The colonizing bacterial cells and their DNA were detected in fracture callus but not in other deep tissues. Contamination was precluded by lack of isolates in disinfected cutis, subcutis, muscles, and materials used for sampling cultured after surgery. We suggest that certain strains of bacteria dwell in normal tissues of lower limbs and may cause inflammation upon stimulation by trauma. Their source may be tissue fluid, superficial and deep lymphatics, and lymph serving the physiologic transport to the regional lymph nodes of microorganisms penetrating foot skin during microinjuries.