Doctor My Father Is Suffering From Diabetis,cellulitis And Osteomalitis. Recently

Doctor my father is suffering from diabetis,cellulitis and osteomalitis. Recently we have eliminated infection,pus and infected bones from foot by Surgery.By using VAC Machine the wound is healed..no antibiotic is useful on his wound except Colistine..now it looks alike that toe of that foot has infection what to do? Please Guide me