title: In vitro effect of tinidazole and furazolidone on metronidazole-resistant Trichomonas vaginalis.
abstract: Trichomonas vaginalis is a common sexually transmitted protozoan parasite. Although often considered simply a nuisance infection, T. vaginalis has been implicated in premature rupture of placental membranes and increases in the risk of acquiring human immunodeficiency virus. Metronidazole, a 5-nitroimidazole, is currently the drug of choice to treat T. vaginalis infection. Because some patients have severe reactions to metronidazole and others are infected with metronidazole-resistant T. vaginalis, we were prompted to investigate alternative therapies. Tinidazole, another 5-nitroimidazole used in other countries to treat T. vaginalis infections, and furazolidone, a nitrofuran presently used to treat giardiasis and infections with some anaerobic enteric bacteria, were investigated for effectiveness against 9 metronidazole-susceptible and 12 metronidazole-resistant T. vaginalis patient isolates. The in vitro aerobic and anaerobic minimum lethal concentrations (MLC) and the time for drug efficacy were determined. Tinidazole killed the metronidazole-susceptible isolates at a low MLC but was effective against only 4 of the 12 metronidazole-resistant isolates. In contrast, furazolidone was effective at a low MLC for all isolates. When tinidazole was effective, it required > 6 h to kill trichomonads. However, furazolidone killed both metronidazole-susceptible and resistant trichomonads within 2 to 3 h of exposure. These data suggest that furazolidone may be a good candidate for treating metronidazole-resistant trichomoniasis and that further investigation of this drug is warranted.
authors.affiliation: National Center for Infectious Diseases, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Atlanta, Georgia 30341-3717, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Narcisi
authors.forename: W E
authors.initials: WE
authors.lastname: Secor
mesh_terms: D000818:Animals; D000994:Antitrichomonal Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial / Q000235:genetics; D005664:Furazolidone / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008795:Metronidazole / Q000494:pharmacology; D013997:Time Factors; D014011:Tinidazole / Q000494:pharmacology*; D014246:Trichomonas vaginalis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000994:Antitrichomonal Agents; D014011:Tinidazole; D008795:Metronidazole; D005664:Furazolidone