The Case Study
A 37-year-old woman is brought to the emergency room where you are working triage. She has an extremely swollen right lower leg. You see what appears to be an old surgical wound on her mid-calf, with rough scar tissue surrounded by purplish-red skin. She is in an enormous amount of pain. Her husband indicates she had a group of moles removed from the area a little more than a week ago. The wound initially appeared to heal, but 2 days ago the incision started looking bigger, became quite swollen, and very hot to the touch. In hoping that the condition would resolve on its own, she didn’t seek treatment…until today!
Recognizing the severity of the condition, you call the attending physician immediately! The patient is sent to surgery where the wound is debrided. Gram-positive cocci growing in chains are cultured from the wound. She is transferred to intensive care and put on a high dose of IV antibiotics for the next 36 hours. The next day, her leg is amputated below the knee. Following surgery, she remains in the hospital for two months and requires long-term antimicrobial therapy and multiple skin grafts.
1. What is the etiologic agent of her “condition”? What led you to your conclusion?
Be wary of circumstantial evidence (symptoms) – you want concrete evidence (lab results) to convict your suspect!
2. How is the etiologic agent transmitted?
3. In this case, why was amputation the best solution for the infection?
4. How would the organism appear when grown on a blood agar plate? If the organism produces hemolysins, are they alpha or beta?
5. Suppose you work in a small hospital with limited resources and do not have funds available to perform all the tests listed above in a-f.
a. Which tests would be useful in confirming your diagnosis?
Why would this test help to confirm your “suspect”?
What are the results for your suspect?
b. Which tests would not be useful in confirming your diagnosis?
Why isn’t the test appropriate for the etiologic agent?
What is the test typically used for?
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