Flashcards in Principles of infectious disease Deck (38):
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
T/F: Spores are metabolically active.
How does bacterial infection cause fever?
endotoxin activates macrophages to release IL-1 and TNF, causing fever
Name 5 common zoonotic bacteria.
Borrelia burgdorferi, Brucella, Francisella tularensis, Yersinia pestis, Pasteirella multocida
Enterobaceriaceae: describe O, K, and H antigens
O - somatic, polysaccharide of endotoxin
K - capsular, related to virulence
H - flagellar, found in motile species
What kind of bacteria form spores and when?
certain gram + rods when nutrients are limited
Where is beta-lactamase in bacteria? What does it do?
periplasm of gram - bacteria
enzyme hydrolyzes beta-lactam antibiotics, conferring resistance
What molecule is specific to gram - bacterial cell membranes?
What are exotoxins and endotoxins, chemically speaking?
exotoxins tend to be polypeptides, while endotoxins are usually lipopolysaccharides
How could bacterial infection cause hypotension?
endotoxin induces macrophages to release nitric oxide -> vasodilation, hypotension
can also activate alternate complement pathway C3a, causing hypotension
Which organisms have exotoxin that acts by ADP ribosylation?
Corynebacterium diphtheriae, Escherichia coli, Vibrio cholerae, and Bordetalla pertussis
What helps organisms adhere to indwelling catheters?
glycocalyx (composed of polysaccharide)
Name the dominant normal flora on the teeth.
Being in a newborn nursery is a risk factor for which two pathogens?
CMV and RSV
Name the dominant normal flora in the oropharynx.
Name the dominant normal flora in the vagina.
Lactobacillus, E. coli, group B strep.
What disinfecting procedure kills spores?
Which pathogen is most associated with total parenteral nutrition?
Where do bacteria keep their exotoxin or endotoxin genes?
exotoxin genes on plasmids or bacteriophages
endotoxin genes on bacterial chromosomes
T/F: we can vaccinate against exotoxins and endotoxins
we have toxoid vaccines against exotoxins for diseases like tetanus, botulism and diphtheria, but there are no vaccines against endotoxins
T/F: Spores are highly resistant to destruction by heat and chemicals.
Gram for gram, which is more fatal: exotoxin or endotoxin?
Name the dominant normal flora in the colon.
Bacteriodes fragilis > E. coli
How is catalase a virulence factor?
it degrades H2O2, an antimicrobial product of PMNs
Name the dominant normal flora of the nose.
Are vaccines available for encapsulated bacteria?
What are two of the most common causes of nosocomial infections?
E. coli (UTI) and Staph. aureus (wound infection)
What are spores made of? What do they protect from?
keratin-like coat, dipicolinic acid
provide resistance to dehydration, heat and chemicals
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
Spores have ___ acid in their core.
What are the two pathogens most commonly associated with urinary catheterization?
E. coli, Proteus mirabilis
What is the most likely pathogen when a water source (water aerosols) is involved?
Name four organisms with IgA proteases.
Strep. pneumoniae, N. meningitidis, N. gonorhoeae, H. influenzae
What pathogen is often found on respiratory therapy equipment?
What is the main virulence factor of encapsulated bacteria and how does it confer virulence?
polysaccharide capsule is antiphagocytic
Which has greater heat stability: endotoxin or exotoxin?
Name the dominant normal flora in the skin.