RESUMO
In more than two-thirds of the diabetic foot ulcer (DFUs) cases, lower limb amputation of foot ulceration is caused by the infection. The role of transition a metal complex as a therapeutic compound is becoming increasingly important. In vitro, four groups of antibiotics and one sulfa drug were tested against diabetic foot resistant bacteria. Using three concentrations of two different prepared metal complexes: copper (Cu) and silver (Ag) - isoniazid (Iso) and nicotinamide (Nicot) were tested against diabetic foot isolates. Results revealed that ß-lactam drugs (cephradine and piperacillin) showed the minimum averages of MIC 265 µg/ml against Gram-positive and Gram-negative isolates. Silver isoniazid (Iso-Ag-1) metal complex was selected depending on the maximum averages of MIC against both types of clinical isolates. The combination between ß-lactams and Iso-Ag-1 showed maximum FICI averages of 0.24 for Gram-positive and 0.28 for Gram-negative. In addition, a combination between Iso-Ag-1 with squilla chitosan nanoparticles (CSSq-nAg) showed averages of synergistic index by 0.23 against Staphylococcus aureus and 0.13, 0.30, and 0.27 against E. coli, K. pneumoniae, and Ps. aeruginosa, respectively. Final formula of Iso-Ag-1+CSSq-nAg + ß-lactams (cephradine and piperacillin) showed a synergistic effect at FICI = 0.044 and 0.047, against G+ve and -ve, respectively. These two combinations showed a slight toxicity against the water flea Daphnia magna by 3.49 and 3.6 ppm, respectively. Results suggest the use of Iso-Ag-1-CSSq-nAg as enhancing agent in combination with ß-lactams as a blind therapy in pharmaceutical preparations.
