A case of metronidazole-resistant Trichomonas vaginalis in pregnancy

Trichomonas vaginalis is a sexually transmitted protozoan infection resulting in vulvo-vaginitis and altered vaginal discharge in symptomatic women. Trichomoniasis has been implicated in causing adverse pregnancy outcomes such as low birth weight and pre-term labour. Metronidazole is the recommended first-line treatment for trichomonal infection. Other nitroimidazoles, such as tinidazole, are used as alternative regimens with similar activity but at a greater expense. Treatment failure usually represents patient non-compliance or re-infection, although metronidazole resistance has previously been documented. Antimicrobial susceptibility testing for T. vaginalis is currently not available in the UK. Patients with disease unresponsive to first-line treatments pose a major challenge, as therapeutic options are limited. We present the case of a patient with presumed resistant infection during pregnancy, and the additional treatment issues that this presented.