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Questions and Answers
Why does Campylobacter jejuni utilize lipooligosaccharides (LOS) instead of lipopolysaccharides (LPS), and what is the clinical significance of this adaptation?
Why does Campylobacter jejuni utilize lipooligosaccharides (LOS) instead of lipopolysaccharides (LPS), and what is the clinical significance of this adaptation?
- LOS provides enhanced structural integrity to the bacterial cell wall compared to LPS, allowing it to withstand the harsh conditions of the gastrointestinal tract.
- LOS increases the bacterium’s resistance to antibiotics, ensuring its survival during treatment with common antibiotics like erythromycin or ciprofloxacin.
- LOS mimics human nerve gangliosides, triggering an autoimmune response leading to Guillain-Barré Syndrome (GBS) due to molecular mimicry. (correct)
- LOS facilitates the bacterium’s adherence to the intestinal epithelium, promoting colonization and infection within the host.
Campylobacter jejuni is known for its specific growth requirements. Which of the following conditions is crucial for its cultivation in a laboratory setting, and why is it important?
Campylobacter jejuni is known for its specific growth requirements. Which of the following conditions is crucial for its cultivation in a laboratory setting, and why is it important?
- Supplementation with high concentrations of salt to inhibit the growth of other intestinal flora and promote selective growth of _Campylobacter jejuni_.
- Incubation at 37°C in an aerobic environment to mimic human body temperature and atmospheric oxygen levels.
- Incubation at 42°C in a microaerophilic environment to suppress competing bacteria and provide optimal growth conditions. (correct)
- Growth on MacConkey agar to differentiate _Campylobacter jejuni_ from other Gram-negative bacteria based on lactose fermentation.
How does Campylobacter jejuni's enterotoxin contribute to the pathophysiology of gastroenteritis, and what cellular mechanism is primarily affected?
How does Campylobacter jejuni's enterotoxin contribute to the pathophysiology of gastroenteritis, and what cellular mechanism is primarily affected?
- It promotes the release of inflammatory cytokines, leading to inflammatory colitis and severe abdominal pain.
- It inhibits the absorption of glucose in the small intestine, resulting in osmotic diarrhea.
- It stimulates increased adenylate cyclase activity, leading to electrolyte and fluid imbalance and causing watery diarrhea. (correct)
- It directly damages the intestinal epithelium, causing ulceration and bleeding, leading to bloody stools.
What is the most plausible means of transmission of Campylobacter jejuni to humans and what public health intervention would be most effective in preventing its spread?
What is the most plausible means of transmission of Campylobacter jejuni to humans and what public health intervention would be most effective in preventing its spread?
What is the rationale behind using blood agar containing antibiotics incubated at 42°C with 5% oxygen and 10% CO2 for isolating Campylobacter jejuni from a stool sample?
What is the rationale behind using blood agar containing antibiotics incubated at 42°C with 5% oxygen and 10% CO2 for isolating Campylobacter jejuni from a stool sample?
Which of the following clinical manifestations is least likely to be directly caused by bacteremia resulting from Campylobacter jejuni infection?
Which of the following clinical manifestations is least likely to be directly caused by bacteremia resulting from Campylobacter jejuni infection?
What is the underlying mechanism by which Campylobacter jejuni infection can lead to reactive arthritis and Reiter’s syndrome?
What is the underlying mechanism by which Campylobacter jejuni infection can lead to reactive arthritis and Reiter’s syndrome?
Why is erythromycin or ciprofloxacin prescribed for Campylobacter jejuni enterocolitis, and what is a potential limitation of using these antibiotics?
Why is erythromycin or ciprofloxacin prescribed for Campylobacter jejuni enterocolitis, and what is a potential limitation of using these antibiotics?
Given that Campylobacter jejuni is oxidase positive and sensitive to nalidixic acid, how are these characteristics utilized in its laboratory identification?
Given that Campylobacter jejuni is oxidase positive and sensitive to nalidixic acid, how are these characteristics utilized in its laboratory identification?
Consider a scenario where several people who attended a barbecue develop enterocolitis. Stool samples are collected, and Campylobacter jejuni is suspected. Besides culture, what other diagnostic approach could confirm Campylobacter as the causative agent and potentially suggest a source of the outbreak?
Consider a scenario where several people who attended a barbecue develop enterocolitis. Stool samples are collected, and Campylobacter jejuni is suspected. Besides culture, what other diagnostic approach could confirm Campylobacter as the causative agent and potentially suggest a source of the outbreak?
Flashcards
Campylobacter jejuni
Campylobacter jejuni
Most common cause of bacterial gastroenteritis worldwide, especially in children.
C. jejuni characteristics
C. jejuni characteristics
Curved, motile, Gram-negative rod that is microaerophilic and grows best at 42°C.
C. jejuni's LOS
C. jejuni's LOS
Instead of LPS, this bacteria contains lipooligosaccharides (LOS) that mimic human nerve gangliosides which triggers autoimmune response, leading to Guillain-Barré Syndrome (GBS).
C. jejuni special media
C. jejuni special media
Skirrow agar, Butzler agar, and campy blood agar contain antibiotics to suppress competing bacteria and also provide essential nutrients for C. jejuni growth.
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C. jejuni transmission
C. jejuni transmission
Resides in GI tract of birds. Transmitted by eating raw/undercooked poultry, direct contact w/ infected pets, drinking unpasteurized milk, or drinking contaminated water.
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C. jejuni enterotoxin
C. jejuni enterotoxin
Enterotoxin results in increased adenylate cyclase activity, causing electrolyte and fluid imbalance, leading to watery, foul-smelling diarrhea.
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C. jejuni enterocolitis
C. jejuni enterocolitis
Watery, foul-smelling diarrhea, bloody stools, fever, and severe abdominal pain often occur.
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C. jejuni molecular mimicry
C. jejuni molecular mimicry
Molecular mimicry of LOS can cause reactive arthritis and Reiter’s syndrome: conjunctivitis, arthritis, and urethritis.
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C. jejuni lab diagnosis
C. jejuni lab diagnosis
Use blood agar containing antibiotics incubated at 42°C with 5% oxygen and 10% CO2. Fails to grow at 25°C. Oxidase positive and sensitivity to nalidixic acid.
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C. jejuni treatment
C. jejuni treatment
Enterocolitis treated with erythromycin or ciprofloxacin.
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- Campylobacter jejuni is the most common global cause of bacterial gastroenteritis, especially in children.
- It is a curved, motile, Gram-negative rod.
- This bacterium is microaerophilic, thriving in 5% oxygen.
- It grows optimally at 42°C (107°F).
- C. jejuni possesses a polysaccharide capsule.
- Instead of LPS, it contains lipoligosaccharides (LOS) that mimic human nerve gangliosides, leading to Guillain-Barré Syndrome (GBS).
- GBS is often preceded by C. jejuni infection due to cross-reacting antibodies.
- C. jejuni requires specific nutrients and special media for growth such as Skirrow agar, Butzler agar, and campy blood agar.
- It is oxidase positive.
- It is a zoonotic bacterium residing in the GI tract of birds, transmitted via raw/undercooked poultry.
- Transmission can also occur through contact with infected pets (puppies), unpasteurized milk (cows), and contaminated water (fecal-oral route).
- Children are particularly susceptible to infection.
- C. jejuni secretes cytotoxin, leading to inflammatory colitis.
- Its enterotoxin, similar to cholera toxin, results in increased adenylate cyclase activity, causing watery diarrhea.
- Infection leads to enterocolitis, characterized by watery, foul-smelling diarrhea, bloody stools, fever, and severe abdominal pain.
- Bacteremia can occur, causing fever and malaise.
- LOS-driven molecular mimicry can also cause reactive arthritis, including Reiter’s syndrome (conjunctivitis, arthritis, urethritis).
- Diagnosis involves stool sample analysis using blood agar with antibiotics, incubated at 42°C with 5% oxygen and 10% CO2. It will not grow at 25C.
- C. jejuni is sensitive to nalidixic acid.
- Gram stain will appear gram-negative.
- Enterocolitis is treated with erythromycin or ciprofloxacin.
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