HEALTH CARE-ASSOCIATED PNEUMONIA EPIDEMIOLOGY
In community-acquired pneumonia, the majority of studies have documented that Streptococcus pneumonia is the most common pathogen,followed by atypical pathogens and Haemophilus influenzae. In hospital-acquired and ventilator-associated pneumonia, concerns swell for resistant pathogens, particularly methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Recent studies suggest that health care-associated pneumonia etiology may be most similar to hospital-acquired and ventilator-associated pneumonia, and this is reflected by the inclusion of health care-associated pneumonia in the 2005 nosocomial pneumonia guidelines.