Extracellular Synthesis of Bioactive Silver Nanoparticles Using Brevibacillus sp. MAHUQ-41 and Their Potential Application Against Drug-Resistant Bacterial Pathogens Listeria monocytogenes and Yersinia enterocolitica

The purpose of current study was the green synthesis of bioactive silver nanoparticles (AgNPs) using <i>Brevibacillus</i> sp. MAHUQ-41 and the exploration of their role in controlling drug-resistant bacterial pathogens <i>Listeria monocytogenes</i> and <i>Yersinia enterocolitica</i>. The culture supernatant of strain MAHUQ-41 was employed for a simple and eco-friendly synthesis of biofunctional silver nanoparticles (AgNPs). The resulting nanoparticles were analyzed using several techniques, including UV-Visible spectroscopy, XRD, FE-TEM, FTIR, and DLS. The UV-Vis spectral analysis of the AgNPs synthesized via <i>Brevibacillus</i> sp. MAHUQ-41 revealed a prominent absorption peak at 400 nm. FE-TEM results confirmed spherical-shaped 15-60 nm sized nanoparticles. XRD results indicated that the synthesized AgNPs were crystalline in nature. The FTIR spectrum determined various functional groups on the surface of synthesized nanoparticles. Potent antibacterial properties were observed in green-synthesized AgNPs against tested pathogens. The MIC value of extracellular synthesized AgNPs for both pathogenic bacteria was 6.2 µg/mL, and the MBCs were 25.0 µg/mL and 12.5 µg/mL for <i>L. monocytogenes</i> and <i>Y. enterocolitica,</i> respectively. Treatment by synthesized AgNPs resulted in morphological alterations and structural damages in both <i>L. monocytogenes</i> and <i>Y. enterocolitica</i>. These alterations can interfere with regular cellular activities, potentially resulting in cell death. This study is the first to report the antimicrobial properties of silver nanoparticles synthesized using <i>Brevibacillus</i> sp. MAHUQ-41. The findings obtained in the present study supported the role of <i>Brevibacillus</i> sp. MAHUQ-41-mediated synthesized AgNPs in controlling drug-resistant bacterial pathogens <i>L. monocytogenes</i> and <i>Y. enterocolitica</i>.