Nisin-Loaded Niosomes as a Novel Nanocarrier System against Predominant Gram-Negative Uropathogens

Abstract

Urinary tract infections (UTIs) caused by Gram-negative bacteria such as E. coli, P. aeruginosa and P. mirabilis are a serious health concern due to their ability to establish biofilm and antibitotic resistance. Niosomes loaded with nisin were formulated and analyzed in this study to evaluate their potential as a new nanocarrier system against major Gram-negative uropathogens. The formulations were characterized for particle size, zeta potential and encapsulation efficiency and their antibacterial activity was evaluated by MIC and MBIC assays against clinical and veterinary isolates. Acidic formulations provided vesicles of less than 400 nm with increased stability, while neutral pH promoted higher encapsulation efficiency. Nisin release and antibiofilm activity increased under acidic conditions with MIC values of 3.13-25 μg/mL; P. mirabilis was the most susceptible and P. aeruginosa the most resistant bacteria. The prevention of biofilm formation was more evident on E. coli thus validating the dual action of the system against planktonic and sessile cells. These results imply that nisin-loaded niosomes are promising therapeutic method for the controlling of Gram-negative UTIs in clinical and veterinary settings.