Antibiotics

Question 1

Benzyl penicillin (penicillin G)

Answer 1

Original naturally occurring penicillin
Beta lactam - disrupts peptidoglycan synthesis (PBPs)
Largely acts against Gram(+) bacteria
Many Gram(-) bacteria are resistant due to presence of impermeable outer layer
Best choice for IV treatment of pneumococcal, meningococcal and S. pyogenes infection

Question 2

Amoxicillin and ampicillin

Answer 2

Beta lactam penicillin
Better oral absorption
Better Gram(-) activity
Covers streptococci, enterococci and some coliforms

Question 3

Co-amoxiclav

Answer 3

Beta lactam penicillin
Amoxicillin + clvulanic acid = beta lactamse inhibitor
Extended spectrum
Covers beta lactamase producing coliforms

Question 4

Fluocloxacillin

Answer 4

Beta lactam penicillin

First choice of treatment in staphylococcal infection

Question 5

Piperacillin

Answer 5

Beta lactam penicillin
Extended gram negative coverage
Anti-anaerobic activity
Active against E. faecalis
Only one active against Pseudomonas spp
Used in combination with tazobactam = beta lactamse inh

Question 6

Imipenem, meropenem

Answer 6

Carbapenems = beta lactam penicillin subgroup
Widest spectrum of all
Cover anaerobes
Active against most bacteria

Question 7

Cephalosporins

Answer 7

Divided into generations based on order of appearance
Activity against Gram(-) increases with generations
Activity against Gram(+) decreases with generations
Encourage C. difficile infection

Question 8

Cephradine

Answer 8

First generation cephalosporin

Question 9

Cefuroxime

Answer 9

Second generation cephalosporin

Question 10

Ceftriaxone

Answer 10

Third generation cephalosporin

Question 11

Ceftazidine

Answer 11

Third generation cephalosporin

Only one with activity against Pseudomonas spp

Question 12

Glycopeptides

Answer 12

Inhibit cell wall synthesis
Act at a stage prior to beta lactams
Unable to penetrate Gram(-) cell walls
Only active against Gram(+) bacteria
Active against both aerobes and anaerobes
Parenteral use only (not absorbed from GI tract)

Question 13

Vancomycin

Answer 13

Glycopeptide
Ototoxic, nephrotoxic, skin rash
Requires slow infusion and monitoring

Question 14

Teicoplanin

Answer 14

Glycopeptide
Less toxic
Single daily dosing

Question 15

Aminoglycosides

Answer 15

Inhibitors of protein synthesis
Primarily used in Gram(-) infections (coliforms, pseudomonas)
Active against staphylococci
Inactive against streptococci
Parenteral use only

Question 16

Gentamicin

Answer 16

Aminoglycoside
Ototoxic, nephrotoxic
Requires careful dosing and monitoring

Question 17

Macrolides

Answer 17

Inhibitors of protein synthesis
Newer ones have lower MICs
Mainly active against Gram(+) bacteria
Good alternatives to penicillins in patients with penicillin hypersensitivity
Effective against organisms causing atypical pneumonias e.g. C. psittacci, C. burnetti and M. pneumoniae
First choice therapy in Legionella pneumophila
S. aureus, S. pyogenes and S. pneumonia are resistant

Question 18

Clarithromycin

Answer 18

Macrolide

Question 19

Erythromycin

Answer 19

Macrolide

Question 20

Azithromycin

Answer 20

Newer macrolide

Single dose treatment of Chlamydia

Question 21

Tetracyclins

Answer 21

Inhibitors of protein synthesis
Few limited applications in genital tract infections with chlamidya and respiratory tract infections with C. psittacci and M. pneumoniae
Not indicated for pregnant women
Not indicated in children under 12 - deposited in teeth and bone

Question 22

Oxazolidinones

Answer 22

Inhibitors of protein synthesis

Question 23

Linezolid

Answer 23

Oxazolidinone
Active against MRSA
Can be given orally
Can cause BM suppression

Question 24

Cyclic lipopetides

Answer 24

Inhibitors of protein synthesis

Question 25

Daptomycin

Answer 25

Cyclic lipopetides Active against Gram(+) bacteria only Active against MRSA

Question 26

Trimethoprim

Answer 26

Inhibitor of nucleic acid synthesis (purine) | Alone used in UTIs

Question 27

Co-trimoxazole

Answer 27

Inhibitor of nucleic acid synthesis (purine) Combination of trimethoprim and sulphamethoxazole Treatment of chest infections Less likely to cause C. difficile infection

Question 28

Fluoroquinolones

Answer 28

Inhibitors of DNA synthesis Both oral and parenteral use Mostly effective against Gram(-) bacteria Cannot be used in children due to interference with cartilage growth

Question 29

Ciprofloxacin

Answer 29

Newer generation quionolone Only oral treatment for Pseudomonas spp Activity against staphylococci acceptable Activity against steptococci poor

Question 30

Levofloxacin

Answer 30

Newer quinolone | Active against pneumococci

Question 31

Nalidixic acid

Answer 31

First generation quinolone Urinary antiseptic - only used in UTIs Only active against gram negative aerobe coliforms

Question 32

Metronidazole

Answer 32

Antibiotic of choice for anaerobic infections

Question 33

Fusidic acid

Answer 33

Only indicated against staphylococci Usually in combination with flucloxacillin DIffuses well into bone and tissue - staphylococcal osteomyelitis and pneumonia

Question 34

Clindamycin

Answer 34

``` Lincosamide antibiotic Active against Gram(+) bacteria Active against anaerobes Good tissue penetration Oral administration Causes pseudo-membranous colitis ```

Question 35

Nitrofurantoin

Answer 35

Urinary antiseptic used in UTIs