title: Risk of Pseudomonas aeruginosa cross-colonisation in patients with cystic fibrosis within a holiday camp--a molecular-epidemiological study.
abstract: OBJECTIVE
  A study on the molecular epidemiology of Pseudomonas aeruginosa in patients with cystic fibrosis (CF) from Germany (N = 18) and Israel (N = 12) is presented. The aim is to provide an answer to the question as to whether or not social contact outside the hospital environment involves a potential risk for person-to-person spread of this pathogen.
  
  
  METHODS
  Sputa from German and Israeli patients were obtained while these were attending a holiday camp in Israel. The sputum samples were analysed with regard to Pseudomonas aeruginosa. Strains dissimilar in macroscopic appearance and/or antibiotic resistance patterns were genotyped using pulsed-field gel electrophoresis after digestion of genomic DNA with restriction endonuclease Spel. The genetic polymorphism of DNA fragment patterns of all strains (N = 146) was studied for their overall relatedness using a fingerprint software system.
  
  
  RESULTS
  Most of the German patients (77.7%) were colonised persistently by a unique clonal type during the four-week screening period. Isolates obtained from Israeli patients displayed a very close clonal relationship and a higher antibiotic resistance as a result of preceding epidemic spread of certain clones before the camp. Additionally, isolates showing identical PFGE patterns were demonstrated once in a single male Israeli patient and in one female German patient, suggesting previous cross-colonisation.
  
  
  CONCLUSIONS
  The occurrence of person-to-person spread through social contact in patients with CF is supported by our findings, but remains a rare event outside the hospital environment, provided appropriate hygienic measures are applied.
authors.affiliation: Institute of Medical Microbiology, Frankfurt University Clinic, Frankfurt/Main, Federal Republic of Germany. K.Hunfeld@em.uni-frankfurt.de
authors.forename: K P
authors.initials: KP
authors.lastname: Hunfeld
authors.forename: C
authors.initials: C
authors.lastname: Schmidt
authors.forename: B
authors.initials: B
authors.lastname: Krackhardt
authors.forename: H G
authors.initials: HG
authors.lastname: Posselt
authors.forename: J
authors.initials: J
authors.lastname: Bargon
authors.forename: Y
authors.initials: Y
authors.lastname: Yahaf
authors.forename: V
authors.initials: V
authors.lastname: Schäfer
authors.forename: V
authors.initials: V
authors.lastname: Brade
authors.forename: T A
authors.initials: TA
authors.lastname: Wichelhaus
mesh_terms: D000328:Adult; D003550:Cystic Fibrosis / Q000150:complications*; D018562:Disease Transmission, Infectious / Q000706:statistics & numerical data*; D004352:Drug Resistance, Microbial; D005260:Female; D005838:Genotype; D005858:Germany / Q000453:epidemiology / Q000208:ethnology; D006693:Holidays; D006801:Humans; D015994:Incidence; D007557:Israel / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000635:transmission*; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D014195:Travel