title: Direct antimicrobial susceptibility testing method for analysis of sputum collected from patients with cystic fibrosis.
abstract: BACKGROUND
  Chronic Pseudomonas aeruginosa colonisation and subsequent exacerbations in patients with cystic fibrosis (CF) require antimicrobial treatment. But since multiple morphotypes and other Gram-negative bacteria with different antibiotic susceptibilities are often isolated inside the same sputum sample, bacteriological analysis is difficult.
  
  
  METHODS
  To simplify this analysis, we explored a direct sputum antimicrobial susceptibility testing (DSST) method by applying E test directly on plates inoculated with the sputum. A total of 316 samples collected from CF patients were analysed and compared with standard procedures (SP) for the identification and antimicrobial susceptibility testing of all Gram-negative bacterial species.
  
  
  RESULTS
  DSST was as efficient as SP to detect P. aeruginosa including the mucoid morphotype in monomicrobial specimen, but was less sensible to detect all Gram-negative bacteria present in the same sample. It allowed the direct reading of the MIC inhibiting all Gram-negative bacteria. Agreements between these global MICs with the cumulative antibiotics susceptibility of all Gram-negative bacteria measured by SP were excellent for tobramycin and imipenem (>96%) and satisfactory for ticarcillin, ceftazidime, aztreonam and ciprofloxacin (90.4% to 94.3%). In conclusion, the DSST method is an efficient and easy antibiotic susceptibility testing method.
authors.affiliation: EA 3925, Laboratoire de Bactériologie - Hygiène, Centre de Biologie, Centre Hospitalier Universitaire, 59037 Lille, France.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Zebouh
authors.forename: Caroline
authors.initials: C
authors.lastname: Thomas
authors.forename: Patrick
authors.initials: P
authors.lastname: Honderlick
authors.forename: Ludovic
authors.initials: L
authors.lastname: Lemee
authors.forename: Christine
authors.initials: C
authors.lastname: Segonds
authors.forename: Frédéric
authors.initials: F
authors.lastname: Wallet
authors.forename: Marie-Odile
authors.initials: MO
authors.lastname: Husson
mesh_terms: D000293:Adolescent; D000328:Adult; D003550:Cystic Fibrosis / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods*; D013183:Sputum / Q000382:microbiology*