Biofilm-associated genes correlates with biofilm phenotypes in Pseudomonas aeruginosa treated with nano-Fe۳O۴ and nano-Ag

BACKGROUND AND OBJECTIVESThe opportunistic human pathogen Pseudomonas aeruginosa endorse biofilm-associated infections that enhanced resistance to antimicrobial agents. There are few effective treatments for P. aeruginosa biofilm-associated infections, necessitating novel therapeutic to target biofilm. The objectives of this study were to investigate anti-planktonic activity, ability to inhibit pre-formed biofilm, and to investigate the expression levels of biofilm-associated genes in pre-formed biofilms after (nano-Fe۳O۴ and nano-Ag) treatments.MATERIALS AND METHODSIn this study, we monitored the anti-planktonic and anti-biofilm activities of nano-Fe۳O۴ and nano-Ag against P. aeruginosa by minimum inhibition concentrations (MIC), minimum bactericidal concentration (MBC), crystal violet staining, XTT Assays and light microscopy using various microbiological protocols. We performed expression analysis of biofilm-associated genes in P. aeruginosa treated with various concentrations of nano-Fe۳O۴ and nano-Ag based on the MIC by quantitative Real-time PCR method.RESULTS AND DISCUSSIONThe nano-Fe۳O۴ and nano-Ag represented great antibacterial properties at concentration of ۵۰ and ۱.۶۲۵ μg/mL, respectively. The MBC values of nano-Fe۳O۴ and nano-Ag were ۱۰۰ and ۳.۱۲۵ μg/mL, respectively. The crystal violet and XTT assays on P. aeruginosa biofilm quantification demonstrated a significant reduction of biomass and metabolic activities in response to various concentrations (۲× MIC, ۱× MIC and ½× MIC) of nano-Fe۳O۴ and nano-Ag. The resultant biofilms were viewed with light microscopy, which show a significant difference in biofilm density exposed to the nano-Fe۳O۴ and nano-Ag as compared with untreated control. Moreover, the relative expression profiles of PELA and PSLA showed alterations in expression levels by the treatment with nanoparticles in a concentration dependent manner, which correlated with the biofilm phenotypes in P. aeruginosa.CONCLUSIONThe potential of nano-Fe۳O۴ and nano-Ag could reduce the expression of PELA and PSLA as important of biofilm-associated genes. Although more research is needed, the use of nano-Fe۳O۴ and nano-Ag as a new therapeutics in P. aeruginosa infections is recommended.

کلیدواژه ها:

Biofilm ، Nanoparticles ، PELA ، PSLA