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Flashcards in Introduction to Pathogens Deck (15):
1

bacterial strain

population of organisms w/in a species that descends from a single organism

2

how do strains evolve

mutation or acquiring new genes via horizontal transfer

3

what are the ways bacteria obtain new genes?

1 conjugation- (mating b/t bacteria)

2 transduction- (DNA moved via bacteriophage from one cell to another)

transformation- bacteria take up free DNA from environment

4

bacterial serotype

strain that is differentiated by serological means

5

what is serotyping?

the use of antisera containing antibodies reactive to bacterial surface antigens

6

what are the common bacterial antigens?

O- polysaccharide component of LPS- repeating sugars that can vary w/in a strain

H- the flagellar antigen

K- polysaccharide capsule component

7

are infections caused by a single strain or multiple? epidemics?

both single strains

8

infectious dose

approximate number of microbes that on average are required to cause an infection

9

virulence factors

secreted enzymes involved in nutrient acquisition that directly cause damage to the host (direct damage, immune modulation, diarreha, cough, etc)

can be referred to as toxins/exotoxins b/c they are excreted from the cell

10

virulence determinant

virulence factors that are required for disease

11

endotoxin

lipid A component of LPS

causes fever and shock

12

how does the host innate immune system respond to low [endotoxin]

1 macrophages activated and secrete TNF

2 increased phagocyte/lymphocyte/platlet activation and migration

3 phagocytosis of bacteria

4 occlusion of local blood vessels

5 plasma cells drain to local lymph

6 infection removed

13

endotoxic shock

caused by excess endotoxin; highly lethal

causes:
1 fever
2 inflammation
3 hypotension
4 DIC/bleeding
5 organ ischemia and failure

treated w/ oxygen, fluids, medicine to control BP

14

bacteremia

presence of bacteria in the blood

15

septicemia

body wide response to bacteria or bacterial products in the blood