Related Experiment Video
Updated: Jun 24, 2026
Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes
Published on: August 9, 2011
Listeria monocytogenes genes supporting growth under standard laboratory cultivation conditions and during macrophage
Martin A Fischer1, Tim Engelgeh1, Patricia Rothe1
1FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany.
Abstract:
The Gram-positive bacterium Listeria monocytogenes occurs widespread in the environment and infects humans when ingested along with contaminated food. Such infections are particularly dangerous for risk group patients, for whom they represent a life-threatening disease. To invent novel strategies to control contamination and disease, it is important to identify those cellular processes that maintain pathogen growth inside and outside the host. Here, we have applied transposon insertion sequencing (Tn-Seq) to L. monocytogenes for the identification of such processes on a genome-wide scale. Our approach identified 394 open reading frames that are required for growth under standard laboratory conditions and 42 further genes, which become necessary during intracellular growth in macrophages. Most of these genes encode components of the translation machinery and act in chromosome-related processes, cell division, and biosynthesis of the cellular envelope. Several cofactor biosynthesis pathways and 29 genes with unknown functions are also required for growth, suggesting novel options for the development of antilisterial drugs. Among the genes specifically required during intracellular growth are known virulence factors, genes compensating intracellular auxotrophies, and several cell division genes. Our experiments also highlight the importance of PASTA kinase signaling for general viability and of glycine metabolism and chromosome segregation for efficient intracellular growth of L. monocytogenes.
Insights
Transposon insertion sequencing identified essential genes for Listeria monocytogenes growth. This reveals new targets for developing drugs against this dangerous foodborne pathogen.
Area of Science:
- Microbiology
- Genomics
- Pathogen Biology
Background:
- Listeria monocytogenes is a Gram-positive bacterium prevalent in the environment.
- Foodborne infections pose severe risks, especially to vulnerable populations.
- Understanding pathogen cellular processes is crucial for developing control strategies.
Purpose of the Study:
- To identify essential cellular processes for L. monocytogenes growth both in vitro and in vivo.
- To discover novel targets for antilisterial drug development.
Main Methods:
- Genome-wide transposon insertion sequencing (Tn-Seq) was applied to L. monocytogenes.
- Analysis of gene requirements under standard laboratory conditions and during intracellular growth in macrophages.
Main Results:
- 394 open reading frames essential for standard growth were identified.
- 42 additional genes were essential for intracellular growth in macrophages.
- Key processes identified include translation, cell division, envelope biosynthesis, cofactor biosynthesis, and unknown function genes.
- Specific genes for intracellular growth include virulence factors, auxotrophy compensation, and cell division genes.
- PASTA kinase signaling, glycine metabolism, and chromosome segregation were highlighted for viability and intracellular growth.
Conclusions:
- Tn-Seq is effective for identifying essential genes in L. monocytogenes.
- The study identified numerous genes critical for pathogen survival and virulence.
- Findings suggest novel avenues for antilisterial drug discovery, targeting identified pathways and unknown genes.
