title: Nosocomial legionnaires' disease: lessons from a four-year prospective study.
abstract: We studied all cases of nosocomial pneumonia at our 800-bed tertiary care hospital from September 1983 to September 1987. Of the 813 cases of nosocomial pneumonia, 31 (3.8%) were definite (isolation of organism or fourfold rise in titer) and 21 (2.5%) were possible cases (single or stable antibody titer of greater than or equal to 1:256) of legionnaires' disease. The definite cases involved a more severe form of pneumonia and a significantly higher mortality rate--64% versus 14% (p less than 0.0009) compared with the possible cases. Despite attempted comprehensive surveillance, only four (13%) of the definite cases of legionnaires' disease were found that would not have been diagnosed if the study were not ongoing. The yield from adequate (4- to 6-week convalescent serum samples) serologic testing was 5%, whereas the yield from sputum culture was 11%. We conclude that targeted surveillance of immunosuppressed patients with nosocomial pneumonia by culture of respiratory tract secretions for Legionella pneumophila is adequate for monitoring for the presence of legionnaires' disease in a hospital.
authors.affiliation: Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: T J
authors.initials: TJ
authors.lastname: Marrie
authors.forename: S
authors.initials: S
authors.lastname: MacDonald
authors.forename: K
authors.initials: K
authors.lastname: Clarke
authors.forename: D
authors.initials: D
authors.lastname: Haldane
mesh_terms: D003428:Cross Infection / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D005260:Female; D005455:Fluorescent Antibody Technique; D006746:Hospital Bed Capacity, 500 and over; D006757:Hospital Units; D006801:Humans; D007875:Legionella / Q000302:isolation & purification*; D007877:Legionnaires' Disease / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009674:Nova Scotia; D011446:Prospective Studies; D014881:Water Supply