WBR0076
| Author | [[PageAuthor::William J Gibson (reviewed by Template:Rim, Jad)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology, MainCategory::Pathology |
| Sub Category | SubCategory::Dermatology, SubCategory::General Principles, SubCategory::Infectious Disease |
| Prompt | [[Prompt::A 34-year-old man who works in a wool factory presents to the emergency room with a boil-like black ulcer which developed on his neck over the past 2 days.
Which component of the organism causing this disease induces the production of TNF and IL-1?]] |
| Answer A | AnswerA::Peptidoglycan |
| Answer A Explanation | [[AnswerAExp::Peptidoglycan is composed of a sugar backbone with cross-linking by peptide side chains. It provides support for bacterial cells and protects against osmotic forces but does not directly induce IL-1 and TNF.]] |
| Answer B | AnswerB::Lipoteichoic acid |
| Answer B Explanation | [[AnswerBExp::Bacillus anthracis is a gram positive rod, whose lipoteichoic acid stimulates the production of IL-1 and TNF.]] |
| Answer C | AnswerC::Lipid A |
| Answer C Explanation | [[AnswerCExp::Lipid A is a molecule found on the outer membrane of gram negative bacteria. It induces the production of TNF and IL-1, but the bacteria suspected by this clinical presentation is Bacillus anthracis, a gram-positive organism.]] |
| Answer D | AnswerD::D-Glutamate capsule |
| Answer D Explanation | [[AnswerDExp::Bacillus anthracis is the only organism with a D-Glutamate capsule. However, it does not induce the production of IL-1 and TNF.]] |
| Answer E | AnswerE::Glycocalyx |
| Answer E Explanation | [[AnswerEExp::The glycocalyx mediates bacterial adhesion to structures such as catheters, biological membranes and other surfaces. It does not directly induce IL-1 and TNF.]] |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The patient in this passage has become infected with Bacillus anthracis, a gram-positive, spore forming rod. Most people who get sick from anthrax are exposed while working with infected animals or animal products such as wool, hides, or hair.
- Inhalation anthrax can occur when a person inhales spores that are in the air (aerosolized) during the industrial processing of contaminated materials, such as wool, hides, or hair. Inhalation anthrax has alternatively been called ‘Woolsorter’s Disease’. - Cutaneous anthrax can occur when workers who handle contaminated animal products get spores in a cut or scrape on their skin. In this case, the patient has contracted Cutaneous anthrax. The lesion is usually a black eschar. When anthrax spores get into the skin, usually through a cut or scrape, a person can develop cutaneous anthrax. This can happen when a person handles infected animals or contaminated animal products like wool, hides, or hair. Cutaneous anthrax is most common on the head, neck, forearms, and hands. It affects the skin and tissue around the site of infection. Cutaneous anthrax is the most common form of anthrax infection, and it is also considered to be the least dangerous. Infection usually develops from 1 to 7 days after exposure. Without treatment, up to 20% of people with cutaneous anthrax may die. However, with proper treatment (usually ciprofloxacin or doxycycline with some restrictions), almost all patients with cutaneous anthrax survive. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Microbiology, WBRKeyword::Bacteria, WBRKeyword::Anthrax, WBRKeyword::Inflammation, WBRKeyword::Immune |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
