The effect of micafungin and anti-bacterial agents on pseudomonas aeruginosa biofilm formation in BALB-c mice -

Abstract

Background: Pseudomonas aeruginosa is notorious for its biofilm forming capacity, which reduces the accessibility of antibacterial agents and renders the host defenses ineffective in clearing such infections. 1,3-β-D-glucan is a key component in the fungal cell wall and extracellular matrix (ECM) of Candida albicans biofilms. 1,3-β-D-glucan is discovered to be present as a periplasmic glucan and within the Extra-Cellular Matrix (ECM) of the P. aeruginosa biofilm. Micafungin, an anti-fungal drug, is known to inhibit the synthesis of β-D-glucans. Previous in-vitro experiments assessed the inhibitory effect of micafungin on biofilm formation and survival rates in BALB-c mice. This project aims at evaluating the effect of micafungin, singly or in combination with levofloxacin or ceftazidime on P. aeruginosa biofilm formation, by 1) determining the transcription levels of biofilm forming encoding genes (pelC, algC,and ndvB) in treated and untreated BALB-c mice, 2) measuring the thickness of biofilms in treated and untreated samples from BALB-c mice by confocal-scanning-laser-microscopy (CSLM),. Methods: The effect of micafungin along with levofloxacin and ceftazidime on P. aeruginosa was assessed in-vitro on biofilms grown on microtiter plates and spectrophotometry. The relative gene transcription levels of P. aeruginosa biofilm-encoding pelC, algC, and ndvB genes, for pellicles, alginate and cell wall 1,3- β -D-glucan, respectively, were performed on RNA extracted samples from in-vivo experiments, in the presence of micafungin and-or levofloxacin or ceftazidime, by Quantitative Reverse Transcription PCR (RT-qPCR) experiments. Visualization and thickness calculation by Z-stacking of micafungin treated and untreated P. aeruginosa biofilms obtained from in-vitro and in-vivo samples, as determined by CSLM after staining with ethidium bromide and calcofluor-white. Results: In-vitro results of treated-biofilms grown on microtiter plates showed phenotypic inhibition of biofilm formation by micafun