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Published on: September 30, 2014
The safe enterocin DD14 is a leaderless two-peptide bacteriocin with anti-Clostridium perfringens activity
Delphine L Caly1, Mickaël Chevalier1, Christophe Flahaut2
1Univ. Lille, INRA, Univ. Artois, Univ. Littoral Côte d'Opale, EA 7394 - ICV - Institut Charles Viollette, F-59000 Lille, France.
Abstract:
Enterococcus faecalis 14, a strain previously isolated from meconium, displayed activity against four Clostridium perfringens isolates when co-cultured on agar plates. The anti-Clostridium activity was ascribed to the production of enterocin DD14, which was subsequently purified. The minimum inhibitory concentration (MIC) of enterocin DD14 against one collection strain and one clinical C. perfringens strain was determined at 50 µg/mL. Furthermore, using the intestinal epithelial cell line IPEC-1, it was shown that E. faecalis 14 was not cytotoxic after 24 h of contact, and no cytotoxicity was observed when IPEC-1 cells were incubated with pure enterocin DD14 for 4 h. Enterocin DD14 was characterised using mass spectrometry and was shown to consist of two small proteins of 5200.74 Da and 5206.41 Da, respectively. The two peptides (DD14A and DD14B) have highly similar amino acid sequences and no signal peptide, which classifies enterocin DD14 as a class IIb leaderless two-peptide bacteriocin. The genes encoding DD14A and DD14B were sequenced and were shown to be 100% identical to other previously described enterocins MR10A and MR10B, in contrast to the producing strains, which are different. Consequently, the present in vitro study supports the potential of this E. faecalis 14 strain and/or its purified enterocin DD14 as putative anti-C. perfringens compounds in chickens.
Insights
Enterococcus faecalis 14 produces enterocin DD14, a bacteriocin effective against Clostridium perfringens. This non-cytotoxic compound shows potential as an anti-C. perfringens agent for chickens.
Area of Science:
- Microbiology
- Bacteriology
- Food Safety
Background:
- Clostridium perfringens is a significant pathogen in poultry.
- Bacteriocins are antimicrobial peptides with potential to control bacterial infections.
- Enterococcus faecalis is a known producer of bacteriocins.
Purpose of the Study:
- To investigate the anti-Clostridium activity of Enterococcus faecalis 14.
- To characterize the bacteriocin produced by E. faecalis 14.
- To evaluate the safety and efficacy of E. faecalis 14 and its bacteriocin as potential anti-C. perfringens agents in chickens.
Main Methods:
- Co-culturing E. faecalis 14 with C. perfringens isolates on agar plates.
- Purification and characterization of enterocin DD14 using mass spectrometry.
- Determination of minimum inhibitory concentration (MIC) and cytotoxicity assays using IPEC-1 cell line.
- Sequencing of genes encoding enterocin DD14 peptides.
Main Results:
- E. faecalis 14 demonstrated significant anti-Clostridium activity.
- Enterocin DD14, composed of two peptides (DD14A and DD14B), was purified.
- MIC of enterocin DD14 was 50 µg/mL against C. perfringens.
- E. faecalis 14 and enterocin DD14 showed no cytotoxicity to IPEC-1 cells.
- Enterocin DD14 is a class IIb leaderless two-peptide bacteriocin.
Conclusions:
- Enterococcus faecalis 14 and its enterocin DD14 exhibit promising anti-C. perfringens activity.
- The non-cytotoxic nature of enterocin DD14 supports its potential use in poultry.
- Further in vitro studies support the application of E. faecalis 14 and enterocin DD14 as anti-C. perfringens compounds in chickens.
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