1791. The Impact of a β-lactam Allergy Assessment on Aztreonam Utilization Within a Healthcare System

BACKGROUND: Penicillin allergies are the most commonly reported drug allergies and are documented in up to 17% of patients. Incomplete reaction histories and exaggerated concerns regarding the risk of cross-reactivity often leads to unnecessary avoidance of β-lactams in patients with reported allergies. Utilization of alternative non-β-lactam therapy in patients with reported allergies has been associated with increased incidence of multidrug-resistant organisms, including C. difficile infection. Per the Infectious Diseases Society of America guidelines for implementing an antibiotic stewardship program (ASP), ASPs should promote allergy assessments and penicillin skin testing in patients with a history of a β-lactam allergy. Implementation of penicillin skin testing in the acute care setting is often limited by the education, skill, and time required in administering and interpreting the result. Investigators sought to assess the impact of a β-lactam allergy assessment on aztreonam utilization within a healthcare system. METHODS: This is a multicenter, retrospective study comparing aztreonam utilization in five hospitals within a healthcare system after implementation of a β-lactam allergy assessment. The program included education as well as development of criteria for utilization and a β-lactam allergy assessment algorithm. A β-lactam allergy assessment was performed on any patient with an order for aztreonam. The Mann–Whitney U test was used to assess the impact of the restriction program on aztreonam utilization and expenditure. RESULTS: The hospital system experienced roughly a 50% decrease in aztreonam days of therapy per 1,000 patient-days [P < 0.01] and 67% reduction in annual expenditure [P < 0.05]. Of the 204 patients with an order for aztreonam, 151 (74%) patients received at least one dose; however, 97 (48%) patients ultimately received and tolerated a β-lactam. Only 112 (55%) patients had a prior reported reaction with 68 (61%) of those having a history of a Type I reaction. CONCLUSION: Implementation of a β-lactam allergy assessment for patients with reported allergies can enhance appropriate use of β-lactams and result in reduced aztreonam utilization and expenditure. DISCLOSURES: All authors: No reported disclosures.