Antimicrobial agents

Question 1

Beta Lactams

• Target?
• classes?
• examples?
• used to treat?

Answer 1

• Inhibit cell wall synthesis
• Penicillins, cephalosporins, carbapenems
• Benzylpenicillin, ceftriaxone, meropenem
• Treats Gram +ves, and 3rd generation ceph’s and carb’s treat some Gram -ve

Question 2

Glycopeptides

• Target?
• examples?
• used to treat?

Answer 2

• Inhibit cell wall synthesis
• Vancomycin, Teicoplanin
• MRSA, C.Diff

Question 3

Aminoglycosides

• Target?
• examples?
• used to treat?

Answer 3

• Inhibit protein synthesis
• Gentamicin
• Gram negative sepsis

Question 4

Tetracyclines

• Target?
• examples?
• used to treat?

Answer 4

• Inhibit protein synthesis
• Doxycycline
• Intracellular - chlamydia

Question 5

Macrolides

• Target?
• examples?
• used to treat?

Answer 5

• Inhibit Protein synthesis
• Erythromycin
• Gram +ve (PCN allergy)

Question 6

Chloramphenicol

• Target?
• examples?
• used to treat?

Answer 6

• Inhibit protein synthesis
• Eye drops
• Bacterial conjunctivitis

Question 7

Oxazolidinones

• Target?
• examples?
• used to treat?

Answer 7

• Inhibit protein synthesis
• Linezolid
• Gram +ve, MRSA +VRE

Question 8

Fluoroquinolones

• Target?
• examples?
• used to treat?

Answer 8

• Inhibit DNA synthesis
• Ciprofloxacin
• Gram -ve

Question 9

Nitroimidazoles

• Target?
• examples?
• used to treat?

Answer 9

• Inhibit DNA synthesis
• Metronidazole
• Anaerobes and Protozoa

Question 10

Rifamycin

• Target?
• examples?
• used to treat?

Answer 10

• Inhibit RNA synthesis
• Rifampicin
• Mycobacteria- used in TB

Question 11

Polymyxin

• Target?
• examples?
• used to treat?

Answer 11

• Cell membrane toxin
• Colistin
• Gram -ve

Question 12

Cyclic lipopeptide

• Target?
• examples?
• used to treat?

Answer 12

• Cell membrane toxin
• Daptomycin
• Gram +ve, MRSA + VRE

Question 13

Sulfonamides

• Target?
• examples?
• used to treat?

Answer 13

• Inhibit folate metabolism
• Sulphamethoxazole
• PCP

Question 14

Diaminopyrimidines

• Target?
• examples?
• used to treat?

Answer 14

• Inhibit folate metabolism
• Trimethoprim
• UTI

Question 15

Name 2 of the most common Gram +ve organisms

Answer 15

Staphylococcus Streptococcus

Question 16

Name 2 of the most common Gram -ve organisms

Answer 16

E. coli Psuedomonas

Question 17

Define a broad-spectrum antibiotic

Answer 17

An antibiotic that acts against a wide range of disease-causing bacteria, including both Gram-positive and Gram-negative bacteria. A narrow-spectrum antibiotic is only effective against specific families of bacteria.

Question 18

List 4 commonly prescribed broad-spectrum antibiotics

Answer 18

Co-amoxiclav Tazocin Ciprofloxacin Meropenem

Question 19

List 3 commonly prescribed narrow-spectrum antibiotics

Answer 19

Flucloxacillin Metronidazole Gentamicin

Question 20

The mnemonic BEAT is used to remember the 4 mechanisms of antibiotic resistance. List the 4 mechanisms and give an example of each

Answer 20

• Bypass antibiotic-sensitive step in pathways (eg MRSA) - Enzyme-mediated drug inactivation (eg beta-lactamases) - Accumulation impairment (eg tetracycline resistance) - Target modification (eg quinolone resistance)

Question 21

What is the most common causative organism for skin infections?

Answer 21

Staph aureus

Question 22

Which antibiotic is typically used for the empirical treatment of skin infections?

Answer 22

Flucloxacillin (unless allergic or MRSA +ve)

Question 23

What is the most common causative organism for pharyngitis?

Answer 23

Beta-haemolytic strep

Question 24

Which antibiotic is typically used for the empirical treatment of pharyngitis?

Answer 24

Benzylpenicllin

Question 25

Which antibiotic is typically used for the empirical treatment of mild community-acquired pneumonia?

Answer 25

Amoxicillin

Question 26

Which 2 antibiotics are typically used for the empirical treatment of severe community-acquired pneumonia?

Answer 26

Cefuroxime and Clarithromycin

Question 27

Which antibiotic is typically used for the empirical treatment of hospital-acquired pneumonia?

Answer 27

Cefuroxime

Question 28

What are the 2 most common causative organisms for bacterial meningitis?

Answer 28

Meningococcus / streptococcus

Question 29

Which antibiotic is typically used for the empirical treatment of bacterial meningitis?

Answer 29

Ceftriaxone OR Amoxicillin if listeria suspected - ie if pt is very young, old or immunocompromised

Question 30

Which antibiotic is typically used for the empirical treatment of community acquired UTI?

Answer 30

Trimethoprim (for 3 days)

Question 31

Which antibiotic is typically used for the empirical treatment of hospital-acquired (nosocomial) UTI?

Answer 31

Co-amoxiclav OR Cephalexin

Question 32

Which antibiotics are typically used for the empirical treatment of severe sepsis?

Answer 32

Cefuroxime, Metronidazole +/- Gentamicin

Question 33

Which antibiotics are typically used for the empirical treatment of neutropaenic sepsis?

Answer 33

Tazocin + Gentamicin

Question 34

What is the most common causative organism for bacterial colitis?

Answer 34

Clostridium difficile

Question 35

Which antibiotic is typically used for the empirical treatment of bacterial colitis?

Answer 35

Metronidazole PO (+ any cephalosporins must be STOPPED)