Antimicrobial Drugs Flashcards
Any chemical that has an affect on a body process.
Ex: alcohol, caffeine, tobacco
Drugs
Any drug used to treat a disease
Ex: vaccines, cancer tx, antibiotics, insulin
Chemotherapeutic drugs
Any drug that is used to treat bacterial infections exclusively
Antiviral- virus
Antifungal- fungus
Antibiotics
Range of effectiveness/spectrum of action
Origin- natural, semi synthetic and synthetic
Mechanism of action
How chemotherapy is described
The # of different kinds of pathogens a drug acts on
Spectrum of action
One specific target/microbe
“Like a shot gun”
Disadvantage- can’t use for prophylaxis
Narrow spectrum antibiotics
Wide variety of bacteria
Disadvantage- may allow for secondary or super infections to develop
Broad spectrum antibiotic
Molds: penicillin and cephalosporin
Bacteria: bacillus and streptomyces
Natural origin
Natural drugs that have been slightly altered
Synthetic origin
Completely man made
Synthetic origin
The broader its actions = kill more types of bacteria
More stable in the stomach
Better absorbed in the intestines
Altered to combat antibiotic resistance in resistant bacteria.
Advantages to synthetic drugs
- Inhibit cell wall synthesis
- Disruption of cytoplasmic membranes
- Inhibit protein synthesis
- Inhibit metabolic pathways
- Drugs attack nucleic acids
Mechanisms of action
Attach to new NAG/NAM units and blocks addition to a growing cell wall.
Used against penicillin resistant microbes.
Glycopeptides
Beta lactam
Natural: by molds
Broad spectrum
Inhibits enzymes that build peptidoglycan, usually bacteria dial.
Issues- GI & allergy
Penicillin
Beta lactam
Natural to almost fully synthetic
Narrow but broader in successive generations
Inhibits enzyme that build peptidoglycan, slightly different shape & bacteriocidal
Issues: GI & allergy
Cephalosporin
Glycopeptide
Natural
Narrow: gram + most effective
Binds to NAG & NAM, so they can’t be added to the cell wall. Bacteriocidal
Issues: kidney & hearing damage and GI upset
Vancomycin
Aminoglycosides
Natural
Broad: often used with gram -
Block ribosomes, bacteriocidal
Issues: hearing loss, vertigo and kidney damage
Streptomycin
Macrolides
Natural
Narrow
Block ribosomes, bacteriostatic
Issues: GI upset and jaundice
Erythromycin
Tetracycline
Broad
Block ribosomes, bacteriostatic
Issues: wide spread resistance, stains teeth & affects bone growth
Doxycycline
Polypeptides
Natural (soil)
Narrow: gram -
Membranes, bacteriocidal at high concentrations
Issues: kidney and liver damage and hearing loss
Polymixin B
Synthetic
Narrow: gram -
Blocks enzymes that make folic acid, bacteriostatic
Issues: nausea, allergy and photosensitivity
Sulfonamides & trimethroprim
Quinolones
Synthetic broad
Blocks grease needed for DNA replication, bacteriocidal
Issues: inhibits bone growth & seizures
Ciprofloxin
RNA synthesis inhibitors
Broad: used against mycobacteria
RNA polymerase - transcription, bacteriocidal
Issues: orange fluids secreted from body
Rifampin
- Intrinsic- Efflux pumps to expel toxins
- Acquired via horizontal gene transfer- exchange of plasmids through conjugation pili
- Acquired via mutation in DNA- may change shape of bacterial enzymes active site, repurpose enzyme
Antibiotic resistance
- Prevention of drug entry: deceased cell permeability
- Removal of drug: active efflux pumps
- Enzymatic inactivation: beta lactamase
- Altered target- modified drug receptor
- Synthesis of resistant metabolic pathway
Mechanisms of resistance
Antibiotic diffusion test
Susceptible, intermediate & resistant
Kirby Bauer test
