Comparative Study of Antibacterial Effect on Silver Dressing of Negative Pressure Wound

Inclusion Criteria: * The patient above 20 years and has type I, II of diabetes mellitus foot ulcer * Infected ulcer has one of below. 1. clinically infection symptom in ulcer area : warmth, erythema, tenderness/swelling * induration, purulent discharge etc. 2. Confirmed case of bacteria in wound culture. 3. Conformed case of abnormal range of erythrocyte sedimentation rate (ESR)/C-reactive protein(CRP) level in lab. * Has to be applied NPWT because suture is impossible in ulcer area. * The patient voluntary agreed to this protocol. * In the opinion of investigator, It is suitable to participate in this study. Exclusion Criteria: * Infection in bone so patient need amputation * Female with childbearing, lactating or not agree to prevent pregnancy. * Has Sepsis, Osteomyelitis * Has Connective tissue disease of disturbance of healing of wound Ex) Rheumarthritis,systemic lupus erythematosus(SEL), myalgia. * The patient to diagnosis of Sickle sell disease or Charcot's joint. * The patient stability treated chronic wasting disease. * Malignant tumor or history of malignant disease. (Not diagnosis of complete recovery.) * The patient treated chemotherapy, radiation therapy, immune-suppressants therapy,adrenocortical hormones therapy. * Although necrosis tissue is removed, the target ulcer did not heal because of gangrenous, necrosis tissue or purulent pyorrhea. * Has ulcer with cardiac arrhythmia thrombus, venous insufficiency, diabetic necrobiosis lipoidic. * In case of using prohibited concomitant medications during study. a. Oral system steroid b. Immune-suppressive drug c. Unfractionated heparin infusion d. improper drugs in the opinion of investigator. * Hypersensitivity with applicators. (NPWT, Silver) * The patient participated in other clinical trials within 30 days * In the opinion of investigator, the patient is not suitable to participate in this study.