Gram Positive Bacilli: Clostridia Flashcards Preview

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Flashcards in Gram Positive Bacilli: Clostridia Deck (37):
0

False about anaerobes
A. Do not use oxygen
B. Gain energy via redox reactions
C. Make use of inorganic electron acceptors (nitrate, sulfate)
D. Cannot grow on wounds

D. Cannot grow on wounds

They can grow on wounds because of symbiotic relationship with aerobic bacteria. Why? They lower redox potential! Since they can grow on wounds, they give wounds a foul smell.

1

Which is false?
A. Clostridium tetani is an obligate anaerobe.
B. Aerotolerant anarobes use oxygen in their metabolism.
C. Facultative anaerobes can make ATP in the presence of oxygen.
D. Microaerophilrs can only tolerate 2-10% oxygen.

B. Aerotolerant anarobes use oxygen in their metabolism.

They do not use oxygen in metabolism

2

Which is false?:
A) Anaerobes grow quickly (18-24 hours)
B) Clostridium botulinum can withstand 100 degrees Celsius
C)Most Clostridia are saprophytes
D)Clostridium botulinum diminishes at acid pH or high salt concentration

A) bec their growth period is 48-96 hours

3

Substance responsible for heat resistance of anaerobic endospores

Dipicolinate/dipicolinic acid

4

Clostridium botulinum's primary toxin prevents release of , resulting in (_____).

: acetylcholine
(______): flaccid paralysis

5

Most virulent and heat-resistant botulin type; it cleaves SNAP 25

Botulinum toxin Type A

6

Botulinum toxin Type B cleaves __

Synaptobrevin

7

Which is false?
A. Both Botulinum toxin types E and F cleave SNAP 25
B. Both Botulinum toxin types E and F cause infant botulism
C. Botulinism is an intoxication illness and not an infection

A. Both Botulinum toxin types E and F cleave SNAP 25

E and A dapat.

8

Which is false about botulin?
A.The toxin binds to the receptors of presynaptic membrance of sensory neurons of PNS + cranial nerves
B. The toxin does not cause antitoxin to develop in blood
C. The toxin is not immunogenic

A.The toxin binds to the receptors of presynaptic membrance of sensory neurons of PNS + cranial nerves

Motor dapat

9

Infant botulism is diagnosed via contents of
A. Serum
B. Blood
C. Bowel
D. All of the above

C.bowel

10

False about treatment of botulinism
A. Prepared in humans
B. Trivalent (A, B and E) administered intravenously
C. Recovery phase: nerve endings regenerate
D.none of the above

A. Prepared in humans
Horses dapat

11

Use of ___ prevents C.botulinum growth folowing germination of endospores
A. Nitrites
B. Nitrates
C. Sulfites
D. Sulfates

B. Nitrates

12

Main toxin in Clostridium tetani is called __

Tetanospasmin

13

All aid in spore germination and vegetative organism development of C.tetani except;
A. Calcium salts
B. Associated pyogenic infections (with pus)
C. Necrotic tissue
D. High redox potential

D. High redox potential

C.tetani favors low redox potential

14

Which is false?
A. C.tetani is an invasive organism
B. Tetanus Infection occurs only if site is anaerobic
C. Tetanospasmin causes spastic paralysis
D. Tetanospasmin invades CNS via peripheral nerves/blood

A. C.tetani is an invasive organism

It is not invasive; infection is localized in tissue into which spores have been introduced

15

Sequence the ff steps of tetanospasmin's mechanism of action
A. Blocks release of gamma-aminobutyric acid & glycine
B. Migrates to spinal cord and brain stem
C. Binds to receptors on presynaptic membranes of motor neurons
D. Degrades synaptobrevin

C B D A

16

Which is not a clinical manifestation of tetanus?
A. Muscular spasm
B. Abdominal pain and diarrhea
C. Lockjaw
D. Opisthonos

B. Abdominal pain and diarrhea

17

What is opistohonos?

Spasms of back muscles causing head and eels to bow backward

18

Which is false?
A. May be diagnosed as such when neutralization by specific antitoxin is successful
B. Both toxoids and tetanus immune globulin aid in active immunization
C. Administration of penicillin helps, since C.tetani is Gram positive
D. Tetanospasmin has tropism for inhibitory motor neurons of CNS

B. Both toxoids and tetanus immune globulin aid in active immunization

The latter is for passive immunization

19

False about Clostridium perfringes
A. May grow on warm meat dishes
B. Cannot cause Endogenous infections
C. Causes gas gangrene(gas formed at deep wound or injury) and food poisoning

B. Cannot cause Endogenous infections

Endogenous infections may occur since Clostridium perfringes is also part of gut's normal flora

20

Predisposing condition of gas gangrene

Deep penetrating wound contaminate by clostridial spores

21

This toxin of C.perfringes is responsible for tissue damage by hydrolyzing lecithin in cell membranes

Alpha toxin

22

This toxin of C.perfringes increases permeability of GI Wall

Epsilon toxin

23

All are part of enterotoxin's action except
A. Nausea and vomiting
B. Abdominal pain and diarrhea
C. Opisthonos
D.none of the above

C. opisthonos

24

This toxin of C.perfringes hydrolyzes RBC

Theta toxin

25

This toxin of C.perfringes hydrolyzes WBC

Nu toxin

26

This toxin of C.perfringes causes RBC agglutination

Neuraminidase

27

Another name for hyaluronic acid

Spreading factor

28

C.perfringes produce spores that germinate at ___ redox potential
A. High
B. Low
C. Any

B.low

29

Which is not a typical host response to C.perfringes?
A. Fasciitis
B. Crepitation in subCT tissue
C. Trismus
D. Cellulitis

C. Trismus

Trismus: lockjaw! Lockjaw c/o C.tetani

30

Which is false?
A. C.perfringens is found in genital tract of 5% of women
B. Lecithinase activity is tested via precipitation test around colonies grown on blood agar plate
C. Both are false

B. Lecithinase activity is tested via precipitation test around colonies grown on blood agar plate

BAP? Nope, egg yolk media :)

31

Reaction that determins alpha toxin of C.perfringes

Nagler reaction

32

Disease produced by Clostridium difficile; can lead to ulceration of intestinal wall

Pseudomembranous colitis

33

False about Toxin A of C.difficile
A. Causes bloody diarrhea (hemorrhagic necrosis + intestinal inflammation)
B. Potent cytotoxin
C. Both of the above
D. None of the above

B. Potent cytotoxin

It is an enterotoxin, causing fluid accumulation in the bowel. Yung Toxin B=cytotoxin

34

C.difficile Lab identification methods include all except
A. Immunoassay
B. Nucleic acid amplification
C. Cell culture (cytopathic effect determined)
D. Using egg yolk media

D. Using egg yolk media ---> for C.perfringes

History of antibiotic use helps in diagnosis of C.difficile

35

Which is false?
A. Cephalosporin and quinolones are narrow-spectrum antibiotics
B. They kill lots of normal flora species
C. Cephalosporin inhibits cell wall synthesis
D. Quinolone inhibits DNA synthesis

A. Cephalosporin and quinolones are narrow-spectrum antibiotics

Broad dapat

36

True about antibiotic-assoc diarrhea
A. Usually due to clindamycin and ampicillin
B.less severe than classic form of pseudomembranous colitis
C. Both are true
D. Both are false

C.both are true