title: Pathophysiology of pneumonia.
abstract: The development of pneumonia requires that a pathogen reach the alveoli and that the host defenses are overwhelmed by microorganism virulence or by the inoculum size. The endogenous sources of microorganisms are nasal carriers, sinusitis, oropharynx, gastric, or tracheal colonization, and hematogenous spread. Other external sources of contamination, such as intensive care unit workers, aerosols, or fibrobronchoscopy, must be considered as accidental.
authors.affiliation: Surgical Intensive Care Unit, Anesthesiology Department, Hospital Clínic, Villarroel 170, Barcelona 08036, Spain.
authors.forename: Amalia
authors.initials: A
authors.lastname: Alcón
authors.forename: Neus
authors.initials: N
authors.lastname: Fàbregas
authors.forename: Antoni
authors.initials: A
authors.lastname: Torres
mesh_terms: D003428:Cross Infection / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D011015:Pneumonia, Aspiration / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D018410:Pneumonia, Bacterial / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D012137:Respiratory System / Q000382:microbiology / Q000473:pathology; D012307:Risk Factors; D012122:Ventilators, Mechanical / Q000009:adverse effects