Chapter 10 Antimicrobial Agents

Question 1

Paul Ehrlich

Answer 1

Created magic bullets which were an arsenic compounds that killed microbes

Question 2

Alexander Flemming

Answer 2

Develop the first fungi antifungal penicillium crysogenum released from penicilling

Question 3

Gerhad Domagk

Answer 3

Discovered sulfanilamide
which was develop from bacterial antimicrobial and it was the antibiotic that was widely distributed

Question 4

Selman Waksman

Answer 4

He discovered many antibiotics

Question 5

Semi synthesis

Answer 5

Chemically altered antibiotics that are more eefective longer lansting or easier to adminiter than naturally occuring ones

Question 6

Synthesis

Answer 6

Antmicrobials that are completely synthesized in a lab
Ex: Fungi
Penicillium chrysogenum the antimicrobial used is penicillin G
Ex:Bacteria
Bacillus lichenifomis the antibiotic used is bacitracin

Question 7

Chemotherapy

Answer 7

Successful chemotherapy requires selective toxicity to the specific bacteria that is causing harm

Question 8

Antiviral drugs are limited

Answer 8

They are limited because viruses are not living

Question 9

Beta-lactams

Answer 9

Antibiotics that contain a Beta-lactam ring in their chemical structure like penicillin
Beta-lactams are more prominent in Gram-positive microorganisms because they have a ticker peptidoglycan than Gram negative they only have an outer layer

Question 10

Inhibition of synthesis of fungal walls

Answer 10

Targets of polysaccharides is a selective toxic fungal
▪ Echinocandins inhibit the enzyme that
synthesizes glucan

Question 11

Inhibition of Protein Synthesis

Answer 11

▪ Prokaryotic ribosomes are 70S (30S and 50S)
▪ Eukaryotic ribosomes are 80S (40S and 60S)
▪ Drugs can selectively target translation
▪ Mitochondria of animals and humans contain 70S
ribosomes

Question 12

Polymyxin

Answer 12

Disrupts cytoplasmic membranes of Gram-
negative bacteria
▪ Toxic to human kidneys
– Some parasitic drugs act against cytoplasmic
membranes

Question 13

Atovaque

Answer 13

Interferes with electron transport in proctozoa and fungi
Drugs that block activation of viruses
Amantadine, rimantadine, and weak organic
bases prevent viral uncoating.

Question 13

Antimetabolic agents

Answer 13

Can be effective when pathogen and host metabolic processes interfere
Trimethoprim also interferes with nucleotide synthesis.
– Antiviral agents can target unique aspects of viral
metabolism.

Question 14

Inhibition of Nucleic Acid Synthesis

Answer 14

– Several drugs block DNA replication or RNA
transcription
– Drugs often affect both eukaryotic and prokaryotic
cells

Question 15

Attachment antagonists

Answer 15

Block viral attachment or
receptor proteins
– New area of antimicrobial drug development
– Pleconaril blocks viral attachment
– Arildone prevents viral uncoating

Question 16

Ideal antimicrobial agents are

Answer 16

-Readily available
– Inexpensive
– Chemically stable
– Easily administered
– Nontoxic and nonallergenic
– Selectively toxic against wide range of pathogens

Question 17

Narrow spectrum effective against few organisms

Answer 17

specific what the target is
Ex: it can only target like viruses

Question 18

Broad-spectrum effective against many organisms

Answer 18

beneficial because they target a lot pathogens but allowed for secondary infections like giving you yeast infection
– May allow for secondary or superinfections
to develop
– Killing of normal flora reduces microbial
antagonism

Question 19

Effectiveness of antimicrobial

Answer 19

▪ Diffusion susceptibility test
▪ Minimum inhibitory concentration test
▪ Minimum bactericidal concentration test
Zone of inhibition (clear inhibited) (is an area where bacteria cannot grow to due to the presence of antibiotics) meets bacterial growth is called suspetibility test

Question 20

Routes of administration

Answer 20

Topical, Intravenous (administration delivers drug directly to bloodstream),
the intramuscular, oral route,

Question 21

Toxicity

Answer 21

▪ Cause of many adverse reactions poorly
understood
▪ Drugs may be toxic to kidneys, liver, or nerves
▪ Consideration needed when prescribing drugs to
pregnant women
Ex: mild toxicity around the area of a vaccine site

Question 22

Therapeutic index

Answer 22

Is the ratio of the dose of a
drug that can be tolerated to the drug’s effective
Dose (higher the therapeutic the agent the higher the dose)

Question 23

Anaphylactic shock

Answer 23

– Disruption of normal microbiota
▪ May result in secondary infections
▪ Overgrowth of normal flora causing secondary
infections

Question 24

Resistance by bacteria is acquired in two ways:

Answer 24

▪ New mutations of chromosomal genes
▪ Acquisition of R plasmids via transformation,
transduction, and conjugation
(antibiotic do not produce resistant but some pathogens are stronger)

Question 25

Mycobacterium tuberculosis

Answer 25

Produces MfpA protein
– Binds DNA gyrase, preventing the binding of
fluoroquinolone drugs

Question 26

Multiple resistnace

Answer 26

Is when a pathogen acquire resistance to more than one drug they are resistant to at least three antimicrobial agents
Constant used of the drugs eliminates sensitive cells

Question 27

Cross resistance

Answer 27

Can occur when drugs are similar in structure
Inhibit the pathogen so immune system can eliminate

Question 28

Synergism

Answer 28

Occurs when one drug enhances the effect of a second drug

Question 29

Antagonisms

Answer 29

Occurs when drugs interfere with each other

Question 30

Retarding resistance

Answer 30

– Use antimicrobials only when necessary
– Develop new variations of existing drugs
▪ Second-generation drugs
▪ Third-generation drugs

Question 31

Antibiotics used in prokaryotes (mycobacteria gram postive and negative bacteria)

Answer 31

Polymyxin, penicillin, sulfonamides, streptomycin,erythromycin

Question 32

Antibiotics used in Eukaryotes (protozoa, fungi) and viruses

Answer 32

Azoles for yeast infection, acyclovir is uded for viruses