This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Staphylococcal pathogenicity is indicated by- 
Select and explain. 
A. Coagulase positivity, B. Hemolysis, C. Lipoteichoic acid, D. Endotoxin
A: Coagulase positivity
Answer: A: Coagulase positivity 
Explanation: Virulence factors of Staphylococcus aureus

There are numerous virulence factors responsible for the pathogenicity of staph aureus, but the most consistent association of virulence is the production of coagulase and to a lesser extent, fermentation of mannitol.
Coagulase causes activation of prothrombin and leads to fibrin formation around the bacteria, protecting the bacteria from phagocytosis.