Antimicrobial Drugs

Question 1

chemotherapeutic agent

Answer 1

drugs that act against disease

Question 2

antimicrobial drug

Answer 2

drug that treats infection

Question 3

antibiotic

Answer 3

semisynthetic: chemically altered that are more effective than naturally occurring ones
synthetic: completely lab synthesized

Question 4

selective toxicity

Answer 4

targets specific microbe, harmless to host
inhibit specific physiological process
fewer drugs to treat euk infections
even fewer antivirals

Question 5

modes of antimicrobial action

Answer 5

inhibition of cell wall synthesis
inhibition of protein synthesis
disruption of cell membrane
antimetabolites
inhibition of nucleic acid synthesis
(prevention of virus attachment)

Question 6

inhibition of cell wall synthesis

Answer 6

beta lactam ring, against gram positive
can be protected from beta lactamase containing bacteria by semisynthetic addition
vancomycin: bind to cell wall itself, not enzyme
stop NAG and NAM building blocks secretion
decrease mycolic acid formation in mycobacteria

Question 7

inhibition of protein synthesis

Answer 7

targets translation

acts on prokaryote ribosome (70s), can be harmful to human mitochondria

Question 8

disruption of cell membrane

Answer 8

topical ointments, low toxicity, destroys cell membrane of G-, toxic to kidneys
antifungals: stop ergosterol synthesis by binding to inhibiting function
humans susceptible because cholesterol is like ergosterol

Question 9

antimetabolites

Answer 9

competitive inhibitors of microbial enzymes
stop PABA from creating nucleic acids
reverse transcriptase or protease inhibitors

Question 10

inhibition of nucleic acid synthesis

Answer 10

targets replication and transcription
don't treat infections
nucleotide analogs change nucleotide shapes, stop rep, transc, transl
stop prok DNA gyrase
stop prok RNA pol
reverse transcriptase inhibitors

Question 11

prevention of virus attachment

Answer 11

attachment antagonists

Question 12

kirby-baurer

Answer 12

test different antibiotics on bacteria-full plate

“diffusion susceptibility test”

Question 13

MIC / MBC

Answer 13

minimum inhibitory concentration: lowest antimicrobial concentration that will inhibit growth of microbe
minimum bactericidal concentration: lowest bactericidal concentration that will inhibit growth of bacteria

Question 14

side effects of antimicrobials: toxicity

Answer 14

low therapeutic index
hairy black tongue
yellow teeth stains

Question 15

side effects of antimicrobials: allergy

Answer 15

may cause anaphylactic shock

Question 16

side effects of antimicrobials: disruption of normal flora

Answer 16

superinfections

wipe-out of normal flora allows overgrowth of pathogens

Question 17

antibiotic resistance

Answer 17

intracellular macrophages
biofilm protection
chromosomal mutations
R plasmids (conjugation, transformation, transduction)

Question 18

mechanism of resistance

Answer 18

produce enzyme that destroys or deactivates drug
slow/prevent entry of drug into cell by thickening cell walls
alter target of drug so it binds less effectively
alter metabolic chemistry
pump antimicrobial out of cell before action
biofilms retard drug diffusion
tuberculosis produces resistant protein

Question 19

therapeutic index of a drug

Answer 19

conc of a drug that would be toxic / conc of a drug that would cure disease; larger number is safer, penicillin is 10 = good

Question 20

antivirals

Answer 20

prevent viral uncoating

inhibit nucleic acid synthesis

Question 21

antifungals

Answer 21

inhibit ergosteral synthesis

inhibit RNA function