title: Pneumonia due to Pseudomonas aeruginosa: part I: epidemiology, clinical diagnosis, and source.
abstract: Pseudomonas aeruginosa is an uncommon cause of community-acquired pneumonia (CAP), but a common cause of hospital-acquired pneumonia. Controversies exist for diagnostic methods and antibiotic therapy. We review the epidemiology of CAP, including that in patients with HIV and also in hospital-acquired pneumonia, including ventilator-associated pneumonia (VAP) and bronchoscope-associated pneumonia. We performed a literature review of clinical studies involving P aeruginosa pneumonia with an emphasis on treatment and prevention. Pneumonia due to P aeruginosa occurs in several distinct syndromes: (1) CAP, usually in patients with chronic lung disease; (2) hospital-acquired pneumonia, usually occurring in the ICU; and (3) bacteremic P aeruginosa pneumonia, usually in the neutropenic host. Radiologic manifestations are nonspecific. Colonization with P aeruginosa in COPD and in hospitalized patients is a well established phenomenon such that treatment based on respiratory tract cultures may lead to overtreatment. We present circumstantial evidence that the incidence of P aeruginosa has been overestimated for hospital-acquired pneumonia and reflex administration of empirical antipseudomonal antibiotic therapy may be unnecessary. A diagnostic approach with BAL and protected specimen brush using quantitative cultures for patients with VAP led to a decrease in broad-spectrum antibiotic use and improved outcome. Endotracheal aspirate cultures with quantitative counts are commonly used, but validation is lacking. An empirical approach using the Clinical Pulmonary Infection Score is a pragmatic approach that minimizes antibiotic resistance and leads to decreased mortality in patients in the ICU. The source of the P aeruginosa may be endogenous (from respiratory or GI tract colonization) or exogenous from tap water in hospital-acquired pneumonia. The latter source is amenable to preventive measures.
authors.affiliation: Department of Emergency and Critical Care Medicine, St. Marianna University, Kanagawa, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Fujitani
authors.affiliation: Department of Internal Medicine, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Hsin-Yun
authors.initials: HY
authors.lastname: Sun
authors.affiliation: Department of Medicine, University of Pittsburgh, Pittsburgh, PA. Electronic address: vly@pitt.edu.
authors.forename: Victor L
authors.initials: VL
authors.lastname: Yu
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, New York Methodist Hospital, Brooklyn, NY.
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Weingarten
mesh_terms: D003948:Diagnostic Techniques, Respiratory System; D006801:Humans; D015994:Incidence; D018410:Pneumonia, Bacterial / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology; D011552:Pseudomonas Infections / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D015996:Survival Rate; D014481:United States / Q000453:epidemiology