Skip to main content

ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Antimicrobials, Resistance and Chemotherapy
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1506851
This article is part of the Research Topic Innovation in Tackling the Global Challenge of Eradicating Antibiotic-Resistant Microorganisms View all 5 articles

The Black Soldier Fly (Hermetia illucens) Larva presented an Antimicrobial Activity in Response to Clostridioides difficile Exposure

Provisionally accepted
Aviel Melchior Aviel Melchior 1Maya Azrad Maya Azrad 1Boris Fichtman Boris Fichtman 2Avi Peretz Avi Peretz 1*
  • 1 The Baruch Padeh Medical Center, Poriya, Poriah, Israel
  • 2 Faculty of Medicine, Bar-Ilan University, Safed, Tel Aviv, Israel

The final, formatted version of the article will be published soon.

    Background: Clostridioides difficile (C. difficile) infection (CDI) is the primary cause of antibioticassociated diarrhea. Due to its high resistance rate to antibiotics, there is a need for new treatments. Antimicrobial peptides (AMPs) are considered an alternative treatment for various infectious diseases. The black soldier fly (BSF, Hermetia illucens) has one of the largest AMP repertoires among insects. This study evaluated the activity of BSF hemolymph-extracted AMPs, with particular focus on defensin-like peptide 4 (DLP4), against C. difficile isolates.Methods: BSF larvae (BSFL) were injected or fed with pathogenic C. difficile strain 630. The effects of post-infection hemolymph and of synthetic AMPs on 18 clinical antibiotic-resistant C. difficile isolates were assessed by the disk diffusion test. Disk diffusion was also used to determine the minimal inhibitory concentration (MIC) of DLP4 for various C. difficile isolate subcategories. Realtime PCR was conducted to measure expression levels of five hemolymph AMP genes (DLP4, DLP3, CLP1, AttB, STX) in infected larvae. Bacterial cell counts were measured after DLP4 exposure and cytotoxicity of DLP4 against Caco-2 epithelial cells was tested using the XTT method. Bacterial outer layer damage was evaluated by scanning electron microscopy.Results: Hemolymph extracted from C. difficile -infected BSFL had a major inhibitory effect on C. difficile growth. The gene expression levels of all five AMPs were increased following exposure to pathogenic C. difficile. In-vitro evaluation of the five AMPs demonstrated that DLP4 had the greatest antimicrobial effects on C. difficile. DLP4 MICs ranged between 64-250 µg/ml for the different clinical isolates. DLP4 proved bactericidal activity, with a rapid onset of action (1 hour), inducing holes in the bacterial outer layer, while it had no cytotoxic effect on human epithelial cells.The antimicrobial peptide DLP4 from BSF hemolymph bears antimicrobial properties against different antibiotic-resistant C. difficile isolates. DLP4 may represent a promising and novel approach for the treatment of C. difficile infections.

    Keywords: BSF, antimicrobial peptides, DLP4, C. difficile, antibiotic resistance

    Received: 06 Oct 2024; Accepted: 31 Dec 2024.

    Copyright: © 2024 Melchior, Azrad, Fichtman and Peretz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Avi Peretz, The Baruch Padeh Medical Center, Poriya, Poriah, Israel

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.