Microbial ecology of interdigital infections of toe web spaces

The microbial flora of normal and macerated interdigital toe web spaces was qualitatively and quantitatively identified in 77 patients. Dermatophyte fungi were recovered from 11% of normal patients compared with a 31% recovery from patients with macerated interspaces. Macerated interspaces were characterized by a greater recovery of organisms with pathogenic potential, with Staphylococcus aureus recovered from 36% of patients, Micrococcus sedentarius in 37%, Brevibacterium epidermidis in 54%, Corynebacterium minutissimum in 69%, and Pseudomonas species in 26%. The bacterial flora of macerated interspaces showed a significantly higher incidence of resistance to multiple antibiotics, and the recovery of antibiotic-resistant bacteria correlated with the recovery of dermatophytes that produce penicillin-like substances. The results of this study support the hypothesis that overgrowth of the resident bacterial population determines the severity of interdigital toe-web infections.