WBR0063

Author	PageAuthor::William J Gibson (Reviewed by Yazan Daaboul)
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Neurology, SubCategory::Infectious Disease
Prompt	[[Prompt::A 28-year-old man began experiencing numbness in his toes which progressed to symmetrical distal muscle weakness of his lower limbs and currently includes the entire lower limbs and the distal upper limbs. A lumbar puncture is performed and CSF findings demonstrate increased proteins with a normal cell count. The patient is started on intravenous immunoglobulin (IVIg). Which of the following describes the organism most likely to have infected this patient prior to his developing this condition?]]
Answer A	AnswerA::Oxidase-positive, gram-negative, glucose-nonfermenting, and motile rod
Answer A Explanation	AnswerAExp::''Campylobacter jejuni'' is an oxidase-positive, gram-negative, glucose-nonfermenting, comma-shaped, and motile organism that grows at 42 °C. It is classically associated with GBS.
Answer B	AnswerB::Oxidase-positive, gram-negative, glucose-fermenting, and motile rod
Answer B Explanation	AnswerBExp::''Campylobacter jejuni'' is glucose-nonfermenting rod.
Answer C	AnswerC::Oxidase-negative, gram-negative, glucose-fermenting, and non-motile rod
Answer C Explanation	AnswerCExp::''Campylobacter jejuni'' is a glucose-nonfermenting and motile rod.
Answer D	AnswerD::Oxidase-positive, gram-negative, glucose-nonfermenting, and non-motile rod
Answer D Explanation	AnswerDExp::''Campylobacter jejuni'' is a motile rod.
Answer E	AnswerE::Oxidase-negative, gram-positive, glucose-fermenting, and motile rod
Answer E Explanation	AnswerEExp::''Campylobacter jejuni'' is an oxidase-negative, glucose-nonfermenting rod.
Right Answer	RightAnswer::A
Explanation	[[Explanation::This patient has symptoms and signs consistent with Guillain-Barré syndrome (GBS). GBS is an autoimmune peripheral neuropathy characterized by an acute areflexic symmetrical ascending flaccid paralysis that usually occurs several weeks after a self-limited upper respiratory tract or abdominal infection. Campylobacter jejuni is one of the most common organisms associated with GBS. Campylobacter jejuni is an oxidase-positive, gram-negative, glucose-nonfermenting, and motile rod that grows at 42 °C. It is considered a major cause of infectious bloody diarrhea. It is transmitted by the fecal-oral route. Spoiled poultry, meat, and unpasteurized milk are common sources of Campylobacter jejuni gastrointestinal infection. Other less common infectious agents associated with GBS include CMV, EBV, VZV, and Mycoplasma pneumoniae. Educational Objective: Guillain-Barré syndrome is usually preceded by Campylobacter Jejuni infection, an oxidase-positive, gram-negative, glucose-nonfermenting, comma-shaped, motile rod that grows at 42 °C. References: First Aid 2014 page 140 (Campylobacter) First Aid 2014 page 484 (Guillan-Barré syndrome)]]
Approved	Approved::Yes
Keyword	WBRKeyword::Microbiology, WBRKeyword::Neurology, WBRKeyword::Bacteria, WBRKeyword::Gram stain, WBRKeyword::Autoimmune, WBRKeyword::Autoimmunity, WBRKeyword::Guillan-Barré, WBRKeyword::GBS, WBRKeyword::Campylobacter, WBRKeyword::Campylobacter jejuni
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