Case 3 Answers

1.What is the likely cause of this man's diarrhea?

            Salmonella

2. Do these organisms cause diarrhea by invasion or toxin production? Describe what is known of the pathogenesis of diarrhea caused by these organisms?

Invasion. Salmonella surface factor reacts with host cell receptor to stimulate "ruffling" caused by actin rearrangement. Organisms are internalized by pinocytosis, allowing internalization of adjacent salmonellae as well. From there on it is only speculated that the process involves transport across the cell, through the basolateral membrane, giving access to the lymphatic cells of the lamina propria where the organisms induce an inflammatory response. The enterocytes of the large and small bowel are involved.

3. How did the members of  the family become infected?  What is the usual route of infection with this pathogen?

Probably from a raw egg in the Caesar salad.

4. What is the preferred therapy of enteritis due to salmonella?

 Rehydration. Antibiotics have not been shown to affect the clinical course of salmonellosis.  However they are indicated in severely ill individuals in whom bacteremia is suspected or shown.

5.What other clinical syndromes are described with salmonella infection?

 Septicemia, enteric fever (typhoid fever) and asymptomatic carrier state.

6. Given the present distribution systems for meat, poultry and dairy products in the United States, what measures could be adopted to reduce the spread of salmonella infection?

Greater attention to preparation at packing houses including less mixing of lots of meat, cleaning surfaces and instruments after each lot of meat is   processed, disinfection of the meat (irradiation), thorough cooking of meat and egg products.