Antibacterial agents Flashcards Preview

Clinical Pathology > Antibacterial agents > Flashcards

Flashcards in Antibacterial agents Deck (39):
1

definition of antibiotics

chemical product of microbes that inhibits or kills another organism.
OR
Natural substance produced by micro-organisms to kill each other.

2

Define antimicrobial agents

drugs used to kill organism.
synthetic- similar effect to antibiotics
semi synthehtic- modified from antibiotics.

3

2 types of bacterial killing

Bacteristatic- inhibit bacterial growth
Bactericidal- kills bacteria.

4

Define MIC

Minimal inhibitory concentration
concentration of antibiotic at which visible growth is inhibited.

5

Synergism

activity of 2 antimicrobials together is greeter than the sum of their activity separately.

6

Antagonism

one agent dimities the effect of another.

7

Indifference

activity unaffected by that of another.

8

Antibiotic targets include:

cell wall
protein synthesis
DNA synthesis
RNA synthesis
Plasma membrane

9

Main component of bacterial cell wall

Peptidoglycan
found in gram +ve and -ve.

10

2 cell wall synthesis inhibitors

B lactam- affect peptidocylcan cross linking
Glycopeptides.- affect peptidoglycan cross linking.

11

B lactams include:

penicillins- amoxicillin
Cephalosporins- cefuroxime
Carbapenems- meropenem, imipenem
Monobactams- aztreonam

12

Glycopeptide only work on what type of bacteria.

gram +ve bacteria.
cannot penetrate gram -ve outer membrane.

13

Most common example of a glycopeptide

vancomycin

14

Types of protein synthesis inhibitors.

Aminoglycoside
Macrolides Lincosamides Steptogramins (MLS)
Tetracyclines
Oxadolidilones

15

Most common amincoglyoside and mechanism of action

Gentamicin
bind to 30s subunit

16

Most common MLS and mechanism of action.

Erthromycin
Cindamycin
Bind to 50 s subunit

17

Most common Tetracylcines and mechanism of action

Doxytetracycline
bind to 30s subunit

18

Most common Oxazolidinones and mechanism of action

Linezolid
Bind to 50s or 70s subunit.

19

Types of DNA synthesis inhibitors.

Trimethoprim +sulphonamide= Co-trimoxazole.
Quinolones and fluoroquinolones

20

Co-trimooxazole mechanism of action

inhibit folate synthesis by inhibiting- dihydropteroate synthetase.

21

Most common Quinolones and fluoroquinolones and mechanism of action

Ciprofloxacin
Inhibit 1 or both DNA gyrase and topoisomerase.

22

RNA synthesis inhibtior

Rifampicin.

23

Rifamcin mechanism of action

prevents the synthesis of mRNA

24

Uses of colistin

last line drug when resistance to everything has been proved.

25

What type of bacteria is daptomycin used to treat.

Gram +ve
inserts lipophilic tail into cell membrane result in depolarisation

26

General side effects

Nausea, vommiting, headahce and skin rashes.

27

Side effects of aminoglycoslides

Reversible renal impairment on accumulation
Irreversible ototoxicity.- ear.

28

Side effects of B lactams

allergic reactions

29

side effect of linezolid

bone marrow depression

30

What causes c.difficile

to over use of antibiotics.

31

Strategy of antibiotic use

1- Empiric therpay- best guess therapy
2-targeted therapy- predict susceptibility and infecting organism
3-susecptibilty guided treatment- based on cultures.

32

How do you treat bacterial infections

Initially broad spectrum
once diagnosis known use a narrow spectrum antibiotic.

33

Treatment for MRSA

Flucloxacillin

34

Treatment for streptococcus pyogenes

Benzylpenicillin

35

Treatment for anaerobes

Metronidazole

36

3 Reasons for combining antibiotics

to increase efficacy
to provide adequately broad spectrum
To reduce risk of resistance.

37

treatment for gram +ves

vancomycin

38

treatment for gram -ves

cephlosporins

39

Treatment of bacteria is dependent on

concentration at the site of action
right amount of concentration
time