The Potential of Class II Bacteriocins to Modify Gut Microbiota to Improve Host Health

Abstract

Production of bacteriocins is a potential probiotic feature of many lactic acid bacteria (LAB) as it can help prevent the growth of pathogens in gut environments. However, knowledge on bacteriocin producers in situ and their function in the gut of healthy animals is still limited. In this study, we investigated five bacteriocin-producing strains of LAB and their isogenic non-producing mutants for probiotic values. The LAB bacteriocins, sakacin A (SakA), pediocin PA-1 (PedPA-1), enterocins P, Q and L50 (enterocins), plantaricins EF and JK (plantaricins) and garvicin ML (GarML), are all class II bacteriocins, but they differ greatly from each other in terms of inhibition spectrum and physicochemical properties. The strains were supplemented to mice through drinking water and changes on the gut microbiota composition were interpreted using 16S rRNA gene analysis. In general, we observed that overall structure of the gut microbiota remained largely unaffected by the treatments. However, at lower taxonomic levels, some transient but advantageous changes were observed. Some potentially problematic bacteria were inhibited (e.g., Staphylococcus by enterocins, Enterococcaceae by GarML, and Clostridium by plantaricins) and the proportion of LAB was increased in the presence of SakA-, plantaricins- and GarML-producing bacteria. Moreover, the treatment with GarML-producing bacteria co-occurred with decreased triglyceride levels in the host mice. Taken together, our results indicate that several of these bacteriocin producers have potential probiotic properties at diverse levels as they promote favorable changes in the host without major disturbance in gut microbiota, which is important for normal gut functioning.

Modulation of the gut microbiota by prebiotic fibres and bacteriocins

“…The bacteriocins are produced by food- or gut-associated LAB and belong to different subclasses of class II bacteriocins: sakacin A (class IIa), pediocin PA-1 (class IIa), enterocins P, Q and L50 (class IIb and IId), plantaricins EF and JK (class IIb) and garvicin ML (class IIc) [94]. When analysing the microbial community in faeces, it was observed that the overall structure remained largely unaffected in different treatments.…”

“… a   Observations in the presence of bacteriocin-producing strains only; b  observations in the presence of both bacteriocin-producing and non-bacteriocin-producing strains.LAB, lactic acid bacteria.Adapted from [94]. …”

“…They do not exert major disturbances on the commensal gut microbiota, which is important for normal gut functioning. For example, pediocin PA-1, which is very active against pathogenic Listeria spp., does not cause major changes to the gut microbiota in healthy mice or in vitro [94,96]. In addition, the great diversity of bacteriocins, in terms of their antimicrobial spectra and target specificity, can provide us with the opportunity to select certain bacteriocins with defined properties to deal with a specific pathogen or a group of pathogens.…”

Functional potential of bacterial strains in the premature infant gut microbiome is associated with gestational age

“…By analyzing the metabolic potential of each genome, we found evidence that the extent of prematurity, either directly or indirectly, can affect the gut microbiome. Given evidence that a lower gestational age may limit bacteriocin and vitamin production, which are factors that can impact community structure and lead to inflammation 30,31 , these findings may inform our understanding of diseases associated with dysbiosis of the microbiome, especially in very premature infants.…”

Toxin-mediated competition in weakly motile bacteria

“…A true inhibition zone is depicted in Figure 2(c), where the toxin strength has been increased past κ * ; here x R has again been set to its maximum, and therefore x 0 takes its minimum value, i.e. the size of the inhibition zone (29).…”