Antibiotics Families and Classification

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Questions and Answers

What is the primary mechanism of action of beta-lactam antibiotics?

Inhibition of bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs)

What is the key difference in the spectrum of activity between cephalosporins and penicillins?

Cephalosporins have a broader spectrum of activity compared to penicillins

What is the mechanism of action of macrolide antibiotics?

Inhibition of bacterial protein synthesis by binding reversibly to the 50S ribosomal subunit

Which class of antibiotics inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit?

Tetracyclines Signup and view all the answers

What is the mechanism of action of aminoglycosides?

Disruption of bacterial protein synthesis by irreversibly binding to the 30S ribosomal subunit Signup and view all the answers

Which class of antibiotics targets DNA gyrase and topoisomerase IV to inhibit bacterial DNA synthesis?

Quinolones and fluoroquinolones Signup and view all the answers

What is the key difference between quinolones and fluoroquinolones?

Fluoroquinolones have enhanced activity and spectrum compared to quinolones Signup and view all the answers

Why are carbapenems often reserved for severe infections?

Due to their broad spectrum and susceptibility to beta-lactamases Signup and view all the answers

How do sulfonamides inhibit bacterial folic acid synthesis?

Sulfonamides inhibit bacterial folic acid synthesis by competing with para-aminobenzoic acid (PABA), an essential precursor of folic acid. Signup and view all the answers

What is the mechanism of action of glycopeptides such as vancomycin in inhibiting bacterial cell wall synthesis?

Glycopeptides inhibit bacterial cell wall synthesis by binding to the D-alanyl-D-alanine portion of peptidoglycan precursors, preventing cross-linking and weakening the cell wall. Signup and view all the answers

What is the mechanism of action of lipopeptides like daptomycin in disrupting bacterial cell membrane integrity?

Lipopeptides disrupt bacterial cell membrane integrity by forming pores, leading to depolarization and inhibition of DNA, RNA, and protein synthesis. Signup and view all the answers

How does trimethoprim inhibit bacterial folic acid synthesis?

Trimethoprim inhibits bacterial folic acid synthesis by inhibiting dihydrofolate reductase, an enzyme involved in folic acid synthesis. Signup and view all the answers

What is the mechanism of action of oxazolidinones like linezolid in inhibiting bacterial protein synthesis?

Oxazolidinones inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit and preventing formation of the initiation complex. Signup and view all the answers

Study Notes

Antibiotics Classification

Classified into several families based on chemical structure, mechanism of action, and spectrum of activity against bacteria
Classification aids in understanding clinical use, potential side effects, and resistance patterns

Beta-Lactams

Inhibit bacterial cell wall synthesis
Include penicillins, cephalosporins, and carbapenems
Penicillins: bind to penicillin-binding proteins (PBPs), preventing cross-linking of peptidoglycan strands
Cephalosporins: structurally related to penicillins, have a broader spectrum of activity and increased resistance to beta-lactamases
Carbapenems: highly potent, effective against many gram-positive and gram-negative bacteria, often reserved for severe infections

Macrolides

Inhibit bacterial protein synthesis by binding reversibly to the 50S ribosomal subunit
Prevent peptide bond formation and inhibit bacterial growth
Include erythromycin, azithromycin, and clarithromycin

Tetracyclines

Inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit
Prevent attachment of aminoacyl-tRNA to the mRNA-ribosome complex
Include tetracycline, doxycycline, and minocycline

Aminoglycosides

Disrupt bacterial protein synthesis by irreversibly binding to the 30S ribosomal subunit
Cause misreading of mRNA and inhibition of protein synthesis
Include gentamicin, amikacin, and tobramycin

Quinolones and Fluoroquinolones

Inhibit bacterial DNA synthesis by targeting DNA gyrase and topoisomerase IV
Prevent DNA supercoiling and replication
Quinolones include ciprofloxacin and levofloxacin
Fluoroquinolones are a subclass with enhanced activity and spectrum compared to quinolones

Sulfonamides and Trimethoprim

Sulfonamides inhibit bacterial folic acid synthesis by competing with para-aminobenzoic acid (PABA)
Trimethoprim inhibits dihydrofolate reductase, synergizing with sulfonamides in combination therapy
Include sulfamethoxazole and co-trimoxazole

Glycopeptides and Lipopeptides

Glycopeptides inhibit bacterial cell wall synthesis by binding to the D-alanyl-D-alanine portion of peptidoglycan precursors
Prevent cross-linking and weakening of the cell wall
Include vancomycin and teicoplanin
Lipopeptides disrupt bacterial cell membrane integrity by forming pores, leading to depolarization and inhibition of DNA, RNA, and protein synthesis
Include daptomycin

Oxazolidinones

Inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit
Prevent formation of the initiation complex
Include linezolid

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Description

Learn about the different families of antibiotics based on their chemical structure, mechanism of action, and spectrum of activity against bacteria.