Changes in Antibiotic Resistance Patterns in Diabetic Foot Infections Requiring Toe Amputation: A Long-Term Single-Center Retrospective Study.

Objectives

Diabetic foot infections are a major cause of morbidity and amputation, and increasing antibiotic resistance complicates their management. This study aimed to evaluate longitudinal changes in antibiotic resistance among bacterial pathogens isolated from patients undergoing toe amputation due to diabetic foot infections.

Methods

This retrospective, single-center study included patients who underwent toe amputation for diabetic foot infections between 2013 and 2024. Microbiological culture results and antimicrobial susceptibility data were analyzed across three consecutive time periods: 2013-2016, 2017-2020, and 2021-2024.

Results

A total of 351 patients were included (mean age, 64.1 years; 64% male). A history of dialysis was present in 30% of patients, and 54% had a history of prior hospitalization. A total of 351 patients were included in the study. A total of 378 bacterial isolates recovered from positive microbiological cultures were included in the antimicrobial susceptibility analysis. The most frequently isolated microorganisms were Escherichia coli, Enterococcus spp., coagulase-negative Staphylococcus, and Staphylococcus aureus. Among Enterobacterales isolates, statistically significant increases in resistance across the three consecutive time periods were observed for amoxicillin-clavulanate (p = 0.009), piperacillin-tazobactam (p = 0.002), trimethoprim-sulfamethoxazole (p = 0.012), and meropenem (p = 0.027), whereas the increase in imipenem resistance did not reach statistical significance (p = 0.054). Within Staphylococcus spp., a statistically significant increase in resistance across the three consecutive time periods was observed only for ciprofloxacin (p = 0.047).

Conclusions

Changes in antimicrobial resistance rates were observed among bacterial isolates recovered from diabetic foot infections across the three consecutive time periods, highlighting the importance of regional surveillance and up-to-date local resistance data for guiding empirical antibiotic therapy.