Antimicrobial activities of chicken β-defensin (4 and 10) peptides against pathogenic bacteria and fungi.

Haitham A Yacoub,Maged M Mahmoud,Ahmed M Elazzazy,Steve M Harakeh,Ahmed M Al-Hejin,Osama A H Abuzinadah

doi:10.3389/fcimb.2015.00036

Abstract

Host Defense Peptides (HDPs) are small cationic peptides found in several organisms. They play a vital role in innate immunity response and immunomodulatory stimulation. This investigation was designed to study the antimicrobial activities of β-defensin peptide-4 (sAvBD-4) and 10 (sAvBD-4) derived from chickens against pathogenic organisms including bacteria and fungi. Ten bacterial strains and three fungal species were used in investigation. The results showed that the sAvBD-10 displayed a higher bactericidal potency against all the tested bacterial strains than that of sAvBD-4. The exhibited bactericidal activity was significant against almost the different bacterial strains at different peptide concentrations except for that of Pseudomonas aeruginosa (P. aeruginosa) and Streptococcus bovis (Str. bovis) strains where a moderate effect was noted. Both peptides were effective in the inactivation of fungal species tested yielding a killing rate of up to 95%. The results revealed that the synthetic peptides were resistant to salt at a concentration of 50 mM NaCl. However, they lost antimicrobial potency when applied in the presence of high salt concentrations. Based on blood hemolysis studies, a little hemolytic effect was showed in the case of both peptides even when applied at high concentrations. The data obtained from this study indicated that synthetic avian peptides exhibit strong antibacterial and antifungal activity. In conclusion, future work and research should be tailored to a better understanding of the mechanisms of action of those peptides and their potential use in the pharmaceutical industry to help reduce the incidence and impact of infectious agent and be marketed as a naturally occurring antibiotic.

Highlights

Host Defense Peptides (HDPs) are a diverse group of small and cationic peptides that are present in several organisms (Cuperus et al, 2013)
There was a variation in the response of the bacteria to the tested peptides with sAvBD10 showing a better efficacy on average against all the bacteria tested
The results showed that sAvBD-4 inhibited the growth of both Gram-negative and positive bacteria with MIC concentrations as follows: 25 μg/ml [(Staph. epidermidis, Kleb. pneumonia, Sh. sonnei, C. albicans), 50 μg /ml (MRSA, M. luteus, Salm. typhimurium, E. coli, Asp. flavus) and 100 μg/ml for (Str. bovis, Ent. faecalis, Asp. niger)]

Summary

Introduction

Host Defense Peptides (HDPs) are a diverse group of small and cationic peptides that are present in several organisms (Cuperus et al, 2013). Several studies showed that these peptides have additional functions, mainly immunomodulatory ones (Cuperus et al, 2013) They were named as “Host Defense Peptides (HDPs).”. Some reports indicated that HDPs are responsible for differentiation, activation and chemotaxis of leukocytes. They inhibited Lipopolysaccharide (LPS), enhance phagocytosis, DNA uptake and wound healing (Zanetti, 2005; Semple and Dorin, 2012)

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Conclusion