Exploratory investigation on the antibacterial effect of antimicrobial peptides of four mammalian plasmas



Elyass ME, Mahdi AA, Semeih AE, Eltaib FI, Attitalla IH.


Microb Pathog. 2021 Jul;156:104839. doi: 10.1016/j.micpath.2021.104839. Epub 2021 Mar 6.


Antimicrobial peptides (AMPs) are presently being revisited as promising potential antimicrobial combat agents. Acquisition of resistance to AMPs is very rare compared to conventional antibiotics as they kill microbes by direct disruption of cellular components including the microbial membrane and DNA. In this study four sources of mammalian plasma (human, bovine, caprine and ovine) were explored for presence and effectiveness of antimicrobial peptides by the spot-on-lawn method, followed by the agar well diffusion assay to confirm their antibacterial activity. This was followed by determination of their minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) by the broth macrodilusion method. The MICs were compared to those produced by the antibiotics Ampicillin, Amoxicillin, Doxycycline and Metronidazole. All four plasma types exhibited antibacterial activity in their native form (plasma(N)) or in presence of added pepsin (plasma(p)). The highest antibacterial activity was shown by ovine plasma(p) against Klebsiella pneumoniae (MIC at dilution of 1:128), while least activity (MIC at dilution of 1:2) was shown by bovine plasma(p) and ovine plasma(N) against K. pneumoniae, ovine plasma(N) against E. coli, and ovine plasma(p) against Staph. aureus. All plasma sources achieved bactericidal effect. Activity of ovine plasma(N) against K. pneumoniae was higher than that due to Ampilcillin, Amoxicillin, Doxycycline or Metronidazole. The least antibacterial activity was achieved by Ampicillin against K. pneumoniae, E. coli and Bacillus subtilis. Metronidazole had no effect on any of the four bacteria tested. These results indicate that AMPs hold great promise as a valuable renewed tool in the control of pathogenic microbes. CI – Copyright © 2021. Published by Elsevier Ltd.

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Link/DOI: 10.1016/j.micpath.2021.104839