infections involving anaerobes

Question 1

cannot grow if O2 is present (> 5 µM)

– Can’t detoxify toxic reactive oxygen species (free radicals)

Answer 1

Obligate anaerobe

Question 2

grow in very low O2 (nM, ~0.1% O2); can tolerate µM (e.g. Bacteroides fragilis)

Answer 2

Nanaerobe

Question 3

grow ± O2

Answer 3

Facultative anaerobe

Question 4

need O2 (5%) but too much is toxic

Answer 4

Microaerophilic

Question 5

need O2 (~20%) to grow (O2 = electron acceptor)

Answer 5

Obligate aerobes

Question 6

areas of anaerobiosis (3)

Answer 6

1. tissue destruction- abscess
2. poor blood suppl such as the foot of a diabetic patient
3. foreign bodies such as that of artificial hips

Question 7

anaerobes in our body (3)

Answer 7

1. GI
2. mouth
3. vaginal tract

Question 8

anaerobe associated with peritonitis (leakage from bowel intra-abdominal infections

Answer 8

bacteroides fragilis

Question 9

anaerobe involved in infant botulism

Answer 9

c. botulinum

Question 10

anaerobe involved in food poisoning

Answer 10

C. perfringens

Question 11

antibiotic used to treat abscess below diagram such as that seen in bacteroides fragilis in the intra-abdomenal

Answer 11

metronidazole

Question 12

How does B. fragilis survive and grow in abscesses (3)

Answer 12

1. it is a nanaerobe meaning that it can survive in low levels in oxygen
2. evades immune response because they have a capsule which is anti-phagocytic
3. multi-drug resistant

Question 13

area of inflammation that becomes walled-in and surrounded by thick, collagen-containing capsule

Answer 13

Abscess

Question 14

metronidazole work in anaerobically or aerobically

Answer 14

anaerobically

Question 15

B. fragilis resistant to __________

Answer 15

first generation cephalosporins

Question 16

Clostridia is spore-forming or non-spore forming obligate anaerobes

Answer 16

spore-forming

Question 17

Disease caused by clostridial pathogens are ______-mediated

Answer 17

toxin

Question 18

______ are the infectious particle of these obligate anaerobes

Answer 18

Spores

Question 19

Tetanus toxin enters pre-synaptic, inhibitory neurons in spinal cord and brain stem and prevents the release of ______ and _____ resulting in _______?

Answer 19

GABA and glycine

Cannot shut off stimulatory motor impulses – uncontrolled muscle contraction

Question 20

tetanus results in

Answer 20

spastic paralysis
lockjaw
rigid smile

Question 21

Botulinum cleaves ____ proteins that allows the release of ________ resulting in stopping muscle contraction

Answer 21

cleaves SNARE proteins which usually allows the release of acettylcholine but in this case the release is blocked and thus stops muscle contraction

Question 22

botulinum results in

Answer 22

flaccid paralysis due to muscles can not contract

Question 23

infection rout of botulinum

Answer 23

toxin ingested

Question 24

C. perfringens route of entry is (2)

Answer 24

1. pre-formed enterotoxin or vegetative cells ingested

2. spores contaminate puncture wounds

Question 25

C. perfringens when there is wound infection from the spores it results in

Answer 25

gas gangrene: myonecrosis (destroys muscle) and releases alpha toxin which degrades membranes

***** it grows rapidly!!!!