Failure of Empirical Antimicrobial Therapy in Diabetic Foot Ulcer With Chronic Osteomyelitis: A Case Report

Diabetic foot infections (DFIs) are frequent and severe complications of diabetes mellitus that can lead to chronic wounds, osteomyelitis, and even limb amputation if not properly managed. This case report describes the clinical consequences of prolonged empirical antibiotic therapy without culture guidance in a patient with a diabetic foot abscess. A 72-year-old man with type 2 diabetes and hypertension presented with a chronic, non-healing deep foot abscess after receiving 15 consecutive courses of empirical oral antibiotics over eight months. Magnetic resonance imaging suggested osteomyelitis of the fifth metatarsal bone. Urgent surgical drainage and tissue cultures revealed <i>Escherichia coli</i> and <i>Pseudomonas aeruginosa</i>, both resistant to multiple commonly used antibiotics but susceptible to ceftriaxone and carbapenems. Targeted intravenous therapy with ceftriaxone and metronidazole led to rapid improvement within one week and complete healing by the third month. This case emphasizes that prolonged empirical therapy may lead to treatment failure and antimicrobial resistance. Early surgical intervention combined with culture-guided antibiotic selection is crucial for effective management of DFIs and for preventing severe complications such as amputation. This case underscores the importance of multidisciplinary and microbiologically guided approaches.