A healthy 23-year-old woman presents to the clinic for reevaluation of dysuria and vaginal discharge. She has receptive vaginal sex with a single male partner. She was seen 4 weeks prior for persistent symptoms. At the prior visit, nucleic acid amplification testing (NAAT) of a first-catch urine was negative for Neisseria gonorrhea and Chlamydia trachomatis, but positive for Trichomonas vaginalis. She was treated with a 7-day course of oral metronidazole 500 mg twice daily. Her male sex partner did not follow up for evaluation and treatment because he did not have any symptoms. Her male sex partner was referred to clinic and presumptively treated with a single dose of 2 g of oral metronidazole. She undergoes repeat testing, which is negative for C. trachomatis and N. gonorrhea, but positive again for T. vaginalis. She has not been sexually active with her partner since completing treatment.