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42 Cards in this Set

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Acyclovir
A synthetic purine analog that blocks DNA synthesis in certain viruses particularly the herpes simplex virus
Aminoglycosides
a complex group of drugs derived from soil actinomycetes that impares ribosomes function and has antibiotic potential, ex stroptomycin
antibiotics
a chemical substances from one microorganism that can inhibit or kill another microbe even in minute amounts
beta-Lactamase
An enzyme secreted by certain bacteria that cleaves the beta-lactam ring of penicillin and cephalosporin and thus provides for resistance against the antibiotic
Cephalosporins
A group of broad-spectrum antibiotics isolated from the fungus cephalosporiun
Competitively inhibiting
Control process that relies on the ability of metabolic analogs to control microbial growth by successfully competing w/ a necessary enzyme to halt the growth of bacterial cells
Metabolic analog
Enzyme that mimics the natural substrate of an enzyme and vies for its active site
Narrow spectrum
Denotes drugs that are selective and limited in their effect. for ex they inhibit either gram neg or gram pos bacteria, but not both
Polymyxin
A mixture of antibiotic polypeptides from Bacillus polymyxa that are particularily effective against gram neg bacteria.
Resistance factors
Plasmids, typically shared among bacteria by conjugation, that provide resistance to the effects of antibiotics
Selectively Toxic
property of an antimicrobial agent to be highly toxic against its target microbe while being far less toxic to other cells, particulary those of the host organism
Semisynthetic
Drugs which, after being naturally produced by bacteria, fungi or other living sources, are chemically modified in the laboratory
Tetracyclines
A group of broad-spectrum antibiotics w/ a complex 4-ring structure
Sulfanamides
Antimicrobial drugs that interfere with the essential metabolic process of bacteria and some fungi
Broad Spectrum
Antimicrobials effective against a wide variety of microbial types. For ex a drug effective against both gram-pos and gram neg bacteria
Prophylaxis
use of a drug to prevent imminent infection of a person at risk
Antibiotics
Naturally occurring antimicrobials.
Metabolic products of bacteria and fungi
Reduce competition for nutrients and space.
Bacteria
Streptomyces, Bacillus,
Molds
Penicillium, Cephalosporium
Selective toxicity
Drugs that specifically target microbial processes, and not the human host cellular processes. Ideal drug for what you want to kill
Cell Wall Synthesis
Bactericidal
Cycloserine – inhibits the formation of the basic peptidoglycan subunits
Vancomycin – hinders peptidoglycan elongation
Penicillin and cephalosporins – binds and blocks peptidases involved in cross-linking the glycan molecules
Nucleic acid synthesis
Chloroquine – binds and cross-links the double helix.
Other quinolones – inhibits DNA unwinding enzymes.
Viruses
Asidothymidine (AZT)
Analogs of purines and pyrimidines
Protein Synthesis
Aminoglycosides
Binds the 30S ribosome
Misreads mRNA.
Tetracyclines
Blocks attachment of tRNA.
Chloramphenicol
Binds to the 50S ribosome
Prevents peptide bond formation
Cell Membrane
Polymyxins
Interact with membrane phospholipids
Distorts the cell surface
Leakage of proteins and nitrogen bases.
Anit-fungal
Amphoterin B
Forms complexes with sterols in the membrane
Leakage
Can affect human cell membranes (toxicity)
Folic Acid Synthesis
Sulfonamides (sulfa drug) and trimethoprim
-Analogs
-Competitive inhibition
-Prevents the metabolism of DNA, RNA, and amino acid
Penicillin
-Penicillin chrysogenum
-A diverse group (1st, 2nd , 3rd generations)
Natural (penicillin G and V)
-Semisynthetic (ampicillin)
Structure
Thiazolidine ring
Beta-lactam ring
Variable side chain (R group)
Penicillin continued
-Resistance – if bacteria contain penicillinases
-Inhibits cell wall synthesis
-Treat streptococci, meningococci, and spirochete infections
Cephalosporin
-Cephalosporium acremonium (mold)
-Widely administered today
Diverse group (natural and semisynthetic)
-Structure
similar to penicillin except
Main ring is different
Two sites for R groups
Cephalosporin, continued
-Resistant to most pencillinases
-Broad-spectrum – inhibits cell wall synthesis
-3rd generation drugs used to treat enteric bacteria, respiratory, skin, urinary and nervous system infections
Aminoglycosides
-Streptomyces and Micromonospora
-Structure
Amino sugars and an aminocyclitol ring
-Broad-spectrum
-Commonly used to treat -bubonic plague and sexually transmitted diseases
-Inhibits protein synthesis
Tetracycline
-Streptomyces
-Structure –
Diverse
complex series of rings
-Broad spectrum and low cost
-Commonly used to treat sexually transmitted diseases
-Side effects – gastrointestinal disruption
-Inhibits proteins synthesis
Chloramphenicol
-Streptomyces
-Structure - nitrobenzene structure
-Broad-spectrum
-Only made synthetically today
-Treat typhoid fever, brain abscesses
-Side effects – aplastic anemia
-Inhibits protein synthesis
Erythromycin
-Streptomyces
-Structure – macrolide ring
-Broad-spectrum
-Commonly used as prophylactic drug prior to surgery
-Side effects - low toxicity
-Inhibits protein synthesis
Sulfanomides (Sulfa drupgs)
-Synthetic drug
-Based on sulfanilamides
-Used in combination with other synthetics such as trimethoprim
-Commonly used to treat pneumonia in AIDS patients
-Inhibits folic acid synthesis
Polyenes
-Antifungal
-Structure – large complex steroidal structure
-Some toxicity to humans
-Commonly used for skin infections
-Targets the membrane - lost of selective permeability
Antiviral
-Limited drugs available
-Difficult to maintain selective toxicity
-Effective drugs – target viral replication cycle
Entry
Nucleic acid synthesis
Assembly/release
-Interferon – artificial antiviral drug
Antimicrobial Resistance
Resistance factors
New enzymes
Permeability
Alter receptors
Change metabolic patterns
Natural selection
New approaches
New Approaches
Increase drug resistance requires new approaches for developing effective antimicrobials
-Prevent iron –scavenging capabilities
-Inhibit genetic controls (riboswitches)
-Probiotics and prebiotics
Drug and Host Interactions
Toxicity to organs
Allergic reactions
Suppress/alter microflora
Effective drugs
Kirby-Bauer Test
Sensitivity test such as the Kirby-Bauer Test can be used to determine the effectiveness of a drug by measuring the zone of inhibition.
MIC minimum inhibitory concentration
The lower the MIC, the more effective the drug is toward combating the bacterium.
E-Test
It determines the minimum amount of drug to use in the correct amount of time
Zone of inhibition
the area around the drop of antibiotic
Spectrum
What range does this drug work