Nano-strategies in pursuit of efflux pump activeness in Acinetobacter baumannii and Pseudomonas aeruginosa

Abstract Multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa are the two bacteria notorious for nosocomial infections and threats in healthcare settings. Efflux pump is an important mechanism of the antibiotic resistant phenomenon. The emergence of antibiotic-resistant bacteria demands the development of either new antibacterial agents to overcome the distressing situation. The aim of this study was to evaluate the efficacy of chitosan and silver (Ag) nanoparticles (NPs) and their combination with antibiotics to alter the expression level of efflux pumps and any increase in the inhibitory capacity of antibiotics against clinical A.baumannii and P.aeruginosa isolates. To conduct the experiments, initially antibiotic resistant A. baumannii and P. aeruginosa (PAO1) strains were exposed to chitosan and AgNPs with and without ciprofloxacin and gentamicin in their sub inhibitory levels. RNA was then extracted to study the antibacterial effects of the nanoparticles in relation to the expression of the efflux pump using real-time PCR. The present investigation found expression levels of abeM efflux pumps in A.baumannii and mexY efflux pumps in P.aeruginosa decreased after exposing the bacteria to sub-inhibitory concentrations of chitosan, chitosan NPs, and their combination with ciprofloxacin and gentamicin. Conversely, the minimum inhibitory concentration (MIC) levels of ciprofloxacin and gentamicin were found to have increased after exposure to the synthetic substances. Though nanoparticles have found their place in the modern scientific therapeutic world however, before they step into treatment strategies it is necessary to determine their effects either alone or with antibiotics in lowering antibiotic resistance.