chapter 14 Flashcards
(33 cards)
Which was the first antimicrobial agent discovered to treat syphilis?
Salvarsan (arsphenamine)
Who is credited for first finding a naturally occurring antimicrobial agent?
Alexander Fleming (discovered penicillin)
Why might broad spectrum antimicrobials be initially used when treating a patient?
Because the exact pathogen is unknown, and broad-spectrum drugs can target a wide range of bacteria.
What is the therapeutic index?
The ratio of the toxic dose to the therapeutic dose of a drug.
Which organs are particularly susceptible to damage by certain antimicrobial drugs?
Liver and kidneys
How does penicillin work?
It inhibits bacterial cell wall synthesis by interfering with peptidoglycan cross-linking.
What are the classes of beta-lactam antibiotics?
Penicillins, cephalosporins, monobactams, and carbapenems
What mechanism of resistance is used by both MRSA and VRSA?
Alteration of the drug’s target (modified penicillin-binding proteins)
How does bacitracin work?
It inhibits cell wall synthesis by blocking the transport of peptidoglycan precursors.
The aminoglycosides directly target which structure of the bacterial cell?
The 30S subunit of the bacterial ribosome
Which classes of drugs target the 50s subunit?
Macrolides, lincosamides, and chloramphenicol
The macrolides target which feature of the bacterial cell?
The 50S ribosomal subunit involved in protein synthesis
What are the shortcomings of phenicols?
They can cause bone marrow suppression and other toxic effects.
How do polypeptide drugs work?
They disrupt bacterial cell membranes, leading to leakage and cell death.
What is the target of the antimicrobial drug known as rifampin?
RNA polymerase (inhibiting transcription)
What is the target of the class of antimicrobial drugs known as fluoroquinolones?
DNA gyrase and topoisomerase IV
Sulfa drugs (sulfonamides) inhibit which metabolic pathway?
Folic acid synthesis
Why don’t sulfa drugs target mammalian cells?
Because humans obtain folic acid from diet and do not synthesize it.
Why is it difficult to develop drugs that specifically target eukaryotic pathogens?
Eukaryotic pathogens are similar to human cells, increasing the risk of host toxicity.
Which antifungal targets the enzymes that make beta-glucan?
Echinocandins
What type(s) of infection(s) is/are artemisinin-based combination therapies used to treat?
Malaria
Metronidazole and pentamidine are used to treat which type of infection?
Protozoan infections
What does nitazoxanide do in order to treat infections with Giardia and Cryptosporidium as well as against certain parasitic worms?
It inhibits anaerobic metabolism in the pathogens.
Benzimidazoles and avermectins are used to treat which type of infection?
Helminth (parasitic worm) infections
