Metronidazole resistant trichomoniasis successfully treated with paromomycin

An Overview of Mucosa-Associated Protozoa: Challenges in Chemotherapy and Future Perspectives

Parasitic infections caused by protozoans that infect the mucosal surfaces are widely neglected worldwide. Collectively, Entamoeba histolytica, Giardia lamblia, Cryptosporidium spp. and Trichomonas vaginalis infect more than a billion people in the world, being a public health problem mainly in developing countries. However, the exact incidence and prevalence data depend on the population examined. These parasites ultimately cause pathologies that culminate in liver abscesses, malabsorption syndrome, vaginitis, and urethritis, respectively. Despite this, the antimicrobial agents currently used to treat these diseases are limited and often associated with adverse side effects and refractory cases due to the development of resistant parasites. The paucity of drug treatments, absence of vaccines and increasing problems of drug resistance are major concerns for their control and eradication. Herein, potential candidates are reviewed with the overall aim of determining the knowledge gaps and suggest future perspectives for research. This review focuses on this public health problem and focuses on the progress of drug repositioning as a potential strategy for the treatment of mucosal parasites.

Composite thermoresponsive hydrogel with auranofin-loaded nanoparticles for topical treatment of vaginal trichomonad infection

Trichomonas vaginalis is responsible for the most common non-viral sexually-transmitted disease worldwide. Standard treatment is with oral nitro-heterocyclic compounds, metronidazole or tinidazole, but resistance to these drugs is emerging and adverse effects can be problematic. Topical treatment offers potential benefits for increasing local drug concentrations and efficacy, while reducing systemic drug exposure, but no topical strategies are currently approved for trichomoniasis. The anti-rheumatic drug, auranofin (AF), was recently discovered to have significant trichomonacidal activity, but has a long plasma half-life and significant adverse effects. Here, we used this drug as a model to develop a novel topical formulation composed of AF-loaded nanoparticles (NP) embedded in a thermoresponsive hydrogel for intravaginal administration. The AF-NP composite gel showed sustained drug release for at least 12 h, and underwent sol-gel transition with increased viscoelasticity within a minute. Intravaginal administration in mice showed excellent NP retention for >6 h and markedly increased local AF levels, but reduced plasma and liver levels compared to oral treatment with a much higher dose. Furthermore, intravaginal AF-NP gel greatly outperformed oral AF in eliminating vaginal trichomonad infection in mice, while causing no systemic or local toxicity. These results show the potential of the AF-NP hydrogel formulation for effective topical therapy of vaginal infections.

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.

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.

Refractory Trichomoniasis in HIV-positive and HIV-negative Subjects

Trichomonas vaginalis, a common pathogen, remains widely unknown to the public. Its clinical consequences include upper genital tract infection, increased risk of preterm delivery, and increased risk of HIV transmission. Diagnostic tests, especially in men, have historically had low sensitivity, but the recent development of rapid, reliable point-of-care testing is a step toward improved detection. Reliable treatments for trichomoniasis are limited to the nitroimidazoles, and options for cases with either hypersensitivity or resistance remain limited. In select resistant cases, alternatives, most notably paromomycin, may play a role. A complex interaction exists between T. vaginalis and HIV, whereby women with trichomoniasis are at increased risk for HIV and vice versa. It is hoped that diagnosis and treatment of trichomoniasis in women at high risk for HIV may help to lower the incidence of both infections.

Resistance of Trichomonas vaginalis to metronidazole: report of the first three cases from Finland and optimization of in vitro susceptibility testing under various oxygen concentrations

Trichomonas vaginalis is a globally common sexually transmitted human parasite. Many strains of T. vaginalis from around the world have been described to be resistant to the current drug of choice, metronidazole. However, only a few cases of metronidazole resistance have been reported from Europe. The resistant strains cause prolonged infections which are difficult to treat. T. vaginalis infection also increases the risk for human immunodeficiency virus transmission. We present a practical method for determining the resistance of T. vaginalis to 5-nitroimidazoles. The suggested method was developed by determining the MICs and minimal lethal concentrations (MLCs) of metronidazole and ornidazole for T. vaginalis under various aerobic and anaerobic conditions. Using this assay we have found the first three metronidazole-resistant strains from Finland, although the origin of at least one of the strains seems to be Russia. Analysis of the patient-derived and previously characterized isolates showed that metronidazole-resistant strains were also resistant to ornidazole, and MLCs for all strains tested correlated well with the MICs. The suggested MICs of metronidazole for differentiation of sensitive and resistant isolates are >75 microg/ml in an aerobic 24-h assay and >15 microg/ml in an anaerobic 48-h assay.