Antimicrobial drugs

Question 1

Amoxicillin:

How it works

Limitations

Answer 1

1. Amoxicillin: Amoxicillin works by inhibiting bacterial cell wall synthesis, leading to cell lysis.

Its limitation is that it is ineffective against bacteria that produce beta-lactamase, an enzyme that can break down amoxicillin.

Question 2

Bacitracin

How it works

Limitations

Answer 2

2. Bacitracin: Bacitracin interferes with bacterial cell wall synthesis by inhibiting the transport of peptidoglycan precursors.

It is primarily limited to topical use due to potential toxicity if used systemically.

Question 3

Polymyxin

How it works

Limitations

Answer 3

3. Polymyxin: Polymyxin disrupts bacterial cell membranes, causing leakage of cell contents and death.

Its limitation is nephrotoxicity (kidney toxicity), which restricts its use to severe infections or topical applications.

Question 4

Tetracycline

How it works

Limitations

Answer 4

4. Tetracycline: Tetracycline inhibits protein synthesis by binding to 30s the bacterial ribosome and blocking tRNA attachment.

Interferes w/ codon recognition

It can lead to dental staining and bone growth issues, making it unsuitable for children and pregnant women.

Question 5

Ciprofloxacin

How it works

Limitations

Answer 5

5. Ciprofloxacin: Ciprofloxacin interferes with bacterial DNA gyrase, preventing DNA replication and transcription.

Its limitations include potential side effects like tendon damage and resistance development in certain bacteria.

Question 6

INH (Isoniazid)

How it works

Limitations

Answer 6

6. INH (Isoniazid): Isoniazid targets the synthesis of mycolic acid in the cell walls of Mycobacterium tuberculosis.

Its limitation is the risk of liver toxicity, especially in older adults and individuals with preexisting liver conditions.

Question 7

Streptomycin

How it works

Limitations

Answer 7

7. Streptomycin: Streptomycin inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.

Affect initiation and misreads codons

Limitations include potential for hearing loss and kidney damage with prolonged use.

Question 8

Erythromycin

How it works

Limitations

Answer 8

9. Erythromycin: Erythromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit.

Prevents translocation

Some bacteria have developed resistance through changes in ribosomal binding sites or efflux pumps.

Question 9

Sulfanilamide

How it works

Limitations

Answer 9

8. Sulfanilamide: Sulfanilamide inhibits folic acid synthesis by mimicking para-aminobenzoic acid (PABA), which bacteria need for growth.

Its limitation is that it can cause allergic reactions in some people and has limited efficacy against bacteria that can obtain folic acid from the environment.

Question 10

Zanamivir

How it works

Limitations

Answer 10

10. Zanamivir: Zanamivir is an antiviral that inhibits the neuraminidase enzyme of influenza viruses, preventing virus release from infected cells.

Its limitation is that it must be inhaled, which may be problematic for individuals with respiratory conditions.

Question 11

Chloramphenicol

How it works

Limitations

Answer 11

11. Chloramphenicol: Chloramphenicol inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit.

Prevents peptide bond formation

Its use is limited due to the risk of severe side effects, such as aplastic anemia.

Question 12

Acyclovir

How it works

Limitations

Answer 12

12. Acyclovir: Acyclovir is an antiviral that inhibits viral DNA polymerase, specifically targeting herpes simplex viruses.

Limitations include the need for activation by viral enzymes, making it less effective in cells without active viral replication.

Question 13

Rifampin

How it works

Limitations

Answer 13

13. Rifampin: Rifampin inhibits bacterial RNA polymerase, thereby blocking transcription.

Its main limitation is potential liver toxicity and rapid resistance development if not used in combination with other drugs.

Question 14

Nystatin

How it works

Limitations

Answer 14

14. Nystatin: Nystatin binds to ergosterol in fungal cell membranes, leading to cell membrane disruption.

It is limited to topical or oral use due to poor absorption and toxicity in systemic use.

Question 15

Niclosamide

How it works

Limitations

Answer 15

15. Niclosamide: Niclosamide disrupts the energy production and metabolism of intestinal tapeworms.

Its limitation is that it is only effective against adult tapeworms in the intestines and does not kill larvae in other tissues.

Question 16

What are the 4 antibiotics that inhibit proteins synthesis? How?

Answer 16

Streptomycin: binds 30s, affect initiation, misreads codons

Tetracycline: binds 30s, blocks tRNA attachment, interfere with codon recognition

Erythromycin: binds 50s, prevents translocation

Chloramphenicol: binds 50s, prevents peptide bond formation