title: Standard versus biofilm antimicrobial susceptibility testing to guide antibiotic therapy in cystic fibrosis.
abstract: BACKGROUND
  The antibiotics used to treat pulmonary infections in people with cystic fibrosis are typically chosen based on the results of antimicrobial susceptibility testing performed on bacteria traditionally grown in a planktonic mode (grown in a liquid). However, there is considerable evidence to suggest that Pseudomonas aeruginosa actually grows in a biofilm (or slime layer) in the airways of cystic fibrosis patients with chronic pulmonary infections. Therefore, choosing antibiotics based on biofilm rather than conventional antimicrobial susceptibility testing could potentially improve response to treatment of Pseudomonas aeruginosa in people with cystic fibrosis.
  
  
  OBJECTIVE
  To compare biofilm antimicrobial susceptibility testing-driven therapy to conventional antimicrobial susceptibility testing-driven therapy in the treatment of Pseudomonas aeruginosa infection in people with cystic fibrosis.
  
  
  METHODS
  We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched a registry of ongoing trials and the reference lists of relevant articles and reviews.Most recent search: 02 August 2012.
  
  
  METHODS
  Randomized controlled trials of antibiotic therapy based on biofilm antimicrobial susceptibility testing compared to antibiotic therapy based on conventional antimicrobial susceptibility testing in the treatment of Pseudomonas aeruginosa pulmonary infection in individuals with cystic fibrosis.
  
  
  METHODS
  Both authors independently selected trials, assessed their risk of bias and extracted data from eligible trials. Additionally, the authors contacted the trial investigators to obtain further information.
  
  
  RESULTS
  The search identified one multicentre, randomized, double-blind controlled clinical trial eligible for inclusion in the review (39 participants). This trial prospectively assessed whether the use of biofilm antimicrobial susceptibility testing improved microbiological and clinical outcomes in participants with cystic fibrosis who were infected with Pseudomonas aeruginosa. The primary outcome was the change in sputum Pseudomonas aeruginosa density from the beginning to the end of antibiotic therapy. The mean (standard deviation) change in density in log(10) colony forming units per gram was -2.94 (2.83) in the biofilm group and -3.27 (3.09) in the control group, for a mean difference of 0.28 (95% confidence interval -1.98 to 2.54) (P = 0.8). The data did not provide evidence that biofilm susceptibility testing was superior to conventional susceptibility testing.
  
  
  CONCLUSIONS
  The current evidence is insufficient to recommend choosing antibiotics based on biofilm antimicrobial susceptibility testing rather than conventional antimicrobial susceptibility testing in the treatment of Pseudomonas aeruginosa pulmonary infections in people with cystic fibrosis. Future randomized clinical trials on this topic may shed further light on this question.
authors.affiliation: Department of Pediatrics, Division of Infectious Diseases, Hospital for Sick Children, Toronto, Canada. valerie.waters@sickkids.ca
authors.forename: Valerie
authors.initials: V
authors.lastname: Waters
authors.forename: Felix
authors.initials: F
authors.lastname: Ratjen
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D003550:Cystic Fibrosis / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods; D011552:Pseudomonas Infections / Q000188:drug therapy*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D016032:Randomized Controlled Trials as Topic; D012141:Respiratory Tract Infections / Q000188:drug therapy* / Q000382:microbiology; D013183:Sputum / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents