L21: Bacilus and listeria

Question 1

describe the appearance of bacillus under the microscope;

Answer 1

gram positive bacilli in chains ( box car appearance

Question 2

which species of bacillus is non-motile ?

Answer 2

bacillus anthracis

Question 3

where does bacillus anthracis come from ?

Answer 3

from dead animals or soil

Question 4

what are the toxins that are associated with bacillus anthracis ?

Answer 4

lethal factor ( protease ): inhibits cell growth

edema factor ( adenyl cyclase ) : promotes edema

protecting factor : forms pores in cell membrane , allowing lethal and edema factors to enter the cell

Question 5

antibodies against which of bacillus anthracis’ toxins will protect against the disease anthrax ?

Answer 5

antibodies against the protecting factor

Question 6

most anthrax infections are::

Answer 6

cutaneous (95%)

Question 7

how do inhaled bacillus anthracis spores affect the respiratory system ?

Answer 7

they cause hemorrhage of the medistinal lymph nodes

Question 8

hide porters disease is an example of :

Answer 8

cutaneous anthrax

Question 9

wool sorters disease is an example of ?

Answer 9

inhaled bacillus anthracis spores

Question 10

which stain can be used to highlight the polypeptide capsule of bacillus anthracis ?

Answer 10

polychrome methyl blue (mcfadyen ) stain or india ink

Question 11

which species of bacillus can cause food poisoning ?

Answer 11

bacillus cereus

Question 12

how is Bacillus cereus transmitted?

Answer 12

spores germinate on grains such as rice when they are left warm for a long time ( reheated fried rice)

Question 13

what do the enterotoxins of Bacillus cereus do?

Answer 13

one activates adenyl cyclase –> more C AMP —> more Na and Cl secretions from cells —> watery diarrhea (short incubation 4 hours)

the other acts as a super antigen —> nausea , vomiting
(longer incubation 18 hours )

Question 14

what do the enterotoxins of Bacillus cereus do?

Answer 14

one activates adenyl cyclase –> more C AMP —> more Na and Cl secretions from cells —> watery diarrhea (short incubation 4 hours)

the other acts as a super antigen —> nausea , vomiting
(longer incubation 18 hours )

Question 15

listeria :
gram staining :
aerobic conditions :
catalase test :
growth temp.

Answer 15

gram positive
aerobic and facultative anaerobic
catalase positive
4 degrees C , thrives on food stored in fridges

Question 16

what organism has tumbling motility at 24 degrees celcius

Answer 16

listeria

Question 17

how is listeria transmitted ?

Answer 17

through ingestion ( unpasteurized dairy , undercooked meat , raw vegetables )

or through direct contact with domestic animals or their feces

Question 18

what parts of the body can be colonized by listeria ?

Answer 18

colon and female genital tract

Question 19

which organism is considered an intracellular parasite that activated cell mediated immunity ?

Answer 19

listeria

Question 20

protein that helps listeria adhere and invade/?

Answer 20

internalin

Question 21

protein that helps listeria survive within cells ?

Answer 21

lysteriolysin

Question 22

which organism is capable of cel-cell invasion?

Answer 22

listeria

Question 23

listeria is sugar fermenting