A 52-year-old man comes to the physician because of scrotal swelling. He also says that he has occasional urinary

A 52-year-old man comes to the physician because of scrotal swelling. He also says that he has occasional urinary urgency and difficulty completely emptying his bladder. The patient is a former weightlifter, and acknowledges previous steroid use and occasional binge-drinking. Physical examination shows an enlarged prostate and a reducible scrotal mass. A few days later, he develops severe nausea, vomiting, and severe abdominal pain and is brought to the emergency department. His temperature is 37.7°C (99.8°F), pulse is 78/min, respirations are 14/min, and blood pressure is 108/68 mm Hg. Physical examination reveals a distended abdomen and decreased bowel sounds in all four quadrants. The right scrotum is enlarged and edematous. A firm 6 cm mass is palpable with significant tenderness. Abdominal paracentesis is performed and fluid analysis reveals an elevated ammonia level. Gram stain shows gram-negative rods and cocci. Which is the most likely diagnosis?