MCQs on Campylobacter spp and Helicobacter spp: Medical microbiology

                         MCQs on Campylobacter spp and Helicobacter spp

                        Figure: Colonies of Campylobacter jejuni after 48 hours of incubation on a                                                     selective medium in a microaerobic atmosphere. 

                                     (Reference: Bailey & Scott's Diagnostic Microbiology)

1. A 25 year old male arrives at the emergency room with a two-day history of gastrointestinal symptoms. He reports severe abdominal cramps, frequent watery diarrhea, nausea, vomiting, and a low-grade fever. He also mentions that he has had occasional blood in his stool. His symptoms have progressively worsened, and he is becoming dehydrated.

Upon examination, John appears tired and dehydrated. His temperature is 100.8°F, heart rate 110 bpm, blood pressure: 100/70 mm Hg, respiratory rate 20 breaths/min. Abdominal tenderness and cramping,  and hypotension is observed. The patient has no known underlying medical conditions. He mentions that he has been eating at a local restaurant everyday for last four days.

The healthcare team performs various diagnostic tests. Blood tests reveal elevated white blood cell count (indicative of infection), and electrolyte imbalances. Stool culture identifies Campylobacter coli as the causative agent of the infection.

Which of the following antibiotic is commonly recommended for the treatment of infection caused by C. coli?

a) Ciprofloxacin     

b) Erythromycin

c) Rifampin

d) Zidovudine

2) Campylobacter jejuni is a microaerophilic bacteria, which of the following statement is true about the oxygen requirement for the culture and islolation of the bacteria?
a) An atmosphere of O2 (10%) with added CO2 (5%)

b) An atmosphere of O2 (5%) with added CO2 (10%)  >

c) An atmosphere of  O2 (0%) with CO2 (10%)

d) An atmosphere of O2 (10%) with added CO2 (5%) 

3) A 34 year old female working as a office manager in Kathmandu, Nepal visits a local healthcare center with a one month history of recurrent epigastric (upper abdominal) pain. She describes the pain as a burning sensation that occurs between meals and sometimes wakes her up at night. She also mentions a history of occasional heartburn and bloating. She has tried over-the-counter antacids with minimal relief. Her symptoms have been progressively worsening, and she's concerned about her health.

Upon examination, the patient appears generally well-nourished and in no acute distress. Her vital signs are within normal limits.

She has a medical history of occasional heartburn, she is not taking any prescription medications regularly and has no known chronic medical conditions.

Her healthcare provider orders various diagnostic tests, including; Upper Gastrointestinal Endoscopy (EGD) which reveals inflamed and reddened stomach lining with signs of gastritis. Biopsies are taken from the stomach lining for further analysis.

Based on the results of the upper endoscopy and H. pylori testing, the diagnosis is confirmed as Helicobacter pylori gastritis.

Sarah is prescribed a combination of antibiotics (such as clarithromycin and amoxicillin or metronidazole) and a proton pump inhibitor (PPI) for 10-14 days to eradicate the H. pylori infection.

Which staining method is commonly used by pathologists to examine gastric biopsy specimens for the presence of H. pylori?

a) Gram staining

b) Giemsa staining     

d) Hematoxylin and eosin staining

D) Ziehl-Neelsen staining

4) Which biochemical tests are used for the presumptive identification of H. pylori when grown in culture?

a) Gram stain, PCR, and sugar fermentation

b) Oxidase, catalase, and urea breath test 

c) Oxidase, catalase, and rapid urease test    

d) PCR, Giemsa staining, and ELISA

5) Which of the following gram negative bacillus is most commonly associated with a post diarrheal syndrome also known as 'Guillain-Barre syndrome'?
a) Campylobacter jejuni    
b) Campylobacter ureolyticus
c) Helicobacter pylori
d) Helicobacter fennelliae

6) What is the most common transport medium used for stool specimen collected from gastroenteritis infection?

a) Amies Transport Medium

b) Cary-Blair transport medium 

c) 10% Formalin Solution

d) None of the above

7) Helicobacter pylori is associated with all of the following infections, EXCEPT?
a) Burkitt lymphoma  

b) Gastric carcinoma
c) Malt lymphoma

d) Peptic ulcer

8) What environmental conditions, including gas composition, are typically required for the incubation of culture plates to recover Helicobacter spp.?

a) 1% O2, 8% CO2, 90% N2

b) 10% O2, 10% CO2, 80% N2

c) 4% O2, 5% CO2, 5% H2, 86% N2     

d) 21% O2, 0.04% CO2, 78% N2)

9) What type of colonies are typically observed on culture plates after 4 to 7 days of incubation for Helicobacter spp.?

a) Green, filamentous colonies

b) Large, irregular, pink colonies 

c) Smooth, white, raised colonies

d) Small, translucent, circular colonies    

10) Which component is used to replace blood in Campylobacter agar base blood free (CCDA) to support the growth of most Campylobacter species?

a) Charcoal

b) Sodium pyruvate

c) Ferrous sulfate

d) All of the above    

Answers:

1. a) Ciprofloxacin 

2. b) An atmosphere of O2 (5%) with added CO2 (10%) 

3. b) Giemsa staining

4. c) Oxidase, catalase, and rapid urease test 

5. a) Campylobacter jejuni  

6. b) Cary-Blair transport medium

7. a) Burkitt lymphoma 

8. c) 4% O2, 5% CO2, 5% H2, 86% N2

9. d) Small, translucent, circular colonies

10. d) All of the above