Listeria spp. (5)

Gram positive bacilli

gram type and shape of listeria spp.

Facultative anaerobe

oxygen useage of listeria spp.

Non spore forming and non encapsulated

listeria spp. are ___ and ____

4 C

listeria can grow at __ C

4 peritrical

flagella type of listeria spp. ONLY at less then 23 C

Soil, feces, water, effluents, decomposing plants, saprophytes

location listeria spp. live

Cattle

this population maintain listeria spp. in rural locals

Fecal oral, contaminated food

transmission route for listeria spp.

Facultative intracellular

pathogen replication type of listeria spp. primarly in epithelial and macrophage cells

Epithelial and macrophage

cell types invaded by listeria spp.

Listeria monocytogenes

pathogenic listeria spp. in animals and humans causes localized and systemic infections

Listeria ivanovii

pathogenic listeria spp. in animals but rarely in humans, abortions and still births in sheep/cattle

listeria seeligeri

very rarely listeria spp. that causes human disease

listeria innocua, welshimeri, grayi

non pathogenic listeria spp.

EGD Murray and joseph lister

found listeria

Listeriosis

prior to 1970s known as farm animal pathogen causing encephalitis and abortions and circuling disease now caused by food borne pathogen

Newborns, elderly, immunocomprimised

who is at risk for listeriosis

Jensen farms

filed for bankruptcy after criminal charges associated with listeria outbreak in 2011

Deli meats, cheese, vegetables and soft dairy

food associated with listeria outbreaks

Healthy adult

cases of listerious in ______ would present to clinic with mild influenza like illness and minor gastroenteritis

Immunocompromised

cases of listeriosis in ____ would present to clinic with bacterima (chills/fever) cross of BBB malaise, vision and movement issues, paralysis, meningitis and meningoencephalitis

Perinatal listeriosis

linked to immunosuppression of pregnant women and causes still birth, abortion or neonatal sepsis, granulomatous infantiseptica or disseminated listeria abscesses in skin, liver, spleen, brain, or kidney of infants

Neutrophils and t cells

mediate clearance of L. monocytogenes after infection, also treat w antibiotics, no vaccine and there is food testing to prevent infection

LLO (hly), ActA, PlcA, PlcB, Mpl

virulence genes all found on the same chromosome locus in L. monocytogenes

PrfA

transcriptional regulator of the virulence genes in L. monocytogenes and controls InlA and InlB ( not on same operon)

30 C

because there is a thermosensor upstream of prfA at ___ temp there is no virulence gene expression

37 C

because there is a thermossensor upstream of prfA at ___ temp there IS virulence gene expression because the shine delgarno sequence can bind the ribosome

Shine delgarno

at 37 C what does the ribosome bind to to express virulence genes

Goblet cells

non phagocytic cell that has InlA binding to E cadherin L. monocytogenes

Trophoblasts

non phagocytic cells that has InlB bind to MET receptor and soluble InlB binds to GC1QR and GAGs

InlA and E cad

interaction activates adherens junction machinery,

Kinase Src

E cad receptor clustering activates tyrosine ____

Ubiquitin ligase Hakai

phosphorylation of E cad (by Kinase Src) triggers the recruitment of …

Clathrin coated pits

e cad and L. monocytogenes are internalized via…. Or cavosomes in caveolin rich domains

Listerolysin O

LLO aka hly was the first virulence gene in listeria spp and it stands for

LLO

secreted protein toxin that permeabilizes cholesterol rich membranes and mediates bacterial escape from the vacuole by 30 mpi, active at pH 5.5 inside vacuole but not in cytosol ph 7

PEST

this like sequence at the n terminus targets LLO for degradation when it reaches the cytosol

PlcA and PlcB

contribute to escape of listeria from vacuoles (phospholipases)

ActA

listeria virulence factor that harness host cell actin for intracellular motility and cell to cell spread, transmembrane surface protein with actin binding domains

VASP

host protien that binds to proline rich repeats in ActA and recruits profilin which provides actin monomers and then arp2.3 drives branched actin polymerization

Profilin

recruited by VASP and provides actin monomers needed for actin based motility

NPF

ActA is a functional mimic of the ___ that activates the Arp2/3 complex which depolarizes actin filaments

Apical junction complex

tight barrier between enterocytes is due to … which is a thick network of actin and myosin

InlC

secreted listeria factor disrupts Tuba/ n wasp complex to relieve tension at apical junction complex to deform the membrane and contribute to membrane remodeling