Antimicrobials II

Question 1

Aminoglycosides

Answer 1

Gentamicin and Amikacin

Question 2

Aminoglycosides use

Answer 2

Severe sepsis

Question 3

Aminoglycosides- Side Effects (3)

Answer 3

Nephrotoxicity

Ototoxicity

Neuromuscular Blockade

Question 4

How do Macrolides work?

Answer 4

Bind to 50S of bacteria

Question 5

Examples of Macrolides (3)

Answer 5

14-ring: Erythromycin (New- Clarithromycin)

15-ring: Azithromycin

16-ring: Josamycin

Question 6

Macrolides are active against what? (3)

Answer 6

1- Gram-positive cocci

2- Gram-negative coccobacilli

3- Atypical and Intracellular bacteria

Question 7

Macrolides- Uses (2)

Answer 7

Respiratory infection

UTI

Question 8

Macrolides- Side Effects (3)

Answer 8

Generally safe

Given in case of penicillin allergy

GI disturbance

Question 9

Clindamycin- Mechanism of action

Answer 9

50S ribosome

Question 10

What is clindamycin active against? (2)

Answer 10

Gram-positive aerobes

Anaerobes

Question 11

Clindamycin- Side Effects (2)

Answer 11

Clostridium difficile-associated diarrhea

Pseudomembranous colitis

Question 12

Tetracycline- Mechanism of Action (2)

Answer 12

Attach to 30S ribosome to prevent binding to tRNA

Bacteriostatic

Question 13

What is Tetracycline active against? (4)

Answer 13

Chlamaydia
Mycoplasma
Rickettsia
Spirochetes

Question 14

Tetracycline- Side Effects (5)

Answer 14

GI disturbance
Photosensitvity
Deposition in developing bone+teeth (brown discoloration)
Contraindicated in children and pregnancy
Hypersensitivity skin reaction

Question 15

Chloramphenicol- Mechanism of Action (2)

Answer 15

Act on peptidyl transferase enzyme that link amino acids in growing peptide chain

Bacteriostatic agent

Question 16

Chloramphenicol- Side Effect (1)

Answer 16

Irreversible bone marrow aplasia

Question 17

Chloramiphenicol- Clinical Use (2)

Answer 17

Eye drops

Ointments (topical)

Question 18

Fusidic Acid- Properties (5)

Answer 18

Does not bind directly to ribosomes
Anti-staphylococcal only (Narrow)
Bacteriostatic 
Not used alone bc resistance develops during treatment 
Penetrate well to bone

Question 19

Colistin- Mechanism of Action (3)

Answer 19

Bacterial cell membrane

Act with LPS in outer membrane

Potential anti-endotoxin activity (binds and neutralizes LPS)

Question 20

Colistin- Spectrum of Activity

Answer 20

Gram-negative aerobic bacilli

Question 21

Colistin- Toxicity (2)

Answer 21

Neurotoxicity

Nephrotoxicity

Question 22

Linezolid- Mechanism of Action (3)

Answer 22

Inhibits Initiation process of protein synthesis

Inhibits virulence factor expression and decrease toxin production in Gram-positive

Bacteriostatic

Question 23

Linezolid- Spectrum of Activity

Answer 23

Gram-positive bacteria

Question 24

Linezolid- Uses (1)

Answer 24

Against resistant bacteria e.g. MRSA, VRE

Question 25

Linezolid- Side Effects (1)

Answer 25

Thrombocytopenia

Question 26

Tigycycline- what is it used against? (2)

Answer 26

1- Broad (Many Gram +ve and -ve) 2- Multidrug-resistant strains of Gram +ve e.g. MRSA and MRSE, Pencillim-resistant streptococcus pneumonaie, and VRE

Question 27

Tigycycline- Clinical Indications (3)

Answer 27

1- Complicated intra-abdominal infections 2- Complicated skin and soft tissue infections 3- Community-acquired pneumonia

Question 28

Tigycycline- Side Effects (2)

Answer 28

Hepatic toxicity *Not recommended for pregnant women or children <8 years* (Like Tetracycline)

Question 29

Anti-TB drugs (Sterilizing)

Answer 29

Rifampicin Pyrazinamide

Question 30

Anti-TB drugs (Bactercidal)

Answer 30

Isoniazid Ethambutol Streptomycin

Question 31

Anti-TB drugs (Bacteriostatic)

Answer 31

Ethinomide P-aminosalycilic acid

Question 32

Host Factors- Quinolone

Answer 32

*contraindication in children* Damage to cartilage

Question 33

Host Factors- Penicillin and Cephalosporin

Answer 33

Renal function

Question 34

Host Factors- Hepatic

Answer 34

Chloramphenicol —> Gray Baby syndrome Sulphonamides —> Hyperbilirubinaemia —> Kernicterus

Question 35

Host Factors- Ciprofloxacin

Answer 35

Damage growing cartilage

Question 36

Host Factors- Isonazid

Answer 36

Hepatotoxicity *Toxicity starts after 50*

Question 37

Pregnancy- Safety (3)

Answer 37

Penicillin, Cephalosporins, Erythromycin

Question 38

Pregnancy- Teratogenic (3)

Answer 38

Rifampcin, Metronidazole!!, Fluoroqionlones

Question 39

Site of Infection- Meningitis

Answer 39

(Can cross blood-brain barrier) Chloramphenicol- Excellent without inflammation Penicillin + Cephalosporin- Excellent only with Inflammation Aminoglycosides- Poor penetration

Question 40

Site of Infection- Endocarditis

Answer 40

Synergy

Question 41

Site of Infection- Osteomyelitis

Answer 41

Clindamycin Ciprofloxacin Fusidic acid

Question 42

Prophylaxis- Medical (3)

Answer 42

Rheumatic heart diseases Endocarditis Meningococcal meningitis contacts

Question 43

Prophylaxis- Surgery (2)

Answer 43

Before surgery Prevent wound infection