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 Agar is used for Listeria monocytogenes?
Esculin based Listeria selective agars: Oxford agar (OXA) (18) ( M118). After 24 h incubation at 35° C typical Listeria species colonies are approximately 1 mm diameter, gray to black colonies surrounded by a black halo.
Is Aerobe a Listeria?
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%.
What is ActA Listeria?
ActA, an essential virulence factor of Listeria monocytogenes, is an integral membrane protein that is required for intracellular motility, cell-to-cell spread, and rapid dissemination of the bacteria in the infected host.
How does ActA work?
ActA is a bacterial surface protein comprising a membrane-spanning region. In a mammalian cell the bacterial ActA interacts with the Arp2/3 complex and actin monomers to induce actin polymerization on the bacterial surface generating an actin comet tail. The gene encoding ActA is named actA or prtB.
Is Listeria bile esculin positive?
Gram-positive bacilli Listeria are catalase positive (like diphtheroids) and bile aesculin positive (like the enterococci) (see Fig. 3.1).
Is Listeria oxidase positive or negative?
They are catalase positive, oxidase negative and non-sporulating motile bacteria (Bayoub et al., 2010). The genus Listeria harbors seventeen species having Listeria monocytogenes and L. ivanovii as its pathogenic species (Orsi and Wiedmann, 2016).