Identification of bacteria from a non-healing diabetic foot wound by 16 S rDNA sequencing

Approximately 10-20% of diabetic foot wounds fail initial antibiotic treatm ent. It is generally believed that several bacterial species may be present in these types of wounds. Because some of these organ isms can not be easi ly cultured, proper identification is problematic and th us, appropriate tr eatment modalities cannot be applied. This report examined the bacterial fl ora present in a chronic diabetic foot wound that failed antibiotic treatme nt. A tissue sample was collected from the base of the wound and used for s tandard microbiological culturing. DNA from the sample was used to amplify bacterial 16 S rDNA gene sequences and a library of these sequences was mad e. The clones were placed into two major groups on the basis of their melti ng temperatures. Representatives of these groups were sequenced, and inform ation was used to identify the bacteria present in the wound. The culture-b ased method identified a single anaerobic species, Bacteroides fragilis. Th e method employing rDNA sequencing identified B. fragilis as a dominant org anism and Pseudomonas (Janthinobacterium) mephitica as a minor component. T he results indicate that rDNA sequencing approach can be an important tool in the identification of bacteria from wounds. (C) 2000 Academic Press.