In vivo Activity of Silver Nanoparticles Against Pseudomonas aeruginosa Infection in Galleria mellonella

Abstract

<i>Pseudomonas aeruginosa</i> is an opportunistic pathogen associated with life-threatening nosocomial and community-acquired infections. Antibiotic resistance is an immediate threat to public health and demands an urgent action to discovering new antimicrobial agents. One of the best alternatives for pre-clinical tests with animal models is the greater wax moth <i>Galleria mellonella</i>. Here, we evaluated the antipseudomonal activity of silver nanoparticles (AgNPs) against <i>P. aeruginosa</i> strain UCBPP-PA14 using <i>G. mellonella larvae</i>. The AgNPs were synthesized through a non-toxic biogenic process involving microorganism fermentation. The effect of AgNPs was assessed through characterization and quantification of the hemocytic response, nodulation and phenoloxidase cascade. On average, 80% of the <i>larvae</i> infected with <i>P. aeruginosa</i> and prophylactically treated with nanoparticles survived. Both the specific and total <i>larvae</i> hemocyte counts were restored in the treated group. In addition, the nodulation process and the phenoloxidase cascade were less exacerbated when the <i>larvae</i> were exposed to the silver nanoparticles. AgNPs protect the <i>larvae</i> from <i>P. aeruginosa</i> infection by directly killing the bacteria and indirectly by preventing an exacerbated immunological response against the pathogen. Our results suggest that the prophylactic use of AgNPs has a strong protective activity against <i>P. aeruginosa</i> infection.