An 18-year-old patient complains of pain in her lower abdomen, fever of 37.5°C, a significant amount of mucopurulent discharge being produced from her genital tract, and burning pain during urination. Mirror examination and vaginal examination reveal an infiltrated urethra and hyperemic and eroded cervix. The uterus is painful to palpation, the appendages are painful and thickened, the fornices are free. Bacterioscopy of the discharge detects diplococci. What is the most likely diagnosis in this case?