Microbiological Signatures and Clinical Predictors of Severity in Diabetic Foot Infection

Introduction: Diabetic foot infection (DFI) is a major complication of diabetes associated with high rates of amputation, recurrence, and healthcare utilization. The prognostic interaction between clinical and microbiological markers remains unclear. Aim: The present analysis aimed to characterize clinical, inflammatory, and microbiological predictors of course and resource use in surgically managed DFI. Material and methods: We retrospectively analyzed 121 hospitalizations of 86 patients treated surgically for DFI (2021-2025). Clinical, laboratory, and microbiological variables were assessed in relation to amputation, reamputation, rehospitalization, length of stay (LOS), and mortality. Results: Amputation was performed in 72/121 episodes (59.5%), including 57 minor and 15 major procedures. Reamputation occurred in 13/72 cases (18.1%). Rehospitalization was recorded in 42/86 patients (48.8%). Median LOS was 13 days (IQR 8-21). A total of 227 isolates were obtained, with Enterococcus faecalis (38 isolates, 16.7%) and Staphylococcus aureus (28 isolates, 12.3%) being the most frequent. Polymicrobial infections were present in 75/121 episodes (63%). Neuro-ischemic ulcer phenotype independently predicted reamputation (aOR 3.72; p = 0.036). Staphylococcaceae increased the likelihood of rehospitalization (aOR 3.32; p = 0.014). NLR >5 prolonged LOS by 42%, and Enterococcus spp. by 51%. Repeat hospitalizations showed enrichment of ESBL Klebsiella pneumoniae (5 cases) and HLAR E. faecalis (9 cases). Conclusions: Ulcer phenotype and systemic inflammatory response were the strongest predictors of adverse outcomes. Microbiology contributed selective yet clinically meaningful prognostic information, particularly regarding Staphylococcaceae and Enterococcus spp. .