en ميکروب شناسي Microbiology تحقيقي Original Paper <div><strong>ABSTRACT</strong><strong><span dir="RTL"></span></strong><br> <strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Background and objectives: </strong>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&#39;,4&#39;: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<em> Staphylococcus aureus, S. aureus,</em> <em>Streptococcus pyogenes</em>, <em>Pseudomonas aeruginosa</em>, <em>Escherichia coli</em>, <em>Candida albicans, Candida tropicalis </em>and<em> Candida krusei</em>.<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Methods</strong>: 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.<br> <strong>&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</strong><strong>Results</strong>: All synthesized compounds exhibited antibacterial and antifungal activity against the tested microorganisms<strong>.</strong><br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Conclusion</strong>: Our findings indicate the antimicrobial potential of the six novel synthetic triazolo thiadiazin quinoxaline compounds.<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Keywords: </strong>Antimicrobial, <a href="https://www.ncbi.nlm.nih.gov/mesh/68000900">Anti-bacterial agents</a>, <a href="https://www.ncbi.nlm.nih.gov/mesh/68000935">Antifungal agents</a>, Triazolo, Thiadiazin, Quinoxaline.</div> Antimicrobial, Anti-bacterial agents, Antifungal agents, Triazolo, Thiadiazin, Quinoxaline. 20 25 http://mlj.goums.ac.ir/browse.php?a_code=A-10-727-1&slc_lang=en&sid=1 Maryam Kouhkan kouhkanmaryam@gmail.com 100319475328460021549 100319475328460021549 Yes Young Researchers and Elite Club, Urmia Branch, Islamic Azad university, urmia, Iran. Miri Mahmoody 100319475328460021550 100319475328460021550 No Department of Organic Chemistry.Faculty of science, Urmia Branch, Islamic Azad University, Urmia, Iran Jabbar Khalafy 100319475328460021551 100319475328460021551 No Department of Chemistry, Faculty of Science, Urmia University, Urmia 57154, Iran Sima Pourali 100319475328460021552 100319475328460021552 No Depatmant of Biology, Islamic Azad University Electronic Branch, Iran Nasser Samadi 100319475328460021553 100319475328460021553 No Department of bacteriology and Virology, Shiraz University of Medical Sciences, Shiraz, Iran