Antimicrobials 1

Question 0

In terms of chemotherapeutic index, is a higher or lower number better?

Answer 0

Higher

Question 1

How do you calculate chemotherapeutic index?

Answer 1

Therapeutic dose

Question 2

What is the term that refers to the property of antimicrobials causing more harm to pathogens than the host?

Answer 2

Selective toxicity

Question 3

2 methods of action of antimicrobials generally?

Answer 3

Bacteriostatic

Bactericidal

Question 4

What are 3 potential adverse of effects of antimicrobial therapy?

Answer 4

Allergic reaction
Toxic or side effects
Suppression of normal flora

Question 5

2 infections that can arise as a result of the suppression of normal flora by antimicrobial therapy?

Answer 5

C Diff pseudomembranous colitis

Candida

Question 6

How do B lactams work?

Answer 6

Inhibition of cell wall synthesis - B lactam ring competitively and irreversibly inhibits the cross-linking between peptidoglycan strands in the bacterial cell wall

Question 7

What type of bacteria are classified by having a cell wall and are therefore particularly susceptible to B lactams?

Answer 7

Gram positive bacteria

Question 8

What bacterial enzymes convey resistance to B lactam antibiotics?

Answer 8

B lactamase

Question 9

What are 2 examples of aminopenicillins?

Answer 9

Amoxicillin

Ampicillin

Question 10

Why do ampicillin and amoxicillin work against both gram positive and gram negative bacteria?

Answer 10

Gram positive because B lactam

Gram negative because very hydrophilic so can diffuse into cells

Question 11

What is the more common name for penicillin G and by what method must it be administered?

Answer 11

Benzylpenicillin

IV

Question 12

What is the more common name for penicillin V and by what method can it be administered?

Answer 12

Phenoxymethylpenicillin

Oral

Question 13

What is special about flucloxacillin?

Answer 13

It has a structure which inhibits B lactamase activity and is therefore useful against penicillinase producing staphylococci

Question 14

What is co-amoxyclav and why/how does it work?

Answer 14

Amoxicillin + clavulamic acid aka augmentin

Clavulamic acid inhibits most B lactamases

Question 15

What are the main indications for co-amoxyclav?

Answer 15

Respiratory infection and UTIs by organisms which are proven to be resistant to amoxicillin

Question 16

4 examples of antimicrobials which work by inhibiting cell wall synthesis?

Answer 16

Penicillins
Cephalosporins
Vancomycin
Teicoplanin

Question 17

2 examples of first gen cephalosporin?

Answer 17

Cefadroxil

Cephalexin

Question 18

Example of second gen cephalosporin?

Answer 18

Cefuroxime

Question 19

3 examples of third gen cephalosporins?

Answer 19

Cefotaxime
Ceftazadime
Ceftriaxone

Question 20

Moving through the generations, what is the pattern of efficacy?

Answer 20

First and second - gram positives

Third - less gram positive, more gram negative

Question 21

What other advantage do third gen cephalosporins have over first and second gen ones?

Answer 21

More stable vs B lactamases

Question 22

Example of a fourth gen cephalosporin?

Answer 22

Cefepime

Question 23

Example of a fifth gen/advanced gen cephalosporin?

Answer 23

Ceftaroline

Question 24

What is the most exciting use of fifth gen cephalosporin ceftaroline?

Answer 24

Anti-MRSA

Question 25

Uses of vancomycin?

Answer 25

IV for septicaemia MRSA-induced endocarditis Pseudomembranous colitis caused by C Diff

Question 26

What 2 drugs can be used for pseudomembranous colitis caused by C Diff?

Answer 26

Vancomycin | Teicoplanin

Question 27

How do vancomycin and teicoplanin work?

Answer 27

By inhibiting peptidoglycan formation rather than cross linking

Question 28

What is tazocin made up of?

Answer 28

Tazobactam (a B lactamase inhibitor) and piperacillin

Question 29

What is isoniazid?

Answer 29

A cell wall formation inhibitor used first line for TB prevention and treatment

Question 30

4 broad examples of protein synthesis inhibitors?

Answer 30

Aminoglycosides Macrolides Tetracyclines Chloramphenicol

Question 31

2 examples of aminoglycosides?

Answer 31

Gentamycin and streptomycin

Question 32

How do aminoglycosides work?

Answer 32

Bind to the 30S ribosome subunit, blocking initiation of translation

Question 33

Which bacteria are susceptible to aminoglycosides?

Answer 33

Mostly gram negatives but some gram positives

Question 34

What are the 3 main risks of aminoglycoside use?

Answer 34

Ototoxicity via CN8 damage Kidney damage Narrow therapeutic index

Question 35

How do macrolides work? 3 examples?

Answer 35

Bind to 50S subunit (halting protein synthesis) | Clarithromycin, erythromycin, azithromycin

Question 36

What type of bacteria are macrolides good against?

Answer 36

Gram negatives

Question 37

What side effects can erythromycin have?

Answer 37

Nausea and vomiting

Question 38

What is good about azithromycin?

Answer 38

Very long half life so one dose works for a week e.g. For chlamydial urethritis

Question 39

What spectrum do terracyclines and chloramphenicol have?

Answer 39

Broad spectrum

Question 40

What side effect can tetracyclines have on young kids?

Answer 40

Discoloured teeth

Question 41

What are the major risk factors of chloramphenicol?

Answer 41

Bone marrow aplasia Encephalopathy Optic neuritis

Question 42

What effect can chloramphenicol have on neonates?

Answer 42

Grey baby syndrome

Question 43

What is chloramphenicol first line for?

Answer 43

Nothing | Apart from topical use for bacterial conjunctivitis

Question 44

4 examples of nucleic acid synthesis inhibitors?

Answer 44

Sulphonamides Quinolones 5-Nitroimidazoles Rifampicin

Question 45

Examples of sulphonamides? How do they work?

Answer 45

Folic acid synthesis inhibitors | Trimethoprim and co-trimoxazole (sulfamethoxazole)

Question 46

How do quinolones work? 2 examples?

Answer 46

GABA antagonists Ciprofloxacin Nalidixic acid

Question 47

2 examples of 5-nitroimidazoles?

Answer 47

Metronidazole | Tinidazole

Question 48

How does polymixin B work?

Answer 48

Binds to plasma membrane of gram negative bacteria, altering permeability and leading to leakage of contents

Question 49

What method of delivery is used for polymixin B and why?

Answer 49

Topical, because it can work on eukaryotic cells as well

Question 50

What is the fifth method of antimicrobial action?

Answer 50

Inhibition of synthesis of essential metabolites

Question 51

What is trimethoprim an example of?

Answer 51

Sulfonamide

Question 52

What is ciprofloxacin an example of?

Answer 52

Fluoroquinolone

Question 53

What are the carbapenems examples of?

Answer 53

B lactams

Question 54

What are vancomycin and teicoplanin examples of? What is their clinical significance?

Answer 54

Glycopeptide - good vs MRSA

Question 55

What are gentamicin and streptomycin? How do they work?

Answer 55

Aminoglycosides - inhibition of protein synthesis

Question 56

Common carbapenem used in nec fasc infection? With what?

Answer 56

Meropenem (+ clindamycin)

Question 57

What is clindamycin?

Answer 57

A protein synthesis inhibitor

Question 58

3 examples of tetracyclines?

Answer 58

Tetracycline Doxycycline Tigecycline