title: Effect of the increasing use of piperacillin/tazobactam on the incidence of vancomycin-resistant enterococci in four academic medical centers.
abstract: BACKGROUND
  The substitution of piperacillin/tazobactam, ampicillin/sulbactam, or both for third-generation cephalosporins has been associated with reduced vancomycin-resistant enterococci (VRE). However, piperacillin/tazobactam came into widespread use during a period in which the prevalence of VRE increased. We hypothesized that the increasing use of piperacillin/tazobactam and other agents with relatively enhanced anti-enterococcal activity (ie, piperacillin, ampicillin/sulbactam, and ampicillin) has been associated with increased or unchanged rates of VRE in some hospitals.
  
  
  METHODS
  We retrospectively evaluated the correlation between hospital antibiotic use (defined daily doses per 10,000 patient-days of care) and incidence of stool or non-stool VRE isolation. We assessed whether a high or increasing proportion of use of beta-lactam agents with relatively enhanced versus minimal (ie, third-generation cephalosporins and ticarcillin/clavulanate) anti-enterococcal activity would prevent increased VRE.
  
  
  METHODS
  Four academic medical centers.
  
  
  RESULTS
  With the increasing use of piperacillin/tazobactam, the use of beta-lactam agents with enhanced activity against enterococci surpassed the combined use of third-generation cephalosporins and ticarcillin/clavulanate in each hospital. In one hospital, the incidence of VRE was positively correlated with the use of piperacillin/tazobactam or beta-lactam agents with enhanced anti-enterococcal activity (P < .0001). The incidence of VRE rose steadily in another hospital despite relatively high use of beta-lactam agents with enhanced versus minimal anti-enterococcal activity. A negative correlation between VRE and piperacillin/tazobactam or beta-lactam agents with enhanced anti-enterococcal activity was observed in one hospital, but this correlation was not statistically significant.
  
  
  CONCLUSIONS
  Increasing the hospital use of piperacillin/tazobactam and other beta-lactams with relatively enhanced anti-enterococcal activity may not be an effective control measure for VRE.
authors.affiliation: Infectious Diseases Division, University Hospitals of Cleveland, Cleveland, Ohio, USA.
authors.forename: Usha
authors.initials: U
authors.lastname: Stiefel
authors.forename: David L
authors.initials: DL
authors.lastname: Paterson
authors.forename: Nicole J
authors.initials: NJ
authors.lastname: Pultz
authors.forename: Steven M
authors.initials: SM
authors.lastname: Gordon
authors.forename: David C
authors.initials: DC
authors.lastname: Aron
authors.forename: Curtis J
authors.initials: CJ
authors.lastname: Donskey
mesh_terms: D000046:Academic Medical Centers / Q000458:organization & administration*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000494:pharmacology; D016983:Enterococcus / Q000187:drug effects / Q000302:isolation & purification*; D006801:Humans; D009820:Ohio; D010397:Penicillanic Acid / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000494:pharmacology; D010878:Piperacillin / Q000008:administration & dosage* / Q000494:pharmacology; D000078142:Tazobactam; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents; D010397:Penicillanic Acid; D000078142:Tazobactam; D010878:Piperacillin