title: How and why to monitor Pseudomonas aeruginosa infections in the long term at a cystic fibrosis centre.
abstract: BACKGROUND
  Pseudomonas aeruginosa is a major cystic fibrosis (CF) pathogen causing chronic respiratory infections and posing a risk for cross-infection between patients with CF.
  
  
  OBJECTIVE
  To propose an algorithm for long-term surveillance of P. aeruginosa and assess its suitability for monitoring the epidemiological situation at a CF centre with approximately 300 patients.
  
  
  METHODS
  Over a nine-year period, over 300 P. aeruginosa isolates from 131 infected patients were tested by multi-locus sequence typing (MLST) and/or random amplified polymorphic DNA (RAPD) assay.
  
  
  RESULTS
  MLST analysis led to the identification of 97 different sequence types which were distributed among 17 RAPD-generated (pseudo)clusters. This indicates that the easy-to-perform RAPD assay is only suitable for intra-individual, not interindividual, strain analyses. No epidemic strains were observed. Longitudinal analysis revealed that 110 of the 131 patients were infected with the same strain over the observation period, whereas 21 patients had a strain replacement or a new infection. Chronic infection was found in 99 of the 131 patients, and the remaining 32 patients met the criteria for intermittent infection (as defined by the Leeds criteria). Eighteen of the 32 patients (56%) with intermittent infection were infected with the same strain for up to nine years.
  
  
  CONCLUSIONS
  The strain type only changed in 16% of 131 patients with chronic or intermittent infection. As many as 56% of patients considered to have intermittent infection were actually chronically infected with the same strain for many years.
authors.affiliation: Department of Medical Microbiology, 2(nd) Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic.
authors.forename: L
authors.initials: L
authors.lastname: Kalferstova
authors.affiliation: Department of Medical Microbiology, 2(nd) Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic; Department of Paediatrics, 2(nd) Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic.
authors.forename: K
authors.initials: K
authors.lastname: Vilimovska Dedeckova
authors.affiliation: Department of Medical Microbiology, 2(nd) Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Antuskova
authors.affiliation: Department of Medical Microbiology, 2(nd) Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic.
authors.forename: O
authors.initials: O
authors.lastname: Melter
authors.affiliation: Department of Medical Microbiology, 2(nd) Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic; Department of Paediatrics, 2(nd) Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic. Electronic address: pavel.drevinek@lfmotol.cuni.cz.
authors.forename: P
authors.initials: P
authors.lastname: Drevinek
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000453:epidemiology* / Q000635:transmission; D003550:Cystic Fibrosis / Q000150:complications*; D062665:Epidemiological Monitoring; D005260:Female; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D011552:Pseudomonas Infections / Q000453:epidemiology* / Q000635:transmission; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D019105:Random Amplified Polymorphic DNA Technique; D055815:Young Adult
keywords: Chronic infection; Cystic fibrosis; Intermittent infection; MLST; Pseudomonas aeruginosa; RAPD; Surveillance