antimicrobial chemotherapy mechanisms of action and resistance Flashcards Preview

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Flashcards in antimicrobial chemotherapy mechanisms of action and resistance Deck (45)
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1

bactericidal

An antimicrobial that kills bacteria (e.g. the penicillins).

2

Bacteriostatic

An antimicrobial that inhibits growth of bacteria
(e.g. erythromycin).

3

Sensitive

An organism is considered sensitive if it is inhibited or killed
by levels of the antimicrobial that are available at the site of
infection.

4

Resistant

An organism is considered resistant if it is not killed or inhibited
by levels of the antimicrobial that are available at the site of
infection.

5

MIC

Minimal inhibitory concentration is defined as the minimum
concentration of antimicrobial needed to inhibit visible growth
of a given organism.

6

MBC

Minimal bactericidal concentration is defined as the minimum
concentration of the antimicrobial needed to kill a given organism.

7

routes of administration of antimicrobial agents

topical
systemic
parenteral

8

Topical

Applied to a surface, usually skin or to mucous membranes e.g.
conjunctiva.

9

Systemic

Taken internally, either orally or parenterally

10

Parenteral

Administered either intra-venously (iv) or intra-muscularly (im),
occassionally subcutaneously

11

sites of antibiotic action

1. inhibition of cell wall synthesis
2. inhibition of protein synthesis
3. inhibition of nucleic acid synthesis

12

drug groups that inhibit cell wall synthesis

1. β-lactams
2. glycopeptides

13

β-lactams examples

-penicillins and cephalosporins
-benzyl penicillin

14

action of penicillins and cephalosporins

inhibit the synthesis of cell wall by binding to penicillin binding proteins, this inhibits the enzymes that produce cross bridges between carbohydrate.

15

benzyl penicillin

original form of penicillin isolated, less useful than derivatives

16

β-lactamases

enzymes produced by bacteria resistant to β-lactams, they breakdown the functional group, turning them from a toxin to a food.

17

glycopeptides examples

-vancomycin
-teicoplanin

18

vancomycin and teicoplanin action

inhibit the assembly of peptidoglycan precursor

19

vancomycin toxicity

toxicity is very common with vancomycin as small therapeutic range

20

drugs types that inhibit protein synthesis

-aminoglycosides
-macrolides and tetracyclines
-oxazolidinones
-cyclic lipoprotein

21

aminoglycosides use

eg, gentamicin used to treat gram negative infections

22

gentamicin toxicity

it is toxic to requires a careful dosing regime and monitoring of levels

23

examples of macrolides

erythromycin. clarythromycin

24

macrolides and tetracyclines use

used as an alternative to penicillin and used against gram positive bacteria

25

Trimethoprim and sulphamethoxazole action

inhibit different steps in purine
synthesis, and are used in a combined form in the drug co-trimoxazole

26

Oxazolidinones example

Linezolid

27

Linezolid use

used to treat MRSA infections

28

cyclic lipopeptide example

Daptomycin

29

Daptomycin use

used against MRSA and gram positives in general

30

drugs that inhibit nucleic acid synthesis

-Trimethoprim and sulphamethoxazole
- Fluoroquinolones