Cellulitis means an infection of the dermis and subcutaneous tissue and it can be caused by a number of pathogens. The usual culprits are Strep and Staph that enter through a break in the skin. MRSA is a "superbug" Staph infection that is resistant to the usual antibiotics that work for Staph. Infections on the face are of great concern because they can spread to other important structures and even the brain.
(Case from ConsultantLive)