A 33-year-old environmental scientist presents to the clinic…

A 33-year-old environmental scientist presents to the clinic because she has had a foul-smelling discharge from her vagina for the past 3 weeks. She has tried to douche, but it has not improved the odor. She denies itching or burning. On physical examination, you see a gray, thin, homogenous discharge in the vagina without discharge from the cervix. The discharge has a musty odor. The vulva and vaginal mucosa appear normal. You obtain a sample for a wet mount and see epithelial cells with irregular and broken membrane borders. What is your most likely diagnosis?