Staphylococcus aureus

A microbiologist receives a sample from a patient with a suspected skin infection. Gram stain reveals Gram-positive cocci in clusters. Further testing shows the organism is catalase-positive. Which of the following tests would be most crucial to differentiate *Staphylococcus aureus* from other *Staphylococcus* species?

A 65-year-old male develops a fever and localized pain three weeks after undergoing total hip replacement surgery. Blood cultures grow Gram-positive cocci in clusters that are catalase-positive and coagulase-negative. Which of the following organisms is the most likely causative agent, and what is its key virulence factor in this context?

A group of individuals develops sudden onset nausea, vomiting, and abdominal cramps within 2-6 hours after consuming potato salad at a picnic. Fever is notably absent. Which of the following is the most likely causative agent and its mechanism of action?

A patient presents with a severe skin and soft tissue infection. Culture reveals *Staphylococcus aureus* that is resistant to methicillin. The mechanism of methicillin resistance in this organism is primarily due to the acquisition of which of the following?

A Gram stain from a patient's wound infection shows Gram-positive cocci arranged in clusters. Further biochemical testing reveals the organism is catalase-positive. Which of the following statements is TRUE regarding this organism?