Probiotics down-regulate flaA sigma28 promoter in Campylobacter jejuni

Area of Science:

• Microbiology
• Gastrointestinal Health
• Probiotics

Background:

• Lactobacilli and Bifidobacteria are key gut microbes with potential health benefits.
• Probiotics are increasingly used, but scientific evidence for their efficacy is limited.
• Campylobacter jejuni is a significant pathogen affecting gastrointestinal health.

Purpose of the Study:

• To investigate the impact of fermented milk extracts from probiotic bacteria on Campylobacter jejuni growth and gene expression.
• To assess the modulation of the flaA gene in C. jejuni by probiotic strains.

Main Methods:

• Utilized cell-free extracts from milk fermented by ten probiotic strains (five Bifidobacterium, five Lactobacillus).
• Assessed C. jejuni growth inhibition by these extracts.
• Measured flaA gene expression using a luxCDABE reporter system linked to the flaA sigma28 promoter.

Main Results:

• All tested probiotic fermented milk extracts inhibited C. jejuni growth.
• Probiotic extracts significantly down-regulated the flaA sigma28 promoter activity in C. jejuni.
• Non-probiotic strains (Lactococcus lactis, Streptococcus thermophilus) showed less inhibition.

Conclusions:

• Cell-free extracts from fermented milk containing Lactobacilli and Bifidobacteria demonstrate antimicrobial effects against C. jejuni.
• These probiotics can suppress the expression of the C. jejuni flaA gene, a key virulence factor.
• Findings support the potential of specific probiotics in managing C. jejuni infections.