A 38-year-old woman with poorly controlled type 2 diabetes mellitus presents with vulvovaginal itching and thick white vaginal discharge for 2 weeks. On examination, vulvar erythema and edema are noted. Wet mount microscopy shows budding yeast cells and pseudohyphae. Culture on Sabouraud dextrose agar at 37°C grows white, creamy colonies that produce germ tubes in human serum. Which of the following is the most likely organism and the most appropriate first-line treatment?