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