WBR0086: Difference between revisions
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{{WBRQuestion | {{WBRQuestion | ||
|QuestionAuthor={{Ochuko}} (Reviewed by Will Gibson, [[user: Jad Al Danaf]]) | |QuestionAuthor={{Ochuko}} (Reviewed by Will Gibson, [[user: Jad Al Danaf|Jad Al Danaf]]) | ||
|ExamType=USMLE Step 1 | |ExamType=USMLE Step 1 | ||
|MainCategory=Microbiology | |MainCategory=Microbiology | ||
| Line 20: | Line 20: | ||
|MainCategory=Microbiology | |MainCategory=Microbiology | ||
|SubCategory=Infectious Disease | |SubCategory=Infectious Disease | ||
|Prompt=A 38-year-old male presents to the emergency department with a 2-day history of fever, headache, generalized body weakness, mild abdominal pain, diarrhea and vomiting. He had just returned from a trip to Sweden 5 days prior to the onset of his symptoms. He | |Prompt=A 38-year-old male presents to the emergency department with a 2-day history of fever, headache, generalized body weakness, mild abdominal pain, diarrhea and vomiting. He had just returned from a trip to Sweden 5 days prior to the onset of his symptoms. He reports that during his travel, he had tried raw milk for the first time in his life and loved its taste. Physical examination is unremarkable. Laboratory culture of his blood reveals a gram-positive rod with tumbling motility. Which of the following is the most likely causative organism? | ||
|Explanation=The patient in this vignette is suffering from an infection caused by [[Listeria monocytogenes]]. L. monocytogenes is a facultative intracellular gram | |Explanation=The patient in this vignette is suffering from an infection caused by [[Listeria monocytogenes]]. L. monocytogenes is a facultative intracellular [[gram positive]] rod that displays a characteristic "tumbling" motility when viewed on light microscopy. It is beta hemolytic and has a blue-green sheen on blood agar. [[Listeriosis]] is relatively rare and occurs primarily in newborn infants, elderly patients, and patients who are immunocompromised. | ||
Transmission is either food-borne (unpasteurized dairy) or by vaginal transmission during birth. It can cause amnionitis, septicemia, neonatal meningitis, meningitis in immunocompromised patients, or mild gastroenteritis in healthy individuals. | |||
Transmission is either food-borne (unpasteurized dairy) or by vaginal transmission during birth. It can cause [[amnionitis]], [[septicemia]], neonatal meningitis, [[meningitis]] in immunocompromised patients, or mild [[gastroenteritis]] in healthy individuals. | |||
|AnswerA=Actinomyces israelii | |AnswerA=Actinomyces israelii | ||
|AnswerAExp=[[Actinomyces israelii]] is a gram | |AnswerAExp=[[Actinomyces israelii]] is a [[gram positive]] rod that forms long branching filaments resembling [[fungi]]. It causes oral/facial [[abscesses]] that drain through sinus tracts in skin. | ||
|AnswerB=Listeria monocytogenes | |AnswerB=Listeria monocytogenes | ||
|AnswerBExp=[[Listeria monocytogenes]] is a gram | |AnswerBExp=[[Listeria monocytogenes]] is a [[gram positive]] rod with a characteristic tumbling motility. Infection is typically acquired commonly through ingestion of unpasteurized milk/cheese and deli meats or by vaginal delivery. | ||
|AnswerC=Nocardia asteroides | |AnswerC=Nocardia asteroides | ||
|AnswerCExp=[[Nocardia asteroides]] is a gram | |AnswerCExp=[[Nocardia asteroides]] is a [[gram positive]] rod and weakly acid-fast aerobe found in soil. It causes pulmonary infections in immunocompromised patients. | ||
|AnswerD=Salmonella typhi | |AnswerD=Salmonella typhi | ||
|AnswerDExp=[[Salmonella typhi]] is a gram | |AnswerDExp=[[Salmonella typhi]] is a [[gram negative]] rod that causes [[typhoid fever]]. | ||
|AnswerE=Shigella | |AnswerE=Shigella | ||
|AnswerEExp=[[Shigella]] is a gram | |AnswerEExp=[[Shigella]] is a [[gram negative]] non-motile rod causing [[enterocolitis]] or [[shigellosis]], a severe form of dysentery. | ||
|EducationalObjectives=Listeria monocytogenes is a gram | |EducationalObjectives=[[Listeria monocytogenes]] is a [[gram positive]] rod with "tumbling" motility on light microscopy. In healthy adults, it usually causes mild gastrointestinal symptoms. | ||
|References=First Aid 2014 page 133 | |References=First Aid 2014 page 133, CDC.gov [http://www.cdc.gov/pulsenet/pathogens/listeria.html) | ||
Listeriosis: CDC (http://www.cdc.gov/listeria/definition.html] | |||
Listeriosis: CDC (http://www.cdc.gov/listeria/definition.html | |||
|RightAnswer=B | |RightAnswer=B | ||
|WBRKeyword=Microbiology, Listeria, Listeria monocytogenes, Bacteria, Abdominal pain, Diarrhea, Infection, Food poisoning | |WBRKeyword=Microbiology, Listeria, Listeria monocytogenes, Bacteria, Abdominal pain, Diarrhea, Infection, Food poisoning | ||
|Approved=Yes | |Approved=Yes | ||
}} | }} | ||
Revision as of 16:36, 22 March 2014
| Author | [[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1] (Reviewed by Will Gibson, Jad Al Danaf)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::Infectious Disease |
| Prompt | [[Prompt::A 38-year-old male presents to the emergency department with a 2-day history of fever, headache, generalized body weakness, mild abdominal pain, diarrhea and vomiting. He had just returned from a trip to Sweden 5 days prior to the onset of his symptoms. He reports that during his travel, he had tried raw milk for the first time in his life and loved its taste. Physical examination is unremarkable. Laboratory culture of his blood reveals a gram-positive rod with tumbling motility. Which of the following is the most likely causative organism?]] |
| Answer A | AnswerA::Actinomyces israelii |
| Answer A Explanation | [[AnswerAExp::Actinomyces israelii is a gram positive rod that forms long branching filaments resembling fungi. It causes oral/facial abscesses that drain through sinus tracts in skin.]] |
| Answer B | AnswerB::Listeria monocytogenes |
| Answer B Explanation | [[AnswerBExp::Listeria monocytogenes is a gram positive rod with a characteristic tumbling motility. Infection is typically acquired commonly through ingestion of unpasteurized milk/cheese and deli meats or by vaginal delivery.]] |
| Answer C | AnswerC::Nocardia asteroides |
| Answer C Explanation | [[AnswerCExp::Nocardia asteroides is a gram positive rod and weakly acid-fast aerobe found in soil. It causes pulmonary infections in immunocompromised patients.]] |
| Answer D | AnswerD::Salmonella typhi |
| Answer D Explanation | [[AnswerDExp::Salmonella typhi is a gram negative rod that causes typhoid fever.]] |
| Answer E | AnswerE::Shigella |
| Answer E Explanation | [[AnswerEExp::Shigella is a gram negative non-motile rod causing enterocolitis or shigellosis, a severe form of dysentery.]] |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The patient in this vignette is suffering from an infection caused by Listeria monocytogenes. L. monocytogenes is a facultative intracellular gram positive rod that displays a characteristic "tumbling" motility when viewed on light microscopy. It is beta hemolytic and has a blue-green sheen on blood agar. Listeriosis is relatively rare and occurs primarily in newborn infants, elderly patients, and patients who are immunocompromised.
Transmission is either food-borne (unpasteurized dairy) or by vaginal transmission during birth. It can cause amnionitis, septicemia, neonatal meningitis, meningitis in immunocompromised patients, or mild gastroenteritis in healthy individuals. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Microbiology, WBRKeyword::Listeria, WBRKeyword::Listeria monocytogenes, WBRKeyword::Bacteria, WBRKeyword::Abdominal pain, WBRKeyword::Diarrhea, WBRKeyword::Infection, WBRKeyword::Food poisoning |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |