Question

case study:

Denise is a 45-year-old American female who has been admitted to the medical ward after having symptoms of food poisoning and skin rash. Her temperature has been over 38°C and she has been complaining of diarrhea and vomiting. Denise also presented with nasty looking skin rash on her upper and lower extremities. According to Denise, the skin rash has started since she swam in the Owens Lake (in California) 3 days ago. She stated that the rash started as small “red bumps” but started to get worse, deeper and more painful around a cut skin that she had sustained a week ago. She admits that she is not sure whether her current health conditions were caused by her swimming in the lake or because of the takeaway food that she also had on the same day. When Denise was asked about the takeaway food, she recalled that she thought the chicken was not fully cooked when she started eating it. Denise had a skin swab taken and a stool sample was sent for culture and sensitivity. The stool sample analysis confirmed food poisoning with Salmonella enterica and the skin swap results revealed Vibrio Cholerae skin infection.

Q1:

Discuss the mechanism that enables Salmonella enterica to survive the gastric acidity to causing Salmonella infection?

Q2:

Patients infected with Salmonella enterica usually recover within few days without antibiotics. Based on the factors affecting their growth, suggest one reason why this happens and give two ways of prevention from Salmonella infection.

Answer 1

1.Macrophages destroy bacteria by engulfing them in intracellular compartments, which they then acidify to kill or neutralize the bacteria. However, some pathogenic bacteria, such as Salmonella enterica, have evolved to exist and even grow while within these acidified compartments. Salmonella fights acid with acid, by lowering the pH of its own interior in response to the acidification of the Salmonella-containing compartment by the macrophage, and by using that low pH as a signal to turn on genes needed to establish an infection.

2.Strong stomach acid can kill many types of salmonella bacteria in healthy persons.But some medical problems or medications can short-circuit these natural defenses.

Prevention:

1.Wash your hands

Washing your hands thoroughly can help prevent the transfer of salmonella bacteria to your mouth or to any food you're preparing. Wash your hands after you:

• Use the toilet
• Change a diaper
• Handle raw meat or poultry
• Clean up pet feces
• Touch reptiles or birds

2.Cook food thoroughly. Salmonella bacteria are most commonly found in animal products and can be killed by the heat of cooking. Don't serve raw or undercooked eggs, poultry, or meat