Chapter 10 - Biological Method

Question 1

Antimicrobial agents

Answer 1

-drugs that treat infections

Question 2

Chemotherapeutic agents

Answer 2

drugs that act against disease

Question 3

Paul Erlich

Answer 3

“magic bullet”

-arsenic compounds that killed microbes

Question 4

Alexander Fleming

Answer 4

penicillin released from Penicillium

Question 5

Mechanism of actions of microbial drugs

Answer 5

• inhibition of pathogen’s attachment to/recognition of host
• inhibition of cell wall synthesis
• disruption of cytoplasmic membrane
• inhibition of protein synth
• inhibit general metab pathway
• inhibit DNA/RNA synth

Question 6

-inhibition of cell wall synthesis

Answer 6

• cidal
• only effective for growing cells
• prevents bacteria fr increasing amt of peptidoglycan; NO effect on existing peptidoglycan layer
• prevents cross-linkage of NAM subunit
• beta-lactam rings bind to enzymes

Question 7

-inhibition of protein synth

Answer 7

• static

- macrolides (erythromycin)

Question 8

-disruption of cytoplasmic membrane

Answer 8

-cidal

Question 9

-inhibit general metab pathway

Answer 9

• static

- sulfonamides

Question 10

-inhibit DNA/RNA synth

Answer 10

-cidal

Question 11

Vancomycin

Answer 11

inhibits cell wall synthesis (cidal)

-interferes w bridges that link NAM subunits in many GramPos

Question 12

Erythromycin

Answer 12

inhibits protein synth (static)

-gram pos, gram neg, chlamydias, rickettsias

Question 13

Macrolides

Answer 13

inhibits protein synth (static)
-gram pos, gram neg, chlamydias, rickettsias

aka erythromycin

Question 14

Polymyxins

Answer 14

disruption of cytoplasmic membrane (cidal)

• gram neg only
• toxic to human kidneys

Question 15

Sulfonamides

Answer 15

inhibits general metab pathway (static)

-gram pos, gram neg, chlamydias, rickettsias, protozoas

Question 16

3 static mechanism of action of microbial drugs

Answer 16

1 inhibit protein synth
2 inhibit metab pathway
3 inhibit attachment/recognition of host

Question 17

3 cidal mechanism of action of microbial drugs

Answer 17

1 inhibit cell wall synth
2 disrupt cytoplasmic membrane
3 inhibit DNA/RNA synth

Question 18

Penicillin

Answer 18

• inhibits synth of cell wall (peptidoglycan)
• beta-lactams bind to enzymes that cross-link NAM subunits of peptidoglycan
• only effective during log phase

Question 19

advantage of semisynthetic derivatives of beta-lactams

Answer 19

• more stable in acidic environments
• more readily absorbed
• less susceptible to deactivation
• more active against more types of resistant bacteria

Question 20

Bacitracin

Answer 20

inhibits cell wall synthesis (cidal)

-blocks secretion of NAG + NAM fr cytoplams

Question 21

Isoniazid

Answer 21

inhibits cell wall synthesis (cidal)
-disrupts mycolic acid formation in mycobacterial species + used exclusively for treatment of infections w MYCObacteria (TB)

Question 22

Azoles

Answer 22

disrupt cytoplasmic membrane (cidal)

• inhibit ergosterol synth
• broad spectrum drug
• can be used for protozoan, fungi, + worm infections

Question 23

Minimum Inhibitory Concentration Test

Answer 23

minimum concentration of a drug required to completely inhibit growth.

Question 24

Kirby Bauer test

Answer 24

diffusion susceptibility test looks at zone of inhibitions

Question 25

Toxicity

Answer 25

- cause of many adverse rxn - drugs may be toxic to kidneys, liver, nerves - consideration needed when prescribing drugs to pregnant women

Question 26

Tetracyclines

Answer 26

- inhibits protein synth - block tRNA for docking site - becomes incorporated into bones + teeth of a fetus - consideration needed when prescribing drugs to pregnant women

Question 27

Allergies

Answer 27

- allergic rxn are rare but life threatening | - anaphylactic shock

Question 28

Retarding resistance

Answer 28

- maintain high concentration of drug in patient for sufficient time - use antimicrobial agents in combination - use antimicrobial only when necessary

Question 29

synergism vs. antagonism

Answer 29

synergism - works better together. ex) amoxicillin-clavulanic acid + semisynthetic aztreonam antagonism - works against each other ex) penicillin (only works when actively dividing) + erythromycin (stops protein synth which stops growth)

Question 30

penicillin + erthromycin

Answer 30

antagonistic combo

Question 31

Quinolones

Answer 31

- inhibits DNA/RNA synth (cidal) - acts against prokaryotic DNA gyrase - aka ciprofloxacin

Question 32

Ciprofloxacin

Answer 32

- inhibits DNA/RNA synth (cidal) - acts against prokaryotic DNA gyrase - aka quinolones/fluoroquinolones

Question 33

antibiotics that inhibit cell WALL synth

Answer 33

penicillin vancomycin bacitracin isoniazid

Question 34

antibiotics that inhibit protein synth

Answer 34

macrolides/erythromycin | tetracyclines

Question 35

simplest beta-lactams

Answer 35

-only effective against aerobic gram neg

Question 36

antibiotics that disrupt cytoplasmic MEMBRANE

Answer 36

azoles polymyxin amphoterecin B

Question 37

narrow spectrum meds

Answer 37

penicillin, isoniazid

Question 38

broad spectrum meds

Answer 38

erythromycin, sulfonamides, azoles, tetracycline

Question 39

Amphoterecin B

Answer 39

Attached to ergosterol in fungal membranes -disrupts cytoplasmic membrane

Question 40

antibiotics that inhibit DNA/RNA synth

Answer 40

quinolones reverse transcriptase inhibitors (only against retrovirus) nucleotide analogs