title: Geographical differences in first acquisition of Pseudomonas aeruginosa in cystic fibrosis.
abstract: BACKGROUND
  Risk of infection with Pseudomonas aeruginosa in cystic fibrosis (CF) may be associated with environmental factors.
  
  
  OBJECTIVE
  To determine whether residential location is associated with risk of first acquisition of P. aeruginosa.
  
  
  METHODS
  We performed bronchoalveolar lavage and upper airway cultures in children newly diagnosed with CF to identify infection with P. aeruginosa during infancy and early childhood. Children were assessed according to their residence in a regional or metropolitan area. Multilocus sequence typing was used to determine P. aeruginosa genotype. An environmental questionnaire was also administered.
  
  
  RESULTS
  A total of 105 of 120 (87.5%) infants diagnosed with CF were included in this study. Diagnosis in 65 infants (61.9%) followed newborn screening at mean age of 4.6 weeks. Sixty subjects (57.1%) were homozygous ΔF508, and 47 (44.8%) were female. Fifty-five (52.3%) infants were regional, of whom 26 (47.3%), compared with 9 of 50 (18.0%) metropolitan children, acquired infection with P. aeruginosa (odds ratio, 4.084; 95% confidence interval, 1.55-11.30). Age at acquisition was similar (regional: median, 2.31 yr; range, 0.27-5.96 yr; metropolitan: median, 3.10 yr, range, 0.89-3.70 yr). Strain typing identified P. aeruginosa genotypes often encountered in different ecological settings and little evidence of cross-infection. Ninety questionnaires (85.7%) were completed. Those who acquired P. aeruginosa were more likely to be living in a household that used water sprinkler systems (P = 0.032), but no differences were identified to explain increased risk of acquisition of P. aeruginosa in regional children.
  
  
  CONCLUSIONS
  Geographical difference in residence of children with CF was associated with increased risk of first acquisition of P. aeruginosa, usually with strains associated with the environment rather than with cross-infection.
authors.affiliation: Department of Respiratory Medicine, Royal Children's Hospital, Melbourne, Australia.
authors.forename: Sarath C
authors.initials: SC
authors.lastname: Ranganathan
authors.forename: Billy
authors.initials: B
authors.lastname: Skoric
authors.forename: Kay A
authors.initials: KA
authors.lastname: Ramsay
authors.forename: Rosemary
authors.initials: R
authors.lastname: Carzino
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Gibson
authors.forename: Emily
authors.initials: E
authors.lastname: Hart
authors.forename: Jo
authors.initials: J
authors.lastname: Harrison
authors.forename: Scott C
authors.initials: SC
authors.lastname: Bell
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Kidd
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications* / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016017:Odds Ratio; D011159:Population Surveillance; D011552:Pseudomonas Infections / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014739:Victoria / Q000453:epidemiology