Current Knowledge of the Mode of Action and Immunity Mechanisms of LAB-Bacteriocins

Abstract

Bacteriocins produced by lactic acid bacteria (LAB-bacteriocins) may serve as alternatives for aging antibiotics. LAB-bacteriocins can be used alone, or in some cases as potentiating agents to treat bacterial infections. This approach could meet the different calls and politics, which aim to reduce the use of traditional antibiotics and develop novel therapeutic options. Considering the clinical applications of LAB-bacteriocins as a reasonable and desirable therapeutic approach, it is therefore important to assess the advances achieved in understanding their modes of action, and the resistance mechanisms developed by the producing bacteria to their own bacteriocins. Most LAB-bacteriocins act by disturbing the cytoplasmic membrane through forming pores, or by cell wall degradation. Nevertheless, some of these peptides still have unknown modes of action, especially those that are active against Gram-negative bacteria. Regarding immunity, most bacteriocin-producing strains have an immunity mechanism involving an immunity protein and a dedicated ABC transporter system. However, these immunity mechanisms vary from one bacteriocin to another.

Microbial Ecology of Sheep Milk, Artisanal Feta, and Kefalograviera Cheeses. Part II: Technological, Safety, and Probiotic Attributes of Lactic Acid Bacteria Isolates

“…Indeed, the capability of LAB to produce an extended variety of antimicrobial compounds is well established. Among them, production and application of proteinaceous antimicrobial compounds in food biopreservation have drawn specific attention over the last decades [13,14]. Hemolytic and gelatinase activities contribute to virulence of enterococci.…”

Combinations of Peptide-Protein Extracts from Native Probiotics Suppress the Growth of Multidrug-Resistant Staphylococcus aureus and Citrobacter freundii via Membrane Perturbation and Ultrastructural Changes

“…Being larger than peptides these mixture of molecules might be considered “wall breakers”, explaining their activity against multidrug resistant strains, but further analysis is required to detect all the molecules (small and larger) in the extract. According to recent reports, enterolisyn A bacteriocin belongs to this category, acting at the cell wall level inducing the cleavage of the peptide bridge between L-alanine and D-glutamic acid which might explain the antimicrobial effect [ 19 ]. From the genome analysis, the UTNGt21A strain harbor a gene similar to enterolisyn A (data not published) along with other bacteriocin encoding genes that might explain its inhibitory activity and distinct ultrastructural modifications than UTNGt2.…”

“…AMPs are widely used in the food industry as biopreservatives due to their ability to reduce microbial growth and control deterioration in many foods, improving their shelf life without compromising the quality, managing to satisfy consumer demand for safe and secure food [ 17 ]. Thus, AMPs are considered as an alternative to antibiotics against resistant strains [ 18 , 19 ].…”

Anti-adhesion and Anti-inflammatory Potential of the Leaderless Class IIb Bacteriocin Enterocin DD14

“…Bacteriocins produced by LAB, designed therefore LAB-bacteriocins, continue to be subjected to intensive studies in both academic and applied fields. LAB-bacteriocins have been described to have either a narrow or a broad spectrum of action [ 6 , 7 ]. Despite the number of bacteriocins so far characterized, no common classification is approved by the scientific community.…”