Foot infections in diabetes are rarely due to a single microorganism.

The purpose of this study was to investigate the frequency with which multiple organisms can be isolated from severe foot infections in diabetic patients with carefully planned techniques of collection and processing of specimens. One hundred and seventy-seven organisms were isolated from 52 patient admissions (mean 3.4 per infection) at a district hospital. This was compared to a mean of 2.1 organisms per lesion at a local university hospital and 2.3 at a smaller community hospital. Staphylococcus aureus was isolated in about half of all lesions at the three hospitals, while anaerobic organisms were isolated from 30 at the district hospital, 10 at the university hospital, and 4 at the community hospital. This study concludes that, firstly, proper techniques for collection, transportation and examination of culture specimens are important in the isolation of multiple organisms from foot infections in diabetes, and secondly, Staphylococcus aureus is often absent while anaerobic organisms are common.