Antibiotics

Question 1

Define Antimicrobial agent

Answer 1

Substance with inhibitory properties against microorganisms

Minimal effects on mammalian cells

Includes Antibiotics and synthetic compounds

Question 2

Define Antibiotic

Answer 2

Substance produced by microorganisms that:

inhibit the growth (bacteriostatic)
or
kill (bactericidal) other bacteria

Question 3

Define susceptibility

Answer 3

The level of vulnerability of a microorganism to an antimicrobial.

Question 4

Pharmacology of Beta-Lactams

Answer 4

Include penicillin’s, cephalosporins, monobactams, carbapenems

Inhibits transpeptidases > weaken cell wall > lysis of organism

Question 5

Penicillin uses and examples

Answer 5

Narrow: Benzylpenicillin > Streptococci

Moderate: Amoxicillin > Gram-positive + Gram negative

Piperacillin > Pseudomonas aeruginosa

Flucloxacillin RESISTANT to staphylococcal b-lactamase,

Question 6

Cephalosporin examples

Answer 6

Cefuroxime
Ceftazidime
Cefotaxime

Question 7

Carbapenems uses and examples

Answer 7

= Broad spectrum. Treat severe infections: live sepsis, peritonitis

Imipenem
Meropenem
Ertapenem

Question 8

Uses, examples and SE of Glycopeptides

Answer 8

Bactericidal against Gram-POSITIVE bacteria (Staphylococci)

Vancomycin - MRSA ( resistant staph aureus)
Teicoplanin

SE Vancomycin - nephrotoxic, ototoxic, erythematous rash

Useful in pt with B-lactam allergy/ resistant pathogen.

Question 9

Give examples, uses and SE of Aminoglycosides

Answer 9

AMINOGLYCOSIDES

Mechanism: Inhibit 30s ribosome synthesis

Gentamicin
Streptomycin

SE: Nephrotoxic, ototoxic, hypersensitivity

Question 10

Give examples, uses and SE of Tetracyclines

Answer 10

TETRACYCLINE

Mechanism: Inhibit 30s ribosome synthesis

Tetracycline, doxycycline

Use: Chlamydia trachomatis, Mycoplasma spp., Rickettsia spp., Coxiella burnetiid

SE: GI intolerance, bone/teeth deposits

Question 11

Give examples and uses of Macrolides

Answer 11

MACROLIDES

Mechanism: Inhibit 50s ribosome synthesis

Clarithromycin
Azithromycin
Erythromycin

Uses: Streptococcal + Staphylococcal soft-tissue infection; Respiratory infection - Mycoplasma pneumoniae, Legionella

Question 12

Use of clindamycin?

Answer 12

Anaerobes

Cellulitis, osteomyelitis - alternative to Flucloxacillin

Question 13

What colonic disease is associated with 50s ribosome inhibitors?

Answer 13

Pseudomembranous colitis

Question 14

Serious staphylococcal infections are treated with a combination of 1) and 2)

Answer 14

1 - Flucloxacillin

2 - Fusidic Acid

(osteomyelitis, endocarditis)

Question 15

Examples, SE and mechanism of Quinolones

Answer 15

Ciprofloxacin

Mechanism: Inhibit nucleic acid synthesis

SE: GI disturbance, photosensitivity, rash, Neuro disturbance

Question 16

Trimethoprim mechanism, SE, uses

Answer 16

Inhibits folic acid synthesis

Causes folate deficiency :. CI in 1st Trimester PREGNANCY

Use: UTIs

Question 17

Metronidazole mechanism, uses

Answer 17

Mechanism: dysregulates DNA synthesis

Treats anaerobic infections

Question 18

Nitrofurantoin use

Answer 18

Uncomplicated UTI

Can be used in 1st trimester

CI in 3rd trimester

Question 19

Name 2 antibiotics which inhibit folate synthesis

Answer 19

Trimethoprim (CI preg)

Sulfonamide

Question 20

Suitable antibiotics to give someone that is pregnant with a UTI

Answer 20

Nitrofurantoin !!

Cefalexin

Question 21

A lady comes in with a UTI.

Most likely cause?
Treatment?
Treatment if she’s pregnant?

Answer 21

Likely cause: E coli

Treatment: Trimethoprim

Treatment if 1st trimester - Nitrofurantoin

If 3rd trimester - trimethoprim

*Trimethoprim teratogenic