Chapter 13: Antimicrobial Drugs Flashcards
Chemotherapy
Refers to any use of chemicals or drugs to treat disease.
Antimicrobial Drugs
Typically work by destroying or interfering with microbial structures and enzymes, either killing microbial cells or inhibiting of their growth.
Synthetic Microbial
A drug that is developed from a chemical not found in nature.
Semisynthetic Antimicrobial
A chemically modified derivative of a natural antibiotic; designed to increase the range of bacteria targeted, increase stability, decrease toxicity, or confer other properties beneficial for treating infections.
Actinomycetes
The source of more than half of all natural antibiotics and continue to serve as an excellent reservoir for the discovery of novel antimicrobial agents.
Bacteriostatic Drugs
Cause a reversible inhibition of growth, with bacterial growth restarting after elimination of the drug.
Bactericidal Drugs
Kill their target bacteria.
Narrow-Spectrum Antimicrobial
Targets only specific subsets of bacterial pathogens.
Broad-Spectrum Antimicrobial
Targets a variety of bacterial pathogens, including both gram-positive and gram-negative species, and is frequently used as empiric therapy to cover a wide range of potential pathogens while waiting on the laboratory identification of the infecting pathogen.
Polymicrobic Infections
Mixed infection with multiple bacterial species.
Superinfection
Develops when the antibacterial intended for the preexisting infection kills the protective microbiota, allowing another pathogen resistant to the antibacterial to proliferate and cause a secondary infection.
Dosage
The amount of medication given during a certain time interval.
Half-Life of a Drug
Rate at which 50% of a drug is eliminated from the plasma.
Route of Administration
The method used to introduce a drug into the body.
Parenteral Route
Intravenous or intramuscular injection.
Directly Observed Therapy (DOT)
Involves the supervised administration of medications to patients.
Selective Toxicity
It selectively kills or inhibits the growth of microbial targets while causing minimal or no harm to the host.
Antimicrobial Drugs
Are antibacterial because the prokaryotic cell provides a greater variety of unique targets for selective toxicity, in comparison to fungi, parasites, and viruses.
Mode of Action
The way in which a drug affects microbes at the cellular level.
Beta-Lactams
Characterized by the presence of a beta-lactam ring found within the central structure of the drug molecule; block the crosslinking of peptide chains during the biosynthesis of new peptidoglycan in the bacterial cell wall.
Aminopenicillins
Created by adding an amino group to penicillin G; increased spectrum activity against more gram-negative pathogens.
Methicillin
A semisynthetic penicillin that was developed to address the spread of enzymes (penicillinases) that were inactivating the other penicillins.
Cephalosporins
Contain a beta-lactam ring and block the transpeptidase activity of penicillin-binding proteins; however the beta-lactam ring is fused to a six-member ring, rather than the five-member ring found in penicillins.
Bacitracin
Blocks the activity of a specific cell-membrane molecule that is responsible for the movement of peptidoglycan precursors form the cytoplasm to the exterior of the cell, ultimately preventing their incorporation into the cell wall.
Aminoglycosides
Large, highly polar antibacterial drugs that bind to the 30S subunit of bacterial ribosomes, impairing the proofreading ability of the ribosomal complex.
Macrolides
Broad-spectrum, bacteriostatic drugs that black elongation of proteins by inhibiting peptide bond formation between specific combinations of amino acids.
Lincosamides
Although structurally distinct from macrolides, are similar in their mode of action to the macrolides through binding to the 50S ribosomal subunit and preventing peptide bond formation.
Oxazolidinones
Seem to interfere with the formation of the initiation complex (association of the 50S subunit, 30S subunit, and other factors) for translation, and they prevent translocation of the growing protein for the ribosomal A site to the P site.
Reverse Transcriptase Inhibitors
Block the early step of converting viral RNA genome into DNA, and can include competitive nucleoside analog inhibitors and non-nucleoside noncompetitive inhibitors that bind reverse transcriptase and cause an inactivating conformational change.
Protease Inhibitors
Block the processing of viral proteins and prevent viral mutation.
Integrase Inhibitors
Block the activity of the HIV integrase responsible for the recombination of a DNA copy of the viral genome into the host cell chromosome.
Fusion Inhibitors
Prevent the binding of HIV to the host cell coreceptor and the merging of the viral envelope with the host cell membrane, respectively.
Multidrug-Resistant Microbes (MDRs)
Known as “superbugs”; carry one or more resistance mechanism(s), making them resistant to multiple antimicrobials.
Cross-Resistance
A single resistance mechanism confers resistance to multiple antimicrobial drugs.
Antibiogram
A compilation of local antibiotic susceptibility data broken down by bacterial pathogen.
Minimal Inhibitory Concentration (MIC)
The lowest concentration of drug that inhibits visible bacterial growth.
Minimal Inhibitory Concentration (MIC)
The lowest concentration of drug that inhibits visible bacterial growth.
Minimal Bactericidal Concentration (MBC)
The lowest drug concentration that kills > 99.9% of the starting inoculum.
High-Throughput Screening Methods
Use automation to test large numbers of samples simultaneously.
High-Throughput Screening Methods
Use automation to test large numbers of samples simultaneously.
