July 10, 2021
Utilization of an Antibiotic Side-chain-based Cross-reactivity Chart to Improve Surgical ProphylaxisBy Christopher J. Graber, MD, MPH, FIDSA
Clarification of penicillin allergy status has emerged recently as an important antimicrobial stewardship topic, as it can lead to improved prescribing practices. The type of allergic reaction and the specific agent involved are important, as most type I hypersensitivity reactions involve R-group side chains of the β-lactam ring, properties of which differ from one agent to another and thus influence allergy cross-reactivity.
Authors of a recent study in Clinical Infectious Diseases compiled side-chain-based cross-reactivity data into a detailed chart that recommends strategies for assessing risk of allergic reaction based on the agent to be prescribed and the agent to which a patient may have had a prior allergic reaction. Usage of this chart was incorporated into surgical prophylaxis guidance starting in 2014 at their 537-bed community teaching hospital. The authors noted that from January 2012 to September 2014, 950 of 1,119 (84.9%) patients with documented β-lactam allergies received non-β-lactam agents for surgical prophylaxis, which was reduced to 164 of 1,089 (15.1%) patients from July 2016 to September 2018 (P < .001). Cefazolin was used 98.2% of the time when β-lactams were administered. Nine patients total (six receiving alternative therapy and three receiving β-lactam therapy) had likely antibiotic-related allergic reactions; only one of the β-lactam allergies was a type I hypersensitivity reaction (the other two were mild). Thirty-day readmissions were slightly lower in the intervention cohort; no other differences in clinical outcomes were observed.
While most of the observed difference in β-lactam prescribing can likely be attributed to cefazolin not sharing a similar R-group side chain with other β-lactams (and thus overwhelmingly being the most frequently recommended therapy for surgical prophylaxis in patients with documented allergies to other β-lactams), the chart developed in this work (see page 4 of the Supplementary Data) can be of great benefit to antimicrobial stewards in clarifying β-lactam allergy risk to prescribers at their facility.
(Collins et al. Clin Infect Dis. 2021;72(8):1404-12.)
