# P-887. Time for change: Cefazolin prophylaxis is safe for penicillin allergic patients undergoing joint arthroplasty, a single centre experience

## TL;DR

This study shows that cefazolin is safe for penicillin-allergic patients during joint surgery, with low allergy risk and similar infection rates compared to other antibiotics.

## Contribution

Demonstrates the safety of cefazolin in penicillin-allergic patients, supporting its use for surgical prophylaxis and promoting antibiotic stewardship.

## Key findings

- Cefazolin caused mild allergic reactions in 0.8% of patients, compared to 2.3% with clindamycin/vancomycin.
- Surgical site infections were similar between cefazolin and clindamycin/vancomycin groups.
- Most patients were low/medium allergy risk, with no severe reactions observed in either group.

## Abstract

Non-ß-lactam antibiotics are often used for surgical prophylaxis in penicillin allergic (PAL) patients due to fear for adverse events. However, it is not without risk. The avoidance of cefazolin (CFZ) prophylaxis has been shown to increase surgical site infection infections (SSIs), C. difficile infection and antibiotic resistance. It is increasingly known that there is low risk of cross reactivity between penicillin and CFZ, prompting some orthopaedic surgeons to switch to CFZ prophylaxis. We aim to evaluate the safety and efficacy of CFZ in PAL patients undergoing joint arthroplasty at our centre.Table 1:Patient Characteristics and Outcomes

Patient Characteristics and Outcomes

This is a single centre, retrospective, observational study performed as a clinical audit comparing PAL patients ( > 21 years old) receiving CFZ versus clindamycin/ vancomycin (CV) for joint arthroplasty (hip/ knee) at Singapore General Hospital (SGH), between Jan 2023 to Jun 2024. PAL patients with severe cutaneous adverse reaction were excluded. PAL patients were further classified to low (adverse effects without cutaneous/ cardiorespiratory involvement), medium (rash/ angioedema without systemic effects), and high (cardiorespiratory involvement) risk. Surgical prophylaxis was continued for 24 hours as per institution guidelines. The incidence of any reported allergies within 72 hours and SSIs within 90 days of antibiotic use between the 2 groups were reviewed.

A total of 251 patients were included; 119 (47.4%) and 132 (52.6%) patients received CFZ and CV respectively; most were of low/medium risk (245/251, 98%). Possible mild allergic reaction occurred in 1/119 (0.8%) and 3/132 (2.3%) patients from the CFZ (itch) and CV groups (rash in 2 patients, itch in 1 patient) respectively (p= 0.624). All 4 patients were of medium risk.

Post-operative SSIs occurred in 8/119 (6.7%) and 8/132 (6.0%) among CFZ and CV patients respectively (p= 0.830).

CFZ prophylaxis is safe in PAL patients. It is imperative for antibiotic stewardship teams to drive behavioural changes among prescribers to encourage accurate allergy assessment and appropriate CFZ prophylaxis where appropriate. Prescriber education on PAL must be reinforced, and implementation of risk-stratified institution guidelines may be considered.

All Authors: No reported disclosures