A 28-year-old man presents to the emergency department 6 hours after eating raw oysters at a seafood restaurant. He reports acute onset of profuse, watery diarrhea and severe cramping abdominal pain. Vital signs are BP 110/68 mmHg, HR 108 bpm, RR 20/min, temperature 37.2°C. Physical examination reveals moderate dehydration with dry mucous membranes but normal skin turgor. Stool microscopy is negative for blood and WBCs. Stool culture grows oxidase-positive, curved gram-negative rods that require NaCl for growth. Serum potassium is 3.2 mEq/L. Which of the following virulence factors is primarily responsible for the massive secretory diarrhea in this patient?
- A)Lipopolysaccharide (LPS) endotoxin causing mucosal invasion and inflammation
- B)Cholera toxin (ADP-ribosyltransferase) that increases intestinal cAMP and chloride secretionGABARITO
- C)Thermostable direct hemolysin (TDH) causing cytolysis of intestinal epithelial cells
- D)Invasion plasmid antigen (Ipa) mediating bacterial translocation across the epithelium
- E)Shiga toxin-like cytotoxin inhibiting protein synthesis in host cells
Explicação
The organism is Vibrio cholerae, identified by: curved gram-negative rod, oxidase-positive, NaCl requirement, and typical presentation of watery (non-inflammatory) diarrhea 6 hours after seafood ingestion. Cholera toxin is an AB enterotoxin that ADP-ribosylate... Ver explicação completa e trilha adaptativa →