Exam 1 Flashcards

1
Q

Define a Direct Test

A

Detect pathogens or products

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2
Q

Types of direct tests

A

Culture, PCR, Sequencing

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3
Q

Define an Indirect Test

A

Detect immune response (antibody) to pathogen

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4
Q

Types of indirect tests

A

Agglutination, ELISA, Lateral flow

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5
Q

Define Sensitivity

A

Ability to identify TRUE positives

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6
Q

Define Specificty

A

Ability to identify TRUE negatives

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7
Q

Define Positive Predictive Value (PPV)

A

Probability the disease is present when the test is positive

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8
Q

Define Negative Predictive Value (NPP)

A

Probability the disease is not present when the test is negative

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9
Q

Define Prevalence

A

What is the probability of the target condition occurring in the population

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10
Q

How do you calculate Sensitivity?

A

True positives / (all animals tested true positives + false negatives)

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11
Q

How do you calculate Specificity?

A

True negatives / (false positives + true negatives)

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12
Q

Define Screening Test

A

A sensitive test with few false negative results.

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13
Q

Define Confirmatory Test

A

A specific test with few false positive results.

Ideally, this would be a highly sensitive and specific test

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14
Q

What is a Bacterial or Fungal Culture?

A

Identification of bacteria and fungi through: colony and cell morphology characteristics and protein and nutrient-utilization differences

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15
Q

Does a culture require live bacteria/fungi?

A

Yes

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16
Q

How quickly can you get Culture Results?

A

Varies - but can be slow if the bacteria or fungi grow slowly

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17
Q

Sensitivity/Specificity of a culture?

A

Variable

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18
Q

What is PCR?

A

Identification of bacteria through exploitation of DNA sequence differences using DNA primers specific for a pathogen

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19
Q

Specificity/Sensitivity of a PCR?

A

Highly specific and sensitive

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20
Q

How quickly can you get PCR results?

A

Rapid results regardless of the pathogen

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21
Q

Do you need live bacteria/fungi for a PCR?

A

No- can be either live or dead

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22
Q

Can you do antimicrobial susceptibility testing with PCR? Why or why not?

A

No - there is no bacteria to isolate to grow in test

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23
Q

What is Sequencing?

A

Identification of bacteria by sequencing the entire genome or segments of DNA

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24
Q

Do you need live bacteria/fungi for sequencing?

A

No - can be live or dead

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25
Q

Benefits of Sequencing?

A

Allows for extremely specific identification
Allows for evaluation of the presence of genes related to virulence and antimicrobial resistance

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26
Q

Downfalls of sequencing?

A

Expensive and generally slow

Cannot do antimicrobial susceptibility testing as there is no bacterial isolate to grow in test

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27
Q

What is an Agglutination test?

A

Detects antibody by mixing patient serum with antigen of interest

Cross-linking of patient antibody with test antigen creates visible clumping

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28
Q

Specificity/Sensitivity of Agglutination Tests?

A

Less specific, more sensitive

*may see false positives necessitating a second confirmatory test

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29
Q

What is an ELISA?

A

Detects patient antibody to test antigen fixed to the plate

A more high-through put, automated test

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30
Q

Specificity/Sensitivity of ELISAs?

A

Generally good sensitivity and specificity

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31
Q

What is a Lateral Flow Test?

A

A rapid test that detects antigen or antibody

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32
Q

Specificity/Selectivity of a Lateral Flow Test?

A

Generally good specificity and selectivity

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33
Q

Ab Tests:

May see false positives if there is cross-reactivity between ??

A

May see false positives if there is cross-reactivity between pathogen of interest and another agent

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34
Q

Ab Tests:

May see false negatives if ??

A

May see false negatives if early in infection before detectible antibody is available

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35
Q

Ab Tests:

Can detect maternal antibody up to ??? age

A

Can detect maternal antibody up to 6 months of age

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36
Q

Ab Tests:

A single test DOES/DOES NOT differentiate (usually) between a previous infection, current infection or vaccine response

A

A single test does not differentiate (usually) between a previous infection, current infection or vaccine response

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37
Q

Negatives of using a Swab to Sample?

A

Small sample size
Reduced recovery of organisms from swab
Not good for fungi

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38
Q

What is MALDI-TOF?

A

Mass Spec to identify bacteria

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39
Q

Is A. bovis Gram + or Gram - ?

A

Gram +

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40
Q

Is A. Lingnieresii Gram + or Gram - ?

A

Gram -

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41
Q

Is E. coli Gram + or Gram - ?

A

Gram -

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42
Q

Is Salmonella spp. Gram + or Gram - ?

A

Gram -

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43
Q

Is Lawsonia intracellularis Gram + or Gram - ?

A

Gram -

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44
Q

Is C. perf Gram + or Gram - ?

A

Gram +

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45
Q

Is Brachyspira spp. Gram + or Gram - ?

A

Gram -

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46
Q

Which of the following are Facultative Anaerobes?
1. A. bovis
2. A. Lingnieresii
2. E.coli (ETEC/STEC)
3. C.perf
4. Salmonella spp.

A

A. Lingnieresii, E. coli, Salmonella spp.

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47
Q

Which bacteria are Obligate Anaerobes?

A

A. bovis, Brachyspira spp. C. perf
(ABC!)

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48
Q

Which bacteria are Microaerophilic?

A

Lawsonia intracellularis and Campylobacter spp.

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49
Q

Which bacteria are extracellular?

A

A. bovis, A. lingnieresii, Brachyspira spp, C. perf
(AABC)

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50
Q

Which bacteria are Facultative Intracellular?

A

E. coli (ETEC and STEC) and Salmonella spp.

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51
Q

Which bacteria are Obligate intracellular?

A

Lawsonia intracellularis

52
Q

Which bacteria enter due to injury to the mouth/tongue?

A

A. bovis, A lingnieresii

53
Q

Which bacteria form spores?

A

C. perf and Clostridioides difficile

54
Q

Which bacteria are commonly found when feeding raw diets?

A

Salmonella spp. and Campylobacter spp.

55
Q

What is the major predisposing factor of Clostridioides difficile?

A

Hx of antimicrobial use and hospitalization in horses.

56
Q

Which bacteria is unable to be cultured?

A

Lawsonia intracellularis

57
Q

Which bacteria can cause organ failure?

A

C. perf

58
Q

Which bacteria attaches to M cells?

A

Salmonella spp.

59
Q

Which bacteria stimulates crypt cell proliferation?

A

Lawsonia intracellularis

60
Q

Which bacteria may require an antitoxin or neutralizing Ab?

A

C. perf

61
Q

Which bacteria can cause Edema?

A

STEC and C. perf

62
Q

Which bacteria require secondary testing? What are you testing for?

A

STEC and ETEC. PCR to determine is there are virulent genes present.

63
Q

Which bacteria use fimbriae to attach to the host?

A

ETEC, STEC

64
Q

Which bacteria have a predisposing factor of FPT?

A

ETEC, STEC, C. perf

65
Q

Which bacteria use an internal flagella for motility?

A

Brachyspira spp.

66
Q

Main differences between prokaryotes and eukaryotes

A

Prokaryotes: single chromosome. No mebrane bound organelles.
Eukaryotes: multiple chromosomes and membrane bound organelles.

67
Q

Majority of the gram + cell wall is..?

A

a thick layer of peptidoglycan

68
Q

Gram - cell wall is composed of:

A

small peptioglycan layer
outer membrane for protection (LPS)

69
Q

Define an obligate aerobe

A

require oxygen for growth

70
Q

define obligate anaerobes

A

cannot grow in the presence of oxygen

71
Q

define facultative anaerobes

A

can use oxygen, but can grow in other atmospheres too.

72
Q

define microaerophiles

A

need higher levels of CO2

73
Q

a community of microorganisms found on or in a healthy animal

A

Microbiota (AKA normal flora)

74
Q

the microbiota found at a given habitat and the host environment that they inhabit

A

microbiome

75
Q

where do we find microbiota on the body

A

GI tract, upper resp, external eye, skin, lower urogenital tract

76
Q

How is the microbiota established?

A

At birth, gradual maturation with different exposures (feed, stress, animal contact, envrionmental flora..) and genetics

77
Q

role of microbiota in the health of the host

A

development of the immune system, colonization resistance, direct and indirect protection, host nutrition.

78
Q

pathogen

A

a bacteria or fungi that causes Dz

79
Q

pathogenicity

A

ability to cause Dz

80
Q

Virulence

A

the degree of pathogenicity of the bacteria or fungi

81
Q

Colonization

A

presence of bacteria or fungi on body surfaces that do not cause disease, which may be beneficial to the host (aka microbiota)

82
Q

Common predisposing factors of the host

A
  • underlying disease
  • failure of passive transfer
  • immunologically naive
  • nutritional deficiency
83
Q

common predisposing factors (environment)

A
  • build up of pathogen load
  • crowding/stress
  • weather
  • geographic location
  • food/feed quality
  • travel
84
Q

Ingress

A

bacteria gain access to inner areas of the body with external connections but DO NOT cross epithelial barriers

85
Q

Penetration

A

across epithelial barrier into deeper tissues

86
Q

Common predisposing factors for oral infections:

A

‣ Trauma
‣ Foreign bodies
‣ Rough feed
‣ Tumors
‣ Dental issues
‣ Viral infections, especially those that cause oral lesions

87
Q

Common presenting signs of oral infections

A

‣ Swellings
* Abscesses
* Osteomyelitis
‣ Halitosis or fetid odor
‣ Difficulty swallowing, eating or drinking
‣ Tooth decay or loss
‣ Nasal discharge
‣ Salivation
‣ Cough

88
Q

Which bacteria produce endotoxins?

A

E. coli ETEC/STEC, Brachyspira spp.

89
Q

Are endotoxins associated with gram - or gram + outer membranes?

A

Gram negative

90
Q

Does C. perf produce endotoxins, exotoxins, and/or enterotixins?

A

Exotoxins/enterotoxins

91
Q

Which bacteria are microaerophilic?

A

Lawsonia intracellularis, camplytobacter spp.

92
Q

Which bacteria are zoonotic?

A

Salmonella spp, Campylobacter spp.

93
Q

Which bacteria can cause enterotoxemia?

A

STEC and C. perf Type D

94
Q

C. perf Type A with NetF toxin is associated with what disease?

A

hemorrhagic enteritis in foals and dogs

95
Q

What species does C. perf type A affect?

A

Bovine (calves)

96
Q

What species does C. perf type C affect?

A

Neonate Ag Animals

97
Q

What species does C. perf type D affect?

A

Ovine, goats

98
Q

What spescies deos C. perf type G affect?

A

Avian

99
Q

What C. perf types produce alpha toxin?

A

all types have alpha toxin

100
Q

What disease is associated with C. perf Type C?

A

Neonatal hemorrhagic and necrotizing enteritis

101
Q

What disease(s) is associated with C. perf Type D?

A

Ovine enterotoxemia,
enterotemia and enterocolitis in goats

102
Q

What disease is C. perf Type G associated with?

A

Avian necrotic enteritis

103
Q

Species/age associated with ETEC

A

Neonates, first 2-3 days of life

104
Q

Species/age associated with STEC

A

pigs around 4 weeks of age

105
Q

Species/age associated with Salmonella spp?

A

Lots of species, any age

106
Q

Species/age associated with Lawsonia intracellularis

A

pigs, weaning foals

107
Q

Age/species associated with C. perf?

A

Ag animals and occasionally foals within the 1st month of life

108
Q

species associated with brachyspira spp?

A

grower/finisher pigs

109
Q

What type of culture do you need for Brachyspira spp?

A

Anaerobic culture

110
Q

What type of culture do you need for C. perf

A

Anaerobic culture

111
Q

What type of culture do you need for A. bovis?

A

Anaerobic culture

112
Q

What type of culture do you need for a facultative anaerobe?

A

Aerobic

113
Q

which bacteria does not effect the intestinal wall

A

ETEC

114
Q

ETEC produces what type of diarrhea?

A

watery diarrhea (no blood)

115
Q

Salmonella spp. produces what type of diarrhea?

A

Inflammatory diarrhea (+/- blood)

116
Q

Lawsonia intracellularis produces what type of diarrhea?

A

malabsorptive diarrhea (+/- blood)

117
Q

C. perf produces what type of diarrhea?

A

severe hemorrhagic diarrhea

118
Q

Brachyspira spp. produces what type of diarrhea?

A

Malabsorptive diarrhea (mucoid to mucohemorrhagic)

119
Q

What is the toxic E.coli honorable mention that we learned?

A

EHEC

120
Q

What are the non-toxic E.coli honorable mention that we learned?

A

AIEC, EPEC

121
Q

E. coli EHEC is associated with…

A

production of attaching and effacing lesions, AND produces shiga-like toxins. Causes Dz in humans (Adult cattle are the reservoir)

122
Q

E. coli AIEC is associated with…

A

canine granulomatous colitis. Primarily affects boxers and bulldogs. Causes a malabsortive inflammatory diarrhea (+/- blood)

123
Q

E. coli EPEC is associated with….

A

characteristic attaching and effacing lesions. Causes malabsorptive diarrhea. Occurs in most species.

124
Q

Most enterotoxins of C. perf are carried on..?

A

plasmids (not alpha)

125
Q
A