Antimicrobial Agents and Resistance: Part One

Question 1

penicillin works on Gram …

Answer 1

positive bacteria

Question 2

MIC

Answer 2

• Minimum Inhibitory Concentration
• Minimum concentration of antimicrobial that inhibits growth of a standardized concentration of organisms
• Reflects the efficacy of the antibiotic

Question 3

MBC

Answer 3

• Minimum Bactericidal Concentration

Minimum concentration of antimicrobial that kills 100% of a standardized bacterial population

Question 4

Indifference

Answer 4

the effect of two or more drugs is additive

Question 5

Synergism

Answer 5

the effect of two or more drugs is greater than the additive effect of the two drugs individually

Question 6

Antagonism

Answer 6

the effect of two or more drugs is worse than the additive effect of the two drugs individually

Question 7

β-lactam family of antibiotics do what?

Answer 7

• The β -lactam moiety of penicillin binds to, and inhibits the enzyme transpeptidase (also known as Penicillin-Binding Protein=PBP) that cross-links the peptidoglycan chains to form the cell wall.
• The antibiotic causes cytolysis due to the weakening of the cell wall that makes the bacterium susceptible to osmotic pressure.