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NPLEX - Microbiology and Immunology > Principles of infectious disease > Flashcards

Flashcards in Principles of infectious disease Deck (38):
1

What is present in the wall of a gram + bacteria that is not present in a gram negative bacteria?

thick peptidoglycan layer

teichoic acid in wall

2

T/F: Spores are metabolically active.

false

3

How does bacterial infection cause fever?

endotoxin activates macrophages to release IL-1 and TNF, causing fever

4

Name 5 common zoonotic bacteria.

Borrelia burgdorferi, Brucella, Francisella tularensis, Yersinia pestis, Pasteirella multocida

5

Enterobaceriaceae: describe O, K, and H antigens

O - somatic, polysaccharide of endotoxin

K - capsular, related to virulence

H - flagellar, found in motile species

6

What kind of bacteria form spores and when?

certain gram + rods when nutrients are limited

7

Where is beta-lactamase in bacteria? What does it do?

periplasm of gram - bacteria

enzyme hydrolyzes beta-lactam antibiotics, conferring resistance

8

What molecule is specific to gram - bacterial cell membranes?

LPS

9

What are exotoxins and endotoxins, chemically speaking?

exotoxins tend to be polypeptides, while endotoxins are usually lipopolysaccharides

10

How could bacterial infection cause hypotension?

endotoxin induces macrophages to release nitric oxide -> vasodilation, hypotension

can also activate alternate complement pathway C3a, causing hypotension

11

Which organisms have exotoxin that acts by ADP ribosylation?

Corynebacterium diphtheriae, Escherichia coli, Vibrio cholerae, and Bordetalla pertussis

12

What helps organisms adhere to indwelling catheters?

glycocalyx (composed of polysaccharide)

13

Name the dominant normal flora on the teeth.

strep. mutans

14

Being in a newborn nursery is a risk factor for which two pathogens?

CMV and RSV

15

Name the dominant normal flora in the oropharynx.

strep. viridans

16

Name the dominant normal flora in the vagina.

Lactobacillus, E. coli, group B strep.

17

What disinfecting procedure kills spores?

autoclaving

18

Which pathogen is most associated with total parenteral nutrition?

Candida albicans

19

Where do bacteria keep their exotoxin or endotoxin genes?

exotoxin genes on plasmids or bacteriophages

endotoxin genes on bacterial chromosomes

20

T/F: we can vaccinate against exotoxins and endotoxins

false

we have toxoid vaccines against exotoxins for diseases like tetanus, botulism and diphtheria, but there are no vaccines against endotoxins

21

T/F: Spores are highly resistant to destruction by heat and chemicals.

T

22

Gram for gram, which is more fatal: exotoxin or endotoxin?

exotoxin

23

Name the dominant normal flora in the colon.

Bacteriodes fragilis > E. coli

24

How is catalase a virulence factor?

it degrades H2O2, an antimicrobial product of PMNs

25

Name the dominant normal flora of the nose.

Staph. aureus

26

Are vaccines available for encapsulated bacteria?

yes

27

What are two of the most common causes of nosocomial infections?

E. coli (UTI) and Staph. aureus (wound infection)

28

What are spores made of? What do they protect from?

keratin-like coat, dipicolinic acid

provide resistance to dehydration, heat and chemicals

29

What is the major surface antigen of gram + cell walls and which two cytokines does it induce?

teichoic acid - unique to gram + bacteria

induces TNF and IL-1

30

Spores have ___ acid in their core.

dipicolinic

31

What are the two pathogens most commonly associated with urinary catheterization?

E. coli, Proteus mirabilis

32

What is the most likely pathogen when a water source (water aerosols) is involved?

Legionella

33

Name four organisms with IgA proteases.

Strep. pneumoniae, N. meningitidis, N. gonorhoeae, H. influenzae

34

What pathogen is often found on respiratory therapy equipment?

Pseudomonas aeruginosa

35

What is the main virulence factor of encapsulated bacteria and how does it confer virulence?

polysaccharide capsule is antiphagocytic

36

Which has greater heat stability: endotoxin or exotoxin?

endotoxin

37

Name the dominant normal flora in the skin.

Staph. epidermidis

38

How might a bacterial infection cause disseminated intravascular coagulation?

endotoxin can activate Hageman factor which initiates coagulation cascade, causing DIC