Dataset Information

Lactobacillus casei expressing Internalins A and B reduces Listeria monocytogenes interaction with Caco-2 cells in vitro.

ABSTRACT: Listeria monocytogenes has been implicated in a number of outbreaks including the recent largest outbreak in South Africa. Current methods for prevention of foodborne L. monocytogenes infection are inadequate, thus raising a need for an alternative strategy. Probiotic bioengineering is considered a prevailing approach to enhance the efficacy of probiotics for targeted control of pathogens. Here, the ability of Lactobacillus casei expressing the L. monocytogenes invasion proteins Internalins A and B (inlAB) to prevent infection was investigated. The inlAB operon was cloned and surface-expressed on L. casei resulting in a recombinant strain, LbcInl AB , and subsequently, its ability to inhibit adhesion, invasion and translocation of L. monocytogenes through enterocyte-like Caco-2 cells was examined. Cell surface expression of InlAB on the LbcInl AB was confirmed by Western blotting and immunofluorescence staining. The LbcInl AB strain showed significantly higher (P < 0.0001) adherence, invasion and translocation of Caco-2 cells than the wild-type L. casei strain (LbcWT ), as well as reduced L. monocytogenes adhesion, invasion and transcellular passage through the cell monolayer than LbcWT . Furthermore, pre-exposure of Caco-2 cells to LbcInl AB significantly reduced L. monocytogenes-induced cell cytotoxicity and epithelial barrier dysfunction. These results suggest that InlAB-expressing L. casei could be a potential practical approach for prevention of listeriosis.

SUBMITTER: Mathipa MG

PROVIDER: S-EPMC6559204 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Lactobacillus casei expressing Internalins A and B reduces Listeria monocytogenes interaction with Caco-2 cells in vitro.

Mathipa Moloko G MG Thantsha Mapitsi S MS Bhunia Arun K AK

Microbial biotechnology 20190415 4

Listeria monocytogenes has been implicated in a number of outbreaks including the recent largest outbreak in South Africa. Current methods for prevention of foodborne L. monocytogenes infection are inadequate, thus raising a need for an alternative strategy. Probiotic bioengineering is considered a prevailing approach to enhance the efficacy of probiotics for targeted control of pathogens. Here, the ability of Lactobacillus casei expressing the L. monocytogenes invasion proteins Internalins A an ...[more]

PMID: 30989823

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Project description:BackgroundListeria monocytogenes, an intracellular foodborne pathogen, infects immunocompromised hosts. The primary route of transmission is through contaminated food. In the gastrointestinal tract, it traverses the epithelial barrier through intracellular or paracellular routes. Strategies to prevent L. monocytogenes entry can potentially minimize infection in high-risk populations. Listeria adhesion protein (LAP) aids L. monocytogenes in crossing epithelial barriers via the paracellular route. The use of recombinant probiotic bacteria expressing LAP would aid targeted clearance of Listeria from the gut and protect high-risk populations from infection.Methodology/principal findingsThe objective was to investigate the ability of probiotic bacteria or LAP-expressing recombinant probiotic Lactobacillus paracasei (Lbp(LAP)) to prevent L. monocytogenes adhesion, invasion, and transwell-based transepithelial translocation in a Caco-2 cell culture model. Several wild type probiotic bacteria showed strong adhesion to Caco-2 cells but none effectively prevented L. monocytogenes infection. Pre-exposure to Lbp(LAP) for 1, 4, 15, or 24 h significantly (P<0.05) reduced adhesion, invasion, and transepithelial translocation of L. monocytogenes in Caco-2 cells, whereas pre-exposure to parental Lb. paracasei had no significant effect. Similarly, Lbp(LAP) pre-exposure reduced L. monocytogenes translocation by as much as 46% after 24 h. Lbp(LAP) also prevented L. monocytogenes-mediated cell damage and compromise of tight junction integrity. Furthermore, Lbp(LAP) cells reduced L. monocytogenes-mediated cell cytotoxicity by 99.8% after 1 h and 79% after 24 h.Conclusions/significanceWild type probiotic bacteria were unable to prevent L. monocytogenes infection in vitro. In contrast, Lbp(LAP) blocked adhesion, invasion, and translocation of L. monocytogenes by interacting with host cell receptor Hsp60, thereby protecting cells from infection. These data show promise for the use of recombinant probiotics in preventing L. monocytogenes infection in high-risk populations.

Project description:Various Listeria monocytogenes strains may contaminate a single food potentially resulting in simultaneous exposure of consumers to multiple strains. However, L. monocytogenes strains isolated from foods by selective enrichment (SE) might not always represent those that can better survive a patient immune system, due to bias in strain recovery. We investigated the effect of co-cultivation in TSB-Y at 10°C for 8 days on i) the detection of L. monocytogenes strains during SE with the ISO 11290-1:1996/Amd 1:2004 protocol and ii) the in vitro virulence of strains towards the human colon epithelial cancer cell line Caco-2 following exposure to simulated gastric fluid (SGF, pH 2.0/HCl, 37°C). We determined whether the strains, which were favoured by SE, would be effective competitors under challenges related to gastrointestinal passage of the pathogen. Inter-strain competition of L. monocytogenes in TSB-Y determined the relative population of each strain at the beginning of SE. This in turn impacted the outcome of SE (i.e., favoring survival of better fitness competitors) and the levels exposed subsequently to SGF. However, strong growth competitors could be outcompeted after SGF exposure and infection of Caco-2 cells by strains outgrown in TSB-Y and underdetected (or even missed) during enrichment. Our data demonstrate a preferential selection of certain L. monocytogenes strains during enrichments, often not reflecting a selective advantage of strains during infection. These findings highlight a considerable scenario associated with the difficulty to match the source of infection (food) with the L. monocytogenes isolate appearing as the causative agent during listeriosis outbreak investigations.This study is relevant to understanding the processes involved in selection and prevalence of certain L. monocytogenes strains under different environments (i.e foods or sites of humans exposed to the pathogen). It highlights the occurrence of multiple strains in the same food as an important aspect contributing to mismatches between clinical isolates and infection sources during listeriosis outbreak investigations.

Dataset Information

Lactobacillus casei expressing Internalins A and B reduces Listeria monocytogenes interaction with Caco-2 cells in vitro.

Publications

Lactobacillus casei expressing Internalins A and B reduces Listeria monocytogenes interaction with Caco-2 cells in vitro.

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