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Flashcards in Micro V Deck (68):
1

What is the morphology of clostridium tetani?

Gram positive rods

2

Is clostridium tetani an aerobe or an anaerobe?

Anaerobic

3

What is the reservoir for clostridium?

Soil

4

What is the MOA of tetanus toxin?

Toxin blocks release of inhibitory neurotransmitters (Glycine and GABA)  Spastic
paralysis

Cleavage of synaptobrevin

5

What is the tetanus vaccine?

Toxoid

6

What is the most common scenario for acquiring
tetanus?

Rusty nail stick

7

What virus ascends in a retrograde manner to the
CNS?

Rabies

8

What is the treatment for tetanus?

Hyperimmune IVIG + benzos for spasms

9

What are the s/sx of tetanus? (3)

Trismus
Sardonic smile
Arched back

10

What are the top three cases requiring passive and active immunization?

1. Tetanus
2. Rabies
3. HBV (needle stick or mothers)

11

What are the EM findings of Rabies?

Negri bodies

12

What is opisthotonus?

arched back 2/2 tetanus

13

Why are benzos useful for treating tetanus?

Potentiates GABA (which is blocked by tetanus)

14

What is another common scenarios for getting tetanus in developing countries?

Umbilical stump of newborn infants

15

What is the morphology of clostridium botulinum?

Gram positive rods

16

Is clostridium botulinum aerobic or anaerobic?

Anaerobic

17

What is the reservoir for clostridium botulinum?

Spores in the soil =

18

What is the treatment for clostridium botulinum?

antitoxin

19

What is the pathogenesis of clostridium botulinum?

Botulinum toxin inhibits neurotransmitter release from
presynaptic nerve endings by selectively proteolysing
(inhibiting) the synaptic protein synaptobrevin, which
plays a role in calcium-dependent exocytosis of
acetylcholine.

20

What are the foods associated with infant botulism?

Canned food or honey

21

Do adults get infected with clostridium botulinum through spores?

No--only infants whose immune system is not mature

22

What are the s/sx of botulinum?

1. Fixed, dilated pupils
2. Diplopia
3. Dysphagia

23

What is the most common source of botulism in
adults?

The most common source of botulism in adults is canned beans; and in
particular yellow beans

24

What is the most common source of botulism in
babies?

• The common source of botulism in babies is honey.

25

Botulinum toxin is transferred by blood. Tetanus is
transmitted by what?

Botulinum toxin is transferred by blood. Tetanus is transmitted by nerves.

26

What is the morphology of clostridium perfringens? Aerobic?

Gram positive rod
Anaerobic

27

What is the virulence factor for clostridium perfringens?

Lectinthiase

28

What is the pathogenesis of clostridium perfringens?

Lecithinase and sphingomyelinase released from vegetative bacteria, degrade components in cell membranes

29

What is the management strategey of clostridium perfringens?

Debridement of the wound

30

Palpation of the wound infected with clostridium perfringens reveals what?

Crepitus

31

What is the treatment for clostridium perfringens? (3)

PCN
Clindamycin
Metronidazole

32

Does C. perfringens produce exotoxin?

perfringens produces an exotoxin, but it is not virulent in gas
gangrene. The toxin is virulent in C. perfringens enteritis.

33

What is the older name for C. Perfringens?

The older name for C. Perfringens is C. welchii.

34

What is claimed to be the third most common
cause of food poisoning in the USA and United
Kingdom?

Clostridium perfringens enterotoxicity is claimed to be the third most
common food poisoning!

35

What strain of C. perfringens cause gas gangrene?

Strains A and C cause enterotoxicity in humans.

36

What is the name of the toxin that causes gas
gangrene

The toxin involved in gas gangrene is known as -toxin, which has
Lecithinase and sphingomyelinase.

37

All members of the genus clostridia are motile
except what?

Strain A causes both gas gangrene and enterotoxicity!

38

What is the most common way for getting C. perfringens food poisoning?

C. perfringens food poisoning is commonly acquired by eating improperly
cooked beef or pork meat that is soiled with the clostridial spores.

39

What is the mechanism of C. Perfringens cause?

The enterotoxin forms a complex protein that forms pores in the cells of
the intestine and allow potassium ions and fluids to leak out.

40

What is the morphology of C. diff? Aerobic?

Gram positive rod
Anaerobe

41

What is the reservoir for C. diff?

Colon

42

What is the pathogenesis for C. Diff?

Clindamycin and ampicillin decrease normal flora

43

What is the treatment for C. diff?

Metronidazole
Vancomycin

44

What is the function of exotoxin B of C. diff?

Kills mucosa and forms pseudomembranes

45

Clostridium perfringens that causes myonecrosis,
and cellulitis associated with wound infections, is
most likely responsive to what antibiotic?

Treatment of choice for gas gangrene of C. perfringens includes
penicillin and/or clindamycin.

46

What are the three major indications for vanco?

MRSA
C. Diff
Staph Epidermidis

47

What is the CCFA media for c. diff culturing

Cycloserine (kills gram -)
Cefoxitin
Fructose
Agar

48

What is the morphology of Corynebacterium diphtheriae?

Gram positive rods that form chinese characters

49

What is the agar used for corynebacterium?

Tellurite agar

50

What is the pathogenesis for Corynebacterium diphtheriae?

Gray pseudomembranes formed from inhibition of ADP ribosylating eIF-2

51

What are the major complications of Corynebacterium diphtheriae?

Myocardial damage
Neuropathy

52

What are the s/sx of Corynebacterium diphtheriae infection? (3)

-Gray pseudomembranes
-Laryngeal nerve spasms
-CHF

53

What is the treatment for Corynebacterium diphtheriae infection?

Passive immunoglobulins
PCN or erythromycin

54

What other bacteria produces a toxin similar to
diphtheria and blocks the elongation factor
(unzipping effect)?

Pseudomonas

55

What two gram-positive rods are known as
Chinese letter bugs?

Listeria and diphtheria are known as Chinese letter bugs.

56

Diphtheria toxin has tropism for what two organs?

Diphtheria toxin has tropism for: (1) nerves, causing neuritis and lysis of
myelin sheath neuritis (e.g. it causes laryngeal nerve spasm); and (2) for
myocardium, causing necrosis and degeneration of the myocytes.

57

What are the morphological characteristics of listeria monocytogenes? Hemolysis pattern?

Gram positive rods that grow as "chinese letters" on blood agar, with beta hemolysis

58

What are the most important sources for listeria monocytogenes?

-Unpasteurized milk
-Prepackaged meats

59

What is the major diseases caused by listeria monocytogenes?

Meningitis in infants and the elderly

60

What test distinguishes Listeria from B strep?

Catalase test distinguishes the two from each other. Listeria is catalasepositive.

61

The top two DOCs of Listeria are?
Ampicillin and

The second DOC of listeria is TMP/SMX

62

What is Infanti septic granulomatosis?

Infantiseptica is abortion or stillbirth fetus infected with Listeriosis and it is
characterized with granuloma and abscesses

63

Listeria is the second most common cause
meningitis in neonates. What are the first and
third common causes?

The first cause, group B streptococcus; and the 3rd cause, E coli (K1)

64

What four situation after establishing and clinical d of disease warrant administration of passive immunization?

1 Tetanus
2. Botulinum
3. CMV
4. Diphtheria

65

What type of immunity plays an important role in
Listeriosis?

Cell-mediated immunity.

66

Doe pseudomonas ferment lactose

Nah dawg

67

What is the pigment that pseudomonas produces? Smell?

Blue-green pigment
Grape smell

68

What is the treatment for pseudomonas? (3)

Piperacillin
Cipro
Gentamicin