A 68-year-old female is hospitalized after a complete knee replacement. The joint becomes hot and red two days after surgery. An aspirate of the joint is sent to the laboratory. Which of the following organisms would be considered a significant isolate from this body site?

Question

Quizplus · Accepted Answer

All of the options listed are significant isolates from a joint infection site. Catalase-positive, coagulase-negative, gram-positive cocci (often Staphylococcus epidermidis) are common skin flora but can be significant pathogens in prosthetic joint infections. Catalase-positive, coagulase-positive, gram-positive cocci (Staphylococcus aureus) are well-known pathogens that can cause severe infections, including in prosthetic joints. Catalase-positive, indole-positive, anaerobic, non-sporeforming, gram-positive rods could represent organisms like Cutibacterium acnes (formerly Propionibacterium acnes), which, while less common, can still cause significant infections, especially in prosthetic devices.

A 68-Year-Old Female Is Hospitalized After a Complete Knee Replacement