Antibiotics Flashcards
What is selective toxicity in antimicrobials?
The drug’s ability to kill/inhibit the pathogens without severely harming the host.
What is the difference between broad-spectrum and narrow-spectrum?
- Broad spectrum: affects many species.
- Narrow-spectrum: targets a specific group.
How do bacteriostatic and bactericidal drugs differ?
Bacteriostatic:inhibits growth.
bactericidal: kills microbes directly.
How do penicillins work?
Inhibit bacterial cell wall synthesis by blocking peptidoglycan cross-linking.
Why is tetracycline bacteriostatic?
It binds to 30S ribosome, blocking tRNA recruitment and protein synthesis.
What is the target of daptomycin?
Bacterial plasma membrane (forms pores, causing cell death).
Why is ergosterol a key anti-fungal target?
It is found in fungal (not human) membranes; disrupting it weakens the cell.
Name two anti-fungal classes that target ergosterol.
-Azoles (inhibit synthesis).
-Polyenes (bind to ergosterol).
What are two ways bacteria acquire resistance?
-Mutations (vertical evolution).
-Gene transfer (plasmids/conjugation).
How can phage therapy combat resistance?
Bacteriophages infect and kill resistant bacteria without promoting resistance.
Why shouldn’t tetracycline (static) and penicillin (cidal) be combined?
-Penicillin needs active growth to work
-Tetracycline halts growth, reducing penicillin’s effect.
What is HAART for HIV?
Combination therapy (e.g., protease inhibitors + NRTIs) to block multiple viral steps.
What are the two types of antimicrobial resistance?
- Intrinsic resistance: Inherited or natural.
- Acquired resistance:mutations (developed through alteration of microbial genome).
