Green Synthesis of Nickel Oxide Nanoparticles using pea peel extract for Attenuation of Quorum Sensing and Biofilm Formation in Pseudomonas aeruginosa QS107

Quorum sensing (QS) provides a means of communication between bacteria, including pathogenic bacteria. QS plays a crucial role in regulation of virulence factors, allowing bacterial communities to arrive at the required infection levels. The increase of multi-drug resistant (MDR) biofilm forming Pseudomonas aeruginosa strains necessitates the development of alternative therapeutic strategies that target bacterial virulence rather than cell viability. QS and biofilm formation are the key mediators of pathogenicity among MDR P. aeruginosa. The aim of this study was to investigate anti-quorum sensing and antibiofilm activity of nickel oxide nanoparticles (NiO-NPs) against MDR Pseudomonas aeruginosa QS107 (OR756454). P. aeruginosa strain QS107 was identified through 16S rRNA sequencing. NiO nanoparticles were synthesized via an eco-friendly method using pea peel extract (Pisum sativum) as reducing and stabilizing agents. The MDR profile of P. aeruginosa QS 107 was determined by Kirby-Bauer disc diffusion method using a standard panel of antibiotics. The production of N-acyl homoserine lactone (AHL) based QS signaling molecules was investigated using a bacterial biosensor Agrobacterium tumefaciens A136. Biofilm formation was confirmed by crystal violet ring method. The potential of NiO nanoparticles against QS and biofilm formation was carried out using well diffusion agar plate assay. The results of this study revealed that P. aeruginosa QS107 exhibited antibiotic resistance against more than five classes of standard antibiotics. Thus, antibiotic sensitivity testing confirmed QS107 as MDR bacterial strain. The highest antibiotic resistance was observed against Ticarcillin, Piperacillin, Imipenem, and Ciprofloxacin. Moreover, biosensor assay confirmed the robust production of AHL based QS signaling molecules by QS107 isolate. Mainly, NiO-NPs inhibited QS system and effectively disrupted biofilm formation in P. aeruginosa QS 107 at sub-inhibitory concentration. The green synthesized NiO-NPs showed potent quorum-quenching and antibiofilm activity against a clinical isolate of MDR P. aeruginosa QS107. These results suggest that pea peel derived NiO-NPs could serve as potential therapeutic agent to overcome virulence of P. aeruginosa infections where traditional antibiotics fail.