How does Listeria monocytogenes cause infection?

How does Listeria monocytogenes cause infection?

What is listeriosis? Listeriosis is an infection caused by the bacteria Listeria monocytogenes. People become infected by eating foods contaminated with the bacteria. Listeria may infect many different sites in the body, such as the brain, spinal cord membranes, or the bloodstream.

How do you confirm Listeria monocytogenes?

Listeriosis is usually diagnosed when a bacterial culture (a type of laboratory test) grows Listeria monocytogenes from a body tissue or fluid, such as blood, spinal fluid, or the placenta. Listeriosis is treated with antibiotics.

What cells does Listeria monocytogenes infect?

L. monocytogenes enters almost all adherent cells, but the efficiency of uptake can vary over 10,000-fold. Macrophages and macrophage-like cell lines can internalize up to 20 bacteria per cell, whereas fibroblast cell lines internalize less than one bacterium per cell.

Is Listeria monocytogenes VP positive?

Classification. L. monocytogenes is a Gram-positive, non-spore-forming, motile, facultatively anaerobic, rod-shaped bacterium. It is catalase-positive and oxidase-negative, and expresses a beta hemolysin, which causes destruction of red blood cells.

Is Listeria monocytogenes Gram positive or negative?

Listeria monocytogenes is a facultative, intracellular, gram-positive rod that is responsible for causing the infection listeriosis. Listeria causes severe infection in the elderly, neonates and the immunocompromised with only a self-limited gastrointestinal infection in the immunocompetent.

Does Listeria monocytogenes produce a toxin?

Listeria monocytogenes is a foodborne pathogen capable of secreting listeriolysin O (LLO), a pore-forming toxin encoded by the hly gene.

What color is Listeria monocytogenes?

Incubate plates at 37 °C, all Listeria species appear as 1-3 mm diameter blue/green colonies. Additionally, L. monocytogenes and L. ivanovii have an opaque white halo surrounding the colony.

Which media is used for listeria monocytogenes?

Therefore, L. monocytogenes need to be grown in a rich culture medium that provides all of these growth factors. Brain Heart Infusion (BHI) is the most commonly used non-selective media for cultivation of Listeria species.

What diseases does Listeria monocytogenes cause?

Listeriosis can manifest itself as sepsis, meningitis, encephalitis, intrauterine infections and spontaneous abortions in pregnant women. The onsets of these diseases are usually preceded by persistent fever or gastrointestinal symptoms such as nausea, vomiting and diarrhea.

Is Listeria monocytogenes autotrophic or heterotrophic?

For heterotrophic organisms including pathogenic bacteria such as L. monocytogenes and their eukaryotic host cells, simple carbohydrates, amino acids, and glycerol are among the typical carbon sources and, therefore, serve as suitable tracers in these labeling studies.

Is Listeria monocytogenes urease positive?

The biochemical profile of Listeria includes: catalase positive, oxidase negative, fermentation of carbohydrates to acid but not to gas, hydrolysis of esculin and sodium hippurate, methyl red positive, ammonia production from arginine, negative reaction for hydrogen sulfide production, indole negative, nitrate …

Is Listeria monocytogenes Psychrophile?

Listeria monocytogenes is a psychrophilic food-borne pathogen that is problematic for the food industry. Structures of Csps from psychrophilic bacteria have not yet been studied.