A 62-Year-Old Man Is Brought to the Emergency Department Due

question 56

Multiple Choice

A 62-year-old man is brought to the emergency department due to a hand wound and "not feeling very well."  He cut his right hand while cleaning a tropical fish tank at his pet shop yesterday.  Although he applied topical antiseptics to the wound, it progressively became more painful and swollen.  The patient also developed fever and generalized weakness.  He has a history of type 2 diabetes mellitus, hypertension, and chronic kidney disease due to diabetic nephropathy.  He takes methotrexate and intermittent glucocorticoids for rheumatoid arthritis.  The patient drinks 1 or 2 cans of beer daily but does not use tobacco or illicit drugs.  Temperature is 38.9 C (102 F) , blood pressure is 96/50 mm Hg, pulse is 114/min, and respirations are 22/min.  The patient appears ill.  The right hand is diffusely erythematous with hemorrhagic bullae surrounding a 3-cm dorsal laceration.  Laboratory results are as follows: Which of the following is the most likely causative organism of this patient's current condition?

• A)Mycobacterium marinum
• B)Pseudomonas aeruginosa
• C)Sporothrix schenckii
• D)Staphylococcus aureus
• E)Vibrio vulnificus

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Definitions:

Convergent Evolution

The process whereby organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.

Homoplasious Trait

A trait shared by multiple species or individuals due to convergent evolution, not because of a common ancestor.

Monophyletic Group

A set of organisms that includes an ancestral species and all its descendants, representing a single branch on the tree of life.

Paraphyletic

Paraphyletic describes a group of organisms that share a common ancestor, although the group does not include all the descendants of that common ancestor.