title: Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species: risk factors for colonization and impact of antimicrobial formulary interventions on colonization prevalence.
abstract: OBJECTIVE
  The incidence of extended-spectrum beta-lactamase (ESbetaL)-mediated resistance has increased markedly during the past decade. Risk factors for colonization with ESbetaL-producing Escherichia coli and Klebsiella species (ESbetaL-EK) remain unclear, as do methods to control their further emergence.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Two hospitals within a large academic health system: a 725-bed academic tertiary-care medical center and a 344-bed urban community hospital.
  
  
  METHODS
  Thirteen patients with ESbetaL-EK fecal colonization were compared with 46 randomly selected noncolonized controls.
  
  
  RESULTS
  Duration of hospitalization was the only independent risk factor for ESbetaL-EK colonization (odds ratio, 1.11; 95% confidence interval, 1.02 to 1.21). Of note, 8 (62%) of the patients had been admitted from another healthcare facility. In addition, there was evidence for dissemination of a single K oxytoca clone. Finally, the prevalence of ESbetaL-EK colonization decreased from 7.9% to 5.7% following restriction of third-generation cephalosporins (P = .51).
  
  
  CONCLUSIONS
  ESbetaL-EK colonization was associated only with duration of hospitalization and there was no significant reduction following antimicrobial formulary interventions. The evidence for nosocomial spread and the high percentage of patients with ESbetaL-EK admitted from other sites suggest that greater emphasis must be placed on controlling the spread of such organisms within and between institutions.
authors.affiliation: Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6021, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Bisson
authors.forename: Neil O
authors.initials: NO
authors.lastname: Fishman
authors.forename: Jean Baldus
authors.initials: JB
authors.lastname: Patel
authors.forename: Paul H
authors.initials: PH
authors.lastname: Edelstein
authors.forename: Ebbing
authors.initials: E
authors.lastname: Lautenbach
mesh_terms: D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000667:Ampicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002353:Carrier State / Q000453:epidemiology / Q000517:prevention & control*; D016022:Case-Control Studies; D000077723:Cefepime; D002511:Cephalosporins / Q000627:therapeutic use; D003428:Cross Infection / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D017723:Drug Utilization Review; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D005243:Feces / Q000382:microbiology; D005260:Female; D005572:Formularies, Hospital as Topic / Q000592:standards*; D005839:Gentamicins / Q000627:therapeutic use; D006764:Hospitals, Community; D006786:Hospitals, Urban; D006801:Humans; D017053:Infection Control / Q000379:methods; D007710:Klebsiella Infections / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010414:Pennsylvania / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D013407:Sulbactam / Q000627:therapeutic use; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D005839:Gentamicins; C035444:sultamicillin; D000667:Ampicillin; D000077723:Cefepime; D013407:Sulbactam