Question

“This ulcer is stressing me out”

Meg’s a manager at a post office which began to get stressful one day due to a missing package of jewelry. Her staff became very strained attempting to find the missing package and simultaneously calm the customer down. The woman whose expensive package had gone missing accused the post office workers of stealing.

Meg started to experience abdominal pain that came in the middle of the night, which she assumed was due to stress at work. As the issue at work resolved, Meg anticipated feeling better, but instead, was feeling worse. The abdominal pain was now present all the time which started to interfere with sleep. Meg decided to see her doctor, who suspected an ulcer and ordered some tests.

1. It’s possible that Meg’s ulcer is caused by a microbe, but taking a swab sample from her stomach ulcer is difficult due to the location in the human body. Explain why traditional culture based biochemical and genetic testing would not be the ideal method to identify the microbe (which methods require cultures?). Then research and explain how the urea breath test is used to identify microbes which cause peptic ulcers. Is it considered genetic, biochemical or immunological? (2 points)

2. A sample of Meg’s blood was taken to determine if her ulcer is being caused by a microbe. Upon mixing her blood with bacteria cultured in the laboratory, you visualize clumping. State the type of identification method used (genetic, immunological or biochemical) AND the type of reaction or test used. (2 points)

Type of identification	Type of reaction or test used

3. 2 days later, Meg was admitted to the hospital due to severe bloody vomit, which is not a common symptom found in individuals with peptic ulcers and warrants further investigation. You decide to take a stomach biopsy to see if you can culture the bacteria. Upon isolating the bacteria, you start to identify it metabolically. First, you inoculate the bacteria into fluid thioglycollate medium, which determines the bacteria’s oxygen requirements. Use the result below to determine the oxygen requirements of the bacteria. (2 points)

4. Circle one: Is the bacteria infecting Meg considered a psychrotroph, mesophile, thermophile or hyperthermophile? (2 points)

5. You decide to further identify the bacteria by inoculating different biochemical tests. After inoculating a urea test tube and incubating it for 24 hours, you visualize a color change from orange to hot pink, indicating the microbe makes an enzyme called urease. A. Research the pH range of stomach acid? B. Research the function of the urease enzyme. C. Does this microbe use endoenzymes or exoenzymes to neutralize the pH? D. State if the microbe is an acidophile, alkalinophile or neutrophile. (4 points)

A. pH range of stomach acid
B. Function of Urease enzyme (you can use your lab manual for this!)
C. Endoenzyme or Exoenzyme?
D. Acidophile, Neutrophile or Alkalinophile? (Hint: think about the function of urease)

At least four sentences are required. Not all prokaryotes can infect humans. For example, our body temperature is not warm enough for hyperthermophiles to thrive. Explain how temperature and pH levels can influence microbial infections in the human body. From each category (temperature and pH), which types of organisms can infect humans? (8 points)

Answer 1