Protein Synthesis Agents

Question 1

Which are the 5 antibiotics that inhibit the 50S subunit?

Answer 1

• Chloramphenicol
• Clindamicin/Lincomycin
• Macrolides
• Ketolides
• Oxazolidinones

Question 2

Which are the 2 antibiotics that inhibit the 30S subunit?

Answer 2

• Tetracyclines

- Aminoglycosides

Question 3

What is the MOA of Chloramphenicol?

Answer 3

Prevents formation of peptide bond between amino acids

Question 4

What are the characteristics of Clindamycin?

Answer 4

• Prevents movement along the mRNA so the ribosome cannot advance to the next codon
• kills off much of the intestinal flora
• Effective against G+ and G- anaerobes (except C. difficile)
• Can be the cause of C. dif-related pseudomembranous colitis

Question 5

Which two antibiotics can cause of chlostridium dificile related pseudo- membranous colitis?

Answer 5

Daptomycin and Clindamycin

Question 6

What are the characteristics of Macrolides (Erythromycin and Azithromycin)?

Answer 6

• Also prevents movement of the ribosome along the mRNA

- Used to treat Mycoplasma, Chlamydophila, Legionella, Pertussis

Question 7

What are the characteristics of Erythromycin?

Answer 7

• Used to treat GAS, Legionella, Mycoplasma, syphilis, diphtheria, pertussis
• Also for H. pylori and C. jejuni
• Safe for pregnancy

Question 8

What are the characteristics of Azithromycin?

Answer 8

• Effective against many respiratory tract and middle ear pathogens (S. pneumonia, Haemophilus, Moraxella, Mycoplasma, Chlamydophila)
• Only requires 1 dose/day
• Considered a long acting macrolide - has prolonged levels in tissues (lung, macrophages, PMNs) so shorter duration of therapy

Question 9

What are the characteristics of Ketolides?

Answer 9

Ketek (Telithromycin) is the first and only drug in this class

• Similar to macrolide, but different ring structure
• Effective against upper and lower respiratory tract pathogens, including macrolide-resistant S. pneumoniae

Question 10

What are the characteristics of Oxazolidinones?

Answer 10

• Linezolid
• Binds 50S subunit to prevent formation of functional 70S complex
• Effective against MRSA, MDRSP, VRE
• For complicated skin and skin structure infections

Question 11

What are the characteristics of Tetracylcines?

Answer 11

• Prevent the tRNA from entering the A site of the ribosome
• Effective against Mycoplasma and Chlamydophila infections
• Stain teeth

Question 12

What are the characteristics of Aminoglycosides?

Answer 12

• Change the shape of the 30S subunit, causing misreading of the codons
• Generally toxic
• Streptomycin is used to treat plague and tularemia