29. Antimicrobial Susceptibility Testing Flashcards Preview

Elsevier Bacteriology (RVSP) > 29. Antimicrobial Susceptibility Testing > Flashcards

Flashcards in 29. Antimicrobial Susceptibility Testing Deck (39):
1

Quantitative measure of the susceptibility of a bacterial isolate to an antimicrobial agent

MIC

2

Lowest concentration of antibiotic to kill the bacterial isolate in vitro

Minimal bactericidal concentration (MBC)

3

Give the standards for broth dilution, agar dilution, and diffusion

Broth dilution: 5x10^5 CFU/mL
Agar dilution: 1x10^4 CFU/mL
Diffusion: 1x10^8 CFU/mL

4

A chemical substance produced by a microorganism that can inhibit the growth or kill other microorganisms

Antibiotic

5

An agent that kills or supresses growth of microorganisms

Antimicrobial

6

Agents that prevent replication but does not kill the target

Bacteriostatic

7

Agents that result to cell death

Bacteriocidal

8

Examples of bacteriostatic agents

Macrolides
Tetracyclines
Sulfonamides

9

Examples of bacteriocidal agents

β-lactams
Vancomycin
Fluoroquinolones
Rifampin

10

Mechanisms of antimicrobial action

- cell wall inhibitors
- cell membrane inhibitors
- protein synthesis inhibitors
- other metabolic pathways inhibitors (folate metabolism)

11

Cell wall synthesis inhibitors

- β-lactams
- carbapenems
- vancomycin

12

Examples of β-lactams

Penicillin
Cephalosporins

13

Examples of carbapenems and monobactams

Imipenem
Meropenem
Aztreonam

14

Antibiotic that works only on growing cells

Penicillins

15

Penicillins are synergistic with

Aminoglycosides

16

Antibiotic that stops transpeptidation which causes the cell wall of bacteria to develop weak stops

Penicillins

17

Side effect if imipenem is overdosed

CNS toxicity

18

Antibiotics that are broad spectrum, low MICs, but expensive

Carbapenems

19

Mechanism of penicillins

Binds with penicillin-binding protein which stops transpeptidation

20

Mechanism of action of Vancomycin

Stops gram-positive cell wall peptidoglycan chain formation

21

Vancomycin is bactericidal for

Staphylococci
Streptococci

22

Vancomycin is bacteriostatic

Enterococci

23

Antibiotics that are cell membrane inhibitors

Colostin
Amphotericin
Polymyxin

CAP

24

Polymyxin B and Colistin are active against

Gram-negative bacteria

25

Mechanism of action of Polymyxin B and Colistin

Disrupts the gram-negative cell membrane

26

Specific bacteria that Polymyxin B and Colistin are effective against

P. aeruginosa

27

Antibiotics that are DNA/RNA inhibitors

Fluoroquinolones
Metronidazole
Nitrofurantoin
Rifampin

28

Examples of fluoroquinolones

Ciprofloxacin
Levofloxacin

29

Mechanism of action of fluoroquinolones

Inhibits DNA gyrase and/or topoisomerase ---> prevents DNA unwinding and blocks DNA synthesis

30

Mechanism of action of Metronidazole

Damages DNA and other molecules directly

31

Mechanism of action rifampin

Prevents RNA synthesis by inhibiting the DNA-dependent RNA polymerase

32

Antibiotic that has intracellular activity

Rifampin

33

Antibiotics that are protein-synthesis inhibitors

Clindamycin
Linezolid
Aminoglycosides
Macrolides
Quinupristin/dalfopristin
Tetracyclines

CLAMQT

34

Examples of macrolides

Azithromycin
Clarithromycin
Erythromycin
Dirithromycin

ACED

35

Examples of aminoglycosides

Tobramycin
Amikacin
Neomycin
Gentamicin

TANG

36

Examples of Tetracyclines

Doxycycline
Minocycline
Tetracycline

DMT

37

Antibiotics that are inhibitors of intermediate metabolism

Trimethoprim
Sulfamethoxazole

38

Mechanism of action of Trimethoprim and Sulfamethoxazole

Stops folate synthesis

39

Lowest concentration observed to inhibit growth of the isolate in vitro

Minimal inhibitory concentration (MIC)