title: How many infections are caused by patient-to-patient transmission in intensive care units?
abstract: OBJECTIVE
  The proportion of intensive care unit (ICU)-acquired infections that are a consequence of nosocomial cross-transmission between patients in tertiary ICUs is unknown. Such information would be useful for the implementation of appropriate infection control measures.
  
  
  METHODS
  A prospective cohort study during 18 months.
  
  
  METHODS
  Five ICUs from two university hospitals.
  
  
  METHODS
  All patients admitted for >/=48 hrs.
  
  
  METHODS
  ICU-acquired infections were ascertained during daily bedside patient and chart reviews. Episodes of potential cross-transmission were identified by highly discriminating genetic typing of all clinical and surveillance isolates of the ten bacterial species most frequently associated with nosocomial infections in ICUs. Isolation of indistinguishable isolates in two or more patients defined potential transmission episodes.
  
  
  RESULTS
  During 28,498 patient days, 431 ICU-acquired infections and 141 episodes of nosocomial transmissions were identified. A total of 278 infections were caused by the ten species that were genotyped, and 41 of these (14.5%) could be associated with transmissions between patients.
  
  
  CONCLUSIONS
  Infections acquired during treatment in modern tertiary ICUs are common, but a causative role of direct patient-to-patient transmission can only be ascertained for a minority of these infections on the basis of routine microbiological investigations.
authors.affiliation: European Antimicrobial Resistance Surveillance System, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
authors.forename: Hajo
authors.initials: H
authors.lastname: Grundmann
authors.forename: Sina
authors.initials: S
authors.lastname: Bärwolff
authors.forename: Adriana
authors.initials: A
authors.lastname: Tami
authors.forename: Michael
authors.initials: M
authors.lastname: Behnke
authors.forename: Frank
authors.initials: F
authors.lastname: Schwab
authors.forename: Christine
authors.initials: C
authors.lastname: Geffers
authors.forename: Elke
authors.initials: E
authors.lastname: Halle
authors.forename: Ulf B
authors.initials: UB
authors.lastname: Göbel
authors.forename: Reinhold
authors.initials: R
authors.lastname: Schiller
authors.forename: Daniel
authors.initials: D
authors.lastname: Jonas
authors.forename: Ingo
authors.initials: I
authors.lastname: Klare
authors.forename: Klaus
authors.initials: K
authors.lastname: Weist
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Witte
authors.forename: Kathrin
authors.initials: K
authors.lastname: Beck-Beilecke
authors.forename: Martin
authors.initials: M
authors.lastname: Schumacher
authors.forename: Henning
authors.initials: H
authors.lastname: Rüden
authors.forename: Petra
authors.initials: P
authors.lastname: Gastmeier
mesh_terms: D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D011446:Prospective Studies