Chapter 13: Antimicrobial Drugs

Question 1

Chemotherapy

Answer 1

Refers to any use of chemicals or drugs to treat disease.

Question 2

Antimicrobial Drugs

Answer 2

Typically work by destroying or interfering with microbial structures and enzymes, either killing microbial cells or inhibiting of their growth.

Question 3

Synthetic Microbial

Answer 3

A drug that is developed from a chemical not found in nature.

Question 4

Semisynthetic Antimicrobial

Answer 4

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.

Question 5

Actinomycetes

Answer 5

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.

Question 6

Bacteriostatic Drugs

Answer 6

Cause a reversible inhibition of growth, with bacterial growth restarting after elimination of the drug.

Question 7

Bactericidal Drugs

Answer 7

Kill their target bacteria.

Question 8

Narrow-Spectrum Antimicrobial

Answer 8

Targets only specific subsets of bacterial pathogens.

Question 9

Broad-Spectrum Antimicrobial

Answer 9

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.

Question 10

Polymicrobic Infections

Answer 10

Mixed infection with multiple bacterial species.

Question 11

Superinfection

Answer 11

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.

Question 12

Dosage

Answer 12

The amount of medication given during a certain time interval.

Question 13

Half-Life of a Drug

Answer 13

Rate at which 50% of a drug is eliminated from the plasma.

Question 14

Route of Administration

Answer 14

The method used to introduce a drug into the body.

Question 15

Parenteral Route

Answer 15

Intravenous or intramuscular injection.

Question 16

Directly Observed Therapy (DOT)

Answer 16

Involves the supervised administration of medications to patients.

Question 17

Selective Toxicity

Answer 17

It selectively kills or inhibits the growth of microbial targets while causing minimal or no harm to the host.

Question 18

Antimicrobial Drugs

Answer 18

Are antibacterial because the prokaryotic cell provides a greater variety of unique targets for selective toxicity, in comparison to fungi, parasites, and viruses.

Question 19

Mode of Action

Answer 19

The way in which a drug affects microbes at the cellular level.

Question 20

Beta-Lactams

Answer 20

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.

Question 21

Aminopenicillins

Answer 21

Created by adding an amino group to penicillin G; increased spectrum activity against more gram-negative pathogens.

Question 22

Methicillin

Answer 22

A semisynthetic penicillin that was developed to address the spread of enzymes (penicillinases) that were inactivating the other penicillins.

Question 23

Cephalosporins

Answer 23

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.

Question 24

Bacitracin

Answer 24

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.

Question 25

Aminoglycosides

Answer 25

Large, highly polar antibacterial drugs that bind to the 30S subunit of bacterial ribosomes, impairing the proofreading ability of the ribosomal complex.

Question 26

Macrolides

Answer 26

Broad-spectrum, bacteriostatic drugs that black elongation of proteins by inhibiting peptide bond formation between specific combinations of amino acids.

Question 27

Lincosamides

Answer 27

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.

Question 28

Oxazolidinones

Answer 28

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.

Question 29

Reverse Transcriptase Inhibitors

Answer 29

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.

Question 30

Protease Inhibitors

Answer 30

Block the processing of viral proteins and prevent viral mutation.

Question 31

Integrase Inhibitors

Answer 31

Block the activity of the HIV integrase responsible for the recombination of a DNA copy of the viral genome into the host cell chromosome.

Question 32

Fusion Inhibitors

Answer 32

Prevent the binding of HIV to the host cell coreceptor and the merging of the viral envelope with the host cell membrane, respectively.

Question 33

Multidrug-Resistant Microbes (MDRs)

Answer 33

Known as “superbugs”; carry one or more resistance mechanism(s), making them resistant to multiple antimicrobials.

Question 34

Cross-Resistance

Answer 34

A single resistance mechanism confers resistance to multiple antimicrobial drugs.

Question 35

Antibiogram

Answer 35

A compilation of local antibiotic susceptibility data broken down by bacterial pathogen.

Question 36

Minimal Inhibitory Concentration (MIC)

Answer 36

The lowest concentration of drug that inhibits visible bacterial growth.

Question 36

Minimal Inhibitory Concentration (MIC)

Answer 36

The lowest concentration of drug that inhibits visible bacterial growth.

Question 37

Minimal Bactericidal Concentration (MBC)

Answer 37

The lowest drug concentration that kills > 99.9% of the starting inoculum.

Question 38

High-Throughput Screening Methods

Answer 38

Use automation to test large numbers of samples simultaneously.

Question 38

High-Throughput Screening Methods

Answer 38

Use automation to test large numbers of samples simultaneously.