Ch. 12 Study Guide Flashcards
(31 cards)
How did Paul Ehrlich contribute to antimicrobial chemotherapy?
Created Salvarsan: treated syphilis
How did Alexander Flemming contribute to antimicrobial chemotherapy?
Accidentally discovered penicillin
How did Gerhard Domagk contribute to antimicrobial chemotherapy?
Discovered sulfonamides/sulfa drugs
How did Selman Waksman contribute to antimicrobial chemotherapy?
Discovered steptomycin: first antibiotic effective against tuberculosis
What is the primary natural source of new antimicrobial agents?
antibiotics from microorganisms
Define Antibiotic
Chemical produced by a microorganism to kill or inhibit another
Define antimicrobial drug
A drug designed to kill or inhibit microorganisms
Define synthetic antimicrobials
drugs synthesized entirely in a lab thru chemical reactions
Define semi-synthetic antimicrobial
Drugs that are derived from natural sources and then chemically modified in a lab
Contrast narrow and broad-spectrum drugs
Narrow: selective and limited in their effects
Broad: affect many types, both grams, and atypical bacteria
Are drug actions cidal or static?
either, can be both
How does the disk-diffusion test determine the level of antibacterial drug activity?
Drugs diffuses from disk into agar, forming concentration gradient with bacteria sample. Bigger zone of inhibition= larger susceptibility to the drug
How does the dilution susceptibility test determine the level of antibacterial drug activity?
Antibiotic is diluted through tubes, given equal amounts of a bacteria, growth inhibition shows drug effectiveness
How does the Etest determine antimicrobial drug activity?
Enables determination of MIC
What is the MIC?
Minimal inhibitory concentration: smallest concentration of a drug needed to visibly control microbial growth
What is the MLC?
Minimum lethal concentration
What are the 5 major antibacterial drug mechanisms of action?
- Inhibition of cell wall synthesis
- Breakdown of cell membrane
- Interference with DNA/RNA function
- Inhibition of protein synthesis
- Blockage of key metabolic pathways
How are the 5 mechanisms of antibacterial drug action selectively toxic?
- Cell wall synthesis attack: human cells dont have cell walls
- Membrane attack: human cells lack LPS
- DNA/RNA attack: human cells lack DNA Gyrase
- Ribosomal attack: humans lack 70s ribosomes
- metabolic pathway attack: humans lack folic acid pathway
Relate a side effect toxicity of antiribosomal drugs to its mechanism of action
Tetracycline interferes with calcium growth such as teeth and fetal bone development
Why are there fewer antifungal agents than antibacterial agents?
Fungal cells are eukaryotic, like human cells, so antifungal drugs can harm human cells too
Polyhenes target ergesterol in fungal membrane
Why are there fewer antiprotozoan agents than antibacterial agents?
protozoans are eukaryotic like human cells
What are the 4 primary routes of delivery for antimicrobial drugs?
PO: orally
IM: intramuscular
IV: intravenous
Topical
What are 5 practices that have contributed to antimicrobial drug resistance?
- Inappropriate use of antibiotics
- Non healthcare-use (overuse): Triclosan
- Increasing immunocompromised population
- Prolonged survival of debilitated patients
- Global travel
What are 5 countermeasures to address antimicrobial drug resistance?
- Only use antibiotics when necessary, and complete the full course
- Use narrow spectrum (timely identification is important)
- Conservative empiric treatment: use broad spectrum as last resort
- More emphasis on prevention: wash hands
- Education!!!
- Combination therapy of multiple drugs (bactrines)
- Develop new antibiotics and alternative therapies
