Bacterial samples were collected from consecutive diabetic patients with foot wounds at the Vascular Surgery Unit and the Diabetic Foot Unit of Alexandria Main University Hospital, Faculty of Medicine, Alexandria University. Samples isolated, purified and identified using the conventional methods including colony morphology, Gram stain and biochemical tests. Three different chitosans were prepared from chitin of 3 different sources (crab, shrimp and squilla) and tested against diabetic foot isolates. Shrimp chitosan showed maximum activity against bothGram- ositive and Gram-negative bacteria. Three nucleic acid derivatives (Barbital, Barbituric acid and Thiobarbituric acid) and 14 nucleic acid metal complexes (Cu-Barbital, Fe-Barbital, Cu-FeBarbital, Zn-Barbital, Co-Barbituric acid, Cu-FeBarbituric acid, Fe-Barbituric acid, Ni-Barbituric acid, Hg-Thiobarbituric acid, Pd-Thiobarbituric acid, CoThiouracil, Hg-Thiouracil, Co-Guanine and Cu-FeGuanine) were tested against diabetic foot isolates. The three ligands “Barbital, Barbituric acid and Thiobarbituric acid” showed low resistance against Klebsiella pneumoniae and Shigella sonnei compared with its complexes which showed high resistance. The metal complexes showed more activity than the ligands for both Gram-positive and Gramnegative bacteria. Best 6 nucleic acid metal complexes showed the most activity for both Gram-positive and Gram-negative bacteria were chosen and then undergone combination tests with chitosans. 

Keywords: Chitosans; Nucleic acids; Complexes; Bacterial samples; Biochemical reactions; Grampositive and Gram-negative bacteria.