T. vaginalis treatment. However, 5-nitroimidazole resistance has been increasingly recognized and may occur in up to 10% of infections. We aimed to delineate mechanisms of T. vaginalis resistance using transcriptome profiling of metronidazole (MTZ)-resistant and sensitive T. vaginalis clinical isolates. In vitro, 5-nitroimidazole susceptibility testing was performed to determine minimum lethal concentrations (MLCs) for T. vaginalis isolates obtained from women who had failed treatment (n = 4) or were successfully cured (n = 4). RNA sequencing, bioinformatics, and biostatistical analyses were performed to identify differentially expressed genes (DEGs) in the MTZ-resistant vs. sensitive T. vaginalis isolates. RNA sequencing identified 304 DEGs, 134 upregulated genes and 170 downregulated genes in the resistant isolates. Future studies with more T. vaginalis isolates with a broad range of MLCs are needed to determine which genes may represent the best alternative targets in drug-resistant strains.

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.

Secnidazole: a treatment for trichomoniasis in adolescents and adults

INTRODUCTION

Single-dose 2-g oral secnidazole (SEC), newly approved by the U.S. Food and Drug administration (FDA) for treatment of trichomoniasis, is a potent 5-nitroimidazole with selective toxicity against various micro-organisms. It has been used internationally to treat trichomoniasis, bacterial vaginosis, and other infections for decades. Trichomoniasis is the most common non-viral sexually transmitted infection worldwide and is associated with significant morbidity. In comparison to the only other FDA-approved treatments for trichomoniasis in the United States - metronidazole and tinidazole - SEC has favorable pharmacokinetics, including a longer half-life and a lower minimal lethal concentration.

AREAS COVERED

This work summarizes the chemistry and pharmacology of SEC and reviews the evidence on its efficacy, tolerability, and safety for the treatment of trichomoniasis.

EXPERT OPINION

SEC is an efficacious, well tolerated, and safe treatment for patients aged ≥12 years with trichomoniasis. Single-dose administration makes it a favorable treatment option, especially in cases where adherence to multi-dose treatment regimens may be low.

Detection of metronidazole resistance in Trichomonas vaginalis using uncultured vaginal swabs

Trichomonas vaginalis (T. vaginalis) is the most prevalent sexually transmitted infection (STI) globally. Metronidazole is the drug of choice for treating T. vaginalis infections although metronidazole-resistant T. vaginalis has been reported in clinical isolates. The purpose of this study was to determine the presence of mutations in nitroreductase genes associated with metronidazole resistance in vaginal swabs testing positive for T. vaginalis. This study included 385 human immunodeficiency virus (HIV)-positive pregnant women. Vaginal swabs were collected from consenting pregnant women and used for the detection of T. vaginalis using the TaqMan assay. From the vaginal swabs, nitroreductase genes ntr4 and ntr6 containing mutations associated with metronidazole resistance were amplified using a quantitative polymerase chain reaction (PCR) assay. To validate the PCR assay, T. vaginalis cultured isolates with known metronidazole resistance profiles were used as controls in the mutation detection assays. The prevalence of T. vaginalis in the study population was 12.2% (47/385). Mutations associated with resistance to metronidazole were detected in more than 40% of the samples tested, i.e. 21/47 (45%) and 24/47 (51%) for ntr4 and ntr6, respectively. A total of 19 samples (40%) carried mutations for both ntr4 and ntr6 genes associated with metronidazole resistance. The validation assays showed a positive correlation between phenotypic and genotypic resistance profiles. This study found a high prevalence of mutations associated with metronidazole resistance. This is concerning since metronidazole is currently used in the syndromic management of STIs in South Africa. Molecular-based assays for monitoring metronidazole resistance profiles using nitroreductase genes may serve as a feasible method for antimicrobial surveillance studies for T. vaginalis.

Secnidazole for Trichomoniasis in Women and Men

INTRODUCTION

Secnidazole (SEC), newly FDA-approved for trichomoniasis, is a potent 5-nitroimidazole with selective toxicity against various infections. It has been used internationally to treat trichomoniasis, bacterial vaginosis, and other infections for decades. Trichomoniasis is the most common non-viral sexually transmitted infection worldwide and is associated with significant morbidity. In comparison to the only other approved treatments for trichomoniasis in the U.S.-metronidazole and tinidazole-SEC has favorable pharmacokinetics, including a longer half-life, and a lower minimal lethal concentration against Trichomonas vaginalis.

OBJECTIVES

Provide an updated, comprehensive review of the literature evaluating SEC as a treatment for trichomoniasis in women and men.

METHODS

We conducted a search to identify existing research on SEC and trichomoniasis. On August 6, 2021, we searched MEDLINE using the terms "secnidazole" and "trichomon.*" We excluded reviews, editorials, case reports, and small case series.

RESULTS

We identified 29 articles; 14 of which were included: 5 reported in vitro pharmacologic data on SEC, 6 were observational studies, and 4 were controlled clinical trials (1 observational study also reported in vitro pharmacologic data). Six studies reported data on women only, 1 on men only, and 3 on women and men. These studies showed that SEC-as a single dose or 3-day course-had comparable efficacy to multi-dose metronidazole for treating trichomoniasis in women and men, was generally well tolerated by patients, and had a favorable pharmacokinetic profile. A single 2-g dose of SEC also led to a microbiologic cure rate of 92.2% in the first randomized, double-blind, placebo-controlled study of trichomonas-infected US-based women.

CONCLUSION

SEC is an efficacious and safe treatment for women and men with trichomoniasis. Single-dose administration makes it a favorable treatment option for patients, especially in cases where adherence to other multi-dose treatment regimens could be problematic. Christina A. Muzny and Olivia T. Van Gerwen. Secnidazole for Trichomoniasis in Women and Men. Sex Med Rev 2022;10:255-262.

A review on Trichomonas vaginalis infections in women from Africa

Background

Trichomoniasis is the most common sexually transmitted infection (STI) with an estimated annual incidence of 276.4 million cases globally and about 30 million cases in sub-Saharan Africa. Trichomoniasis has been found to be associated with various health complications including pelvic inflammatory disease (PID), significant pregnancy complications, cervical cancer, prostatitis, infertility and the acquisition of human immunodeficiency virus (HIV).

Aim

Despite being a highly prevalent infection in the African continent, there is no review article published that solely focusses on Trichomonas vaginalis (T. vaginalis) infections in women from Africa. This review aims to fill this gap in the literature.

Method

An electronic search of online databases was used to identify and extract relevant research articles related to the epidemiology, health complications and treatment associated with T. vaginalis in women from Africa.

Results

Within the African continent, South Africa has reported the highest prevalence rate for this infection. A combination of sociodemographic, behavioural and biological factors has been shown to be associated with infection. Trichomonas vaginalis infection is associated with the acquisition of HIV, cervical cancer and PIDs in various female populations across the continent. Emerging patterns of resistance to metronidazole have been reported in women from South Africa. Currently, there is no effective vaccine against this pathogen despite efforts at vaccine development.

Conclusion

Based on the high prevalence and health consequences associated with T. vaginalis, there is a need for improved screening programmes that will lead to early diagnosis, detection of asymptomatic infections and effective treatment regimens.

Morita-Baylis-Hillman adducts derived from thymol: synthesis, in silico studies and biological activity against Giardia lamblia

Giardiasis is a neglected disease, and there is a need for new molecules with less side effects and better activity against resistant strains. This work describes the evaluation of the giardicidal activity of thymol derivatives produced from the Morita-Baylis-Hillman reaction. Thymol acrylate was reacted with different aromatic aldehydes, using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst. Eleven adducts (8 of them unpublished) with yields between 58 and 80% were obtained from this reaction, which were adequately characterized. The in silico prediction showed theoretical bioavailability after oral administration as well as antiparasitic activity against Giardia lamblia. Compound 4 showed better biological activity against G. lamblia. In addition to presenting antigiardial activity 24 times better than thymol, this MBHA was obtained in a short reaction time (3 h) with a yield (80%) superior to the other investigated molecules. The molecule was more active than the precursors (thymol and MBHA 12) and did not show cytotoxicity against HEK-293 or HT-29 cells. In conclusion, this study presents a new class of drugs with better antigiardial activity in relation to thymol, acting as a basis for the synthesis of new bioactive molecules. Molecular hybridization technique combined with the Morita-Baylis-Hillman reaction provided new thymol derivatives with giardicidal activity superior to the precursor molecules.

Successful treatment with secnidazole for trichomoniasis in the setting of metronidazole hypersensitivity

Limited effective treatment options currently exist for trichomoniasis management among patients with metronidazole hypersensitivity. We report a patient with a documented history of metronidazole hypersensitivity who initially was treated with nitazoxanide but demonstrated clinical and microbiological failure. Secnidazole was subsequently used for treatment, which resulted in clinical and microbiological cure without observation of cross-reactivity. Secnidazole may represent a potential treatment option for trichomoniasis in patients with metronidazole hypersensitivity after consultation with an infectious disease specialist.

Trichomonas vaginalis and growing concern over drug resistance: a systematic review

In the late 90s, a sharp increase of treatment failures of Trichomonas vaginalis (TV) infections with metronidazole (MTZ) was reported, representing a problem due to limited treatment options. We proposed to review the available evidence on the frequency of MTZ resistance by TV isolates and the relationship between treatment failure and in vitro resistance to MTZ. A systematic review based on the PRISMA guidelines was conducted by searching published studies in three different databases (PubMed, Scopus and Web of Science) up to December 2020. The extracted studies were uploaded to Covidence software; screening was guided based on inclusion and exclusion criteria. Additionally, different articles were included through other sources. For each article, study design, objectives, study population and key outcomes were summarized. We found 403 references from the databases and four extra studies. After duplicate removal and screening of title, abstract and full text, 27 studies were included. The selected studies were published between 1983 and 2019; all except one addressed only vaginal TV infection. We identified four major populations in vitro MTZ resistance: two studies evaluated female adolescents; other two assessed HIV-positive women. Fifteen studies considered MTZ resistance in newly diagnosed vaginal TV infection. Finally, eight articles studied in vitro susceptibility of isolates from women with clinical resistant trichomoniasis. High level of in vitro MTZ resistance was rare; low-moderate level was described in most of the cases. Although clinical resistance to MTZ of trichomoniasis was widely reported, there was a paucity of prospective controlled studies. Our review unveiled the need to standardize susceptibility testing, to define breakpoints for detection of MTZ-resistant isolates and to correlate with clinical outcome. It is important to establish criteria to define clinical resistance to MTZ. Such a consensus would foster the development of surveillance studies about clinical and microbiological response to MTZ treatment.

Recent advances in the molecular biology of the protist parasite Trichomonas vaginalis

Trichomonas vaginalis is an anaerobic/microaerophilic protist parasite which causes trichomoniasis, one of the most prevalent sexually transmitted diseases worldwide. T. vaginalis not only is important as a human pathogen but also is of great biological interest because of its peculiar cell biology and metabolism, in earlier times fostering the erroneous notion that this microorganism is at the root of eukaryotic evolution. This review summarizes the major advances in the last five years in the T. vaginalis field with regard to genetics, molecular biology, ecology, and pathogenicity of the parasite.

HIV susceptibility in women: The roles of genital inflammation, sexually transmitted infections and the genital microbiome

Given that heterosexual transmission of HIV across the genital mucosa is the most common route of infection in women, an in-depth understanding of the biological mechanisms associated with HIV risk in the female genital tract (FGT) is essential for effective control of the epidemic. Genital pro-inflammatory cytokines are well-described biological co-factors to HIV risk. Increased levels of pro-inflammatory cytokines in the FGT have been associated with a 3-fold higher-risk of acquiring HIV, presumably through involvement in barrier compromise and the recruitment of highly activated HIV target cells to the site of initial viral infection and replication. Sexually transmitted infections (STIs) and bacterial vaginosis (BV) are suggested possible contributors to genital inflammation in the FGT, and this, coupled with the relationship between genital inflammation and HIV risk, underscores the importance of effective treatment of STI and BV in the promotion of women's health. In most low- and middle-income countries, STIs are treated syndromically, a practice providing rapid treatment without identifying the infection source. However, this approach has been associated with over-diagnosis and the overuse of drugs. Further, because many women with STIs are asymptomatic, syndromic management also fails to treat a vast proportion of infected women. Although several studies have explored the role of STIs and the vaginal microbiome on genital inflammation and HIV risk, the impact of STI and BV management on genital inflammation remains poorly understood. This review aimed to collate the evidence on how BV and STI management efforts affect genital inflammation and the genital microbiome in women.

Thermosensitive hydrogels for vaginal delivery of secnidazole as an approach to overcome the systemic side-effects of oral preparations

Secnidazole (SEC) has been suggested as an alternative agent against Trichomonas vaginalis to overcome the adverse effects, antimicrobial resistance problems and poor adherence to the currently available therapy. Once no topical formulation may be found in the market until now, SEC was incorporated in thermosensitive bioadhesive systems to extend the contact time in the mucosa and to avoid a systemic drug disposition. Formulations containing 20% poloxamer 407, 1% poloxamer 188 and 1 or 2.5% chitosan showed suitable sol-gel transition temperature (> 30 °C), presenting a fast gelation time (100-115 s). Rheological, dynamic light scattering and infrared spectroscopy analysis suggested molecular interactions among polymers. Chitosan increased the mucoadhesion strength of the formulations. In addition, hydrogels showed a tendency to decrease the drug transport rate through mucosa when compared to the control. Mucin was also added onto mucosa for a more realistic simulation of permeability/retention. In the presence of this agent, hydrogels containing chitosan reduced the permeability/retention of the drug in approximately 2.0-fold when compared to the control. Therefore, the hydrogels presented suitable characteristics to remain in the vaginal environment, which would result in effective local treatment of trichomoniasis.

Lack of association between Mycoplasma hominis and Trichomonas vaginalis symbiosis in relation to metronidazole resistance

Resistance mechanisms of Trichomonas vaginalis to metronidazole are still not well understood. It has been shown that Mycoplasma hominis has the ability to establish an endosymbiotic relationship with T. vaginalis. This study investigated the association between T. vaginalis and M. hominis symbiosis in relation to metronidazole resistance. This study included 362 pregnant women from the King Edward VIII hospital in South Africa. The women provided self-collected vaginal swabs for the diagnosis of T. vaginalis by culture. Metronidazole susceptibility using the broth-microdilution assay was performed. Detection of the 16S rRNA from M. hominis using T. vaginalis genomic DNA as the template was performed. All statistical analysis was conducted in R statistical computing software. A total of 21 culture positive isolates were obtained resulting in a prevalence of 5.8% for T. vaginalis in the study population. Under anaerobic incubation, 52.4% (11/21) of the isolates were susceptible to metronidazole (MIC ≤ 1 μg/ml). Intermediate resistance (MIC of 2 μg/ml) and full resistance (4 μg/ml) was observed in 38.1% (8/21) and 9.5% (2/21) of the isolates, respectively. The majority of the isolates 95% (19/20) were susceptible to metronidazole under aerobic conditions. Only one isolate had a MIC of 50 μg/ml. M. hominis was shown to be present in 85.7% (18/21) of the T. vaginalis isolates. However, there was no significant association between metronidazole susceptibility and T. vaginalis-M. hominis symbiosis. This study provides evidence of emerging metronidazole resistance in T. vaginalis. However, these resistance profiles were not associated with M. hominis symbiosis.

Vaginitis: Review on Drug Resistance

Female genital tract infections have a high incidence among different age groups and represent an important impact on public health. Among them, vaginitis refers to inflammation of the vulva and/or vagina due to the presence of pathogens that cause trichomoniasis, bacterial vaginosis, and vulvovaginal candidiasis. Several discomforts are associated with these infections, as well as pregnancy complications and the facilitation of HIV transmission and acquisition. The increasing resistance of microorganisms to drugs used in therapy is remarkable, since women report the recurrence of these infections and associated comorbidities. Different resistant mechanisms already described for the drugs used in the therapy against Trichomonas vaginalis, Candida spp., and Gardnerella vaginalis, as well as aspects related to pathogenesis and treatment, are discussed in this review. This study aims to contribute to drug design, avoiding therapy ineffectiveness due to drug resistance. Effective alternative therapies to treat vaginitis will reduce the recurrence of infections and, consequently, the high costs generated in the health system, improving women's well-being.

Optimising treatments for sexually transmitted infections: surveillance, pharmacokinetics and pharmacodynamics, therapeutic strategies, and molecular resistance prediction

Progressive antimicrobial resistance in Neisseria gonorrhoeae, Mycoplasma genitalium, and Trichomonas vaginalis has created a pressing need for treatment optimisations for sexually transmitted infections (STIs). In this Review, we aim to highlight urgent needs in global STI management, including: (1) improved surveillance to monitor antimicrobial resistance and clinical outcomes; (2) systematic pharmacokinetic and pharmacodynamic evaluations to ensure resistance suppression and bacterial eradication at all sites of infection; (3) development of novel, affordable antimicrobials; and (4) advancements in new molecular and point-of-care tests to detect antimicrobial resistance determinants. Antimicrobial resistance among STIs is a global public health crisis. Continuous efforts to develop novel antimicrobials will be essential, in addition to other public health interventions to reduce the global STI burden. Apart from prevention through safer sexual practices, the development of STI vaccines to prevent transmission is a crucial research priority.

Análise de prescrições de antimicrobianos na Atenção Primária à Saúde

RESUMO Objetivo Avaliar receitas com prescrição de antimicrobianos retidas nas unidades de saúde da Atenção Primária de uma capital da região Nordeste do Brasil. Método Estudo avaliativo, analítico. Foram utilizadas as informações da central de distribuição de medicamentos essenciais e as receitas com prescrição de antimicrobianos. Resultados Foram analisadas 2.232 receitas, nas quais o metronidazol (250 mg) foi prescrito em 28% das receitas avaliadas, a forma farmacêutica “comprimido” em 30,7% e a forma de administração “oral” em 78,2%. Nas receitas prescritas por enfermeiros, 80,7% destinavam-se para usuários com infecção sexualmente transmissível. Com exceção da forma farmacêutica, somente 34,7% das receitas estavam em concordância com as recomendações do protocolo de Enfermagem. Há, ainda, inexistência de informações sobre a concentração (43,7%), a posologia (39,9%) e o tempo de tratamento (36,8%). Conclusão As receitas com prescrição de antimicrobianos avaliadas não seguem com precisão as orientações da Resolução nº 20/2011, e nem do protocolo de Enfermagem instituído.

Management of Resistant Trichomoniasis

PURPOSE OF REVIEW

Trichomonas vaginalis is the most prevalent sexually transmitted parasite in the USA; resistant infection is emerging. New drug therapies and dosing regimens of standard therapies are being studied to treat resistant infection.

RECENT FINDINGS

Diagnosis of trichomoniasis has become more sensitive, specific, and widely available with the advent of nucleic acid amplification tests (NAATs). Women with resistant trichomoniasis should be treated with high-dose regimens of metronidazole or tinidazole. Alternative treatment options have been described, and there has been some success particularly with high-dose tinidazole/intravaginal paromomycin cream combination, intravaginal boric acid, and intravaginal metronidazole/miconazole. Resistant trichomoniasis is a growing public health concern with implications for long-term health consequences. More data are needed to further evaluate mechanisms by which resistance occurs as well as promising therapies for those affected.