After eating a cheeseburger, French fries, and Ice cream for dinner one night, a 6-year-old girl develops nausea, mild abdominal cramping, and a slight fever. Three days later, her parents notice that she is passing dark stools and dark urine and appears fatigued and weak. On physical examination, she has a temperature of 37.9 , pulse 88/min, respirations 18/min, and blood pressure 140/90mmHg. Scattered petechiae are present ℃ on the extremities. Laboratory findings show a serum creatinine level of 2.2mg/dL and urea nitrogen level of 20 mg/dL. Urinalysis shows a pH of 6, specific gravity 1.016, 2+hematuria, and no protein or glucose. A renal biopsy specimen shows small thrombi within glomerular capillary loops. Which of the following diseases is most likely to produce these findings?