Question

Jack was thankful he had declined the offer of spicy Mexican food with his coworkers. The pain was worse, burning from his navel to his breastbone. It always peaked at night and when he was hungry. “It's just the stress from work,” Jack told himself.

Jack chewed up a handful of Tums, and made toast and tea for his late dinner. Despite the antacids and bland meal, Jack's gastric distress intensified. Two hours later, Jack vomited and was terrified to see bright red blood mixed in with his regurgitated toast. He drove immediately to the hospital.

After examining Jack, Dr. McAfee said, “You have all the symptoms of a gastric ulcer: persistent burning belly pain worsening at night, weight loss, and nausea. Your experience tonight plus the dark stools you reported means the ulcer is bleeding. I'm going to order a test to confirm this diagnosis so we can get you started on antibiotics.”

Jack responded with surprise. “You said I had an ulcer, not an infection. What do I need antibiotics for?”

Dr. McAfee explained that most gastric ulcers are the result of a bacterial infection (Figure a). As the microorganism thrives in the

mucus layer protecting the stomach surface, its activity can weaken the coating. Sensitive stomach tissues are exposed to both acid and the bacteria, which degrade the lining and cause ulcer formation.

a. Helicobacter pylori, the microbe that causes most gastric ulcers

1. Which microorganism is infecting Jack and causing his gastric ulcer? Describe its morphology.
2. What is the pH of the stomach acid irritating the lining of Jack's stomach?

In the morning, Jack underwent an endoscopy, a procedure involving the insertion of a tube with a tiny camera down the esophagus and into the stomach. After directly viewing the damaged lining, the physician performed a biopsy by collecting a small tissue sample near the ulcer and examining it.

At his follow-up appointment, the physician explained that Jack's CLO test was positive, indicating that his ulcer was caused by infection (Figure b). His biopsied tissue was inserted into a small container of urea agar mixed with the pH indicator, phenol red. Bacteria infecting the tissue used urease to convert the urea into carbon dioxide and ammonia, raising the pH and changing the indicator from yellow to hot pink.

b. The CLO test packet

3. Examine the CLO test packet. Does the pH as acidic or basic? How do you know?

Jack's physician wrote a prescription for 2 weeks of antibiotics plus Protonix, a drug to inhibit acid pumps in his stomach. The doctor explained that the infecting bacteria can also raise the pH in the stomach just as they did in the CLO test. Gastric tissues compensate by secreting more acid, which in turn aggravates the ulcer. “So doctor, if the excess acid can destroy my stomach lining, why doesn't it kill the infecting bacteria?” Jack asked.

This bacterial species is adapted to the harsh conditions of your stomach and capable of withstanding the low pH that kills most other pathogens,” answered the doctor. “Finish your prescriptions and you'll be in good shape…remember, stress and spicy food can aggravate an ulcer, but the bacteria caused it.”

4. Which antibiotic was likely prescribed to treat Jack's ulcer?
5. What microorganisms compose the normal microbiota of the stomach? Why?

Answer 1

Answer

According to the given question-

Considering all the information given in the question

Jack has the symptoms of gastric ulcer in which continuous burning belly pain was observed during the night,it also leads to weight loss, and nausea.  The most gastric ulcers are due to bacterial infections. Because these bacteria resides in the mucus layer which protect the liNing of stomach which results in weaking of coating causing the stomach layer to get sensitive for both bacteria as well as for the acid present in stomach causing degradation of the surface lining which results in ulcer formation.

(1)Helicobacter pylori- also celled  Campylobacter pylori, belongs to group of  gram-negative bacteria and have helical shape structure and also are , microaerophiles  lived in  stomach responsible for causing gastric ulcers.Helicobacter pylori are about 3 μm long and have a diameter of about 0.5μm. and also have the capability to form biofilms. It also have six flagella.

(2) pH of the stomach should be basic and more than pH of 8 which causing irritation along the lining of stomach causing pain when the tissue comes in contact with the acids. These microorganisms also causes sores in the lining of stomach due to which the stomach cancer occur.

(3) CLO test- The CLO test is also called Rapid urease test, or Campylobacter-like organism test used for diagnosis of Helicobacter pylori to check the capability of bacteria to secrete urease enzyme that convert urea to ammonia as well as carbon dioxide molecule.

Here phenol red was used as indicator which indicated the colour from yellow to hot pink . This indicator changes colour from yellow to red between pH 6.6 to 8.0 and gives dark pink colour above pH 8.1.

So here the pH sholud be more than 8.1.

(4) Doctor prescribed the antibiotics protonix which is also called as pantopranazole used for the stomach ulcers. This antibiotics work as proton pump inhibitors. Doctor suggested that the microorganisms that are causing ulcers are increasing the pH of the stomach linings where they resides but this effect was diminished upto a certain level due to the acid pump which are continuously working due to reflex of food present in the stomach. So this antibiotics block the acid pump and prevent the release of proton due to which the pH of stomach increses that may can damage the microorganisms that are causing the increase of pH .

(5)  normal microbiota present in the human stomach are several species of bacteria, fungi, archea, organism of protista and some viruses also that maintains normal functioning of digestive system of humans.