Jahrom University of Medical Sciences Pars Journal of Medical Sciences 2717-0284 15 3 2022 12 25 Antimicrobial activity of Oscillatoria cyanobacterum Antimicrobial activity of Oscillatoria cyanobacterum 42 48 700366 10.52547/jmj.15.3.7 FA Ali Salehzadeh Journal Article 2022 12 25   Background and aim: Due to the increase of bacterial resistance to common antibiotics, tendency towards using natural compounds with antimicrobial activity was increased. Mean while, many bacterial species show multi or pan-resistant phenotypes. Many of these multidrug resistant (MDR) bacteria can cause life-threatening infections, being a major concern both in the hospital and the community. Therefore, in this study, we investigated the antimicrobial properties of cyanobacteria Oscillatoria sp < span dir="RTL">.   Methods: The antimicrobial effect of cyanobacteria of Oscillatoria in concentrations of 50 mg/ml was investigated. The antimicrobial properties of cyanobacteria extract supernatant using in well diffusion agar was investigated. Moreover the minimum inhibitory concentration (MIC) was performed against human pathogenic bacteria such as, S. aureus, B. subtilis, P. aeruginosa and E. coli.   Findings: We observed the highest antimicrobial activity against E. coli bacteria with inhibition zone a diameter of 24 mm and the lowest antibacterial effect against P.aeruginosa with inhibition zone a diameter 14mm. In addition, the minimum inhibitory concentration of Oscillatoria extract against E. coli and Pseudomonas was documented in 3/125 and 12/5 mg/mL respectively.   Conclusion: Our results indicated that the methanolic extract of Oscillatoria had the proper antimicrobial activity against human pathogens and this inhibiotion was dose-dependent.   Keywords: Oscillatoria, Human Pathogens, Antimicrobial activity, Well diffusion agar     Background and aim: Due to the increase of bacterial resistance to common antibiotics, tendency towards using natural compounds with antimicrobial activity was increased. Mean while, many bacterial species show multi or pan-resistant phenotypes. Many of these multidrug resistant (MDR) bacteria can cause life-threatening infections, being a major concern both in the hospital and the community. Therefore, in this study, we investigated the antimicrobial properties of cyanobacteria Oscillatoria sp < span dir="RTL">.   Methods: The antimicrobial effect of cyanobacteria of Oscillatoria in concentrations of 50 mg/ml was investigated. The antimicrobial properties of cyanobacteria extract supernatant using in well diffusion agar was investigated. Moreover the minimum inhibitory concentration (MIC) was performed against human pathogenic bacteria such as, S. aureus, B. subtilis, P. aeruginosa and E. coli.   Findings: We observed the highest antimicrobial activity against E. coli bacteria with inhibition zone a diameter of 24 mm and the lowest antibacterial effect against P.aeruginosa with inhibition zone a diameter 14mm. In addition, the minimum inhibitory concentration of Oscillatoria extract against E. coli and Pseudomonas was documented in 3/125 and 12/5 mg/mL respectively.   Conclusion: Our results indicated that the methanolic extract of Oscillatoria had the proper antimicrobial activity against human pathogens and this inhibiotion was dose-dependent.   Keywords: Oscillatoria, Human Pathogens, Antimicrobial activity, Well diffusion agar   https://jmj.jums.ac.ir/article_700366_2c3f704d85cb580a578b00d41d3b7984.pdf