WBR0063

Author	PageAuthor::William J Gibson
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Neurology, SubCategory::Infectious Disease
Prompt	[[Prompt::A 28-year-old male has developed an inflammatory disease causing demyelination of peripheral nerves. He began experiencing numbness in his toes which progressed to distal muscle weakness of his lower limb and has now progressed to include the entire lower limb and the distal upper limb. CSF findings include increased protein with a normal cell count. The patient is started on intravenous immunoglubulin. Which of the following describes the organism most likely to have infected this patient prior to his developing this condition?]]
Answer A	AnswerA::Comma shaped, oxidase positive, gram negative organism which grows at 42C.
Answer A Explanation	AnswerAExp::Campylobacter jejuni is a comma shaped, oxidase positive, gram negative organism which grows at 42C.
Answer B	AnswerB::Gram positive rod with tumbling motility
Answer B Explanation	AnswerBExp::Listeria monocytogenes is a gram-positive rod with tumbling motility. L. monocytogenes causes meningitis in newborns and may cause food-borne illness through ingestion of unpasteurized milk.
Answer C	AnswerC::Gram negative, urease positive rod.
Answer C Explanation	AnswerCExp::Helicobacter pylori is a gram negative, urease positive rod that causes gastric ulcers.
Answer D	AnswerD::Gram positive, spore forming rod
Answer D Explanation	[[AnswerDExp::Clostridium species and Baccilus anthracis are both gram positive, spore forming rods.]]
Answer E	AnswerE::Lancet shaped, gram positive diplococci.
Answer E Explanation	AnswerEExp::Streptococcus pneumoniae is a lancet shaped, gram positive diplococcus.
Right Answer	RightAnswer::A
Explanation	[[Explanation::The patient in this vignette has Guillain-Barré syndrome, a progressive autoimmune demyelinating disease of peripheral nerves. Guillain-Barré is known to be preceded by Campylobacter jejuni in particular. Campylobacter jejuni is a comma shaped, oxidase positive, gram negative organism that grows at 42C. Educational Objective: Guillain-Barré is known to be preceded by Campylobacter Jejuni, a Comma shaped, oxidase positive, gram negative organism that grows at 42C. References: First Aid 2014 page 140 (Camplyobacter) First Aid 2014 page 484 (Guillan-Barré)]]
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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