Antibiotics

Question 1

β-Lactam antibiotics

Answer 1

Penicillin Cephalosporins

Inhibit cross-linking of polysaccharides in the cell wall by blocking transpeptidase enzyme, inhibition of cell-wall synthesis via inhibition of peptidoglycan synthesis.

Resistance:Altered membrane-binding protein is observed with resistance to Beta-lactam antibiotics.

Question 2

Aminoglycosides

Answer 2

Gentamicin Tobramycin

Inhibit protein synthesis (the mechanism is through irreversible binding to cytoplasmic 30S-ribosomal subunit)

Question 3

Clindamycin and macrolides

Answer 3

Clindamycin ,Erythromycin, Clarithromycin, Azithromycin

Inhibit the dissociation of peptidyl-transfer RNA from ribosomes during translocation (the mechanism is through binding to 50S-ribosomal subunit)

Question 4

Tetracyclines

Answer 4

Inhibit protein synthesis (binds to
50S-ribosomal subunit)

Three specific mechanisms of tetracycline resistance have been identified: increased tetracycline efflux, ribosome protection, and tetracycline modification.

Question 5

Glycopeptides

Answer 5

Vancomycin Teicoplanin

Interfere with the insertion of glycan subunits into the cell wall. MRSA developed resistance by mutation mecA encoding an altered penicillin binding protein. CVL is responsible for reisitance, differentiates community and hospital strains.

Question 6

Rifampin

Answer 6

Inhibits RNA polymerase F

Bacteria develop rapid resistance to Rifampin when used as monotherapy.

Resistance:Three specific mechanisms of tetracycline resistance have been identified: increased tetracycline efflux, ribosome protection, and tetracycline modification.

Question 7

Quinolones

Answer 7

Ciprofloxacin Levofloxacin Ofloxacin

Inhibit DNA gyrase

Question 8

Oxazolidinones

Answer 8

Linezolid

Inhibits protein synthesis (binds to 50S-ribosomal subunits)