Antibacterial agents intro

Question 1

Define bacteristatic

Answer 1

Inhibit bacterial growth

Protein synthesis inhibitors

Question 2

Define Bactericidal

Answer 2

Kill bacteria

Cell wall-active agents

Question 3

Define Minimum inhibitory concentration – MIC

Answer 3

Minimum concentration of antibiotic at which visible growth is inhibited

Question 4

Define Synergism

Answer 4

Activity of two antimicrobials given together is greater than the sum of their activity if given separately

Question 5

Define Antagonism

Answer 5

One agent diminishes the activity of another

Question 6

Define Indifference

Answer 6

Activity unaffected by the addition of another agent

Question 7

What are the 2 main antibacterial mechanisms?

Answer 7

Inhibition of critical process in bacterial cells (Enzymes, molecules or structures)

Selective toxicity
(Target not present in human host or target significantly different in human host)

Question 8

What are 5 main antibiotic targets in a bacterial cell?

Answer 8

Cell wall
Protein synthesis 
DNA synthesis
RNA synthesis
Plasma membrane

Question 9

What is the major component of bacterial cell walls?

Answer 9

Peptidoglycan

made up of NAM and NAG

Question 10

Which 2 types of antibiotics are cell-wall synthesis inhibitors?

Answer 10

β-lactams

Glycopeptides

Question 11

Name 4 β-lactam antibiotics categories

Answer 11

Penicillins
Cephalosporins
Carbapenems
Monobactams

Question 12

Name 2 glycopeptide antibiotics

Answer 12

vancomycin, teicoplanin

Question 13

What are the 4 main groups of protein synthesis inhibiting antibiotics?

Answer 13

Aminoglycosides
MLS (macrocodes, lincosamides, steptogramins)
Tetracyclines
Oxazolidinones

Question 14

What are some examples of aminoglycosides?

Answer 14

Gentamicin, amikacin

Question 15

What are some MLS antibiotics?

Answer 15

Erythromycin, clarithromycin

Clindamycin

Question 16

Give an example of an oxazolidinone

Answer 16

Linezolid.

Question 17

What are some DNA synthesis inhibitor antibiotic categories?

Answer 17

Trimethoprim, Sulfonamides,

Quinolones and fluoroquinolones

Question 18

What are examples of quinolones?

Answer 18

nalidixic acid, ciprofloxacin, levofloxacin

Question 19

What is Colistin?

Answer 19

Plasma membrane agent. Absolute last resort gram-negative antibiotic.

Question 20

What is an RNA synthesis inhibitor?

Answer 20

Rifampicin

Question 21

What are the antibiotic-specific adverse effects of aminoglycosides?

Answer 21

Reversible renal impairment on accumulation
Irreversible ototoxicity
Therapeutic drug monitoring indicated

Question 22

What are the antibiotic-specific adverse effects of Β-lactams?

Answer 22

Main problems are allergic reactions
Generalised rash 1-10%
Anaphylaxis approx. 0.01%

Question 23

What is the antibiotic-specific adverse effect of Linezolid?

Answer 23

Bone marrow depression

Question 24

Which 4 antibiotics commonly precipitate C.Diff infection?

Answer 24

Co-amoxiclav (amoxicillin-clavulanate)
Cephalosporins
Ciprofloxacin (fluoroquinolone)
Clindamycin (MLS)

Question 25

What is the key antibiotic combination for:

flucloxacillin?

Answer 25

Staphylococcus aureus (not MRSA)

Question 26

What is the key antibiotic combination for:

benzylpenicillin?

Answer 26

Streptococcus pyogenes

Question 27

What is the key antibiotic combination for:

cephalosporins?

Answer 27

gram-negative bacilli

Question 28

What is the key antibiotic combination for:

metronidazole?

Answer 28

anaerobes

Question 29

What is the key antibiotic combination for:

vancomycin?

Answer 29

Gram-positives (MRSA)

Question 30

What is the key antibiotic combination for:

meropenem?

Answer 30

most clinically-relevant bacteria

Question 31

When is combination therapy appropriate?

Answer 31

to increase efficacy

to provide adequately broad spectrum

to reduce resistance