A 40-year-old male presents with fever and rhinorrhea for 3 days, followed by nausea, vomiting, oliguria, and fatigue. Blood pressure is 160/100 mmHg, hemoglobin 70 g/L, serum creatinine 707.2 μmol/L (8 mg/dL), blood urea nitrogen 57 mmol/L (100 mg/dL), total plasma protein 48 g/L, and ultrasound shows both kidneys with a long axis of 8 cm. The most likely diagnosis is: