Controlling microbial growth in the body antimicrobial drugs ch 10

Question 1

who discovered sulfanilamide? what was noteworthy about its use in medicine

Answer 1

Gerhard domagk, widley used antibiotics

Question 2

what are 2 contributions from Selman Waksman

Answer 2

he discovered antibiotics penicillin and staphylococcus

Question 3

which disease was streptomycin used to treat when it first became available

Answer 3

streptomyces griseus

Question 4

what are semi-synthetic antibiotics and synthietic antibiotics

Answer 4

semi synthetic are chemically altered antibiotic and modified natural forms of antibiotics
synthetic drugs are lab designed

Question 5

which group of antimicrobial chemicals constitute the largest class?

Answer 5

penicillin

Question 6

in general, why are there relatively fewer drugs available to treat fungal infections or viral infections

Answer 6

fungal cant kill them because your own eukarytoic kill by killing your own cell
Virus (prevent attachment) kill by killing your own cells live in our cells

Question 7

what are 4 mechanisms that we discussed by which antibiotics can kill bacteria give example of an antibiotic for each mechanism

Essay question…

Answer 7

1) Inhibition of bacterial cell wall synthesis
Prokaryotes: penicillins, cephalosporins, vancomycin, bacitracin
2) Inhibition of protein synthesis
Prokaryotes: tetracyclines, streptomycin, erythromycin
Eukaryotes: neomycin
3) Disruption of the cytoplasmic membrane
Gram- bacteria: polymyxins; Gram+ bacteria: gramicidin
Fungi and Protozoa: azoles, amphotericin B
4) Inhibition of DNA synthesis and other metabolic pathways
Prokaryotes (mostly): sulfonamides
5) Inhibition of viruses (attachment/replication)
Hepatitis C: ribavirin; Rhinovirus: pleconaril
Herpes virus: acyclovir

Question 8

what does( action spectrum mean?) What is the difference between narrow spectrum drugs and broad spectrum drugs

Answer 8

different kinds of pathogens
effective against few groups
effective against many groups

Question 9

why are drugs that target the bacterial cell wall effective only on growing bacteria

Answer 9

prevent bacteria from increasing amount of peptidoglycan (cell wall material) cell wall is weak*

Question 10

whats step of cell wall synthesis is inhibited by penicillin family antibiotics.

Answer 10

beta lac tams block cross linking of peptidoglycan chains

weaken the cell to rupture.

Question 11

What happens to a bacterial cell when its cell wall is weakened by penicillin treatment

Answer 11

it burst. Osmosis *

Question 12

why can some drugs selectively inhibit protein synthesis in bacteria

Answer 12

target bacterial ribosomes and inhibit protein synthesis (70 s bacteria)
Can not survive with out production of new proteins (80s humans)

Question 13

what are there sometimes side effects from using tetracycline

Answer 13

Mitochondria in humans and animals are damaged because they contain 70 s ribosomes affects bone marrow + liver.

Question 14

explain how amphotericin can kill fungal cells. why is amphotericin not effective against bacteria

Answer 14

attaches to ergosterol its a component in the membrane bacteria doesn’t have ergosterol

Question 15

Besides amphotericin, what is a second major class of anti fungal drugs

Answer 15

Azores-such as fluconzole and allylamines such as Terbinafine are two other classes of anti-fungal drugs that disrupt cytoplasmic membranes

Question 16

why are inhibitors of DNA synthesis not often useful as therapeutic agents

Answer 16

they have little effect on eukayotes or viruses

Question 17

what are 4 important features to evaluate when prescribing antimicrobial drugs

Answer 17

ideal-available inexpensive
features to evaluate-safety and side effects
spectrum-narrow -timely
Efficacy-different test

Question 18

What info is needed in order to best prescribe a narrow spectrum antibiotic

Answer 18

Accurate, timely diagnosis.

Question 19

what are two possible problems with the use broad spectrum drugs.

Answer 19

secondary infection such as vaginitis

Question 20

what are three different test for evaluating the effectiveness of an antibiotic

Answer 20

susceptibility test
minimum inhibitory concentration test
minimum bactericidal concentration test

Question 21

which effectiveness test is bacterial

Answer 21

minimum bactericidal concentration test

Question 22

what is the general goal of administering antimicrobial agents in humans

Answer 22

to help with disease

Question 23

Describe the 4 means of administration of drugs in humans with advantages and disadvantages associated with each means

Answer 23

tropical applications- for external infections
oral route
intramuscular- needle
intravenous- drugs to bloodstream

Question 24

what are 3 common safety and side effects with the use of antimicrobials

Answer 24

toxicity- substance can damage organisms
allergies- hypersensitivity disorder in the immune system
disruption -secondary infection

Question 25

what does toxicity mean

Answer 25

the degree to which a substance can damage organisms (Allergies)*

Question 26

what problem can develope when ones normal microbiota are disrupted

Answer 26

secondary infection

Question 27

what are 2 processes by which bacteria can develop resistance to an antibiotic

Answer 27

new mutation, resistance plasmids

Question 28

can antibiotic create mutations in bacteria. If not, how do antibiotics affect cell growth.

Answer 28

yes, new mutations of chromosomes

resistance plasmids with genes

Question 29

what is a super bug

Answer 29

when 3 or more meds dont work

Question 30

what are 4 practices important for people to undertake in order to limit the occurrence of antibiotic resistance among bacteria

Answer 30

maintain concentrations
don't discontinue a drug too early 
use combination
limit the use
making new drugs