MICROBIOLOGY
Case Study a
Infections of the Skin, Eyes, and Underlying Tissues
It was so exciting! Caitlyn was the only freshman girl selected for Varsity Singers, her high schoolâs touring show choir. Their summer âretreatâ was a six-day mega-rehearsal to learn all of the choreography for their upcoming show season. Monday through Saturday the week before school resumed, the 28 performers danced from 8 A M to 8 P M in their un-air-conditioned gymnasium. Caitlyn didnât particularly mind the hot, humid rehearsal conditions, but sweating profusely in dance leotards every day was really starting to aggravate the acne on her shoulders and back. After a special preliminary performance for their families on Saturday night, Caitlyn showered and dressed to go home. It was then she discovered a very large, angry âpimpleâ that rubbed uncomfortably on the back waistband of her jeans. By morning, it was raised and the size of a dime. Caitlynâs mother washed the
affected area, cleansed it with hydrogen peroxide, and applied an antibiotic ointment, telling her they would call the doctor tomorrow if it didnât improve.
What possible infections might Caitlyn have?
What microbes would normally cause these infections? Are these microorganisms normal skin ï¬ora, pathogens, or both? Explain.
Monday morning, the ï¬rst day of school, Caitlynâs back was sore. âA great way to start high school,â she thought. Caitlynâs mother took her to the pediatricianâs ofï¬ce right after school. The PA examined her back and was alarmed to see a lesion almost two inches in diameter. It was tender to the touch with poorly demarcated margins. The region was raised, warm, and Erythematous (reddened) with several smaller red lines radiating outward.
What is your diagnosis? Describe the nature of this condition.
After consulting with the pediatrician, Keï¬ex was prescribed for Caitlyn. She was sent home with instructions to monitor the infection. If it was not obviously improved by the next day, she was to return for reevaluation.
To what class of antibiotics does Keï¬ex belong? How does this drug work? What group of microbes is especially susceptible to it?
On Tuesday morning, Caitlyn went immediately to see her pediatrician. The lesion was the size of an egg and quite sore. Caitlyn also presented with a temperature of 38.4°C (101.2°F). Motrin and compresses were advised as comfort measures. The Keï¬ex was continued and the lesion cultured for laboratory
analysis. Again, she was told to return if she didnât notice improvement.
How would you collect a specimen from Caitlynâs lesion? Name several types of transport media commonly used. Why is it so important to appropriately transport a specimen to the microbiology laboratory?
What media will likely be inoculated when this sample arrives in the laboratory? State your reason(s) for choosing the media youâve indicated.
In addition to media inoculation, what other procedure will be performed immediately using the specimen?