Staphylococcus aureus is a gram-positive, catalase-positive, coagulase-positive cocci in clusters. S. aureus can cause inflammatory diseases, including skin infections, pneumonia, endocarditis, septic arthritis, osteomyelitis, and abscesses.

Why is Staphylococcus aureus Gram-positive?

Gram-positive bacteria such as Staphylococcus aureus have cell walls that lack an outer membrane. Instead, they have a single cytoplasmic membrane surrounded by a thick exposed peptidoglycan layer.

Is Staphylococcus aureus MRSA Gram-positive or negative?

MRSA refers to particular strains of gram-positive bacteria Staphylococcus aureus (S. aureus) that are resistant to methicillin. S. aureus is common and frequently present in or on human skin.