Does Listeria monocytogenes grow on blood agar?
monocytogenes and L. innocua, the most frequently encountered non-pathogenic Listeria species. Hemolysis, a major differential characteristic of Listeria species, may be, in some cases (especially for environmental and food isolates), difficult to read on blood agar.
What is the colony morphology of Listeria monocytogenes?
Morphology of Listeria The morphology of the genus Listeria is small, Gram-positive coccobacilli or rod-shaped having a size of 1-3µmX 0.5 µm. They are motile at 25°C showings tumbling motility but are non-motile at37°C. They produce peritrichous flagella optimally at 20-30°C, but they can not produce flagella at all.
What agar does Listeria monocytogenes grow on?
Meuller-Hinton agar
The diagnosis of L. monocytogenes requires a culture of the bacteria from the blood, cerebral spinal fluid, or placental fluid. Once in the lab, Listeria species grows on a special type of agar called Meuller-Hinton agar. Culture will reveal gram-positive rods with colonies that are beta-hemolytic.
Can Listeria be alpha hemolytic?
ivanovii while a narrow zone of α-hemolysis was the characteristic of L. monocytogenes or L. seeligeri[21]. Christie, Atkins, Munch and Petersen (CAMP) test All the Listeria isolates were tested by CAMP test.
What is the appearance of Listeria monocytogenes on blood sheep agar?
Listeria monocytogenes is beta-hemolytic on sheep blood agar plates but often produce only narrow zones of hemolysis that frequently do not extend much beyond the edge of the colonies. Microscopy: Gram-positive, asporogenous, motile(at 28°C), short rods.
Is Listeria monocytogenes aerobic or anaerobic?
Listeria monocytogenes is a Gram positive facultative anaerobe that causes listeriosis, a disease that mainly affects the immune-compromised, the elderly, infants and pregnant women. In the susceptible immune challenged population, listeriosis is very severe and has a fatality rate of up to 30%.
Does Listeria monocytogenes grow on MacConkey Agar?
Grow at/on: pH 5.5-9.6 (pH 7.2-7.6 optimum). Temperature range 0-45 ºC. Grow on 40% bile agar. Weak growth on MacConkey agar.
What 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.
Does Listeria monocytogenes show hemolysis on blood agar?
How is Listeria monocytogenes culture in the lab?
monocytogenes 10403s, can also be cultivated in Tryptic Soy Broth (TSB). In the laboratory, L. monocytogenes are grown in liquid media at temperatures that reflect either environmental conditions (4 to 30 °C) or mammalian body temperature (~37 °C).
What are the characteristics of Listeria monocytogenes?
Listeria spp. are small gram-positive rod (0.5–4 μm in diameter and 0.5–2 μm in length), non-spore-forming, facultative anaerobic, catalase-positive, and oxidase-negative organisms. Listeria has tumbling motility at 20–25°C due to peritrichous flagella.
Does Listeria monocytogenes grow on chocolate agar?
A small, whitish, moist colony with a narrow zone of beta hemolysis around and under the colonies was noted on Blood agar plates. Growth was noted on Chocolate and anaerobic Brucella agar plate.
How common is Listeria during pregnancy?
Listeriosis is rare in non-pregnant healthy adults, but the infection is up to 20 times more common in pregnant women, according to a review in Obstetrics and Gynecology. Most pregnant women have no symptoms or problems from the infection. However, the fetus is highly susceptible to this type of bacterium.