title: Colistin and tobramycin resistance during long- term use of selective decontamination strategies in the intensive care unit: a post hoc analysis.
abstract: BACKGROUND
  Selective decontamination of the digestive tract (SDD) and selective oropharyngeal decontamination (SOD) have been shown to improve intensive care unit (ICU) patients' outcomes. The aim of this study was to determine the effects of long-term use of SDD and SOD on colistin and tobramycin resistance among gram-negative bacteria.
  
  
  METHODS
  We performed a post hoc analysis of two consecutive multicentre cluster-randomised trials with crossover of interventions. SDD and SOD were alternately but continuously used during 7 years in five Dutch ICUs participating in two consecutive cluster-randomised trials. In both trials, to measure colistin and tobramycin resistance among gram-negative bacteria, rectal and respiratory samples were obtained monthly from all patients present in the ICU.
  
  
  RESULTS
  The prevalence of tobramycin resistance in respiratory and rectal samples decreased significantly during long-term use of SOD and SDD. (rectal samples risk ratio (RR) 0.35 (0.23 to 0.53); respiratory samples RR 0.48 (0.32 to 0.73), SDD compared to standard care). Colistin resistance in rectal and respiratory samples did not change (rectal samples RR 0.63 (0.29 to 1.38); respiratory samples RR 1.26 (0.35 to 4.57), SDD compared to standard care).
  
  
  CONCLUSIONS
  In this study, in a setting with low antimicrobial resistance rates, the prevalence of resistance against colistin and tobramycin among gram-negative isolates did not increase during a mean of 7 years of SDD or SOD use.
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. B.H.J.Wittekamp@umcutrecht.nl.
authors.forename: Bastiaan H J
authors.initials: BH
authors.lastname: Wittekamp
authors.affiliation: Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. E.A.N.Oostdijk@umcutrecht.nl.
authors.forename: Evelien A N
authors.initials: EA
authors.lastname: Oostdijk
authors.affiliation: CAPE, Critical Care, Anesthesiology, Peri-operative and Emergency Medicine Research Program, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands. A.M.G.A.de.Smet@umcg.nl.
authors.forename: Anne Marie G A
authors.initials: AM
authors.lastname: de Smet
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. MBonten@umcutrecht.nl.|Department of Medical Microbiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. MBonten@umcutrecht.nl.
authors.forename: Marc J M
authors.initials: MJ
authors.lastname: Bonten
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D003091:Colistin / Q000008:administration & dosage*; D003666:Decontamination / Q000379:methods*; D024881:Drug Resistance, Bacterial; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D007362:Intensive Care Units; D009960:Oropharynx / Q000382:microbiology; D016032:Randomized Controlled Trials as Topic; D012141:Respiratory Tract Infections / Q000382:microbiology*; D014031:Tobramycin / Q000008:administration & dosage*
chemical_list: D000900:Anti-Bacterial Agents; D014031:Tobramycin; D003091:Colistin