Antimicrobial drugs and resistance Flashcards Preview

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Flashcards in Antimicrobial drugs and resistance Deck (20):
1

antimicrobial drugs

-compounds that kill or control the growth of microorganisms in the host
-selective toxicity
-two broad categories
-synthetic and natural

2

synthetic antimicrobial drugs

-growth factor analogs
-quinolones

3

Growth factor analogs

-structurally similar to growth factors but do not function in the cell
*analogs similar to vitamins, amino acids, and other compounds
-sulfa drugs: discovered by Domagk
*inhibit growth of bacteria (ex. sulfanilamide) by inhibiting folic acid synthesis and thus nucleic acid synthesis

4

quinolones

-inhibit DNA gyrase (ex. ciprofloxacin), prevent DNA supercoiling
-activate against broth gram-negative and gram-positive bacteria

5

Natural antimicrobial drugs

-antibiotics
-produced by bacteria and fungi
-

6

beta-lactam antibiotics (B-lactem)

-cell wall synthesis inhibitors
(ex penicillins and cephalosporins)
-comprise of over 50% of antibiotics used around the world

7

penicillins

-discovered by alexander fleming
-target cell wall (peptidoglycan synthesis)
*transpeptidation
-effective against gram positive bacteria
*some synthetic forms active against gram negative bacteria

8

B-lactem antibiotics 2 typos

-penicillin
-cephalosporins

9

Cephalosporins

-fungus, cephalosporium sp.
-structurally different from penicillins
-similar mode of action to penicillins
-broader spectrum than penicillins
-resistant to B-lactamases
-commonly used to treat gonorrhea

10

antibiotics from bacteria

-aminoglycosides
-marcolides
-tetracyclines
-novel antibiotics

11

aminoglycosides

-amino sugars bonded by glycosidic linkage
*eg streptomycin, kanamycin, neomycin, gentamicin
-target 30S subunit of the ribosome
-useful against gram negative bacteria
*not as commonly used
*last resort antibiotics

12

Macrolides

-lactone rings bonded to sugars
-eg. erythromycin (streptomyces erythreus)
-broad spectrum
-target 50S subunit of the ribosome
*partial inhibition of protein synthesis
*->preferential translation of some proteins

13

Tetracyclines

-produced by several species of streptomyces
-broad spectrum
-natural and semisynthetic
-inhibit 30S subunit of ribosome
-most widely used antibiotic along with penicillins
*veterinary and as growth promoters -> resistance

14

novel antibiotics

-daptomycin
-platensimycin

15

daptomycin

-produced by streptomyces
-cyclic lipopeptide -active against gram positives
-forms pores in CM ->depolarization

16

platensimycin

-new class of antibiotics
-fatty acid biosynthesis inhibitor
*no host toxicity
-broad-spectrum including MRSA and VRE

17

antimicrobial drug resistance

-ability of a microorganisms to resist the effects of an antimicrobial agent to which it is normally sensitive
-chromosomal Vs plasmid-encoded
-mechanisms of resistance

18

resistance mechanisms

-resistance (R) plasmids
-widespread antibiotic usage in medicine, veterinary, and agriculture selects for resistance
-80% of all antibiotic produced used for agricultural practices

19

two types of resistance mechanisms

-methicillin-resistant staphylococcus aureus -MRSA
-Vanocomycin-resistant enterococci -VRE

20

preventiving antimicrobial resistance

-prevention of infections
-rapid, conclusive diagnosis
-prevent use of antimicrobials
-prevention of transmission