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Jul 4, 2023 · 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.
Jun 11, 2024 · Listeria is a short gram-positive rod that occurs singly or in short chains. However, the identification of Listeria on Gram stain may be challenging. Listeria may resemble pneumococci (diplococci) or diphtheroids (Corynebacteria) or be gram variable and confused with Haemophilus species .
Aug 23, 2023 · The Gram stain indicates a bacterial pathogen consistent with Listeria monocytogenes. L. monocytogenes is usually transmitted by ingestion of contaminated foods such as raw vegetables, dairy products and meat.
Listeria monocytogenes is a Gram-positive bacterium, in the phylum Bacillota, named after Joseph Lister. Its ability to grow at temperatures as low as 0 °C permits multiplication at typical refrigeration temperatures, greatly increasing its ability to evade control in human foodstuffs.
Listeria monocytogenes Identification Chart. Summary. Major pathogen found in Cerebral Spinal Fluid (CSF) and Blood only. Characteristics. CSF showing Polymorphonuclear leukocytes (PMNs), Monocytes, and Gram-positive rods (may be intracellular). (a-c)Regular small Gram (+) rods. May be short or longer.
Listeria monocytogenes is a Gram-positive, rod shaped non-acid fast, non-spore-forming, catalase positive bacterium that ferments glucose producing lactic acid. The bacterium is ubiquitous in soil, water, animal excreta and plants.
Sep 10, 2023 · Small Gram-positive rod, non-spore-forming [ Fig 1 ]. O and H antigens designate Listeria serotypes. Sero-types 1/2a, 1/2b, and 4b cause almost all human infections, and serotype 4b is associated with outbreaks. Isolated from environmental sources such as water, sewerage and foodstuffs.
Nov 20, 2023 · Listeria occurs singly or in short chains. On Gram stain, Listeria may resemble pneumococci (diplococci), enterococci, or diphtheroids (Corynebacteria) or be gram variable and be confused with Haemophilus species .
May 3, 2022 · Listeria monocytogenes is a Gram‐positive bacterium of 0.5–4 μm in diameter and 0.5–2 μm in length that is unable to produce spores. The microorganism is facultatively anaerobic, generally motile due to the presence of flagella at temperature range of 22–28°C but nonmotile above 30°C (Allerberger, 2003 ).
Aug 10, 2022 · Listeria organisms are motile in wet mounts of CSF. CSF Gram stain results are positive in less than 50% of patients. CSF analysis reveals pleocytosis, and CSF protein levels are moderately...
