Antibiotic combinations in polymicrobic diabetic foot infections.

ABSTRACT

OBJECTIVE: The aim of this study was to evaluate synergistic potential of antibiotic combinations against pathogenic microorganisms isolated from patients with diabetic foot wounds. RESEARCH DESIGN AND METHODS: 272 diabetic foot patients were studied prospectively over a two-year period. Tissue curettage samples from ulcer base were processed microbiologically to isolate aerobic as well as anaerobic pathogens. [775 isolates] Antibiotic susceptibility testing [MIC/MBC], from amongst these organisms revealed 75 multiresistant organisms, of which only 69 strains could be further studied to assess synergistic effect of various antibiotic combinations by the microtitre checkerboard assay technique. RESULTS: The checkerboard synergy studies showed that overall, synergy could be demonstrated in 21.74% to 59.57%. Amongst the 14 combinations tested, it was found that four combinations could be of worthwhile clinical significance, namely Amikacin/Piperacillin [AK + PP] [77.50%]; Ampicillin-Sulbactum/Piperacillin [AS + PP] [76.92%]; Ampicillin Sulbactum/Cefoperazone [AS + CP] [74.47%], and Ofloxacillin/Cefotaxime [OF + CT] [71.43%]. CONCLUSIONS: Amikacin/Piperacillin is a combination that has been proven to be of synergistic potential. This study not only confirms this observation but also showed that Ampitum-Sulbactum in combination with either Piperacillin or Cefoperazone was equally efficacious. Furthermore, it was also observed that Ofloxacillin/Cefotaxime combination could be almost equally useful. The study thus emphasizes that antibiotic combinations which are synergistic can be of great clinical significance in the management of patients with diabetic foot infections.