Break vial first and wet swab for dry skin areas or conjunctival cultures. All streptococci are catalase negative. Staphylococci are Gram positive, and divide at right angles forming tetrads seen on Gram stain.
Colonies are much larger than the tiny beta hemolytic colonies of the streptococci.
Alpha toxin causes septic shock. Methicillin resistance is due to altered penicillin binding proteins. Susceptibility to infection is increased in patients with neutrophil defects like chronic granulomatous disease and neutropenia. Therapy - Nafcillin, oxacillin, first or second generation cephalosporins or vancomycin.