Drugs to treat Bacterial Infections

Question 1

What are bactericidal antibiotics?

Answer 1

Drugs that kill the bacteria

Question 2

What are bacteriostatic antibiotics?

Answer 2

Drugs that inhibit growth of bacteria

Question 3

How can antibiotics be classified?

Answer 3

Mode of action
Spectrum of activity
Mechanism

Question 4

Describe how beta lactams inhibit cell wall synthesis

Answer 4

It inhibits the transpeptidases which form the oligopeptide cross links between the glycan chains

Question 5

Give examples of penicillins

Answer 5

Benzylpenicillin
Ampicillin
Amoxicillin
Carbenicillin
Flucoxacillin

Question 6

What are properties of penicillins?

Answer 6

Lipid insoluble

Short half life

Question 7

What are side effects of beta lactams?

Answer 7

Anaphylaxis

GI tract disturbances

Question 8

What do penicillins treat?

Answer 8

Bacterial meningitis
Pneumonia
Skin infections
UTIs

Question 9

What are properties of cephalosporins?

Answer 9

Lipid soluble

Short half life

Question 10

What are cephalosporins used to treat?

Answer 10

Septicaemia
Meningitis
Pneumonia
Biliary tract infections

Question 11

What causes beta lactam resistance?

Answer 11

The bacteria produce beta-lactamase to break the beta lactam ring

Question 12

How can beta lactam resistance be overcome?

Answer 12

Modifying the ring or administering with beta lactam inhibitors

Question 13

What drugs are not affected by beta lactamase?

Answer 13

Flucloxacillin
Carbapenem
Monobactam

Question 14

Which drugs besides beta lactams inhibit cell wall synthesis?

Answer 14

Bacitracin
Vancomycin
Cycloserine

Question 15

What is the mechanism of sulphonamide?

Answer 15

Inhibits dihydropterate synthase in folic acid production to prevent synthesis of purines

Question 16

Sulphonamides: route of administration, side effects and uses

Answer 16

Oral
Nausea, vomiting, hepatitis, rashes
Infected burns, IBD, chlamydia

Question 17

What is the mechanism of trimethoprim?

Answer 17

Inhibits dihydrofolate reductase in folic acid production to prevent synthesis of purines

Question 18

Trimethoprim: route of administration, side effects and uses

Answer 18

Oral
Nausea, vomiting, rashes, blood disorders, folate deficiency
UTI and respiratory infections

Question 19

What is the mechanism of tetracyclines?

Answer 19

Competes with aminoacyl tRNA for the A binding site on ribosomes

Question 20

Tetracyclines: route of administration, side effects and uses

Answer 20

Oral or parenteral
GI irritation, teeth staining, toxicity to liver, kidneys & bone marrow
Rickettial and chlamydial infections

Question 21

What is the mechanism of chloramphenicol?

Answer 21

Blocks peptidyl transferase

Question 22

Chloramphenicol: route of administration, side effects and uses

Answer 22

Oral
Bone marrow depression, vomiting, diarrhoea, grey colouring
Penicillin resistant meningitis, conjunctivitis

Question 23

What is the mechanism of aminoglycosides?

Answer 23

Causes abnormal codon to anti-codon recognition

Question 24

Aminoglycosides: route of administration, side effects and uses

Answer 24

IV or IM
Ototoxicity or nephrotoxicity
Serious aerobic gram negative bacilli infections

Question 25

What is the mechanism of macrolides?

Answer 25

Inhibits tRNA translocation

Question 26

Macrolides: route of administration and uses

Answer 26

Oral | Treating penicillin sensitive patients

Question 27

What is the mechanism of quinolones?

Answer 27

Act on topoisomerases to interfere with DNA coiling

Question 28

Quinolones: route of administration, side effects and uses

Answer 28

Oral GI tract disturbances, hypersensitivity UTIs, respiratory infections

Question 29

What is the mechanism of rifampicin?

Answer 29

Inhibits RNA polymerase

Question 30

Rifampicin: route of administration, side effects and uses

Answer 30

Oral Skin eruptions, fever, GI disturbances, hepatotoxicity Tuberculosis and leprosy

Question 31

Describe how drugs become resistant to chlorampenicol

Answer 31

Enzymes produced to acetylate the drug

Question 32

Describe how drugs become resistant to aminoglycosides

Answer 32

Enzymes produced to acetylate, phosphorylate or adenylate the drug

Question 33

Describe how drugs become resistant to erythromycin

Answer 33

Methylates rRNA to prevent binding of the antibiotic

Question 34

Describe how drugs become resistant to tetracycline

Answer 34

Produces a membrane transporter

Question 35

Describe how drugs become resistant to trimethoprim

Answer 35

Creates a mutant dihydrofolate reductase