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53 Cards in this Set
- Front
- Back
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Define drugs
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Chemicals that physiology in anner manner
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What kind of drugs act against disease?
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chemotherapeutic agents
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___ are drugs used to treat infections
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antimicrobial agents
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_____ is the use of chemicals that selectively kill pathogens while having little or no effect on the patient.
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chemotherapy
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who coined the term antibiotics?
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Fleming
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What was the first practical antimicrobial agents used?
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Sulfanilamides
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More than half of all antibiotics and semi-synthetics are derived from species of ___.
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streptomyces
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List the mechanisms by which antimicrobial drugs affect the growth of pathogens
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1. Inhibition of cell wall synthesis
2.Inhibition of protein synthesis 3. Disruption of cytoplasmic membrane 4. Inhibition of metabolic pathways 5. Inhibition of nucleic acid synthesis 6.Prevention of pathogen's attachment to, or recognitioin of, host. |
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What is the key to chemotherapy?
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Selective toxicity
why? because of differences in structure of metabolism between pathogen and host |
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The most common antibacterial agents act by ....
give an example of this agent |
preventing the cross linkage of NAM subunits
beta-lactams such as penicillins and cephalosporins |
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Describe how beta lactams work
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irreversibly bind to enzymes that cross link NAM subunits thus inhibiting peptidoglycan formation. This leads to the cell walls being weaker and more susceptible to osmotic forces which cause lysing of the cell.
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What are the simplest beta lactams used and why are they seldom used?
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monobactams, becaue they are only affective against aerobic gram negative bacteria
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What drugs affect alanine-alanine bridges? (links NAMS together)
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Vancomycin and cycloserine
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Which drug prevents cell wall formation? (blocks secretion of NAG from NAM)
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Bacitracin
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Why is leprosy and tuberculosis hard to treat and what would you treat with?
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They have an additional layer of arabinogalactan-mycoloc acid layer covering the cell walls.
Isoniazid and Ethambutol |
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Which antimicrobials target 30s ribosomal subunits?
What happens |
Aminoglycosides (like streptomycin and gentamicin) and tetracyclines
Induces conformational change or blocks tRNA docking site preventing additional amino acid formation |
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Blockage of the 50s ribosomal subunit prevents _____.
Examples include... |
translation
lincosamides and macrolides(also streptogramins) |
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What are the newest types of drugs that block protein synthesis?
example |
antisense nuclei acids
Fomiversen |
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Gramicidin controls microbial growth by...
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disrupting the cytoplasmic membrane of a targeted cell.
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Polyenes controls microbial growth by...
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Disruption of cytoplasmic membranes
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Which of the following is not antifungal?
a. gramicidin b. polyenes c. Azoles d. allyamines |
a. gramicidin
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polymxin is effective against gram ___ bacteria.
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negative
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atovaquone controls microbial growth by...
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inhibiting metabolism
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The following heavy metals (arsenic, antimoy, and mercury) controls microbial growth by...
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inhibiting metabolsim
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sulfonamides are structural analongs of _____.
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PABA (para0aminobenzoic acid)
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trimethoporin controls microbial growth by...
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inhibits metabolic pathways
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actinomycin controls microbial growth by...
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inhibiting nucleic acid synthesis
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nucleotide analogs controls microbial growth by...
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inhibiting nucleic acid synthesis
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Where are nucleotide analogs used and why?
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Usually in viral infections because viral DNA polymerases are tens to hundreds times more likely to incorporate nonfunctional nucleotides into nucleic acids than are host polymerase enzymes.
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Which antimicrobial drugs involved in nucleic acid synthesis are active against prokaryotic DNA specifically?
how do they work? |
quinolones and fluoroquinalones
they inhibit DNA gyrase |
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True or False
Rifampin is more toxic to prokaryotes |
True
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Rifampin is used primarily against ____ and functions to ____.
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mycobacterium tuberculosis
inhibit nucleic acid synthesis |
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_____ is used to treat leprosy and functions to ____.
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Clofazimine
inhibit nucleic acid synthesis |
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____ and ____ is used to treat against protozoans and functions by _____.
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pentamidine and propamidine isethionate
inhibiting nucleic acid synthesis |
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What's a major downfall of useing monoclonal antibodies?
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You must administer it BEFORE the infection.
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What can you use to block viral attachment?
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sugar or peptide analogs of either receptor or attachement proteins
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____ and ___ are examples of attachment analogs.
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arildone and pleconaril
(against polioviruses and cold viruses) |
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Why aren't most chemcials effective in treating disease>
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1. may be toxic to humans
2. expensive 3. produced in minute quantities 4. lack potency |
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List some characteristics of an ideas antimicrobial agent
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1. readily available
2. inexpensice 3. chemically stable 4. easily administered 5. nontoxic and nonallergenic 6. selectively toxic against a wide range of pathogens |
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____ is defined as the number of different kinds of pathogens a drug acts against.
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Spectrum of action
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Give an example of some broad spectrium drugs
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erythrimycin, tetracyline, sulfonamides
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What's a downfall to using broad spectrum antibiotics?
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superinfection - happens because killing normal microbiota reduces microbial antagonism
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List some methods used to test efficacy.
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Diffusion susceptability test, minimum inhibitory concentration test, minimum bactericidal concentration test
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What are you looking for in a diffusion susceptibility (aka Kirby Bauer)___test?
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zone of inhibition
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Diffusion susceptibilty tests enable scientists to classift pathogens as ____, ___, or ____ to each drug.
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susceptible, intermediate, or resistant
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_____ is the smallest amount of the drug that will inhibit growth and reproduction of a pathogen.
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Minimum inhibitory concentration
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what test determines minimum inhibitory concertation and combines aspects of MIC test and a diffusion susceptibility test?
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E test
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_____ is the lowest concentration of drug for which no growth occurs in subcultures
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minimum bactericidal concentration.
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What are the three main categories of side effects?
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Toxicity, allergies, and disruption of normal microbiota
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How do cells acquire resistance?
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Through mutations of chromosomal genes or by acquiring r plasmids via transformation, transduction, or conjugation
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What are some mechanisms of resistance
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resistant bacteria may produce an enzyme that destroys or deactivates the drug (ex. beta lactamases), may slow or prevent the entry of the drug into the cell, may alter the receptor of the drug, may alter metabolic chemistry, may pump drug out of the cell before drug can act
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Multiple drug resistant pathogens are resistant to ___ or more types of antimicrobials
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3
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Give examples of multiple drug resistant pathogens
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staphylococcus, streptococcus, enterococcus, pseudomonas, mycobacterium
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