Micro Quiz 2

Synthetic agents

Drugs made in a pharmaceutical lab

Antibiotics

Drugs that are products of or derived from living microorganisms

Semisynthetic

Drugs include synthetic and antibiotic elements

Selective toxicity

Drug that should harm the pathogen but not the host

Toxic dose

Concentration causing harm to the host

Therapeutic dose

Concentration eliminating pathogens in the host

Chemotherapeutic dose

Ratio of toxic dose to therapeutic dose; high = safer.

Beta-lactam antibiotics

Contain beta-lactam ring; destroyed by beta-lactamase enzymes.

Penicillin

Inhibit peptidoglycan synthesis (cell wall); Most widely used antibiotic; Part of beta-lactam group

Carbapenems

Inhibit peptidoglycan synthesis (cell wall); Highly resistant to beta-lactamase enzymes and are used as a last resort.

Monobactams

Inhibit peptidoglycan synthesis (cell wall); Are only effective against aerobic Gram-negative bacteria

Glycopeptide

Inhibit peptidoglycan synthesis (cell wall); Vancomycin kills gram positive bacteria

Cephalosporins

Used in cases of penicillin resistance or penicillin allergy by the patient; Newest ones are better; Inhibit peptidoglycan synthesis

Sulfonamides

Inhibit folic acid synthesis

Polymyxin B, daptomycin

Disrupt cell membrane.

Daptomycin

Kills gram positive bacteria

Polymyxin

Kills gram negative bacteria

Aminoglycosides, tetracyclines, chloramphenicol

Inhibit protein synthesis (ribosomes).

Side effects of tetracyclines

Tooth discoloration.

Side effects of chloramphenicol

Aplastic anemia & gray syndrome.

Rifampin

Interferes with RNA synthesis

Quinolones

Inhibit DNA replication. Examples: Ciprofloxacin & Levofloxacin

What are the two main categories of antimicrobial agents?

Synthetic agents and antibiotics derived from living microorganisms.