Bactericidal potentials of silver nanoparticles: Novel aspects against multidrug resistance bacteria

Bacteria develop resistance against antibiotics through various pathways, thus reduce their therapeutic efficacy. Multidrug resistance (MDR) has emerged as a major medical concern and has reduced the clinical outcomes of currently used drugs. Nanomedicine is a growing biomedical science and finds diverse applications both in drug delivery and diagnosis. Silver nanoparticles (AgNPs) have been found highly active against viruses, bacteria, and other eukaryotic microorganisms. The bactericidal potential of AgNPs has been well established against both MDR and non-MDR strains of bacteria. Bacteria develop MDR against antibiotics through decreasing membrane permeability, altering the antibiotics target proteins, inactivating antibiotics by the enzymatic action, and developing drugs efflux system. AgNPs achieve a broad spectrum of bactericidal activity against MDR bacteria through their adhesion to bacterial membrane, penetration into the cells, arresting various vital cellular activities, causing structural disruption through production of oxidative stresses, and inhibiting bacterial biofilm formation. The chapter summarizes the mechanisms involved in the development of resistance to antibiotics in bacterial strains. It also explains complete outline of AgNPs-prompted cell reaction in bacteria through which they reverse or inhibit bacterial resistance.