Antibacterial Activity of Subtilosin Alone and Combined with Curcumin, Poly-Lysine and Zinc Lactate Against Listeria monocytogenes Strains

Abstract

In this paper, the antibacterial effects of the Bacillus amyloliquefaciens-produced bacteriocin subtilosin, both alone and in combination with curcumin, ε-poly-L-lysine (poly-lysine), or zinc lactate, were examined against Listeria monocytogenes. Results indicated that subtilosin inhibits both of the studied bacterial strains, Scott A (wild-type, nisin sensitive) and NR30 (nisin resistant). However, L. monocytogenes Scott A was more sensitive to subtilosin and pure curcumin. In addition, subtilosin was more active at an acidic pH. Subtilosin in combination with encapsulated curcumin displayed partial synergy against L. monocytogenes ScottA. It also had synergistic activity against both L. monocytogenes Scott A and L. monocytogenes NR30 when combined with zinc lactate. Only an additive effect was observed for subtilosin when combined with non-encapsulated curcumin or poly-lysine against the mentioned strains. Thus, using the combination of subtilosin with curcumin, poly-lysine, or zinc lactate, a lower effective dose can be used to control L. monocytogenes infection. Our findings suggest that subtilosin could be used as alternative bacteriocin to nisin, providing an opportunity to use a novel natural and efficacious biopreservative against L. monocytogenes in food preservation. This is the first report on the effects of the combination of subtilosin with natural antimicrobials on L. monocytogenes.

The Natural Antimicrobial Peptide Subtilosin Acts Synergistically with Glycerol Monolaurate, Lauric Arginate, and ε-Poly- l -Lysine against Bacterial Vaginosis-Associated Pathogens but Not Human Lactobacilli

“…The third antimicrobial compound, polylysine, was previously demonstrated to synergize with both nisin and subtilosin against the food-borne pathogen Listeria monocytogenes (1,5), supporting the possibility of synergy with subtilosin against G. vaginalis. As previously described, an isobologram was constructed using the individual MICs of subtilosin and polylysine ( Table 1).…”

“…Considering the multitude of health risks associated with BV, ideally, there would be a low possibility of BV-associated organisms developing resistance to these new alternatives. The multiple-hurdle approach is therefore ideal, since it uses combinations of synergistic substances in concentrations lower than their individual effective doses (1). The use of more than one antimicrobial, especially those with differing mechanisms of action, makes it very difficult for the pathogen to overcome each "hurdle" and lowers the chances of significant numbers of cells surviving (5).…”

“…Badaoui Najjar et al (5) showed that nisin, a bacteriocin generally recognized as safe (GRAS) for several food preservation purposes, acts syner-gistically with -poly-L-lysine (hereafter referred to as polylysine) against the food-borne pathogens Listeria monocytogenes and Bacillus cereus. On a related note, Amrouche et al (1) demonstrated that subtilosin has synergy with nano-encapsulated curcumin, a plant phytochemical with antimicrobial activity, zinc lactate, and polylysine against L. monocytogenes.…”

A Review on Antibacterial, Antiviral, and Antifungal Activity of Curcumin

“…aureus ATCC 25923 strain. Bacteriocin subtilosin isolated from B. amyloliquefaciens in combination with encapsulated curcumin revealed partial synergism against wild-type and nisin sensitive strains of L. monocytogenes Scott A [48]. In another in vivo study using 500  μ g/disc of curcumin against clinical isolate of Staph.…”

Bacteriocins and their position in the next wave of conventional antibiotics

“…polylysine against the bacterial vaginosis-associated pathogen Gardnerella vaginalis [91][92][93]. Furthermore, it has been shown that the two-peptide lacticin 3147 synergistically interacts with polymyxin to inhibit Cronobacter spp.…”