Listeria monocytogenes Flagella Are Used for Motility, Not as Adhesins, To Increase Host Cell Invasion Original paper
Researched by:
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Divine Aleru
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Divine Aleru
Read MoreI am a biochemist with a deep curiosity for the human microbiome and how it shapes human health, and I enjoy making microbiome science more accessible through research and writing. With 2 years experience in microbiome research, I have curated microbiome studies, analyzed microbial signatures, and now focus on interventions as a Microbiome Signatures and Interventions Research Coordinator.
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Microbes
Microbes
Microbes are microscopic organisms living in and on the human body, shaping health through digestion, vitamin production, and immune protection. When microbial balance is disrupted, disease can occur. This guide explains key microbe types—bacteria, viruses, fungi, protozoa, and archaea—plus major pathogenic and beneficial examples.
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Divine Aleru
Read More
Researched by:
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Divine Aleru
ID
Divine Aleru
Read More
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Divine Aleru
What was studied?
This study examined the role of flagella in Listeria monocytogenes invasion of host cells, focusing on whether flagella function as adhesins or are primarily used for motility to increase host cell invasion. The study utilized both motile and nonmotile mutants to analyze the effect of flagella on adhesion, invasion, and early colonization of the intestinal tract in mice.
Who was studied?
The study focused on Listeria monocytogenes, specifically analyzing various strains, including motile wild-type strains, nonmotile flagellin-deficient strains (flaA mutants), and flagellated but nonmotile strains (motBD23A mutants). Human epithelial cells (Caco-2) were used for adhesion and invasion assays, and mice were used for in vivo infection studies.
What were the most important findings?
The study concluded that flagella in Listeria monocytogenes do not function as adhesins but are essential for motility, which significantly enhances invasion into human epithelial cells. While flagellated bacteria did not adhere better to host cells than nonflagellated bacteria, motility was crucial for invasion, as nonmotile bacteria showed reduced invasion capabilities. Additionally, the presence of flagella increased the ability of Listeria to outcompete nonmotile strains during early colonization of the mouse intestines and liver, suggesting that motility facilitates initial tissue colonization after oral infection. Flagellated but nonmotile bacteria did not show increased adhesion or invasion, indicating that the physical force generated by motility aids in host cell invasion. Overall, the flagellar filament functions as a motility device rather than as an adhesion factor, and motility is important for effective Listeria monocytogenes infection, particularly at early stages.
What are the greatest implications of this study?
This study has important implications for understanding the pathogenicity of Listeria monocytogenes and its ability to cause infection. The findings suggest that interventions targeting flagella-mediated motility could help reduce Listeria’s ability to invade host tissues, offering potential strategies for controlling Listeria infections. Additionally, understanding that flagella are not adhesins challenges previous assumptions about how Listeria adheres to host cells and provides new insights into the role of bacterial motility in infection. The study also highlights the need to consider motility in the development of new therapeutic approaches and food safety measures to combat foodborne pathogens like Listeria monocytogenes.
Listeria monocytogenes
Listeria monocytogenes is an opportunistic pathogen capable of surviving in diverse environments, including soil, water, and decaying vegetation. L. monocytogenes has the unique ability to evade the immune system by moving directly from cell to cell within the host. This intracellular lifestyle allows the bacterium to avoid extracellular immune detection, contributing to its ability to cause invasive diseases like meningitis and septicemia, particularly in the elderly and immunocompromised.