Background: Diabetic foot infections are a leading cause of lower extremity amputations. Our study examines the microbiota of diabetic skin prior to ulcer development or infection.
Methods: In a case-control study, outpatient males were recruited at a veterans hospital. Subjects were swabbed at four cutaneous sites, one from the forearm and three from the foot. Quantitative PCR (qPCR) with primers and probes specific for bacteria, Staphylococcus sp, Staphylococcus aureus, and fungi were performed on all samples. High-throughput 16S rRNA sequencing was performed on forearm and plantar foot samples.
Results: qPCR analysis in 30 diabetic and 30 control subjects showed no differences in total numbers of bacteria or fungi at any site. Increased log(10) Staphylococcus aureus, quantified by nuc gene copies, were present in diabetic men at the plantar foot. High-throughput 16S rRNA sequencing found that for the foot, controls (n=24) are dominated by Staphylococcus, while diabetics (n=23) were more diverse at the genus level. The forearm microbiota had similar diversity in diabetic and control groups.Conclusions.?The feet of diabetic men had decreased populations of Staphylococcus sps, while maintaining larger populations of S. aureus, and increased bacterial diversity compared to controls. These ecologic changes may affect risk for wound infections.