Streamlining Bacillus Strain Selection Against Listeria monocytogenes Using a Fluorescence-Based Infection Assay...

Area of Science:

• Food microbiology
• Probiotics
• Bacterial pathogenesis

Background:

• Listeria monocytogenes poses a significant public health risk as a foodborne pathogen.
• Its ability to invade host cells necessitates strategies to control its spread and impact.

Purpose of the Study:

• To develop and validate a screening pipeline for identifying probiotic Bacillus strains.
• To assess the efficacy of these strains against Listeria monocytogenes.

Main Methods:

• Screened 26 Bacillus isolates for antimicrobial activity, gastrointestinal resilience, and cell adhesion.
• Utilized a fluorescence-based assay to evaluate cytoprotection against L. monocytogenes.
• Validated promising strains in vitro and in vivo using a murine listeriosis model.

Main Results:

• Bacillus subtilis CECT 8266 demonstrated complete inhibition of intracellular L. monocytogenes replication.
• In vivo studies showed a 6-fold reduction in splenic bacterial burden.
• Genomic analysis revealed bacteriocin clusters and identified safety-related genetic elements.

Conclusions:

• The developed pipeline efficiently identifies probiotic Bacillus strains with protective capabilities.
• Bacillus subtilis CECT 8266 shows significant potential for food safety and health applications due to its demonstrated efficacy, resilience, and safety.