[Metronidazole-resistant trichomoniasis and successful therapy following high dosage]

A patient is reported who suffered for several months from a Trichomonas vaginalis infection that was resistant to the usual low-dose treatment with 5-nitro-imidazole derivatives. Following various ineffective therapeutic trials, the agent was isolated in order to determine its sensitivity to 5-nitro-imidazole. The resistance of the isolate to metronidazole was confirmed in vitro and in an animal experiment; the patient was therefore treated with high daily doses of metronidazole, 3 x 750 mg orally as well as 2 x 100 mg topically for 14 days. Substitution therapy with zinc was administered in order to normalize the patient's relatively low zinc serum levels. These measures finally led to a clinical cure and elimination of the pathogenic agent. This is the first confirmed case of a metronidazole-resistant Trichomonas vaginalis infection reported in the Federal Republic of Germany.