A 24-year-old man comes to the emergency department due to severe nausea and vomiting 2 hours after a church picnic. He ate chicken salad that had been sitting out in the sun. The patient has no prior medical conditions. Temperature is 37.2 C (98.9 F), blood pressure is 126/84 mm Hg, and pulse is 86/min. No abdominal tenderness is present, and bowel sounds are normal. Blood cell counts and serum chemistry studies are within normal limits. Symptoms improve significantly within several hours with supportive care. Which of the following is the most likely cause of this patient's symptoms?

Question

A 24-year-old man comes to the emergency department due to severe nausea and vomiting 2 hours after a church picnic.  He ate chicken salad that had been sitting out in the sun.  The patient has no prior medical conditions.  Temperature is 37.2 C (98.9 F), blood pressure is 126/84 mm Hg, and pulse is 86/min.  No abdominal tenderness is present, and bowel sounds are normal.  Blood cell counts and serum chemistry studies are within normal limits.  Symptoms improve significantly within several hours with supportive care.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec160b_3827_b398_9249_b9bfd772a26f_MD0001_00 Enterotoxigenic Staphylococcus aureus is a leading cause of foodborne illness. This pathogen inoculates food during unsanitary preparation by an asymptomatic carrier. Storage of the food at room temperature for extended periods (eg, picnic, pot luck meal) allows the bacteria to proliferate and generate a heat-stable enterotoxin. Ingestion of the preformed toxin leads to rapid-onset illness that includes nausea, vomiting, and abdominal pain. Occasionally, mild fever and diarrhea may also be present. Symptoms resolve in a few hours with symptomatic care. Because the disease is due to the ingestion of a preformed toxin, no person-to-person transmission occurs. However, outbreaks may arise when people eat the same contaminated food at an event or party. High risk foods include dairy products, produce, precooked meat, eggs, and mayonnaise-based salads (eg, chicken salad). A similar clinical picture of rapid-onset nausea, vomiting, and abdominal cramping can be seen with food-borne illness due to Bacillus cereus, which also produces a heat-stable enterotoxin. B cereus characteristically contaminates starchy foods (eg, rice); illness is often associated with reheated rice. (Choices A, B, and D) Foodborne illness can also be caused by other bacterial mechanisms, such as: However, gastroenteritis due to these bacteria generally takes >24 hours to manifest, as the bacteria require time to proliferate and subsequently produce enterotoxin and/or invade the intestinal epithelium. (Choice E) Most gram-negative enteric pathogens contain endotoxin (lipopolysaccharide) that is released upon cell lysis. However, endotoxin released in the gastrointestinal tract is not typically absorbed in sufficient quantities to cause systemic illness. Endotoxin-mediated illness (eg, sepsis) occurs when gram-negative bacteria are present in the bloodstream. Educational objective: Staphylococcal food poisoning is mediated by the ingestion of a preformed, heat-stable enterotoxin that induces rapid-onset (<6 hours) nausea and vomiting. Most cases arise due to improper food handling and storage. Common culprit foods include eggs, dairy products, and mayonnaise-based salads.

A 24-Year-Old Man Comes to the Emergency Department Due to Severe