Trichomonas vaginalis

A 19-year-old woman comes to the clinic with a history of burning micturition, increased frequency of urination, and malodorous vaginal discharge. She is sexually active with three sexual partners. Her male partner does not use condoms when engaging in vaginal intercourse. Temperature is 37.0°C (98.6°F), pulse is 90/min, respirations are 20/min, and blood pressure is 120/75 mmHg. The patient’s abdomen is soft and nontender. Speculum examination reveals purulent, malodorous discharge and a friable, erythematous cervix with punctate hemorrhages. Cervical motion tenderness is absent on bimanual examination. The pH of the vaginal discharge is 5.5. An external genital examination is unremarkable.  Which of the following findings is likely to be seen on further laboratory evaluation?