Case History: Staphylococcus aureus Gram-stain of knee aspirate a Mr. S is a 43 year-old IDDM deli chef who cut his left arm while working. Over the next several days he noticed redness, swelling, and tenderness at the site of the injury. He then developed fever, chills and a swollen, painful R-knee. a He presents to the ED with fever of 39C, shaking chills, and a swollen, tender R- knee. Laboratory: WBC 17K & L-shift, gram-stain of R-knee aspirate: WBC's and gram-positive cocci in clusters, blood cx: 2/2 for S. aureus (Methicillin susceptible).Case History: (cont') Questions - Treatment: Surgical drainage of R-knee, I&D of L-arm - What was the source of the S . aureus? abscess, IV Nafcillin - Does Mr. S have any risk factors for S. aureus - The day after admission, the local health dept notes that 6 colonization and infection? persons who patronized the deli developed severe nausea, - What virulence factors does S. aureus possess that allows vomiting and diarrhea 3-6 hours after eating there it to cause abscesses and bacteremia? - Cultures of chicken-salad from the deli refrigerator reveal - How did the S. aureus cause food poisoning? S. aureus. Isolates from Mr. S' bloodstream and the - How should Mr. S be treated for his staph infection? chicken salad are epidemiologically typed by PFGE of chromosomal DNA and found to be genetically identical..

1. Case History: Staphylococcus aureus Gram-stain of knee aspirate a Mr. S is a 43 year-old IDDM
deli chef who cut his left arm while working. Over the next several days he noticed redness,
swelling, and tenderness at the site of the injury. He then developed fever, chills and a swollen,
painful R-knee. a He presents to the ED with fever of 39C, shaking chills, and a swollen, tender R-
knee. Laboratory: WBC 17K & L-shift, gram-stain of R-knee aspirate: WBC's and gram-positive
cocci in clusters, blood cx: 2/2 for S. aureus (Methicillin susceptible).Case History: (cont')
Questions - Treatment: Surgical drainage of R-knee, I&D of L-arm - What was the source of the S
. aureus? abscess, IV Nafcillin - Does Mr. S have any risk factors for S. aureus - The day after
admission, the local health dept notes that 6 colonization and infection? persons who patronized
the deli developed severe nausea, - What virulence factors does S. aureus possess that allows
vomiting and diarrhea 3-6 hours after eating there it to cause abscesses and bacteremia? -
Cultures of chicken-salad from the deli refrigerator reveal - How did the S. aureus cause food
poisoning? S. aureus. Isolates from Mr. S' bloodstream and the - How should Mr. S be treated for
his staph infection? chicken salad are epidemiologically typed by PFGE of chromosomal DNA and
found to be genetically identical.