Resistance to Antibiotics Flashcards Preview

Micro/Immuno Part 2 > Resistance to Antibiotics > Flashcards

Flashcards in Resistance to Antibiotics Deck (16):
1

natural resistance

-chromosomally mediated and is predictable
-innate
-structural or functional characteristics

2

mutational resistance

-random mutation
-secondary resistance occurring after therapy with the antimicrobial agent in question has begun

3

transferable resistance

-plasmid mediated through
-conjugation
-transduction
-transformation
-horizontal gene transfer

4

transposons

-genetic element
-can't self replicate
-translocate as unit from one chromosome to another or between chromosome and plasmid or phage
-code functional genes
-flanked by identical short seq-inverted repeats

5

insertion

-can't self replicate
-transferred
-don't encode genes
-encodes functions involved in insertion events and contain promoter seq
--flanked by identical short seq-inverted repeats

6

integrons

-mobile DNA elements with ability to capture genes-resistance-site specific recom
-genes that are captured on are gene cassettes (circular protected DNA)
-recom hot spot
-own integrase function and has efficient promoter site near 5' end
-as gene gets farther from promoter, expression go down-can be moved closer to promoter to increase expression

7

mechanisms of antibiotic resistance

-enzymatic inactivation
-decreased perm
-efflux
-alteration of target site
-protection of target site
-overproduction of target site
-bypass inhibited process

8

decreased perm

-passage of antibiotics normally through porins
-bigger is more neg-less likely to penetrate
-mutations in porins-increased resistance
-resistance to aminoglycosides and carbapenems is associated with lack of production of outer membrane proteins

9

efflux

tetracyclines
-macrolides and streptogramins
fluoroquinolones

10

altered target sites

tetra, macro, lincosamides, aminoglycosides-failure of ribosomal binding site

11

alteration of cell wall-VRE

-e faecalis-alteration to cell wall- vanco can't bind

12

alteration of target enzymes

-b lactams-bind to PBP- alteration of PBP can lead to resistance
-MRSA-mecA gene

13

protection of target sites

-tetra-can't bind

14

overproduction

sulfonamides and trimethoprim

15

bypass inhibition

-auxotrophs. growth factors different
-enterococci
-change in thymidylate synthase-highly resistant to sulfa

16

binding of antibiotic

-VISA
-traps vanco