Antimicrobial Peptides Produced by Bacteria: The Bacteriocins

Abstract

Bacteriocins are the subset of antimicrobial peptides (AMPs) produced by bacteria. They are small amphipathic peptides that interact with bacterial membranes leading to cell death. Most of the best known are produced by lactic acid bacteria used as food fermentation starters, because of their potential use as food preservatives. Bacteriocins are divided into two groups: lantibiotics that present posttranslational condensation rings and unmodified peptides. The first are subdivided into elongated versus globular lantibiotics, while four subgroups are recognized among unmodified bacteriocins. The genetic organization is in clusters that may reside into plasmids or transposons, formed by the structural gene, the export and immunity determinants, the quorum sensing governing production and any modification genes. Bacteriocins are active at extremely low concentrations (nM range) due to a dual mode of action: (a) binding to the membrane phospholipids and (b) specific recognition of surface components, both of which collaborate in pore formation. Development of resistance to bacteriocins is very infrequent due to the presence of two targets and is usually due to unspecific modifications of the cell envelope. Bacteriocins are used as food preservatives, either after total or partial purification or as extracts of producing bacteria. In situ production is also used, with the advantage of producing early lysis of the starter bacteria and ripening acceleration of the fermented product. They may also form part of hurdle technologies and be incorporated into packaging systems to allow extended liberation. Medical and veterinary applications are in their infancy but good results have been obtained against infection by Gram-positive bacteria and Helicobacter pylori.

Bacteriocins, Antimicrobial Peptides from Bacterial Origin: Overview of Their Biology and Their Impact against Multidrug-Resistant Bacteria

“…Bacteriocins received a lot of interest as potential antimicrobial agents against different bacterial, fungal and viral species [10][11][12], and even against natural resistant structures such as bacterial biofilms [13,14]. These natural ribosomally synthetized peptides are produced by bacteria living in a competitive polymicrobial environment and are used to eliminate other bacterial species, particularly closely related ones [15][16][17]. Thus, the diversity of the different bacteriocins among bacteria provide a broad spectrum of activity [18][19][20].…”

Antibacterial and antifungal activity of crude and freeze-dried bacteriocin-like inhibitory substance produced by Pediococcus pentosaceus

“…The strain-dependent efficiency of CB or water-diluted BLIS may be explained by interaction between BLIS and plasma membrane and consequent formation of pores, which is a common occurrence among most LAB bacteriocins. BLIS may have also interacted with receptors or docking molecules, in a specific way for a specific strain depending on its membrane lipid composition and membrane potential threshold 49 , abrogating essential cell pathways which account for BLIS potency 50 . At the other BLIS dilutions (1:10, 1:50 and 1:100, v/v), L. innocua showed growth (logCFU/mL = 8.22 ± 0.00, 8.11 ± 0.29, 8.11 ± 0.31, respectively) similar to that in the control (logCFU/mL = 8.25 ± 0.06).…”

Sorting out the Superbugs: Potential of Sortase A Inhibitors among Other Antimicrobial Strategies to Tackle the Problem of Antibiotic Resistance

“…Bacteriocins are highly potent bactericidal agents representing a subclass of antimicrobial peptides produced by bacteria. In general terms these can be classified as either post-translationally modified (class I) or made up of peptides with unmodified amino acids (class II) [ 45 ]. The discovery of bacteriocins is attributed to André Gratia, who described the first bacteriocin (colicin V) produced by verotoxin-producing E. coli strain to act against other nearby E. coli in 1925 [ 46 ].…”