Activity of Chitosans in combination with antibiotics in Pseudomonas aeruginosa

Abstract

Chitosan and its derivative water soluble Chitosan oligosaccharide are used in a variety of applications in pharmaceutical preparations. In this study, 2 wild (ATCC 15729 and PAO1) and 2 mutant strains (PT121 and PT149) of P. aeruginosa are investigated for drug-drug interactions in vitro. 10 antimicrobial agents (antibiotics) are combined with different degree of deacetylated Chitosans and Chitosan oligosaccharide. All the chitosans show synergistic activity with sulfamethoxazole, a sulfonamide antimicrobial agent. It is interesting to observe that the MIC value for the MexEF-OprN overexpressing mutant strain of P. aeruginosa is 5 fold higher than the other strains under investigation suggesting a possible role of this efflux pump in Sulfamethoxazole efflux. The findings suggest on the use of chitosans as enhancing agent in combination with antibiotics in pharmaceutical preparations.

Keywords: Chitosan; Synergy; additive; chitin; combination therapy; drug resistance..

Figure 1

A: MICs of different antibiotics against P. aeruginosa ATCC15279. B: MICs of different chitosans and chitosan oligosaccharide against P. aeruginosa ATCC15279

Figure 1

A: MICs of different antibiotics against P. aeruginosa ATCC15279. B: MICs of different chitosans and chitosan oligosaccharide against P. aeruginosa ATCC15279

Figure 2

Antibacterial activity of acetate buffer showing acetate ions concentration verses OD at 600nm.

Figure 3

The reduction in MIC of Sulfamethoxazole (sulf) after combination with ¼ MIC of chitosan (8µg/ml) and ¼ MIC of Chitosan oligosaccharide (512 µg/ml) against different strains of P.aeruginosa. Yellow is P aeruginosa ATCC15279; Blue is P aeruginosa PT121 ; Cyan is P aeruginosa PT149 and Green is P aeruginosa PAO1.

Figure 4

Population analysis of P. aeruginosa in combination of chitosans and Sulfamethoxazole. (1/4 MIC of chitosan/ Chitosan oligosaccharide and 1/8 MIC of Sulfamethoxazole)