chapter 14!

Question 1

what antibiotic classes /drug inhibit cell wall synthesis?

Answer 1

• all are bactericidal.

1. natural penicillins: PCN V and PCN G.
2. semi-synthetic penicillins: Oxacillin.
3. aminopenicillins: Ampicillin.
4. penicillin + B-lactamase inhibitor: Amoxicillin + clavulanic acid = Augmentin.
5. Carbapens: Imipenem/cilastatin = Primaxin.
6. Monobactam: Aztreonam.
7. Cephalosporins: 1st gen = only gm (+)
   2nd - 5th gen = extended spectrum.

NON B-LACTAM RINGS
8. polypeptide: Bacitracin and Vancomycin.

ANTIMYCOBACTERIAL
9. anti-mycolic acid: Isoniazid and Ethambutanol.

Question 2

what drugs inhibit protein synthesis?

Answer 2

• all are bacteriostatic.

1. Nitrofurantoin: attacks bacterial ribosomal proteins. PRODRUG.
2. Chloramphenicol: attacks the 50s subunit of the 70s ribosome.
3. Aminoglycoside family: streptomycin, neomycin, and gentamycin. attack the 30s subunit of the 70s ribosome.
4. Tetracycline: interferes with tRNA attachment, what binds the amino acid to the mRNA strand.
5. Macrolides: Erythromycin; blocks the ribosomal tunnel.

Question 3

what drugs inhibit nucleic acid replication?

Answer 3

• are all bactericidal.

1. Rifamycin: Rifampin; mycobacteria. red urine and tears.

2: Quinolones aka Fluroquinolones: Ciprofloxacin (Cipro); causes the inhibition of DNA gyrase.

Question 4

what drugs injure the plasma membrane?

Answer 4

• are all bactericidal.

1. Lipopeptides: Polymycin B; disrupts the fatty acid biosynthesis.

Question 5

what drugs cause competitive inhibition of essential metabolites?

Answer 5

• bactericidal.

1. sulfanamides: sulfanilamide + trimethoprim.
   drug synergism.

Question 6

Paul Ehlrich

Answer 6

“magic bullet” and selective toxicity.

Question 7

Alexander Flemming

Answer 7

S. aureus inhibited by penicillin mold; first ABX.

Question 8

selective toxicity

Answer 8

selectively finding and destroying pathogens without damaging the host.

Question 9

chemotherapy

Answer 9

the use of chemicals to treat disease.

Question 10

antibiosis

Answer 10

the MECHANISM of inhibitory action.

Question 11

antibiotic

Answer 11

a substance/med produced by the microbe itself that in small amounts inhibits another microbe (organic).

Question 12

antimicrobial drugs

Answer 12

FULLY SYNTHETIC.

Question 13

semi-synthetic

Answer 13

substances chemically modified or manipulated in the lab.

Question 14

narrow spectrum

Answer 14

gm - OR gm +

Question 15

broad spectrum

Answer 15

gm + AND gm -

Question 16

bacteriostatic

Answer 16

inhibits bacterial growth

Question 17

bacteriocidal

Answer 17

kills all microbes.

Question 18

superbug

Answer 18

bacteria that are resistant to a large number of ABX.

Question 19

half of ABX are produced by

Answer 19

Streptomyces

Question 20

the target of antifungal drugs

Answer 20

injure the plasma membrane and target the sterols since fungi have ergosterol present instead of cholesterol.

1. interrupting the biosynthesis kills the cell and injures the plasma membrane, causing cellular contents to leak out.

Question 21

antifungal drugs include

Answer 21

1. Polyenes
   i. Nyastatin: treats thrush or oral candida.
2. Azoles
   i. imidazoles like Clotramazole and Micoazole.
   treats tropical infections of the skin.

Question 22

Kirby-Bauer Test

Answer 22

measures the zone diameter of the ABX compared to a table.
MIC: minimum inhibitory concentration. the smallest effective dose to inhibit growth.

inversely related to the zone of inhibition.
small zone = big MIC : need more chemicals to inhibit growth.
big zone = small MIC : less chemicals needed to inhibit growth.

Question 23

E-Test

Answer 23

determines MIC using an epsilometer with the ABX.
only tests one drug.

Question 24

broth dilution test

Answer 24

determines the MIC (minimum inhibitory concentration) and the MBC (minimal bacteriocidal concentration).

tests if the bacteria is able to grow at all ABX concentrations, when its resistant and sensitive.

Question 25

therapeutic index

Answer 25

the ratio of a drug dose that is toxic to humans compared to the minimal effective dose.
assesses the risks against the benefits.

TI = TD50/ED50
TD50: toxic dose to 50% of the population
ED50: effective dose to 50% of the population.

! safety zone: a larger zone is better for over the counter while a narrow zone must be monitored by the hospital.