Bacterial population of chronic crural ulcers: is there a difference between the diabetic, the venous, and the arterial ulcer?

Background: At the Surgical Department of Surgery of the University Hospita l Wurzburg microbiological examinations were performed of the ulcer grounds from patients with diabetic-neuropathic, diabetic-ischemic, venous, and ar terial leg ulcers. The aim of the examination was to evaluate possible diff erences in the healing process of these ulcers based on the knowledge of th eir bacterial populations. Patients and methods: In a period of four months, 63 patients were consecut ively examined by taking a bacteriological swab of their ulcer area. The he aling process of their wounds was followed and related to the impact of bac terial colonisation and clinical signs of infection. Results: 95% of the venous and arterial leg ulcers had a positive smear, wh ereas only 70% of diabetic ulcers were positive for bacterial growth. Bacte rial population of the three ulcer entities, however did not differ signifi cantly. 100% of the clinically infected venous and arterial ulcers but only 80% of the diabetic wounds revealed a positive smear On the other hand, on ly 22% of the venous ulcers with a positive smear developed a clinical infe ction in contrast to 70% of the arterial and diabetic. Venous ulcers showed only in a few patients prolonged healing, even in cases of marked bacteria l contamination. Despite of clinical signs of infection however; diabetic w ounds sometimes did nor reveal a positive wound smear (20%). All infected v enous, but only 20% of the infected ischemic ulcers healed satisfactorily. Arterial wounds with no bacterial growth healed significantly better than c ontaminated wounds. This difference was nor significant in the other entiti es. Radical removal of the infection by minor amputation increased the heal ing rate in diabetic ulcers over 80%, whereas ischemic wounds did not profi t from this therapy. Conclusions: A positive bacterial wound smear is not inevitably correlated with a protracted leg ulcer healing. Nevertheless a fulminant infection oft en developed in diabetic ulcers despite the initial inability to demonstrat e bacterial growth. In order to start antibiotic treatment as early as poss ible, a wound smear should be obtained routinely from patients with diabeti c ulcers. In chronic venous ulcers, a routine swab does not appear to be in dicated as it bears no clinical consequences. The same applies to patients with surgically fully treated peripheral arterial occlusive disease. As isc hemia presents the limiting factor; antibiotic therapy in case of infection will not prevent imminent amputation.