Podcast
Questions and Answers
Which characteristic of Campylobacter jejuni is most critical for its survival and propagation within its specific niche?
Which characteristic of Campylobacter jejuni is most critical for its survival and propagation within its specific niche?
- Its production of lipopolysaccharides (LPS) which enhances its ability to colonize diverse hosts.
- Its rapid growth rate, allowing it to quickly outcompete other gut flora.
- Its optimal growth temperature of 42°C, which inhibits most other bacteria. (correct)
- Its ability to thrive in a standard atmospheric environment.
A public health investigation reveals a cluster of gastroenteritis cases linked to a local petting zoo. Considering the epidemiology of Campylobacter jejuni, which intervention would be most effective in preventing further infections?
A public health investigation reveals a cluster of gastroenteritis cases linked to a local petting zoo. Considering the epidemiology of Campylobacter jejuni, which intervention would be most effective in preventing further infections?
- Vaccinating all the animals in the petting zoo against *Campylobacter jejuni*.
- Administering prophylactic antibiotics to all visitors of the petting zoo.
- Implementing strict handwashing protocols and educating visitors about the risks of animal contact. (correct)
- Closing the petting zoo indefinitely.
What is the most likely mechanism by which Campylobacter jejuni infection leads to the development of Guillain-Barré Syndrome (GBS)?
What is the most likely mechanism by which Campylobacter jejuni infection leads to the development of Guillain-Barré Syndrome (GBS)?
- Direct neurotoxicity of *Campylobacter jejuni* cytotoxins on peripheral nerves.
- Suppression of the host's immune response, allowing opportunistic infections to damage nerve cells.
- Molecular mimicry involving lipooligosaccharides (LOS) that triggers an autoimmune response. (correct)
- Invasion of the central nervous system by *Campylobacter jejuni* leading to neuronal damage.
A patient presents with enterocolitis characterized by watery diarrhea, abdominal pain, and fever. Stool cultures are positive for Gram-negative, microaerophilic bacteria that grow optimally at 42°C. The isolate is also oxidase positive and sensitive to nalidixic acid. What is the most appropriate treatment?
A patient presents with enterocolitis characterized by watery diarrhea, abdominal pain, and fever. Stool cultures are positive for Gram-negative, microaerophilic bacteria that grow optimally at 42°C. The isolate is also oxidase positive and sensitive to nalidixic acid. What is the most appropriate treatment?
Which of the following virulence factors of Campylobacter jejuni directly contributes to the inflammatory response observed in enterocolitis?
Which of the following virulence factors of Campylobacter jejuni directly contributes to the inflammatory response observed in enterocolitis?
Why is MacConkey agar not typically used for the primary isolation of Campylobacter jejuni from stool samples?
Why is MacConkey agar not typically used for the primary isolation of Campylobacter jejuni from stool samples?
Why is a microaerophilic atmosphere crucial for the successful cultivation of Campylobacter jejuni in the laboratory?
Why is a microaerophilic atmosphere crucial for the successful cultivation of Campylobacter jejuni in the laboratory?
What is the significance of Campylobacter jejuni's enterotoxin in the pathogenesis of diarrheal disease?
What is the significance of Campylobacter jejuni's enterotoxin in the pathogenesis of diarrheal disease?
A patient who recently recovered from Campylobacter jejuni enteritis presents with conjunctivitis, arthritis, and urethritis. Which of the following conditions is most likely associated with these symptoms?
A patient who recently recovered from Campylobacter jejuni enteritis presents with conjunctivitis, arthritis, and urethritis. Which of the following conditions is most likely associated with these symptoms?
Given that cows are common carriers of Campylobacter jejuni, what specific measure is most effective at preventing transmission to humans through dairy products?
Given that cows are common carriers of Campylobacter jejuni, what specific measure is most effective at preventing transmission to humans through dairy products?
Flashcards
Campylobacter jejuni
Campylobacter jejuni
Most common cause of bacterial gastroenteritis worldwide, especially in children.
C. jejuni Morphology
C. jejuni Morphology
Curved (comma or S-shaped), motile, Gram-negative rods that are microaerophilic.
C. jejuni Growth Conditions
C. jejuni Growth Conditions
Grows best in 5% oxygen at 42°C. Special media (Skirrow, Butzler, campy blood agar) is required to suppress competing bacteria.
C. jejuni Transmission
C. jejuni Transmission
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C. jejuni Virulence Factors
C. jejuni Virulence Factors
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C. jejuni Clinical Signs
C. jejuni Clinical Signs
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Reactive Arthritis & C. jejuni
Reactive Arthritis & C. jejuni
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C. jejuni Diagnosis
C. jejuni Diagnosis
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C. jejuni Treatment
C. jejuni Treatment
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C. jejuni and GBS
C. jejuni and GBS
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Study Notes
- Campylobacter jejuni (C. jejuni) is a leading cause of bacterial gastroenteritis, especially in children, worldwide.
- C. jejuni infection can lead to Guillain-Barré syndrome (GBS) because antibodies formed against it cross-react with nerve antigens.
- The name "Campylobacter" means "curved," reflecting its comma or S-shape.
- C. jejuni are motile, Gram-negative rods.
- This bacterium thrives in a microaerophilic environment with only 5% oxygen.
- Optimal growth occurs at 42°C (107°F).
- C. jejuni possesses an outer polysaccharide capsule.
- Lipooligosaccharides (LOS) in its cell wall mimic nerve gangliosides, causing autoimmune GBS through molecular mimicry.
- Skirrow, Butzler, and campy blood agar are used to culture C. jejuni because they contain antibiotics that suppress competing bacteria and provide essential nutrients.
Epidemiology
- It is a zoonotic disease primarily transmitted from animals to humans via the fecal-oral route.
- Birds are a reservoir, with transmission occurring through raw or undercooked poultry.
- Unpasteurized milk can transmit the bacteria from cows, which are common carriers.
- Direct contact with infected pets, especially puppies shedding the bacteria in their stool, can also lead to transmission.
- Children are the most susceptible.
- C. jejuni growth is slow and easily outcompeted by normal gut flora.
- It requires specific nutrients.
- C. jejuni is oxidase positive.
Virulence Factors
- A secreted cytotoxin contributes to inflammatory colitis.
- An enterotoxin, similar to cholera toxin, increases adenylate cyclase activity causing electrolyte and fluid imbalance, leading to watery diarrhea.
Clinical Manifestations
- Enterocolitis starts with watery, foul-smelling diarrhea, progresses to bloody stools, and includes fever and severe abdominal pain.
- Systemic infections, mainly bacteremia, are more common with C. jejuni, causing fever and malaise.
- C. jejuni-related gastroenteritis is linked to Guillain-Barré Syndrome (GBS), the most frequent cause of acute neuromuscular paralysis.
- GBS is an autoimmune response where C. jejuni antibodies cross-react with neuronal antigens.
- Reactive arthritis, including Reiter’s syndrome (conjunctivitis, arthritis, urethritis), can also result from the molecular mimicry of C. jejuni.
Laboratory Diagnosis
- Stool samples are cultured.
- Blood agar with antibiotics inhibits other fecal bacteria.
- Incubation at 42°C with 5% oxygen and 10% CO2 is necessary for growth.
- Identification is confirmed by its inability to grow at 25°C and oxidase positivity, as well as sensitivity to nalidixic acid.
- Gram stain will show gram-negative bacteria
Treatment
- Enterocolitis is treated with erythromycin or ciprofloxacin.
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