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MIcro Exam 1 > 2011 > Flashcards

2011 Flashcards

1
Q

_ _________ is the cause of exudative epidermitis in pigs

A

Staphylococcus hyicus subspecies 1

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2
Q

___________________________ is a bacterial organism associated with bumblefoot in pet birds.

A

Staphlyococcus aureus

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3
Q

_____________ is the most common cause of abscesses in small ruminants

A

Corynebacteria pseudotuberculosis var ovis

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4
Q

___________________ is the test used to place members of the genus Streptococcus into groups.

A

Lancefeild test

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5
Q

___________________________ is a swine pathogen that produces muramidase-released protein (MRP) and suilysin

A

Streptococcus suis

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6
Q

___________________________ is an obligate intramammary pathogen of dairy cattle

A

Streptococcus aglactiae

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7
Q

___________________________ is an organism that commonly grows on plants and in soil and intestinal tracts of herbivores and causes neurologic disease and abortions in cattle, sheep and others.

A

Listeria monocytogenes

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8
Q

___________________________ is an organism that produces a toxin which breaks down the phagosomal membrane which allows the organism to grow in the cytosol

A

Listeria monocytogenes: listeriolysin O

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9
Q

___________________________ has a very broad host range that is highly dependent on the serotype of the organism (a given host may only be infected by one or two serotypes).

A

Eryosipothrix rhusiopathiae

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10
Q

___________________________ is an organism that causes an ascending infection of the urinary tract of cattle.

A

Corynebacterium renale

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11
Q

___________________________ is the cause of ulcerative posthititis of sheep and goats.

A

Corynebacterium renale

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12
Q

List the complete names of the three components of the Bacillus anthracis toxin and the function of two of them.

A

Protective antigen
acts as B subunit, binds receptor, allows entry of EF/LF
Lethal factor
Cleaves MAP/ERK kinase, interferes w signal transduction to CD4+ lymphocytes/fibroblasts inhibiting IL2 pdx and proliferative CD4+ T cell proliferation
Edema factor
Activates adenyl cyclase, interferes w/ cellular activity

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13
Q

Why are beta-lactam antimicrobials active only against bacteria that are actively growing?

A

Interfere with transpepidase (PBP) involved in the crosslinking peptidoglycan, transpeptidase is only functioning when the cell is growing actively

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14
Q

Why is antibody against bacterial flagella not usually very beneficial for a host?

A

Antibody is attached well away from the bacteria cell wall and any complement that is fixed cannot facilitate killing, most antibody could do is slow down the bacterial motility but that is unlikely

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15
Q

Explain why bacteria that form microcolonies are so successful as pathogens?

A

Because you cant kill us all!- phagocytes cannot phagocytose and kill the whole colony

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16
Q

Why do bacterial capsules tend to be relatively poor antigens?

A

Capsules are usually composed of very simple polysaccharides that do not have sufficient complexity to stimulate a good immune response

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17
Q

Explain why host antibodies alone are relatively ineffective at killing bacteria

A

Antibody molecules do not have any method of damaging bacterial cells directly with the exception of mycoplasmas which lack a cell wall. Antibody is only active as an opsonin (for phagocytosis), through complement, or by inhibiting adherence or other functions.

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18
Q

Outline an easy method for converting a proteinaceous toxin into a toxoid.

A

Grow organism or isolate the toxin itself from the organism, add formalin, incubate overnight

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19
Q

Outline an easy method for converting a proteinaceous toxin into a toxoid.

A

Grow organism or isolate the toxin itself from the organism, add formalin, incubate overnight

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20
Q

What are defensins and where are they produced?a. What are they? ___________________b. Where are they produced? _______________

A

A. relatively small antimicrobial polypeptides

B. commonly produced in epithelial cells of the intestine, respiratory tract, mammary gland, skin, kidney, eye and tongue, also produced by granulocytes

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21
Q

Explain how stepwise development of resistance to an antimicrobial occurs.

A

When exposed to an antimicrobial, some bacterial w/ a low level of resistance survive and multiply
Survivors are exposed to higher level of same drug, few with a higher level of resistance survive and multiply
This continues w/ increases concentrations of a given drug

22
Q

The enterotoxins of Staphylococcus aureus are superantigens. Why do they never cause fatal disease typical of superantigens?

A

They are active on intestinal epithelium and apparently do not get into the systemic circulation in sufficient quantity or are altered when absorbed.

Some will get into circulation, however and since the emesis is deu to systemic effects, if they are inhaled or injected, the enterotoxins are very potent (0.0004 micrograms of SEB causes emesis) higher doeses can kill

23
Q

List three general types of cytolytic toxins (three different mechanisms of action).

A

Thiol activated or sulfydrl activated- sequester cholesterol on cell membranes
Phospholipases
RTX or pore forming

24
Q

One of your equine clients is participating in a vaccine trial for influenza virus and part of the pre-study examination is determination of immunoglobulin levels in his horses. One of the horses had a serum IgA level that was four times normal levels. Is this horse at increased risk for developing purpura hemorrhagica? Explain

A

Very Unlikely- IgA would need to be specific for the M-protein of Stretococcus equi. S ewui is unlikely to stimulate that high of a titer

25
Q

T/F Bacterial lipopolysaccharides can activate complement by both the classical and alternate pathways.

A

True

26
Q

T/F The peptidoglycan of gram positive organisms is more rigid that that of gram negative organisms because of the more extensive crosslinking of the N-acetyl muramic acid (NAM).

A

True

27
Q

T/F The peptidoglycan of gram positive organisms is more rigid that that of gram negative organisms because of the teichoic acids that are a major component of some gram positive bacteria.

A

True

28
Q

T/F Teichoic and lipoteichoic acids are dominant cell antigens in many gram positive bacteria.

A

True

29
Q

T/F Teichoic acids of Staphylococcus aureus can be released from the cell, combine with antibody and consume complement components up through C5.

A

True

30
Q

T/F Porin proteins are important components of gram positive bacteria.

A

False

31
Q

T/F The M-protein of Streptococcus equi is a fimbrial protein.

A

False

32
Q

T/F The more dependent a protective immune response is to a single bacterial or viral antigen, the more likely it will be that some animals will not respond to that antigen.

A

True

33
Q

T/F T-helper 2 responses are more likely than T-helper 1 responses to result in a cytotoxic response to bacterial antigens.

A

False

34
Q

T/F Endotoxin that binds to CD14 in the serum is rapidly transferred to lipoprotein which enhances its toxicity.

A

False

35
Q

T/F Bacterial A-B structure toxins often bind to cell receptors for hormones or vitamins.

A

True

36
Q

T/F The B portion of an A-B structure toxin is usually a better immunogenic protein because it is larger than the A-portion.

A

True

37
Q

T/F Endogenous biological response modifiers are commonly used in veterinary medical practice.

A

False

38
Q

T/F Breakpoints are not commonly available for animal pathogens to guide antimicrobial therapy.

A

True

39
Q

t/f Chloramphenicol use in food-producing animals in the U.S. is strictly prohibited.

A

True

40
Q

T/F Draxxin (tulathromycin) and Zactran (gamithromycin) are older macrolide antimicrobials that are rapidly eliminated from tissues and are generally not a concern for tissue residues in meat and milk.

A

False

41
Q

T/F Staphylococcus schleiferi is the most common cause of pyoderma and otitis externa in dogs.

A

False

42
Q

T/F Beta-hemolytic streptococci do not readily develop resistance to beta-lactam antimicrobials.

A

True

43
Q

T/F Trueperella pyogenes infections are most commonly seen in ruminants but a wide range of animals have sporadic infections.

A

True

44
Q

T/F Erysipelothrix rhusiopathiae has developed resistance to beta-lactam antibiotics because of the overuse of these antibiotics in turkey production.

A

False

45
Q

T/F Rhodococcus equi commonly causes intraperitoneal abscesses in horses that rupture and lead to the death.

A

False

46
Q

Which of the following is not a property of peptidoglycan?

a. It usually decreases the resistance of a host to infectious agents.
b. It can have toxic effects on an infected host.
c. It can stimulate macrophages to produce interleukin 1 (IL1).
d. It can activate B cells
e. It protects the bacterial cell from the environment

A

a. It usually decreases the resistance of a host to infectious agents.

47
Q

Antigenic shift

a. Is commonly used by pathogens that cause acute, fatal diseases.
b. Is commonly used by pathogens that grow well in abscesses.
c. Is commonly used by pathogens that have polypeptide capsules.
d. Is commonly used by pathogens that form microcolonies.
e. All the above
f. None of the above.

A

f. None of the above.

48
Q

Antigenic similarity

a. Is used by most pathogenic bacteria to avoid the immune response.
b. Is commonly used by pathogens that grow well in abscesses.
c. Is commonly used by pathogens that have polypeptide capsules.
d. Is commonly used by pathogens that use inconspicuous adherence.
e. None of the above.

A

d. Is commonly used by pathogens that use inconspicuous adherence.

49
Q

Which of the following organisms is most likely to stimulate a CD8+ T-cell response?

A

c. Listeria monocytogenes

50
Q

The DNase of Staphylococcus aureus:

a. Is actually a nuclease that breaks down both DNA and RNA
b. Is important for survival of the organism inside abscesses.
c. Is important for organisms that cause dermatitis and other superficial infections.
d. Only a and b above.
e. Only a and c above.

A

d. Only a and b above.

51
Q

Group A streptococci

a. Are represented by only one species (Streptococcus canis).
b. Are mostly isolated from dogs.
c. Are responsible for necrotizing faciitis (flesh-eating bacteria disease).
d. Cause mostly superficial infections
e. None of the above.

A

. Are responsible for necrotizing faciitis (flesh-eating bacteria disease).

MIcro Exam 1 (2 decks)

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