listeria monocytogenes (listeriosis) 2-12-2015.pptx
TRANSCRIPT
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 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
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 2/11
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 3/11
How Hum ns cont ct Listeriosis
dairy products, vegetables, !sh and meat products.
unlike most other harmful bacteria, will grow slowly onfoods stored in a refrigerator.
spread by contact with an infected product or surface hands or counter tops
during food preparation
athogenesis and athology
enters through the "astro # intestinal tract
cell wall surface protein called $nteranalin
interacts with % #&'%*$+ and enters intoepithelial cells
produce Listeriolysin ) membrane-damaging toin(
preads from cell to cell
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 4/11
Pathogenesis
$nternalin %-cadherin
Phagocytosis
into
epithelial
cells
Phagocytio
ssBy
macropha
ges
and
hepatocytes
Phagolysosome
formation
(acidiccondition)
LysteriolysinO
secretion
Release from
phagolysosome
Inducing actin
polymeriation incytoplasm
!orming lopods
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 5/11
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.
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 6/11
%pidemiology 1-19; of healthy humans are asymptomatic intestinal
carriers $nfections and diseases 3ost common in pregnant women,
3ild <=u-like> illness in 5rd trimester
can be transmitted to a newborn, via vaginal colonization or
placenta 3ay initiate abortion (miscarriage)
still birth
premature delivery
or infected newborn.
epticemia and meningitis
between birth and third week of life caused by serotype $? b and has a signi!cant mortality
rate
"ranulomatous skin lesions # rare
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 7/11
Listeriosis In Adults
2acteremia and 3enigeoencephalitis =u-like symptoms for about four days
occur most commonly in $mmunosuppressed patients in whom Listeria is one of the morecommon cause of 3eningitis
isease can be insidious to fulminant
iagnosis
iagnosis dependent on isolation of rganisms in
cultures obtained and direct microscopic eamination &@, 2lood, and other =uids narrow zone of beta-hemolysis
/umbling movement, 3ovement in 49 A
/reatment
'mpicillin
%rythromycin
$ntravenous #rimethoprim $ %ulphmetho&aole
&ephalosporins and @luroBuinoles are not active against L.monocytogens
' commination of "entamycin and 'mpicillin on clinical basis
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 8/11
Ideal 'ay to preventListeriosis &ompletely cook all meats and eggs.
&arefully wash raw vegetables before eating. Ceep raw meat away from raw vegetables and prepared
foods. 'fter cutting raw meat, wash the cutting board withdetergent before using it for vegetables.
'void drinking unpasteurized milk or foods made from suchmilk.
Dash hands thoroughly after handling raw meat. @ollow the instructions on food labels. bserve food
epiration dates and storage conditions.
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 9/11
Life cycle of
Listeria
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 10/11
Listeria tumbling
motility
7/21/2019 Listeria monocytogenes (Listeriosis) 2-12-2015.pptx
http://slidepdf.com/reader/full/listeria-monocytogenes-listeriosis-2-12-2015pptx 11/11