The Infected Diabetic Foot: A Microbiological Analysis

Abstract

Category: Basic Sciences/Biologics; Diabetes Introduction/Purpose: Diabetic foot infections show increasing prevalence. Their therapy is time consuming and expensive. Standardized antibiotic treatments do not exist. Suboptimal antibiotic therapy increases the morbidity of the patient. The aim of the study was to evaluate the dominating bacterial colonization in the diabetic foot. Furthermore we evaluated the changes of the colonization during surgical and antibiotic treatment and the efficiency of the therapy. Methods: The study included 100 patients with a diabetic foot syndrome and a pedal ulcer. Ulcers were classified according to Wagner Classification. HbA1c, CRP and patients BMI were documented. All patients underwent an angiologic investigation with arterial doppler ultrasonography and TcpO2 measurement. An MRI of the affected foot was performed to rule out osteomyelitis. All patients underwent surgical and antibiotic treatment. Surgery included debridement, abscess drainage, VAK therapy, bony resection, minor amputation, resection arthroplasty, Helal osteotomies. Osteomyelitis was pathologically verified. Microbiological results of superficial and deep smears, which were taken during the surgical therapy were analyzed. The antibiotic treatment was adapted to the bacterial resistance. Results: The duration of antibiotic treatment varied from 1 to 136 days (Mean:19.6 days, SD:17.3 ). The mean number of surgical interventions was 2.6. The dominating initial antibiotic treatment was Clindamycin/ Cefuroxim (48%) followed by Clindamycin (11%),Cefuroxim (7%), Clindamycin/ Ciprofloxacin (6%), Tazobactam (3%). The dominating bacteria were gram +. The difference of the percentage distribution compared to the gram- bacteria was statistically significant. The only significant percentage change of the antibiotic treatment was seen after the first surgical intervention, when the initial antibiotic treatment was significantly more effective against gram - bacteria. A change of the antibiotic treatment was seen with 1. Clindamycin / Ciprofloxacin in 66%, 2. Tazobactam in 67%, 3.Clindamycin in 36% and Clindamycin/ Cefuroxim in 35%. Conclusion: The dominating bacteria of the infected diabetic feet were gram +. The initial i.v. antibiotic treatment with Clindamycin/ Cefuroxim was effective in 66%. An optimization of the initial antibiotic treatment with greater focus on the gram + bacteria seems to be necessary.