P06 Antibiotic usage post lower limb amputation in a single UK centre: do we need a targeted national approach?
Authors: Maddox Nicola L , Burnett Hannah , Hardy Thomas , Kennedy Matthew S 
Published: January 2025

Abstract

Background
Over 150 000 lower limb amputations (LLA) occur globally per year with surgical site infection (SSI) being a common complication. There is no clear UK national guidance or consensus regarding antibiotic usage post LLA and the extent of the problem is unknown since notification of vascular SSIs to the UK Health Security Agency is not compulsory. In our centre, co-amoxiclav was adopted as post-operative LLA prophylaxis for patients without penicillin allergy.

Objectives
As part of antimicrobial stewardship activities, we aimed to reduce broad spectrum antibiotic usage. We present a data set detailing antibiotic usage post LLA; specifically focusing upon subsequent SSIs and Clostridioides difficile infection in patients receiving post-operative prophylactic antibiotics.

Methods
We retrospectively analysed all LLA from September 2020 to October 2023. A total of 132 patient records were identified from EPIC. We surveyed UK trusts to identify their antibiotic practice post LLA with 14 responses.

Results
Overall, 91% (n=120) received antibiotics post-operatively. There was a wide variety of antimicrobials and course lengths; the majority were prescribed co-amoxiclav (54%, n=65) and received a course length of 1–5 days (52%, n=62). Thirty-six percent (n=20) had an SSI of which 95% (n=19) received post-operative antibiotics. Eighty-five percent (n=17) had diabetes mellitus. Fifty-five percent (n=11) returned to theatre and one patient (who received antibiotics) died. A total of 4.5% (n=6) acquired C. difficile infection; 100% had antibiotics post-operatively with an average course length of 5.3 days prior to laboratory diagnosis. Sixty-six percent (n=4) received co-amoxiclav. The overall all-cause mortality was 24%; 5 died during admission and 26 died post-admission. Table 1 provides a detailed breakdown of antibiotic lengths and outcomes. Table 2 details pre-operative and post-operative LLA antibiotic guidance in 14 UK trusts. Table 1.Detailed breakdown of antibiotic lengths and outcomes No antibioticsAntibiotics for 24 h (2 doses or 1 day)Antibiotics for 1–5 daysAntibiotics &gt;5 daysAntibiotics &gt;7 daysTotal patients, n122463627Surgical site infection, % (n)8.3 (1)25 (6)11 (7)33.3 (2)14.8 (4)Return to theatre, %012.5 (3)14 (9)33.3 (2)14.8 (4)C. difficile, %08.3 (2)4.7 (3)03.7 (1) Table 2.Pre-operative and post-operative LLA antibiotic guidance in 14 UK trustsTrust namePre-operative antibiotic prophylaxisPost-operative antibiotic prophylaxisUniversity Hospitals BirminghamCo-amoxiclavCo-amoxiclav 48 h then wound reviewRoyal Free, LondonTeicoplanin + gentamicin + metronidazoleMetronidazole for 5 daysLeeds Teaching HospitalsFlucloxacillin + metronidazole + gentamicin for first 24 hDoxycycline 100 mg BD PO + metronidazole 400 mg TDS PO for maximum 4 daysRoyal National Orthopaedic HospitalTeicoplanin + gentamicin + metronidazoleNo further antibioticsUnited Lincolnshire HospitalsCo-amoxiclavCo-amoxiclav for 5 days if following major traumaNo further antibiotics if planned/diabetes, etc.GloucestershireFlucloxacillin + metronidazole + gentamicin for 24 hNo further antibioticsUniversity Hospitals PlymouthCo-amoxiclav for 24 hNo further antibioticsUniversity Hospitals Bristol & WesternCo-amoxiclavNo further antibiotics unless there is residual infected tissueHull University Teaching HospitalsFlucloxacillin + gentamicin + metronidazoleDoxycycline 100 mg BD PO + metronidazole 400 mg TDS PO for 5 daysPortsmouth Hospitals UniversityFlucloxacillin 1 g IVNo further antibioticsEast Sussex HealthcareBenzylpenicillin IVBenzylpenicillin for 5 days or metronidazole 400 mg TDS for 5 days if oralKettering GHNoneBedfordGentamicin, teicoplanin, metronidazole for 5 daysNorthampton GHCo-amoxiclav for 5 days

Conclusions
We have demonstrated the lack of standardized UK antimicrobial practice post LLA. Our data set enabled greater understanding of antimicrobial stewardship within LLA surgery and subsequently, we implemented formal post LLA guidance for antimicrobials; incorporating a more rational approach whilst minimizing the risk of C. difficile infection and continuing effective SSI cover. We will re-audit in the future to assess the effectiveness of this change.