ABSTRACT
Community-acquired pneumonias (CAP) are still caused by Streptococcus pneumoniae, Hemophilus influenzae, or Moraxella catarrhalis. Legionella and Chlamydia pneumoniae have been defined as important atypical pathogens causing CAP. Klebsiella causes CAP primarily in patients with chronic alcoholism or in chronic care facilities. Normal hosts do not present with ``unusual pathogens'' e.g., Staphylococcus aureus or Pseudomonas aeruginosa. The clinical severity of a bacterial pneumonia has important prognostic implications and predicts admission to intensive care units, duration of therapy, and complications. The factors that determine the severity of a CAP are less related to the pathogen than the underlying cardiopulmonary status of the patient as well as the patient's humoral immunity. Relatively avirulent pathogens may result in severe CAP in patients with diminished/absent splenic function or significant cardiopulmonary disease. A critical concept is to appreciate that the selection of antimicrobial therapy is not dependent on co-morbidities since the antimicrobial therapy is directed against the pathogen and not the co-morbidities. Therefore the treatment of CAP, whether moderate or severe is with the same antibiotic at the same dose. Many antibiotic regimens are equally efficacious in the treatment of CAP. The most cost effective optimal regimen covers both typical and atypical pathogens, e.g., levofloxacin, and is currently the preferred antibiotic approach to moderate or severe CAP in the CCU.
KEYWORD
Severe community-acquired pneumonia - CAP in the CCU - antibiotic treatment of CAP
