Clinical usefulness of quantifying microbial load from diabetic foot ulcers: A multicenter cohort study

Abstract

AimsTo evaluate if microbial load from diabetic foot ulcers (DFUs) can help in predicting outcomes. MethodsA multicenter prospective cohort study was performed in an outpatient setting (September 1, 2017-January 31, 2019) in diabetic patients with DFU.Quantitative cultures from DFU tissue biopsies at a baseline visit were obtained; high and low microbial loads were defined as ≥6logCFU/mL and <6logCFU/mL, respectively. Diagnosis of DFU infection was made and managed according to established guidelines. The outcome was evaluated at 6 month-visit as failure (persistence/new infection/amputation) or cure. ResultsOut of 65 patients, 52 (80%) had long-standing DFUs (≥4 weeks), with high microbial load in 19 (29%).DFU infection (n = 24, 37%) was not associated with high microbial load in all patients but those with shorter DFU duration.Treatment failure occurred in 20/57 (35%) patients; high DFU microbial load was associated with worse outcome (n = 9/20, 45% failure rate, adjusted OR4.69; 95% CI, 1.22–18.09; p = 0.03),mainly due to the subgroup of patients with high microbial load and long-stand DFUs. ConclusionsSince patients with high microbial load had a worse outcome, quantitative cultures from DFUs can identify patients who would benefit from antibiotic therapy.