SRS103 - The microbiological profile of diabetic foot infections: historical trends and relationship with amputation

Abstract Introduction Diabetic foot infections (DFI) are one of the most severe and costly complications of diabetes mellitus. Understanding the microbial composition of DFIs is required to deliver appropriate anti-microbial therapy and to establish prognosis. We aimed to evaluate historical trends in the microbiological profile of DFIs, and to explore the relationship between antimicrobial resistance and the risk of amputation. Methods This was a retrospective study of patients with DFI treated in a tertiary vascular surgery centre between 2014 and 2024. The prevalence of different DFI organisms and the percentage of isolates exhibiting resistance to DFI first-line antibiotics was calculated. Statistical analyses were conducted using R statistical software version 4.2.3. Results There were 1070 tissue cultures collected from 274 patients (215 males, 78.5%). The prevalence of Enterococcus faecalis (R2 = 0.486, P = 0.017) and Proteus mirabilis (R2 = 0.515, P = 0.0294) increased over time. The proportion of patients who grew an isolate resistant to the first-line antibiotics used in cases of penicillin allergy increased over time (R2 = 0.620, P = 0.004). Growing an organism resistant to first-line antibiotic options was significantly associated with undergoing an amputation (P < 0.0001). Conclusions The microbiological landscape of DFIs is evolving. There is a concerning rise in antibiotic resistance to first-line antibiotics used in penicillin-allergic patients. The presence of resistant organisms is strongly associated with a higher risk of amputation. These findings underscore the need for continuous surveillance of DFI microbiology and resistance patterns to guide empirical therapy and improve patient outcomes.