Listeria Monocytogenes

Question 1

what shape does listeria monocytogenes have?

Answer 1

rods

Question 2

what Foods are associated with this bacteria *?

Answer 2

• Soft cheeses
• Deli meats
• Cabbages (coleslaw)
• Unpasteurized milk products

Question 3

who is at high risk for severe infection with listeria?

Answer 3

weakened or immature immune system: *

• Developing fetus, newborn infants (via infected mother) *
• Older adults (65 yrs or older) *
• Individuals with defective cell-mediated immunity*

Question 4

listeria monocytogenes is considered what type of organism?

Answer 4

Facultative Intracellular parasite *

Question 5

is listeria motile?

Answer 5

yes

Question 6

what type of motility does listeria have?

Answer 6

tumbling motility

Question 7

in what temp. does listeria grow?

Answer 7

cold temp.

Question 8

what is an example of a food where listeria grows?

Answer 8

hot dogs *

Question 9

how does listeria transmit?

Answer 9

foodborne and from mother to fetus *

Question 10

where will listeria attach to when ingeted?

Answer 10

to macrophages and intestinal epithelium

Question 11

what will allow listeria to allows escape from phagosome of macrophages?

Answer 11

Listeriolysin-O*(hemolysin)

Question 12

what will allow Listeria to spread from cytoplasm of one host cell to another host cell?

Answer 12

actin-jet filament → jet motility *

Question 13

what tissues does listeria prefer?

Answer 13

placenta and central nervous system

Question 14

how well do antibodies act towards listeria?

Answer 14

Antibodies to Listeria are ineffective due to being intracellular

Question 15

what immunity is needed to attack listeria infection?

Answer 15

cell-mediated immunity

Question 16

what can an infection with listeria cause in Pregnant women *?

Answer 16

miscarriage*

Question 17

what can an infection with listeria cause in newborns* if infection occurs in early onset?

Answer 17

granulomatosis infantiseptica

Question 18

what can an infection with listeria cause in newborns* if infection occurs in late onset?

Answer 18

Septicemia and meningitis

Question 19

what can an infection with listeria cause in immunocompromised individuals and older adults?

Answer 19

Septicemia and meningitis

Question 20

what is Granulomatosis infantiseptica* found in neonatal listeriosis?

Answer 20

disease acquired transplacentally that causes disseminated abscesses and granulomas *

Question 21

How is Meningitis* acquired in neonatal listeriosis? What is it accompanied with usually?

Answer 21

• Transmission during delivery
• Usually accompanied by septicemia

Question 22

how is listeria monocytogenes diagnosed?

Answer 22

1) Gram stain of CSF * and will find:

• Intracellular & extracellular short GPRs (coccobacilli)
• “Tumbling motility”**

2) Cold enrichment *
* put specimen in nutrient broth in refrigerator

Question 23

what is the treatment for Treatment of Listeriosis?

Answer 23

• Penicillin / ampicillin + gentamycin * *

Question 24

why can’t cephalosporins be used for listeria monocytogenes?

Answer 24

Cannot use cephalosporins (Listeria are naturally resistant)***

Question 25

if a mother has antibodies against listeria and is pregnant, is her fetus at risk?

Answer 25

yes, and may lead to spontaneous abortion