Listeria monocytogenes and Rothia Lecture Notes

Comprehensive vocabulary flashcards covering the pathogenesis, epidemiology, clinical pathology, and laboratory diagnosis of Listeria monocytogenes and Rothia species.

Listeria monocytogenes

The only clinically significant species within the genus Listeria known to cause infection in humans.

Listeria ivanovii

A species of Listeria that is primarily an animal pathogen.

Listeriolysin O (Leukocidin)

The most significant virulence factor of L. monocytogenes; a cytolysin that destroys the phagosome membrane by pore-formation, allowing the bacteria to avoid immune destruction.

Ami (Autolysin Amidase)

An adhesin that allows L. monocytogenes to bind with an unknown receptor during host cell colonization.

Internalin A

A surface protein that drives the invasion of intestinal epithelial cells by using cadherin as a receptor.

Internalin B

A surface protein that promotes deeper tissue invasion by binding to receptor segments in the endothelium and hepatocytes.

Act A

A factor responsible for actin polymerization within host cells, facilitating cell-to-cell spreading.

Filopods (?)

The forceful invaginations or extensions produced in a new target cell as L. monocytogenes enters from a previously infected cell.

Siderophores

Molecules produced by the bacteria that compete with transferrin for iron.

Granulomatosis infantiseptica

An early-onset intrauterine neonatal systemic septic infection characterized by the formation of lesions and granuloma in the fetus' organs.

Cold enrichment technique

A special processing procedure for fastidious organisms where the sample is incubated in broth at $4^{\circ}C$ for several weeks to enhance recovery.

MOX medium (Modified Oxford Medium)

A type of Colistin-Nalidixic Acid (CNA) medium with added auxotrophic nutrients used to isolate Listeria.

Auxotrophic

Refers to the requirement of L. monocytogenes for seven additional amino acids (arginine, cystiene, glutaminee, isoleucine, leucine, methionine, and valine) and four vitamins (biotin, riboflavin, thiamine, and thiotic acid).

Tumbling motility

The characteristic "end over end" movement of L. monocytogenes observed during wet motility examinations at $20-25^{\circ}C$.

Umbrella growth

An inverted Christmas tree-like growth pattern observed in SIM medium at $20-25^{\circ}C$, characteristic of L. monocytogenes.

Block-type hemolysis

The specific CAMP reaction result for L. monocytogenes, characterized by a lack of an arrow of hemolysis at the junction of the test organism.

PIPL-C (Phosphatidylinositol specific phospholipase C)

An enzyme produced only by L. monocytogenes and L. ivanovii that destroys the phospholipid bilayer in human epithelial tissues; its activity is measured using chromogenic media.

Serotype 4b

The specific serotype of L. monocytogenes that causes the most foodborne infections.

Immuno-capture assay

A technique using magnetic beads coated with specific antibodies to separate Listeria from competing microflora and inhibitory food components.

Rothia mucilaginosa

A gram-positive coccus belonging to the family Micrococcaceae linked to endocarditis, bacteremia, and pneumonia.

Rothia dentacariosa

A member of the normal human oropharyngeal microbiota found in saliva and supragingival plaque, associated with endocarditis.