Chicken Nano-Defensin-9 Displays Potent Antimicrobial Activities Against Multidrug Resistant Bacteria and Fungi

This investigation was designed to study the antimicrobial activities of chicken β-defensin derived peptide-9 against pathogenic organisms including bacterial and fungal species. Eight bacterial strains and two fungal species were used in study to investigate the antimicrobial activity of custom made synthetic chicken β-defensin-9. The Minimal Inhibition Concentration (MIC), Kill Curves, salinity effect on the antibacterial activity of peptides and hemolysis activities of this peptide were determined. The results showed that the sAvBD-9 displayed higher bactericidal potency against all tested bacterial strains. The exhibited bactericidal activity was higher against almost all bacteria strains at all peptide concentrations except for that of   P. aeruginosa which showed a moderate impact. The synthetic AvBD -9 was effective in inactivation of fungal species with a killing rate exceeding the 98 % level. This reveal that the synthetic peptide was resistant to salt when added at a concentration of 50mM NaCl, However, their antimicrobial activity was compromised when applied in the presence of salt concentrations of 100 mM and 150mM NaCl. It's interesting to be noting that a little and low hemolytic effect a little or low hemolytic effect was observed for both peptides even when applied at higher concentrations. Our results presented that the first time to use term “nano-defensin” for the avian β-defensin-9 based on its nano size and shape that is less than 10 nm as captured by using transmission electron microscope (TEM). The results revealed that at different concentrations of MIC a completely damage was observed and full exit of cytoplasmic contents take a place and finally complete cell death. The data obtained for synthetic avian peptides would be shed light regarding their potential applications in the pharmaceutical industry to help the incidence of infections and to be advocated as a naturally occurring antibiotic.