ABSTRACT
             Background and objectives: Antimicrobial resistance is a serious threat to global public health. The overuse and misuse of antibiotics are the most important contributing factors to development of antibiotic resistance. Thus, there is an urgent need to identify and discover new compounds against drug-resistant microorganisms. We have previously synthesized new series of 3-substituted 5H-(1,2,4)triazolo(3',4':2,3) (1,3,4)thiadiazino(5,6-b)quinoxaline derivatives (4a-4f). Here, we evaluate the antimicrobial activity of these derivatives against methicillin-resistant Staphylococcus aureus, S. aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Candida tropicalis and Candida krusei.
             Methods: The agar well diffusion and agar dilution methods were used for determining inhibition zone diameter and minimum inhibitory concentration during preliminary evaluation of antimicrobial activity.
             Results: All synthesized compounds exhibited antibacterial and antifungal activity against the tested microorganisms.
             Conclusion: Our findings indicate the antimicrobial potential of the six novel synthetic triazolo thiadiazin quinoxaline compounds.
             Keywords: Antimicrobial, Anti-bacterial agents, Antifungal agents, Triazolo, Thiadiazin, Quinoxaline.