Evaluation of the Inhibitory Effect of Chitosan Nanoparticles on Biofilm Forming Escherichia coli Isolated from Omphalitis Cases

Abstract

To experimentally evaluate chitosan nanoparticles (ChNPs) as alternative to antibiotics on controlling biofilm forming E. coli isolated from omphalitis cases. A total of 100 yolk sac samples were collected from diseased and dead chicks (1-10 days old) suffered from omphalitis. Yolk sacs were collected from different farms at Assiut city, Egypt. Out of 100 collected samples, a total of 36 E. coli isolates were isolated with a prevalence rate of 36%, these isolates belonged to 11 different serotypes, which showed biofilm production that confirmed experimentally by two methods (crystal violet assay and congo red agar), all biofilm producers of E. coli serotypes showed resistance to one or more antibiotics by disc diffusion method. Chitosan nanoparticles exhibited superior antimicrobial activity against all the 11 E. coli strains in comparison with used antibiotics, the maximum inhibition zone diameter recorded was 32 mm at concentration of 0.1% (ChNPs) and the lowest was 11 mm by Agar well diffusion assay. In Ovo colonization with 0.1 % chitosan nanoparticles at the 18th day of incubation through amniotic route had positive impacts on bacterial count of recovered E. coli isolates (2.9×105 CFU) without any adverse effect on hatchability.