Detection of anaerobic infection in diabetic foot ulcer using PCR technique and the status of metronidazole therapy on treatment outcome

Abstract

Metronidazole is the drug of choice for anaerobic infection in diabetic foot ulcers (DFU) for a majority of clinicians. The present study was conducted to determine if Metronidazole is really making a difference in the healing of DFU. Methods. Deep tissue samples from the wound area of 61 diabetic foot patients were tested for anaerobic bacterial infection (Peptostreptococcus productus, Bacteroides, and Clostridium) by polymerase chain reaction (PCR). PCR-positive patients were randomized into 2 groups: Metronidazole and non-Metronidazole. Antibiotics for the control of infection were given in both groups as per clinical condition of patients. Treatment outcome was assessed by complete healing of the wound. Results. Out of 61 patients, PCR detected evidence of anaerobic infection in 32 (52%), while culture methods detected only 5 (8%) (Clostridium spp.), hence emphasizing the significance of the PCR technique over culture methods in detection of microbes. In this study, Clostridium was found with maximum prevalence of n (75%), followed by Bacteroides with n (53.1%), and Peptostreptococcus productus with n (40.6 %). Across all Wagner Ulcer Classification grades, Clostridium was the most prevalent anaerobe, and significantly associated with wound age and total leukocyte count. No difference was noted in wound healing in both groups at the end of 16 weeks. Conclusions. The authors propose that it is not mandatory to supplement Metronidazole in antibiotic regime for treatment of DFU.