title: The impact of penicillin skin testing on clinical practice and antimicrobial stewardship.
abstract: BACKGROUND
  Penicillin skin testing (PST) is a simple and reliable way of diagnosing penicillin allergy. After being off the market for 4 years, penicilloyl-polylysine was reintroduced in 2009 as PRE-PEN. We describe the negative predictive value (NPV) of PST and the impact on antibiotic selection in a sample of hospitalized patients with a reported history of penicillin allergy.
  
  
  METHODS
  We introduced a quality improvement process at our 861-bed tertiary care hospital that used PST to guide antibiotic usage in patients with a history consistent with an immunoglobulin E (IgE)-mediated reaction to penicillin. Subjects with a negative PST were then transitioned to a β-lactam agent for the remainder of their therapy. NPV of skin testing was established at 24-hour follow-up. We are reporting the result of 146 patients tested between March 2012 and July 2012.
  
  
  RESULTS
  A total of 146 patients with a history of penicillin allergy and negative PST were treated with β-lactam antibiotics. Of these, only 1 subject experienced an allergic reaction to the PST. The remaining 145 patients tolerated a full course of β-lactam therapy without an allergic response, giving the PST a 100% NPV. We estimated that PST-guided antibiotic alteration for these patients resulted in an estimated annual savings of $82,000.
  
  
  CONCLUSIONS
  Patients with a history of penicillin allergy who have a negative PST result are at a low risk of developing an immediate-type hypersensitivity reaction to β-lactam antibiotics. The increased use of PST may help improve antibiotic stewardship in the hospital setting.
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, Brody School of Medicine-East Carolina University, Greenville, NC 27834, USA. ramzyrimawi@hotmail.com
authors.forename: Ramzy H
authors.initials: RH
authors.lastname: Rimawi
authors.forename: Paul P
authors.initials: PP
authors.lastname: Cook
authors.forename: Michael
authors.initials: M
authors.lastname: Gooch
authors.forename: Badih
authors.initials: B
authors.lastname: Kabchi
authors.forename: Muhammad S
authors.initials: MS
authors.lastname: Ashraf
authors.forename: Bassam H
authors.initials: BH
authors.lastname: Rimawi
authors.forename: Mulugeta
authors.initials: M
authors.lastname: Gebregziabher
authors.forename: Dawd S
authors.initials: DS
authors.lastname: Siraj
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000890:Anti-Infective Agents / Q000009:adverse effects*; D004342:Drug Hypersensitivity / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D005260:Female; D006760:Hospitalization / Q000639:trends; D006784:Hospitals, Teaching / Q000379:methods* / Q000592:standards / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000009:adverse effects*; D012882:Skin Tests / Q000379:methods / Q000592:standards / Q000639:trends; D055815:Young Adult
chemical_list: D000890:Anti-Infective Agents; D010406:Penicillins