Biogenic synthesis and effect of silver nanoparticles (AgNPs) to combat catheter-related urinary tract infections

Silver nanoparticles (AgNPs) have been considered as antimicrobial agents for decades. Rather than chemical synthesis, biosynthesis of AgNPs is emerging as a significant and effective method. This study mainly focused on synthesizing eco-friendly AgNPs from coral-associated bacteria. A total of 57 coral bacterial isolates were screened and the isolate MGL- D10 was selected for synthesizing AgNPs. The isolate MGL- D10 was identified as Alcaligenes sp. using 16S rDNA sequence based phylogenetic analysis. The synthesized AgNPs MGL- D10 was then characterized using UV-Vis spectroscopy, FTIR, and X-ray diffraction (XRD) analysis. Further, the morphology and the size of the synthesized AgNPs was observed through Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Microscopic analysis revealed the size of the synthesized AgNPs MGL- D10 was 30-50 nm. The synthesized AgNPs MGL- D10 showed antimicrobial activity against urinary tract infection (UTI) causing clinical isolates such as Bacillus sp., E. coll., K. pneumonia, P. aeruginosa, S. aureus and C. albicans. Antibiofilm effect of synthesized AgNPs MGL- D10 against S. aureus was assessed using confocal laser scanning microscopy. Catheter experiments also proved the antibiofilm and antimicrobial effect of synthesized AgNPs MGL- D10. The obtained results exhibit that the coating of synthesized AgNPs MGL- D10 on catheters effectively inhibited the growth and biofilm formation of UTI causing pathogens. The present study will pave a way for successful and eco-friendly methods of protection against urinary tract infection causing pathogens and nosocomial infections.