7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 1/11 (Listeriosis ) What is Listeriosis ? a serious infection caused by eating food contaminated with the bacterium Listeria Monocytogenes, has recently been recognized as an important public health problem. WHO ARE AT RISK WITH LISTERIOSIS ? persons of advanced age pregnant women new-borns and adults with weakened immune systems People who are taking immune-suppressing medication persons without these risk factors can also rarely be aected General characteristics rod-shaped aerobic and motile gram positive intracellular pathogen invades the cytoplasm of living cells It develops a distinctive rocket tail push through the cytoplasm these "rockets" push bacteria into neighboring cells, propagating the infection
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a serious infection caused by eating food contaminated with the bacteriumListeria Monocytogenes, has recently been recognized as an importantpublic health problem.
WHO ARE AT RISK WITH LISTERIOSIS ?
persons of advanced age
pregnant women
new-borns and adults with weakened immune systems
People who are taking immune-suppressing medication
persons without these risk factors can also rarely be aected
General characteristics
rod-shaped aerobic and motile gram positive intracellular pathogen
invades the cytoplasm of living cells
It develops a distinctive rocket tail
push through the cytoplasm
these "rockets" push bacteria into neighboring cells, propagating theinfection
epithelial cells via the interactions of the surface proteins $nl' and $nl2 with %-cadherin and the 3et receptor, respectively. (4) ninternalization, L.monocytogenes is engulfed in a phagocytic vacuole.(5) L. monocytogenes lyses vacuolar membranes by means of the toin LL.(6) L. monocytogenes uses the protein 'ct' to harness the actin polymerizationmachinery and facilitate its intracellular movement via the formation of so-calledactin 7comet tails.8 (9) L. monocytogenes eploits actin-based motility for direct
cell-to-cell spread to allow the dissemination of the infection to neighboring cells viathe formation of plasma membrane protrusions. (:) nce internalized byneighboring cells, L. monocytogenes is con!ned in a double-membrane vacuolefrom which it escapes to restart its life cycle.