WBR291

Author	[[PageAuthor::Gerald Chi (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Gastrointestinal
Prompt	[[Prompt::A 25-year-old man presents to the clinic with abdominal cramps, general malaise, fever, and bloody diarrhea 6 hours after consuming undercooked poultry. Two of his family members also have similar symptoms. Laboratory studies identify the causal agent as microaerophilic, gram-negative, curved rods. Which of the following descriptions of the causative pathogen is true?]]
Answer A	AnswerA::Negative for glucose fermentation test
Answer A Explanation	AnswerAExp::''Campylobacter jejuni'' is negative for glucose fermentation test.
Answer B	AnswerB::Negative for catalase test
Answer B Explanation	AnswerBExp::''Campylobacter jejuni'' is positive for catalase test.
Answer C	AnswerC::Negative for nitrate reduction test
Answer C Explanation	AnswerCExp::''Campylobacter jejuni'' is positive for nitrate reduction test.
Answer D	AnswerD::Negative for oxidase test
Answer D Explanation	AnswerDExp::''Campylobacter jejuni'' is positive for oxidase test.
Answer E	AnswerE::Immotile on wet mount
Answer E Explanation	AnswerEExp::''Campylobacter jejuni'' contains polar flagella and is motile on wet mount.
Right Answer	RightAnswer::A
Explanation	[[Explanation::Campylobacter jejuni is a curved, helical-shaped, non-spore forming, non-glucose-fermenting, microaerophilic, gram-negative bacteria. It is one of the most common causes of human gastroenteritis worldwide. Infection with C. jejuni occurs following invasion of the microorganism of the colonic mucosa with disruption of epithelial cells. C. jejuni has also been associated with subsequent development of Guillain-Barré syndrome, which usually develops two to three weeks after the initial illness. C. jejuni is commonly associated with ingestion of poultry as it naturally colonizes the digestive tract of many bird species. C. jejuni is grown on specially selective agar plates at 42°C, the normal avian body temperature, rather than at 37°C, the temperature at which the majority of other pathogenic bacteria are grown. Since the colonies are oxidase positive, they will usually only grow in scanty amounts on the plates. Microaerophilic conditions are required for abundant growth. A selective blood agar medium (Skirrow's medium) may also be used. The following include the mportant oxidase-positive pathogens: Campylobacter Helicobacter Legionella Neisseria Pseudomonas Vibrio Educational Objective: Campylobacter jejuni is a curved, helical-shaped, non-spore forming, non-glucose-fermenting, microaerophilic, gram-negative bacteria. It is one of the most common causes of human gastroenteritis worldwide. References: First Aid 2014 page 138.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Campylobacter jejuni, WBRKeyword::Gastroenteritis
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