Four Days After Admission to the Hospital for Community-Acquired Pneumonia

Four days after admission to the hospital for community-acquired pneumonia, a 68-year-old woman has abdominal pain and multiple episodes of loose stools. They are watery, foul-smelling, and occasionally streaked with blood. She has approximately 6 episodes daily. She feels tired. She is currently being treated with intravenous ceftriaxone and oral azithromycin. She has hypertension and type 2 diabetes mellitus. Current medications include metformin, enalapril, and chlorthalidone. Abdominal examination shows mild diffuse tenderness throughout the lower quadrants. The abdomen is not distended. The remainder of her examination shows no abnormalities. Her hemoglobin concentration is 12 g/dL, leukocyte count is 14,100/mm3, The toxin responsible for his current condition most directly impairs which of the following components of intestinal mucosal cells?

A) Apical ion transport
B) Cell membrane integrity
C) Cytoskeleton integrity
D) Mitochondrial energy production
E) Ribosomal protein synthesis