Development of chitosan colistin nano-antibiotics and its in-vitro activity against multidrug resistant Acinetobacter baumannii

Gram-negative bacteria are resistant to different antibiotics and thus they are the culprits of serious infections in hospitals. Colistin can be considered at least the possible antibiotic against these microorganisms. In this study, Colistin-chitosan-conjugated nanoparticles (Col-CSNPs) were designed to develop a new comprising of multifunctional Colistin chitosan against Acinetobacter baumannii. Colistin-loaded nanoparticles were equipped with the ionic gelation method. It was characterized by zeta sizer, UV spectrophotometry, x-ray diffraction, and Scanning Electron Microscopy (SEM), which displayed homogeneity both in shape and size. Minimum inhibitory concentration (MIC) was done through microdilution methods for assessment of the effectiveness of developed Colistin-loaded nanoparticles against A. baumannii . The zeta sizer analysis showed the size of nanoparticles in 1% acidic acid was found to be 245nm and had a low polydispersity index (PDI) of 0.26. UV-Vis spectroscopy using a SPUV-1000 spectrophotometer attached to Mwave professional software 2.0 showed a spectrum between 200–900 nm and determined the main absorbing region. In XRD patterns of CS/TPP/ NPs a broad peak at 2θ = 22° was recorded. Outcomes showed that the MIC of a mixture of CSNP and Colistin is lower (0.25µg/ml) than the MIC of Colistin individually (0.5µg/ml). Overall summary of Nano-antibiotics showed a good synergistic effect as compared to Colistin antibiotics. Our research shows a lot of interest in the use of CS as a Nano-carrier system that encapsulates Colistin and for its potential use as Nano-antibiotics to treat resistant infections carried on by considerable Gram-negative A. baumannii.