Staphylococcal Food Poisoning

Staphylococcal food poisoning is an intoxication caused by ingestion of heat stable preformed enterotoxins produced by Staphylococcus aureus in food.

• Foods implicated: cooked ham, cream filled pastries, dairy, salads, and foods handled by carriers (30 percent of people carry S aureus in the nose or on skin) then kept at room temperature.
• Toxin survives cooking (stable at 100 C for 30 minutes), so reheating does not make food safe.
• Incubation is short, 30 minutes to 8 hours (mean 2 to 4 hours).

Abrupt nausea, violent vomiting, abdominal cramps and watery diarrhoea.

• Usually afebrile; hypotension and prostration in severe cases.
• Resolves within 24 to 48 hours; outbreaks affect several people who shared a meal.
• Differential diagnosis: Bacillus cereus emetic syndrome (rice), Clostridium perfringens, norovirus, chemical poisoning (heavy metals, fluoride), scombroid poisoning, mushroom poisoning, early appendicitis.
• Complications: dehydration, hypokalaemia, hypotension, and rarely death in infants, elderly and immunosuppressed.

Clinical, based on short incubation and shared meal; epidemiological investigation.

• Confirmation: enterotoxin assay or detection of S aureus (more than 10^5 organisms per gram) in food, or the same phage type from stool, vomit and food handlers.
• Electrolytes, urea and creatinine for moderate to severe dehydration.

Supportive

• Oral rehydration with low osmolarity solution in small, frequent sips (50 to 100 mL/kg over 4 hours); intravenous Ringer lactate or 0.9 percent sodium chloride for persistent vomiting or severe dehydration (adults 1 to 2 L over 1 hour then reassess; children 20 mL/kg boluses).
• Correct hypokalaemia (potassium chloride 20 to 40 mmol per litre of fluid).

Pharmacological

• Antiemetic: ondansetron 4 to 8 mg oral or IV (children 0.15 mg/kg, maximum 4 mg).
• Antibiotics are not indicated since the illness is toxin mediated.
• Avoid antimotility drugs during the acute vomiting phase.

Public health: report outbreaks, remove implicated food, exclude food handlers with skin infection or nasal carriage, refrigerate prepared food within 2 hours, and keep hot food above 60 C.

Special groups: infants, elderly and pregnant women (admission for fluid support).

Red flags: persistent vomiting beyond 24 hours, hypotension, altered consciousness, blood in vomit or stool (reconsider the diagnosis).

Follow-up: none after recovery; investigate food source in clusters.