Raja Lautu, a 46-year-old woman, has come to the office complaining of vaginal itching and a greenish vaginal discharge with a “fishy” smell. She is sexually active and recently changed partners, but she says her partner has no symptoms. Dr. Williams obtains a vaginal fluid specimen and sends it to the lab for testing. From Raja’s symptoms, which STI might you suspect she is experiencing and why? And how could it be treated?