title: Endemicity, molecular diversity and colonisation routes of Pseudomonas aeruginosa in intensive care units.
abstract: OBJECTIVE
  We carried out a prospective study to evaluate the endemicity of Pseudomonas aeruginosa in intensive care units (ICUs). Pulsed-field gel electrophoresis (PFGE) was used to determine the genotypes of P. aeruginosa isolates. This allowed us to determine the importance of cross-colonisation and the colonisation routes of P. aeruginosa.
  
  
  METHODS
  We screened epidemiological specimens (rectal swab, nose swab and tracheal aspiration) and routine clinical cultures from patients admitted to ICUs during a 2-year period, from 1st January, 1998, to 31st December, 1999.
  
  
  METHODS
  The study was carried out in four separate adult ICUs located in the Franche-Comté region of France. These four units admitted a total of 1,500 patients per year.
  
  
  RESULTS
  A total of 1686 specimens were collected from 473 patients; 122 of these patients were positive on admission, 351 became positive during hospitalisation. The overall incidence of P. aeruginosa was 15.7 cases per 100 patients and 15.1 cases per 1000 days of hospitalisation. Of 184 patients with at least one ICU-acquired positive clinical culture, 104 had been previously identified as carriers by a similar genotype. Typing of 208 non-replicate isolates revealed 101 major DNA patterns. Approximately 50% of P. aeruginosa carriage or colonisation/infection was acquired via cross-transmission; the other cases probably originated from endogenous sources.
  
  
  CONCLUSIONS
  Cross-colonisation seems to play an important role in the general spread of P. aeruginosa in ICUs.
authors.affiliation: Service d'Hygiène Hospitalière et d'Epidémiologie moléculaire, CHU Jean Minjoz, 25030 Besançon, France.
authors.forename: X
authors.initials: X
authors.lastname: Bertrand
authors.forename: M
authors.initials: M
authors.lastname: Thouverez
authors.forename: D
authors.initials: D
authors.lastname: Talon
authors.forename: A
authors.initials: A
authors.lastname: Boillot
authors.forename: G
authors.initials: G
authors.lastname: Capellier
authors.forename: C
authors.initials: C
authors.lastname: Floriot
authors.forename: J P
authors.initials: JP
authors.lastname: Hélias
mesh_terms: D015373:Bacterial Typing Techniques; D002353:Carrier State / Q000453:epidemiology*; D003428:Cross Infection / Q000517:prevention & control* / Q000635:transmission; D016521:Electrophoresis, Gel, Pulsed-Field; D019353:Endemic Diseases / Q000706:statistics & numerical data*; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000517:prevention & control* / Q000635:transmission; D011550:Pseudomonas aeruginosa / Q000235:genetics*