Antimicrobials Flashcards
What is an antimicrobial agent?
Chemical/biological molecule that kills/inhibits growth of a microbe
What is an antibiotic?
An antimicrobial agent that is produced naturally by a microbe
What was the first antibiotic ever discovered?
Penicillin by Sir Alexander Fleming
How does Penicillin work?
Inhibits peptidoglycan synthesis (cell wall)
What does penicillin do to cell wall synthesis?
Inhibits enzyme transpeptidase
How does a b-lactam function?
Inhibits transpeptidation
What is selective toxicity?
Ability to kill/inhibit pathogen without affecting host cell
Name reasons why microbes are resistant to certain antimicrobials.
- lacks target molecule
- impermeable
- modify target of antimicrobial
- can remove antimicrobial from cell
What is intrinsic resistance?
Natural means of resistance against antimicrobials.
How is antibiotic resistance acquired?
Binding site of microbial agents are altered by altered gene sequence
What is the minimum inhibitory concentration?
smallest amount of an agent needed to inhibit growth of a microorganism.
What is the E-test?
Experiment to see if specific antimicrobial is effective against specific microbe.
What is disc diffusion?
Measurement of resistance by diameter of zone of inhibition.
What is the role of Erythromycin?
Prevents elongation (protein synthesis). Reduces production of important proteins needed for bacteria to survive.
What is the role of Quinolones?
Inhibits DNA replication in bacteria. Prevents binary fission.
How does MRSA continue cell wall synthesis in presence of penicillin?
-New transpeptidase doesn’t bind to penicillin so activity is not inhibited.
