title: How outbreaks can contribute to prevention of nosocomial infection: analysis of 1,022 outbreaks.
abstract: OBJECTIVE
  To describe the epidemiology of nosocomial outbreaks published in the scientific literature.
  
  
  METHODS
  Descriptive information was obtained from a sample of 1,022 published nosocomial outbreaks from 1966 to 2002.
  
  
  METHODS
  Published nosocomial outbreaks of the most important nosocomial pathogens were included in the database. A structured questionnaire was devised to extract information in a systematic manner on nosocomial outbreaks published in the literature. The following items were used: the reference, type of study (case reports or studies applying epidemiologic or fingerprinting methods), type of microorganism, setting, patients and personnel involved, type of infection, source of infection, mode of transmission, risk factors identified, and preventive measures applied.
  
  
  RESULTS
  Bloodstream infection was the most frequently identified type of infection (37.0%), followed by gastrointestinal infection (28.5%) and pneumonia (22.9%). In 37% of the outbreaks, the authors were not able to identify the sources. The most frequent sources were patients (25.7%), followed by medical equipment or devices (11.9%), the environment (11.6%), and the staff (10.9%). The mode of transmission remained unclear in 28.3% of the outbreaks. Transmission was by contact in 45.3%, by invasive technique in 16.1%, and through the air in 15.0%. The percentage of outbreaks investigated by case-control studies or cohort studies over the years was small (21% and 9%, respectively, for the whole time period).
  
  
  CONCLUSIONS
  Outbreak reports in the literature are a valuable resource and should be used for educational purposes as well as for preparing outbreak investigations.
authors.affiliation: Institute of Medical Microbiology and Hospital Epidemiology, Medical School Hannover, Hannover, Germany. Gastmeier.Petra@mh-hannover.de
authors.forename: Petra
authors.initials: P
authors.lastname: Gastmeier
authors.forename: Sabine
authors.initials: S
authors.lastname: Stamm-Balderjahn
authors.forename: Sonja
authors.initials: S
authors.lastname: Hansen
authors.forename: Frauke
authors.initials: F
authors.lastname: Nitzschke-Tiemann
authors.forename: Irina
authors.initials: I
authors.lastname: Zuschneid
authors.forename: Katrin
authors.initials: K
authors.lastname: Groneberg
authors.forename: Henning
authors.initials: H
authors.lastname: Rüden
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D002648:Child; D003428:Cross Infection / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control; D016208:Databases, Factual; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D006801:Humans; D016106:Methicillin Resistance; D008875:Middle Aged; D010506:Periodicals as Topic; D013211:Staphylococcus aureus / Q000187:drug effects / Q000472:pathogenicity