title: Ecological effects of selective decontamination on resistant gram-negative bacterial colonization.
abstract: BACKGROUND
  Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) eradicate gram-negative bacteria (GNB) from the intestinal and respiratory tract in intensive care unit (ICU) patients, but their effect on antibiotic resistance remains controversial.
  
  
  OBJECTIVE
  We quantified the effects of SDD and SOD on bacterial ecology in 13 ICUs that participated in a study, in which SDD, SOD, or standard care was used during consecutive periods of 6 months (de Smet AM, Kluytmans JA, Cooper BS, Mascini EM, Benus RF, van der Werf TS, van der Hoeven JG, Pickkers P, Bogaers-Hofman D, van der Meer NJ, et al. N Engl J Med 2009;360:20-31).
  
  
  METHODS
  Point prevalence surveys of rectal and respiratory samples were performed once monthly in all ICU patients (receiving or not receiving SOD/SDD). Effects of SDD on rectal, and of SDD/SOD on respiratory tract, carriage of GNB were determined by comparing results from consecutive point prevalence surveys during intervention (6 mo for SDD and 12 mo for SDD/SOD) with consecutive point prevalence data in the pre- and postintervention periods.
  
  
  RESULTS
  During SDD, average proportions of patients with intestinal colonization with GNB resistant to either ceftazidime, tobramycin, or ciprofloxacin were 5, 7, and 7%, and increased to 15, 13, and 13% postintervention (P < 0.05). During SDD/SOD resistance levels in the respiratory tract were not more than 6% for all three antibiotics but increased gradually (for ceftazidime; P < 0.05 for trend) during intervention and to levels of 10% or more for all three antibiotics postintervention (P < 0.05).
  
  
  CONCLUSIONS
  SOD and SDD have marked effects on the bacterial ecology in an ICU, with rising ceftazidime resistance prevalence rates in the respiratory tract during intervention and a considerable rebound effect of ceftazidime resistance in the intestinal tract after discontinuation of SDD.
authors: Department of Medical Microbiology, University Medical Center Utrecht, GA Utrecht, The Netherlands. E.A.N.Oostdijk@umcutrecht.nl
authors: Evelien A N
authors: EA
authors: Oostdijk
authors: Anne Marie G A
authors: AM
authors: de Smet
authors: Hetty E M
authors: HE
authors: Blok
authors: Emily S
authors: ES
authors: Thieme Groen
authors: Gerard J
authors: GJ
authors: van Asselt
authors: Robin F J
authors: RF
authors: Benus
authors: Sandra A T
authors: SA
authors: Bernards
authors: Ine H M E
authors: IH
authors: Frénay
authors: Arjan R
authors: AR
authors: Jansz
authors: Bartelt M
authors: BM
authors: de Jongh
authors: Jan A
authors: JA
authors: Kaan
authors: Maurine A
authors: MA
authors: Leverstein-van Hall
authors: Ellen M
authors: EM
authors: Mascini
authors: Wouter
authors: W
authors: Pauw
authors: Patrick D J
authors: PD
authors: Sturm
authors: Steven F T
authors: SF
authors: Thijsen
authors: Jan A J W
authors: JA
authors: Kluytmans
authors: Marc J M
authors: MJ
authors: Bonten
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D019072:Antibiotic Prophylaxis / Q000009:adverse effects; D002442:Ceftazidime / Q000627:therapeutic use; D002939:Ciprofloxacin / Q000627:therapeutic use; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology / Q000517:prevention & control; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology / Q000517:prevention & control*; D006801:Humans; D007362:Intensive Care Units; D008137:Longitudinal Studies; D012007:Rectum / Q000382:microbiology; D012137:Respiratory System / Q000382:microbiology; D012141:Respiratory Tract Infections / Q000188:drug therapy / Q000382:microbiology / Q000517:prevention & control*; D014031:Tobramycin / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; D002442:Ceftazidime; D014031:Tobramycin