Chapter 20

Antibiotics

Compounds naturally produced by molds and bacteria that inhibit the growth of or kill other microorganisms.

Selective Toxicity

The ability of antimicrobial drugs to cause greater harm to microorganisms than to the human host.

Spectrum of Activity

The range of bacteria species affected by an antibiotic, categorized as broad spectrum or narrow spectrum.

Half-life

The time required for half of the concentration of a drug to be eliminated from the body.

Antimicrobial Resistance

The ability of bacteria to resist the effects of antimicrobial drugs, categorized as innate/intrinsic or acquired resistance.

B-lactam drugs

Antibiotics that inhibit enzymes critical for peptidoglycan synthesis in bacterial cell walls.

Ribosome

Cellular structure targeted by antimicrobial drugs like aminoglycosides, tetracyclines, macrolides, and lincosamides to inhibit protein synthesis.

Fluoroquinolones

Synthetic drugs that inhibit bacterial DNA topoisomerases, affecting DNA replication and repair.Nucleic acid Synthesis

Sulfonamides

Antibiotics that competitively inhibit enzymes in the folate pathway of bacteria, essential for their growth.

Polymyxin B

An antimicrobial drug that binds to Gram-negative bacterial cell membranes, altering permeability and causing leakage.

synergistic

one drug adds to the activity of another

Antagonistic

one Drug interferes with the other

Additive

no effect

Bacteriostatic Drugs

inhibit bacterial growth, hosts defenses eliminate

Bacterial Drugs

kill bacteria

Drug inactivating enzymes

can inactivate drugs by modifing them

Alteration in Target Molecule

minor changes can prevent antimicrobial drugs from binding

Decreased uptore of Drug

change in porins of outer membrane in Gram Neg bacteria altering permeability and preventing drug uptake

Vancomycin

Cell wall synthesis (Peptidoglycan)

daptomycin

Cell membrane integrity

Trimethoprim

metabolic pathways (Folate Synthesis)

aminogycosides

protien synthesis

Rifamycin

Nucleic acid Synthesis

Tetracyclines

Protein Synthesis