title: The incidence of antimicrobial allergies in hospitalized patients: implications regarding prescribing patterns and emerging bacterial resistance.
abstract: BACKGROUND
  The development of antimicrobial guidelines is one way in which institutions attempt to control emerging resistance, but the real challenge falls on promoting and ensuring adherence to these guidelines. Investigating reasons for the prescribing of alternative antimicrobial agents outside of these guidelines is crucial for modifying practices that may adversely impact institutional antimicrobial goals.
  
  
  METHODS
  Retrospective cross-referencing of computerized pharmacy printouts and concurrent manual medical record review.
  
  
  RESULTS
  Approximately 25% (470/1893) of the patients requiring antimicrobial therapy reported an allergy to at least 1 antimicrobial agent. The most commonly reported antimicrobial allergy was penicillin (295/1893 [15.6%]). Eighty-five patients (18.1%) reported having an allergy to 2 or more antimicrobial agents. Only 4% (27/601) of the reported antimicrobial allergies contained documentation as to the nature of the specific allergic reactions, while a manual medical record review revealed that 32% (23/73) of the antimicrobial allergies contained documentation of the specific allergic reaction. Ninety-eight (39. 7%) of 247 patients reporting an allergy only to penicillin and/or cephalosporin received vancomycin in comparison with 247 (17.4%) of 1423 patients without any antimicrobial allergies (P<.001). Similarly, 53 (21.5%) of 247 patients with reported penicillin and/or cephalosporin allergies received levofloxacin compared with 114 (8.0%) of 1423 patients without any antimicrobial allergy (P<. 001).
  
  
  CONCLUSIONS
  The incidence of penicillin allergy at our institution exceeds population averages. This finding, in combination with limited documentation of drug allergies, appears to lead to the prescribing of alternative antimicrobial agents that do not fit into institutional antimicrobial guidelines and, in some instances, may put the patient at risk for infection and/or colonization with resistant organisms. Use of these alternative agents may adversely impact the ability to manage emerging antimicrobial resistance.
authors.affiliation: Northwestern Memorial Hospital, Galter Carriage House, Room 701B, 215 E Chicago Ave, Chicago, IL 60611, USA. clee@nmh.org
authors.forename: C E
authors.initials: CE
authors.lastname: Lee
authors.forename: T R
authors.initials: TR
authors.lastname: Zembower
authors.forename: M A
authors.initials: MA
authors.lastname: Fotis
authors.forename: M J
authors.initials: MJ
authors.lastname: Postelnick
authors.forename: P A
authors.initials: PA
authors.lastname: Greenberger
authors.forename: L R
authors.initials: LR
authors.lastname: Peterson
authors.forename: G A
authors.initials: GA
authors.lastname: Noskin
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects* / Q000627:therapeutic use; D002641:Chicago / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004342:Drug Hypersensitivity / Q000453:epidemiology* / Q000209:etiology; D004352:Drug Resistance, Microbial; D006753:Hospital Records; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents