Role of Bacteria in Pathogenesis of Lower Leg Ulcers

Abstract

Lower leg ulcer is a circumscribed necrosis of epidermis, skin, and occasionally also muscular fascia, tendon, or even underlying bone with sluggish granulation and delayed covering by keratinocytes migrating from the ulcer margins. Following skin microinjury the colonization of denuded surface by local skin and floating down perineal bacterial flora takes place. The predisposing factors are venous stasis with excess capillary filtrate, high tissue fluid pressure, erythrocyte extravasation, hemosiderosis and fibrosis, or ischemia in atherosclerosis and diabetes with decreased arterial supply of nutrients, or lymph stasis with excess tissue fluid, high tissue fluid pressure and fibrosis, or excessive fat deposition in the subcutis in pathological obesity with excess tissue fluid and high tissue fluid pressure. The common denominator, irrespective of predisposing factors, is colonization of the denuded surfaces by bacteria. Although bacteria may not necessarily be the primary etiological factor, they certainly are responsible for progression of ulcer or delayed healing.