Control of the Food-Borne Pathogen, Shigella flexneri 1457 by Using a Plant Polyphenol Naringenin

Area of Science:

• Microbiology
• Natural Product Chemistry

Background:

• Shigellosis and bacterial dysentery, caused by Shigella flexneri, are significant health concerns.
• Current antibiotic treatments face limitations due to resistance and health concerns, necessitating novel therapeutic strategies.
• Polyphenols, particularly flavonoids, exhibit promising antibacterial properties and can interfere with bacterial biofilm formation.

Purpose of the Study:

• To investigate the efficacy of naringenin against Shigella flexneri.
• To evaluate naringenin's impact on bacterial growth, biofilm formation, and virulence factors.

Main Methods:

• Minimum inhibitory concentration determination.
• Biofilm inhibition assays.
• Scanning electron microscopy (SEM) for morphological analysis.
• Fluorescent-activated cell sorting (FACS) for cell viability assessment.
• Quantitative reverse transcription PCR (qRT-PCR) for gene expression analysis.

Main Results:

• Naringenin inhibited both growth and biofilm formation of Shigella flexneri at 1000 μg/mL.
• SEM revealed morphological alterations in S. flexneri treated with naringenin.
• FACS indicated an 87.76% increase in dead cells upon naringenin treatment.
• qRT-PCR showed downregulation of adhesion, quorum-sensing, and biofilm development genes.

Conclusions:

• Naringenin demonstrates significant antibacterial and anti-biofilm activity against Shigella flexneri.
• Naringenin disrupts bacterial morphology and increases cell death, suggesting a potent antimicrobial mechanism.
• The downregulation of key virulence genes highlights naringenin's potential as a therapeutic agent for shigellosis.