This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
Virulence factors of Staphylococcus aureus include all of the following except one. Which one is the exception? 
Select and explain. 
A. Beta-lactamases, B. Coagulase, C. Enterotoxins, D. M Protein
D: M Protein
Answer: D: M Protein 
Explanation: M proteins are virulence factors of group A Streptococci (Streptococcus pyogenes). All of the other listed virulence factors may be found routinely in S. aureus bacteria.