Antimicorbial Chemotherapy

Question 1

What are chemotherapeutic agents

Answer 1

Chemical agents used to treat disease
They destroy pathogenic microbes or inhibit their growth within a host
Most are antibiotics

Question 2

What are antibiotics

Answer 2

Microbial products or their derivatives that kill susceptible microbes or inhibit their growth
They come from natural resources

Question 3

What did Paul ehrlich do

Answer 3

Developed concept of selective toxicity
Looked at synthetic doses to try and treat disease
Tried treating African sleeping sickness

Question 4

What did sahachiro hata do

Answer 4

Created compound 606 which is completely synthetic
Worked with ehrlich and identified arsenic compounds that treated syphilis

Question 5

What did gerhard domagk and Jacques and Therese trefouel do

Answer 5

Discovered sulfonamides and sulfa drugs which inhibit folic acid synthesis

Question 6

Who first discovered penicillin and who discovered it again

Answer 6

Ernest duchesne then Alexander Fleming because he was a slob, left plates full of staph and came back to find there was a clearing around the bacteria which was penicillin

Question 7

What did heatley do

Answer 7

Experiment on rats to show penicillin was effective in vivo rather than just in vitro

Question 8

What did Selman Waksman do

Answer 8

Streptomycin which was discovered to be an antibiotic against tuberculosis

Question 9

What are the streptomyoces and what do they do

Answer 9

Chloramphenicol, oxytetracycline, neomycin, and tetracycline which are soil bacteria that produce antibiotics naturally to try and kill competitors but are resistant to these antibiotics

Question 10

What is selective toxicity

Answer 10

Ability of a drug to kill or inhibit pathogen while damaging host as little as possible

Question 11

What is a therapeutic dose

Answer 11

Drug level required for clinical treatment of an infection

Question 12

What is a toxic dose

Answer 12

Drug level at which drug becomes too toxic for patient

Question 13

What is the therapeutic index

Answer 13

Ratio of toxic dose to therapeutic dose
The larger the therapeutic dose the better the drug
Therapeutic dose should never be higher because that could be detrimental

Question 14

What are side effects

Answer 14

Undesirable effects of drugs on host cell

Question 15

What are narrow spectrum drugs

Answer 15

Only gets rid of certain bacteria
Example could be only treating gram neg or pos

Question 16

What are broad spectrum drugs

Answer 16

Can treat wider array of bacteria such as treating both gram neg and pos

Question 17

What is a cidal agent

Answer 17

Will kill bacteria

Question 18

What is a static agent

Answer 18

Might not kill bacteria right away but will inhibit processes

Question 19

What is a minimal inhibitory concentration

Answer 19

Lowest concentration of a drug that inhibits growth of a pathogen

Question 20

What is the minimal lethal concentration

Answer 20

Lowest concentration of drug that kills a pathogen

Question 21

What is a crucial structure to all cillins

Answer 21

Beta lactam ring which stops cell wall synthesis

Question 22

What does beta lactamase do

Answer 22

Stops penicillin because it hydrolyzes the bond in the ring
Attacks at the beta lactam ring

Question 23

What structure is the same for every penicillin

Answer 23

6 aminopenicillanic acid

Question 24

What is transpeptidase

Answer 24

Links NAG and NAM amino acids together

Question 25

What does beta lactam do to transpeptidase

Answer 25

It binds to it and inhibits it so peptidoglycan and the cell wall can’t form which means there is nothing to prevent osmotic stress and the cell lyses It only works on bacteria that are synthesizing new peptidoglycan

Question 26

What are two naturally occurring penicillins

Answer 26

G and V which are narrow spectrum Semisynthetic penicillins are more broad than naturally occurring ones

Question 27

What issues can arise from adults being allergic to penicillin

Answer 27

Allergies can lead to violent allergic response and death Penicillin will bind onto rbc due to beta lactam ring opening up which means an epitope is created The epitope is recognized by wbc and immune systems attacks your own rbc

Question 28

What are cephalosporins

Answer 28

Structurally and functionally similar to penicillin They are broad spectrum antibiotics that can be used by most patients that are allergic to penicillin

Question 29

What is a generation and how does this concept connect to cephalosporins

Answer 29

They are groups of drugs that are sequentially developed In cephalosporins they have multiple generations that become more broad each one

Question 30

Why is vancomycin important

Answer 30

Stops transpeptidase by individually blocking transpeptidation Treatment of staphylococcal and enterococcal infections

Question 31

What are vancomycin and teicoplanin

Answer 31

Glycopeptide antibiotics that inhibit cell wall synthesis by binding to terminal peptides

Question 32

How do protein synthesis inhibitors work

Answer 32

Many antibiotics bind specifically to bacterial ribosomes, small or large subunit They inhibit a specific step in protein synthesis

Question 33

What are aminoglycoside antibiotics

Answer 33

Large group with cyclohexane rings and amino sugars Bind to 30s ribosomal subunit which interferes with protein synthesis by directly inhibiting the process and causing misreading of mRNA

Question 34

What are tetracyclines

Answer 34

Four ring structure to which a variety of side chains are attached Broad spectrum and bacteriostatic Can be used to treat acne Combines with 30s ribosome which inhibits binding of aminoacyl tRNA molecules to A site of ribosome which stops new tRNA from coming in

Question 35

What are macrolides

Answer 35

Stop translocation Bind onto 50s ribosome and stop mRNA from moving down to a site to open space for new tRNA Used for patients allergic to penicillin

Question 36

What is erythromycin

Answer 36

Example of Macrolide that is broad spectrum and usually bacteriostatic Binds to 23s and 50s subunit which inhibits translocation and peptide chain elongation

Question 37

What is chloramphenicol

Answer 37

Broad spectrum and chemically synthesized Binds to 23 and 50s ribosome subunit which inhibits peptidyl transferase rxn Only used in life threatening situations

Question 38

What are metabolic antagonists

Answer 38

Act as anti metabolites which antagonize or block functioning metabolic pathways by inhibiting metabolites using key enzymes Are structural analogs which are molecules that are structurally similar to and compete with naturally occurring metabolic intermediates

Question 39

What are sulfonamides or sulfa drugs

Answer 39

Completely synthetic and selectively toxic Structurally related to sulfanilamide which is an analog of paba which is a substrate at the beginning of folic acid synthesis

Question 40

Why are sulfonamides selectively toxic

Answer 40

Due to competitive inhibition of folic acid synthesis enzymes

Question 41

What is trimethoprim

Answer 41

Selectively toxic synthetic antibiotic that interferes with folic acid production Broad spectrum and can be combined with sulfa drugs to increase efficacy of treatment (this combination blocks two steps in folic acid pathway)

Question 42

Why do we need folic acid and how do we get it

Answer 42

Need it to make rna and dna Get it from vegetables or organs juice

Question 43

What is quinolones

Answer 43

Synthetic drug containing the four quinolone ring and was first synthesized by nalidixic acid Acts by inhibiting bacterial dna gyrase and topoisomerase II which disrupts dna replication and repair Broad spectrum bactericidal

Question 44

What is the problem with inhibiting dna gyrase and topoisomerase II

Answer 44

They relieve stress of dna binding too tightly which allows helicase to come through so if they can’t loosen the strands helicase can’t fit