title: Stenotrophomonas maltophilia in cystic fibrosis: improved detection by the use of selective agar and evaluation of antimicrobial resistance.
abstract: BACKGROUND
  We implemented a selective medium for improved detection of Stenotrophomonas maltophilia in sputum samples from CF patients. We also performed antimicrobial susceptibility testing with eight antibiotics.
  
  
  METHODS
  A total of 623 consecutive sputum samples from 165 CF patients in a German CF center were cultured onto conventional media and onto Steno medium agar (SMA). All isolates confirmed as S. maltophilia by biochemical and molecular methods were subjected to antimicrobial susceptibility testing. The following agents were tested by Etest: ceftazidime, levofloxacin, moxifloxacin, tigecycline, trimethoprim-sulfamethoxazole, fosfomycin, colistin, and ticarcillin-clavulanate acid.
  
  
  RESULTS
  Conventional media supported the growth of S. maltophilia in 7.1% of samples, whereas SMA supported its growth in 11.6%, increasing the detection rate to 64%. Trimethoprim-sulfamethoxazole and tigecycline exhibited the highest in vitro activity, whereas ceftazidime, colistin, and ticarcillin-clavulanate acid exhibited higher resistance rates.
  
  
  CONCLUSIONS
  SMA is a promising medium allowing improved isolation of S. maltophilia from sputum samples from CF patients. Trimethoprim-sulfamethoxazole and tigecycline demonstrated excellent inhibitory effects against S. maltophilia, which may suggest a potential clinical effect.
authors.affiliation: Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Goncalves-Vidigal
authors.forename: J
authors.initials: J
authors.lastname: Grosse-Onnebrink
authors.forename: U
authors.initials: U
authors.lastname: Mellies
authors.forename: J
authors.initials: J
authors.lastname: Buer
authors.forename: P-M
authors.initials: PM
authors.lastname: Rath
authors.forename: J
authors.initials: J
authors.lastname: Steinmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000362:Agar; D000368:Aged; D000465:Algorithms; D000890:Anti-Infective Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D003470:Culture Media; D003550:Cystic Fibrosis / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011446:Prospective Studies; D020615:Stenotrophomonas maltophilia / Q000187:drug effects* / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D000890:Anti-Infective Agents; D003470:Culture Media; D000362:Agar