Microbiological and clinical characteristics of diabetic foot infections in northern India.

Introduction: India has the largest diabetic population of 50.8 million that could reach an epidemic proportion by 2030. Diabetic foot infection is one of the dreaded complications of diabetes.  Only a few studies that focus on patterns of diabetic foot infection in our region, where diabetic foot care is inadequate, are available. This study evaluated microbial and clinical characteristics of diabetic foot infections that will be helpful in taking appropriate measures for their management.

Methodology: In this prospective study conducted during 2008-2009, sixty-two diabetic foot patients underwent detailed history, clinical examination, and laboratory investigations including parameters of systemic infections. Microbial culture and sensitivity were performed at the time of presentation.

Results: Among 62 cases, 43.5% had mono-microbial infection, 35.5% had poly-microbial infections, and 21% had sterile culture. Among 82 bacteria isolated, 68% were Gram negative and 32% were Gram positive. Leukocyte counts were higher (16928±9642 versus 14593±6687 cells/mm(3)) and haemoglobin (7.9±2.4 versus 9.2±2.2 mg/dl) lower in poly-microbial compared to mono-microbial infections. Haemoglobin counts were lower and leukocyte counts higher in Gram-negative compared to Gram-positive infections. Patients with sterile cultures also had clinical evidence of persistent infection. Escherichia coli were the most common isolate and piperacillin/tazobactam showed highest sensitivity.

Conclusions: Gram-negative bacteria were most prevalent in diabetic foot infection. It is not uncommon to have culture reports negative despite clinical evidence of infection. This study suggests that piperacillin/tazobactam should be the treatment of choice on an empirical basis prior to a definitive bacteriological study and in cases with negative culture reports.