Bacteriologic analysis of bone biopsy from diabetic foot infections within a VA patient population

Diabetic patients with foot infections were evaluated over a 5-year period from April 2005 to March 2010. Cultures were obtained from 92 patients after surgical debridement. All of the patients were classified as "severe" diabetic foot infections (DFIs) and PEDIS grade 4. Wound specimens were collected by bone biopsy and sent to San Francisco VA Medical Center Microbiology Department for aerobic and anaerobic cultures. Among the 92 cases, the study resulted in a total of 410 pathogens, which 203 pathogens were from bone cultures and 207 pathogens were from soft tissue cultures. 74% of cases were polymicrobial and 26% had growth of a single organism. Staphylococcus aureus presented in 49.35% of bone cultures and 55.38% of soft tissue cultures, Streptococcus species presented in 44.16% and 36.92% respectably and roughly 33% of both bone and soft tissue had staphylococcus coagulase negative present. Gram-negative organisms occurred in 25% of all cultures taken. Pseudomonas accounted for 15% of soft tissue infections but only 1.3% bone cultures. MRSA was found in 17.39% of cultures and VRE was seen in 4.34% of all culture results. Staphylococcus aureus was the most prevalent organisms seen. This study presents a comprehensive microbiological survey of diabetic patients with DFIs within the San Francisco VA Medical Center and this study will help guide physicians to improve clinical outcomes of DFIs by using proper antibiotics.