Title : Addressing hospital associated infections with novel nano-antimicrobial
Hospital acquired infections (HAIs), also called nosocomial infections, are of public health concern as current antibiotics are becoming obsolete due to bacterial pathogens becoming resistance toward antibiotics. Growing body of research suggests nanotechnology potential to avert bacterial resistance through multivalent mode of action leading to cell wall damage. In this study, we tested the inhibitory efficacy and mode of action (MoA) of positively-charged 5 nm amino-functionalized silver nanoparticles (NH2–AgNPs) and compared with negatively-charged 45 nm citrate-functionalized AgNPs (Citrate–AgNPs), and Ag+ ions were used as a positive control. Luria-Bertani broth assay was performed using E. coli K12 as a pathogenic surrogate for HAIs to assess growth inhibition over the period of 72 hrs. using an UV-Vis spectrophotometer, and results were confirmed with electron microscopy. Our results showed at 10 µg Ag/mL, NH2–AgNPs were bactericidal via cell wall damage, Citrate–AgNPs were nontoxic, and Ag+ ions were bacteriostatic against E. coli. In addition, adherent fimbriae expression was inhibited with NH2–AgNPs (0.5-10 µg/mL) or Ag+ ions (only at 10µg/mL) treatments, but with Citrate–AgNPs (0.5-10 µg/mL) adherent fimbriae were fully expressed. These findings suggest that, unlike negatively-charged larger size (45 nm) Citrate–AgNPs, positively-charged small size (5 nm) NH2–AgNPs may serve as a potent bactericidal agent to address the growing HAIs and antibiotic resistance amongst bacteria, promoting patient health and safety.