title: Infection with Burkholderia cepacia complex bacteria and pulmonary exacerbations of cystic fibrosis.
abstract: BACKGROUND
  Studies have shown that cystic fibrosis (CF) patients who are chronically infected with Burkholderia cepacia complex bacteria may potentially acquire new strains of B cepacia. Our objective was to determine whether pulmonary exacerbations of CF are associated with acquisition of new B cepacia strains or with B cepacia strain replacement.
  
  
  METHODS
  Thirty-six patients from seven centers who were chronically infected with B cepacia complex bacteria were prospectively followed up over a 38-month period. Patients had sputum cultures performed every 3 months while clinically stable and at the time of a pulmonary exacerbation. Each B cepacia complex isolate was speciated by polymerase chain reaction amplification of the recA gene to determine species status and was genotyped by pulsed-field gel electrophoresis to determine strain type.
  
  
  RESULTS
  Thirty-five of 36 patients (97%) had chronic infection with Burkholderia cenocepacia III-A during clinical stability. All 36 patients maintained the same species and strain of B cepacia complex at the time of exacerbation as was found during clinical stability. B cepacia complex isolates retrieved during exacerbations were significantly less susceptible to ciprofloxacin, chloramphenicol, piperacillin, meropenem, and tobramycin compared to isolates retrieved from the same patients during clinical stability.
  
  
  CONCLUSIONS
  Adult CF patients infected with B cenocepacia maintain the same strain of B cenocepacia during exacerbations; pulmonary exacerbations are not caused by acquisition of a new B cepacia species or strain. B cepacia isolates retrieved during exacerbations may be more resistant to antibiotics.
authors.affiliation: The Ottawa Hospital, General Campus, 501 Smyth Rd, Ottawa, ON, Canada.
authors.forename: Melissa
authors.initials: M
authors.lastname: St Denis
authors.forename: Karam
authors.initials: K
authors.lastname: Ramotar
authors.forename: Katherine
authors.initials: K
authors.lastname: Vandemheen
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Tullis
authors.forename: Wendy
authors.initials: W
authors.lastname: Ferris
authors.forename: Francis
authors.initials: F
authors.lastname: Chan
authors.forename: Craig
authors.initials: C
authors.lastname: Lee
authors.forename: Robert
authors.initials: R
authors.lastname: Slinger
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Aaron
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D019121:Burkholderia Infections / Q000150:complications* / Q000188:drug therapy / Q000382:microbiology; D042602:Burkholderia cepacia complex / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D003550:Cystic Fibrosis / Q000150:complications* / Q000188:drug therapy; D004269:DNA, Bacterial / Q000235:genetics; D018450:Disease Progression; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D011379:Prognosis; D011446:Prospective Studies; D011938:Rec A Recombinases / Q000235:genetics; D012008:Recurrence; D013183:Sputum / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D011938:Rec A Recombinases