Antibacterial Activity of Chitosan and PAβN on <i>MexAB</i> Expression in Clinical Isolates of Ciprofloxacin Resistant <i>Pseudomonas aeruginosa</i>

Abstract

Background: Pseudomonas aeruginosa is a nosocomial pathogen, acquiring resistance to a wide range of antibiotics. The MexAB-OprM pump can lead to resistance in this organism. Thus, the study was conducted to determine the effect of chitosan and phenylalanine arginyl ß-naphthylamide (PaβN) on the expression of MexAB in isolated ciprofloxacin resistant P. aeruginosa. Objectives: This study investigated the effect of an antibiotic combination on the MexABP. aeruginosa expression. Methods: A total of 30 ciprofloxacin-resistant isolates of P. aeruginosa were collected in this project. Then, chitosan nanoparticles were prepared using the ionic gelation method. Minimum inhibitory concentration (MIC) values were determined for ciprofloxacin, ciprofloxacin + PAßN, chitosan + ciprofloxacin, and chitosan + ciprofloxacin + PAßN using the micro-dilution method. Moreover, the expression level of MexAB genes was measured using real-time polymerase chain reaction. Results: In total, 76.7% of the isolates were identified as multidrug resistant. A significant decrease in the MIC value was observed in groups treated with PAβN compared to those without PAβN. Moreover, the MIC value was significantly lower in the ciprofloxacin chitosan group than in groups without ciprofloxacin. Decreased MexA and MexB mRNA levels were observed in all antibiotic-treated strains compared to the ciprofloxacin-treated group. Conclusions: There is a significant relationship between the increased MexAB expression and resistance to ciprofloxacin (P-value < 0.05). One of the therapeutic concerns is multidrug resistant bacteria, which needs to be addressed by finding new and more effective antibiotics.