Are clindamycin and ciprofloxacin appropriate for the empirical treatment of diabetic foot infections?

The objective of this study was to determine if specific species of microorganisms are associated with severe infection and amputation in patients with a diabetic foot infection and to evaluate the effectiveness of clindamycin and ciprofloxacin in this population. A retrospective cohort study was performed at the University Medical Center Utrecht, The Netherlands, for the period January 1st 2005 to January 1st 2010. Patients with ICD-9 codes 'diabetic foot' were selected from the hospital database. We evaluated the association of Staphylococcus aureus and Gram-negative species (GNS) with severity of infection, number of amputations, and healing rates. No significant association was found between the different microorganisms and infection severity. Coinfections of GNS and S. aureus were significantly associated with amputation compared to infections with only S. aureus [p = 0.016, odds ratio (OR) 4.9, confidence interval (CI) 1.4-16.9]. The empiric antibiotic regimen of clindamycin and ciprofloxacin covered only 85 % of S. aureus and 78 % of GNS diabetic foot infections. In mild diabetic foot infection in the studied population, where methicillin-sensitive S. aureus and streptococci are the most likely pathogens, a beta-lactam antibiotic such as flucloxacillin would likely be more effective than clindamycin. In moderate and severe infections, where GNS as a causative organism cannot be safely excluded, broad-spectrum antibiotic therapy may be more adequate.