ANTIMICROBIAL TREATMENT CH 12 Flashcards
Prophylaxis
The use of a drug to PREVENT infection (vaccine; condom)
Antimicrobial Chemotherapy
The use of chemicals or drugs to control microbial infection
Antimicrobial
All inclusive term used to describe antibacterial, antifungal, or antiviral medications
Antibiotics
Substance used to target bacteria
Semisynthetic vs Synthetic Drugs
Semisynthetic Drugs are found in nature but chemically modified in a lab
Synthetics Drugs are produced entirely in a lab
Narrow vs Broad Spectrum Drugs
Narrow - Limited Ability
Broad Spectrum - Targets an “all” structre (DNA, Ribosomes, cel wall etc)
What is the main goal of antimicrobial treatment?
One that is selectively toxic; Harms microbe but no harm to host
List the four characteristics of an ideal antimicrobial drug
- Kill the microbe not the person
- Function at low concentrations (gets diluted in body)
- Cant break down before killing the pathogen
- Practical and reasonably priced
What are the common sources of antimicrobial drugs? What is penicillin’s classification?
Bacteria and Fungi (but mainly fungi)
- Penicillin is a product of fungi
What are the three things that must be known before starting antimicrobial therapy? How do we gather this infromation?
- Identify the organism (obtain sample and isolate organism)
- Measure the organism’s susceptibility to various drugs (kirby-bauer sensitivity test)
- Medical condition and state of the patient (patient history of allergies and medical conditions specifically LIVER or KIDNEY DISEASE)
T/F: Once antimicrobial sesceptibility is established, choosing the right antibiotic is an easy process
FALSE
What is selective toxicity
Antimicrobial treatments that kill the pathogen without harming the host
How is penicillin selectively toxic?
It inhibits peptidoglycan production in the cell wall of bacteria; works primarily on gram pos+ cells
What organism types are most difficult to achieve selective toxicity with?
Eukaryotic organisms; we share too much of the same structures making it difficult for us to target specific structures
How does selective toxicity play a role in cancer treatments?
Tumor cells are OUR cells; very difficult to target so instead we target cells in the body that grow quickly which has harmful side effects in and throughout the body
How are Rifamycin and Streptovaricin selectively toxic?
They block RNA polmerase;
This stops the fomation of mRNA and Protein synthesis
How is Tetracycline selectively toxic?
Inhibits proteins synthesis by binding to 70s ribosomes and blocking tRNA from enterring
How is Polymyxin B selectively toxic?
Intereferes with cell membrane structure in gram neg- cells by interfering with lipopolysaccharide structure
How is Trimethoprim selectively toxic?
Intereferes with folic acid production which is required for protein formation
(humans eat it, but bacteria MAKE it; so we can target the enzyme the catalyzes folic acid production)
T/F: an antibiotic that acts on the baterial cell wall will have no effect on a human cell
True
T/F: an antibiotic that acts on the bacterial ribosome will have no effect on a human cell
False; our mitochondria have 70s ribosomes
Identify the 5 categories that antibiotics target. Which three are MOST selectively toxic?
- Cell wall*
- Cell membrane
- DNA/RNA
- Ribosomes (protein synthesis)*
- Folic Acid Synthesis*
are the most selectively toxic*
Broad vs Narrow Spectrum Drugs
Broad - Impacts large groups of microbes
Narrow - Impacts only a small group of microbes
For the following drugs, which are considered broad spectrum? What do they work best on?
- Penicillin
- Tetracycline
- Polymyxin
Penicillin: Broad Spectrum; Works best on Gram Pos+
Tetracycline: Broad Spectrum; Everything BUT mycobacteria
Polymyxin: Mycobacteria