The Virulence Factor LLO of <i>Listeria monocytogenes</i> Can Hamper Biofilm Formation and Indirectly Suppress Phage-Lytic Effect
<i>Listeria monocytogenes</i> is a life-threatening bacterial foodborne pathogen that can persist in food-processing facilities for years. Although phages can control <i>L. monocytogenes</i> during food production, phage-resistant bacterial subpopulations can regrow in phage-...
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Foods |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2304-8158/14/15/2554 |
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| Summary: | <i>Listeria monocytogenes</i> is a life-threatening bacterial foodborne pathogen that can persist in food-processing facilities for years. Although phages can control <i>L. monocytogenes</i> during food production, phage-resistant bacterial subpopulations can regrow in phage-treated environments. In this study, an <i>L. monocytogenes hly</i> defective strain, NJ05-Δ<i>hly</i>, was produced, which considerably regulated the interactions between <i>L. monocytogenes</i> and phages. Specifically, we observed a 76.92-fold decrease in the efficiency of plating of the defective strain following infection with the <i>Listeria</i> phage vB-LmoM-NJ05. The lytic effect was notably diminished at multiplicities of infection of 1 and 10. Furthermore, the inactivation of LLO impaired biofilm formation, which was completely suppressed and eliminated following treatment with 10<sup>8</sup> PFU/mL of phage. Additionally, phages protected cells from mitochondrial membrane damage and the accumulation of mitochondrial reactive oxygen species induced by <i>L. monocytogenes</i> invasion. Transcriptomic analysis confirmed these findings, revealing the significant downregulation of genes associated with phage sensitivity, pathogenicity, biofilm formation, and motility in <i>L. monocytogenes</i>. These results underscore the vital role of LLO in regulating the pathogenicity, phage susceptibility, and biofilm formation of <i>L. monocytogenes</i>. These observations highlight the important role of virulence factors in phage applications and provide insights into the potential use of phages for developing biosanitizers. |
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| ISSN: | 2304-8158 |