B2.052 The Microbial World Flashcards Preview

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Flashcards in B2.052 The Microbial World Deck (57)
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1

what are Koch's postulates?

1. the organism is regularly found in the lesion of the disease
2. the organism can be isolated in pure culture on artificial media
3. inoculation of this pure culture produces a similar disease in experimental animals
4. organisms can be recovered from the lesions in the animals

2

what did threat of ID decline in the 1900s?

sanitation and hygiene
chlorination of water
antibiotics
vaccination
animal and pest control

3

why can diseases re-emerge?

evolution of microorganisms
intensive misuse of antibiotics (selection for the proliferation of resistant organisms)
increased globalization
decline in public health in some regions
increase in people with decreased immune function

4

what are the classes of infectious agents?

priors (infectious proteins)
viruses (acellular)
bacteria (prok)
fungi (euk)
parasites (euk)
-protozoans (unicellular)
-helminths (multicellular)

5

rank microorganisms by size

viruses

6

what is the requirement in bacteria to be classified as the same species?

>97% identity in 16s rRNA
high degree of DNA sequence identity
more arbitrary than eukaryotes

7

bacillus

oval

8

coccus

circle

9

diplococcus
streptococcus
staphylococcus

2 cocci
chain of cocci
collection of cocci

10

funky shaped bacteria

coccobacillus: halfway between coccus and bacillus
curved rod
club shaped
spirochete

11

what is unique about the spirochete shape?

very thin
predestined to penetrate tissues

12

what is a spore?

formed under stress conditions
can survive in suboptimal circumstances better than the bacteria themselves
allow colonies to survive

13

what is the function of a capsule?

antiphagocytic
more chronic infection

14

gram positive

thick peptidoglycan cell wall

15

gram negative

thin PG layer with a second membrane
lipopolysaccharides acyl chain linkages with second membrane

16

spirochetes

have lipoproteins expressed on membrane
thing PG layer
flagella in between membranes

17

acid-fast

cant be stained by gram staining
waxy surface
-mycolic acids
-porins
-arabinogalactan

18

commensal

microorganism in symbiotic relationship with host

19

virulence

degree of pathogenicity

20

etiology

cause of disease

21

epidemiology

factors of disease spread
sporadic- small isolated cases
endemic- continually prevailing in a region
epidemic- outbreak
pandemic- worldwide outbreak

22

stages of infection disease

incubation period
prodrome
specific illness (localized or systemic)
convalescence

23

what is prodrome

nonspecific symptoms

24

what is convalescense

after resolution of symptoms to complete recover there can be complications
-chronic carriers
-latent infections
-permanent tissue damage

25

how do you measure virulence

ID50
LD50

26

microbiome of skin

gram+

27

microbiome of respiratory tract

nares- staphylococci

28

microbiome of GI

anaerobes

29

microbiome of GU

anterior urethra- lactobacilli
vagina- lactobacilli, others

30

what parts of the body are generally sterile

upper GU
lower respiratory tract