Pneumonia due to Staphylococcus aureus infection.

Staphylococcus aureus is the second most common infectious agent of pneumonia in the ICU. The virulence of this organism is highlighted by toxins and enzymes that result in severe damage to lung tissue. Clinical features fail to distinguish Staphylococcus aureus pneumonias from other pathogens, and clinical diagnosis has the same limitations that beset other bacterial causes of pneumonia. Effective therapy is dictated by carefully performed susceptibility testing. First-line therapy is with a beta-lactam agent. If BRSA is detected or beta-lactam intolerance occurs, vancomycin should be administered. Despite agents active in vitro, the mortality of this disease remains high, especially if spread through hematogenous routes.