Pharmaceuticals (Jul 2022)

Novel Antimicrobial Peptide “Octoprohibitin” against Multidrug Resistant <i>Acinetobacter baumannii</i>

  • E. H. T. Thulshan Jayathilaka,
  • Dinusha C. Rajapaksha,
  • Chamilani Nikapitiya,
  • Joeun Lee,
  • Mahanama De Zoysa,
  • Ilson Whang

DOI
https://doi.org/10.3390/ph15080928
Journal volume & issue
Vol. 15, no. 8
p. 928

Abstract

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Octoprohibitin is a synthetic antimicrobial peptide (AMP), derived from the prohibitin-2 gene of Octopus minor. It showed substantial activity against multidrug resistant (MDR) Acinetobacter baumannii with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 200 and 400 µg/mL, respectively. Time-kill kinetics and bacterial viability assays confirmed the concentration-dependent antibacterial activity of octoprohibitin against A. baumannii. The morphology and ultrastructure of A. baumannii were altered by treatment with octoprohibitin at the MIC and MBC levels. Furthermore, propidium iodide-fluorescein diacetate (PI-FDA) staining and 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) staining of octoprohibitin-treated A. baumannii revealed membrane permeability alterations and reactive oxygen species (ROS) generation, respectively. Agarose gel retardation results confirmed the DNA-binding ability of octoprohibitin to the genomic DNA of A. baumannii. Furthermore, octoprohibitin showed concentration-dependent inhibition of biofilm formation and eradication. The minimum biofilm inhibition concentration (MBIC) and minimum biofilm eradication concentration (MBEC) of octoprohibitin were 1000 and 1460 µg/mL, respectively. Octoprohibitin produced no significant cytotoxicity up to 800 µg/mL, and no hemolysis was observed up to 400 µg/mL. Furthermore, in vivo analysis in an A. baumannii-infected zebrafish model confirmed the effective bactericidal activity of octoprohibitin with higher cumulative survival percent (46.6%) and fewer pathological signs. Histological analysis showed reduced alterations in the gut, kidney, and gill tissues in the octoprohibitin-treated group compared with those in the phosphate-buffered saline (PBS)-treated group. In conclusion, our results suggest that octoprohibitin is a potential antibacterial and antibiofilm agent against MDR A. baumannii.

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