Comparative Antimicrobial Activity of Ceftazidime, Tobramycin and their Novel Fixed Dose Combination in Some Pathogenic Microorganisms

Ceftazidime belongs to cephalosporin class of antibiotics with broad spectrum activity. Tobramycin is an aminoglycoside antibiotic used to treat various types of bacterial infections, particularly gram negative infections. Combination therapy of ceftazidime tobramycin is adopted in many clinical conditions. In present study, the authors have tried to determine the comparative antimicrobial activity of ceftazidime, tobramycin and their novel Fixed Dose Combination (FDC) in some pathogenic microorganisms. Minimum Inhibitory Concentration (MIC) and Antibiotic Susceptibility Test (AST) were performed. The AST results show that the FDC of these antibiotics significantly increased zone of inhibition in all microorganisms as compared to individual therapy of ceftazidime and tobramycin. In case of Morganella morganii and Citrobacter freundii, gram negative bacteria, the antimicrobial activity was increased by 3.69% and 5.79% in FDC of these antibiotics when compared tobramycin alone. MIC of FDC of ceftazidime and tobramycin in Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus was much lower in comparison to ceftazidime and tobramycin alone. These results indicate that the FDC of ceftazidime and tobramycin has better bactericidal activity in comparison to ceftazidime and tobramycin alone in organisms under study. Keywords: Ceftazidime, tobramycin, fixed dose combination, minimum inhibitory concentration