R Salomoni,1,2 P Léo,2 AF Montemor,2 BG Rinaldi,2 MFA Rodrigues2
1Biotechnology Interunits Pos Graduation Program, University of Sao Paulo – USP, Butantan Institute, Institute for Technological Research – IPT, Sao Paulo, SP, Brazil; 2Industrial Biotechnology Laboratory, Bionanomanufacture Nucleus, Institute for Technological Research – IPT, São Paulo, SP, Brazil
Abstract: Pseudomonas aeruginosa has great intrinsic antimicrobial resistance limiting the number of effective antibiotics. Thus, other antimicrobial agents such as silver nanoparticles (AgNPs) are considered potential agents to help manage and prevent infections. AgNPs can be used in several applications against bacteria resistant to common antibiotics or even multiresistant bacteria such asP. aeruginosa. This study assessed the antimicrobial activity of commercial 10 nm AgNPs on two hospital strains of P. aeruginosa resistant to a large number of antibiotics and a reference strain from a culture collection. All strains were susceptible to 5 µg/mL nanoparticles solution. Reference strains INCQS 0230 and P.a.1 were sensitive to AgNPs at concentrations of 1.25 and 0.156 µg/mL, respectively; however, this was not observed for hospital strain P.a.2, which was more resistant to all antibiotics and AgNPs tested. Cytotoxicity evaluation indicated that AgNPs, up to a concentration of 2.5 µg/mL, are very safe for all cell lines tested. At 5.0 µg/mL, AgNPs had a discrete cytotoxic effect on tumor cells HeLa and HepG2. Results showed the potential of using AgNPs as an alternative to conventional antimicrobial agents that are currently used, and a perspective for application of nanosilver with antibiotics to enhance antimicrobial activity.
Keywords: antimicrobial activity, bacterial resistance, Pseudomonas aeruginosa, silver nanoparticles, AgNPs