Biofabrication of Gold Nanoparticles Using Capsicum annuum Extract and Its Antiquorum Sensing and Antibiofilm Activity against Bacterial Pathogens.

The intensive use of antimicrobial agents has led to the emergence of multidrug resistance (MDR) among microbial pathogens. Such microbial (MDR) infections become more problematic in chronic diseases in which the efficacy of chemotherapeutic agents is highly reduced. To combat the problem of drug resistance, inhibition of bacterial quorum sensing (QS) and biofilms are considered as promising strategies in the development of anti-infective agents. In this study, gold nanoparticles (AuNPs-CA) were biofabricated using Capsicum annuum aqueous extract and characterized. The AuNPs-CA were tested against the QS-controlled virulence factors and biofilms of Pseudomonas aeruginosa PAO1 and Serratia marcescens MTCC 97. AuNPs-CA were found to be crystalline in nature with average particle size 19.97 nm. QS-mediated virulent traits of P. aeruginosa PAO1 such as pyocyanin, pyoverdin, exoprotease activity, elastase activity, rhamnolipids production, and swimming motility were reduced by 91.94, 72.16, 81.82, 65.72, 46.66, and 46.09%, respectively. Similarly, dose-dependent inhibition of virulence factors of S. marcescens MTCC 97 was recorded by the treatment of AuNPs-CA. The biofilm development and exopolysaccharide (EPS) production also decreased significantly. Microscopic analysis revealed that the adherence and colonization of the bacteria on solid support were reduced to a remarkable extent. The findings indicate the possibility of application of green synthesized gold nanoparticles in the management of bacterial infection after careful in vivo investigation.