Peptide-Based Formulation from Lactic Acid Bacteria Impairs the Pathogen Growth in Ananas Comosus (Pineapple)

Abstract

Worldwide, street vending commerce has grown exponentially, representing in some countries, including Ecuador, a significant proportion of food consumed by the urban population. Pineapple is one of the common fruits sold as ready-to-eat slices by ambulant vendors in the street or on public transport at risk of contamination by various microorganisms. Previously, we selected Lactobacillus plantarum UTNCys5-4 and Lactococcus lactis subsp. lactis Gt28 strains producing peptides with high capacity to inhibit pathogen growth in vitro. In this study, the effect of different edited formulations containing a mixture of Cys5-4/Gt28 peptides was evaluated in vitro and ex vitro against a pathogenic cocktail containing E. coli (2), Salmonella (2) and Shigella (1). The growth of bacterial cocktail co-inoculated with cell-free supernatant containing peptides (formulation T1) and precipitated peptides (formulation T6), in a ratio of Cys5-4/Gt28:1:1 (v/v), results in a decrease of total cell viability with 1.85 and 1.2 log CFU/mL orders of magnitude at 6 h of incubation. About the same decrease (1.9 log CFU/g) was observed when pineapple slices artificially inoculated with the pathogenic cocktail were coated with T1 formulation, indicating the capacity to diminish simultaneous pathogens in situ, thus demonstrating its great biological control and protection. However, the E. coli cell counts reduced by 2.08 log CFU/g while Salmonella and Shigella cell counts reduced by 1.43 and 1.91 log CFU/g, respectively, at 5 days of refrigeration. In the untreated pineapple slices, the total cell density was maintained during storage, suggesting the adaptation of the pathogens to the fruit matrix. The peptide-based formulation exerted a bacteriolytic mode of action inducing pathogenic cell death. The results indicate that coating pineapple slices with peptide-based formulation is a promising approach to protect them from further contamination by microbial spoilage as well as an alternative to increase the food safety.

Peptide Extracts from Native Lactic Acid Bacteria Generate Ghost Cells and Spheroplasts upon Interaction with Salmonella enterica, as Promising Food Antimicrobials

“…Filamentation can occur following inhibition or disruption of peptidoglycan synthesis, DNA synthesis inhibition, or damage by a SOS response process [ 34 ]. This result might explain our recent findings showing the effectiveness of the peptide-based formulations containing Gt28 and Cys5-4 peptide extracts in diminishing the cell viability of a pathogenic cocktail consisting of Salmonella sp., Shigella sp., and E. coli cells at the exponential growth phase [ 35 ]. In addition, we demonstrated the grate potential of these peptide-based formulations in the control and protection of pathogenic growth in pineapple fresh-cut chunks.…”

A Novel Weissella cibaria Strain UTNGt21O Isolated from Wild Solanum quitoense Fruit: Genome Sequence and Characterization of a Peptide with Highly Inhibitory Potential toward Gram-Negative Bacteria

“…The spherical shape structure of bacteria is the effect of membrane tension that preserves its outer membrane but has lost the peptidoglycans layer. The production of spheroplasts upon Salmonella cells treated with a combination of peptides from LAB was recently observed [ 21 ]. The untreated E. coli cells were shaped with no damage to the structure of the plasma membrane or the outer membrane, and the cytoplasm appeared to have homogeneous electron density ( Figure 7 A).…”

“…For TEM analysis, the exponential-phase E. coli ATCC25922 and Salmonella enterica subsp. enterica ATCC51741 (1 × 10 8 CFU/mL) cells were treated with 1×, 1.5× and 2× MIC of the peptide UTNGt21O for 6 h at 37 • C following the protocol as previously described [21]. Ultrathin sections were prepared and coated on copper grids and stained with uranyl acetate (Sigma-Aldrich Co. LLC, Saint Louis, MO, USA) and lead citrate (Sigma-Aldrich Co. LLC, Saint Louis, MO, USA).…”

“…After the complete genome was assembled, BLAST analysis was carried out to identify to which species each scaffold showed similarity. Out of 31 contigs analyzed 20 contigs hits matched the core genome of different groups within Weissella and for 11 contigs (15,17,21,23,24,(26)(27)(28)(29)(30)(31) no match was shown in database ( Table S4). The largest contig 1 of the subject query (UTNGt21O) hits W. cibaria genome with an 83 percentage of identity with no gaps (0).…”

Lactic Acid Bacteria as Antibacterial Agents to Extend the Shelf Life of Fresh and Minimally Processed Fruits and Vegetables: Quality and Safety Aspects

“…lactis Gt28 strains against a pathogenic cocktail containing E. coli , Salmonella and Shigella in fresh-cut slices of pineapple. The results, after 5 days preserved in refrigeration, showed a decrease in cell counts of 2.08 log CFU/g, 1.43 log CFU/g, and 1.91 log CFU/g for the E. coli , Salmonella, and Shigella, respectively, indicating that these coatings are a good alternative to chemical compounds, increasing the shelf life and safety of fresh-cut pineapple [ 170 ]. Moreover, coatings with antimicrobial peptides from Lactobacillus plantarum UTNGt2 were used for inhibition of E. coli and Salmonella and the estimation of postharvest quality in fresh tomatoes.…”