antibotics and antibotic resistance (chapter 20)

Antimicrobial

Any chemical that inhibits or kills microbes → Bleach

Antibiotic

Naturally-produced microbe that kills other microbes → Penicillin

Selective toxicity

Ability of antibiotic drugs to cause greater harm to microorganisms that to the human host

Efficacy

How well it works in people

ED50

Efficacy Dose 50% of the population

Toxicity

How harm it is to people

TD50

Toxic Dose for 50% of the population

Therapeutic Index

TD50 / ED50 = relative safety of antibotic

Therapeutic window

Dose range that is safe

Structures and processes

• cell wall

• Plasma membrane

• Nucleic acid

• Metabolic pathways

• Protein

Cell wall class

Bacitracin

Plasma membrane class

Polymyxins

Nucleic acid class

Rifamycins

Metabolic pathways class

Sulfonamids

Protein class

Macrolides

Intrinsic resistance

Resistant because of their structure

Acquired resistance

Resistance through spontaneous mutation or horizontal gene transfer