Studies of antibacterial effects of synthesized silver nanoparticles using a novel thermotolerant Isoptericola variabilis sp. IRSH1 against Staphylococcus aureus and Pseudomonas aeruginosa

Background: Silver nanoparticles can consider as an alternative source for some antibiotic usages due to those effective antibacterial activity and eco-friendly characteristics. Objective: This in vitro study was done to evaluate the inhibitory effect of extracellular synthesized of silver nanoparticles using inexpensive cellulosic materials and supernatant culture of Isoptericola variabilis sp. IRSH1 against Staphylococcus aureus and Pseudomonas aeruginosa. Methods: Silver nanoparticles were produced by extracellular biosynthesis using supernatant culture of a novel thermotolerant Isoptericola variabilis sp.IRSH1 and characterized. The antibacterial activities of the synthesized silver nanoparticles were examined by the standard KirbyBauer disc diffusion method against Staphylococcus aureus and Pseudomonas aeruginosa on Muller-Hinton agar plates. Findings: The silver nanoparticles were produced with an average size of 77 nm and 0.29 polydispersity index (PDI). The inhibition zones of AgNPs (1000 µg/ml) were 10 mm and 11 mm against Staphylococcus aureus and Pseudomonas aeruginosa respectively. Conclusion: The biosynthesized AgNPs has good antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The results indicate Pseudomonas aeruginosa is more sensitive to silver nanoparticles