Question A: It is very probable that she is suffering from food poisoning. Hamburger usually has high levels of E. coli and reports of E.Coli in salad greens are common. E. coli in steak is usually on the surface and the surface of rare steaks is sterilized by broiling. The likelihood that toxigenic E. Coli is the cause of her illness is high.
Question B: Tell the patient that she probably has food poisoning from bacteria and that she should drink fluids to keep hydrated. If her diarrhea is severe, she should drink oral rehydration solutions.
Question C: Diagnosis requires laboratory tests. Campylobacter, Salmonella and E. coli O157:H7 grow on agar. Many foodborne infections require specialized tests. If the diagnosis is to be made, the patient has to seek medical attention, the physician must decide to order diagnostic tests, and the laboratory must use the appropriate procedures.
Risks of eating raw oysters include infection with Vibrio cholerae and Vibrio parahaemolyticus. The type of diarrhea (often described as rice water) reported suggests cholera is the cause of her disease, V. cholerae will colonize the entire intestinal tract, from the jejunum to the colon, and liquid loss resulting from colonization depends on a balance between bacterial growth, toxin production, and host liquid secretion and absorption. The loss of liquids and electrolytes, which can amount to multiple liters a day, is greatest in the small intestine, and the results of liquid loss are dehydration and hypokalemia.