Antibiotics, Anti-microbials, and Resistance (complete) Flashcards Preview

DMD 5245 > Antibiotics, Anti-microbials, and Resistance (complete) > Flashcards

Flashcards in Antibiotics, Anti-microbials, and Resistance (complete) Deck (62):
1

What is a chemotherapeutic agent

a drug that fights against diseases

2

What is an antimicrobial agent

a drug that treats infections

3

What is an Antibiotic

Antimicrobial agents produced by microorganisms that kill or inhibit the growth of other organisms

4

What is a semisynthetic agent

an agent whose parent compound was made by a microbe, but was then chemically modified.

5

which types of antibiotics work to inhibit cell wall synthesis

cephalosporins
penecillins
vancomycin
penems

6

Which types of antibiotics work to inhibit protein synthesis

Eyrthromycin
clindamycin
chloramphenicol
tetracycline
aminoglycosides

7

which types of antibiotics inhibit Nucleic Acid Synthesis

Quinolones (ciproflaxin)
rifampin
sulfa drugs
metronidazole
nucleoside analogs

8

Which types of antibiotics inhibit metabolic pathways

sulfa drugs
trimethoprim
amantadine

9

Which types of antibiotics alter cell membrane permeability

nystatin
amphotericin B
Polymixins

10

how do the Beta-Lactam rings inhibit cell wall synthesis

They bind to the enzymes that are responsible for cross linking NAM subunits of the bacterial cell wall. So when those enzymes are bound, the cell wall can't be properly synthesized, they will be weak, and the bacteria will lyse

11

What are some important beta-lactam drugs

penicillin
methicillin
cephalosporins
monobactams
carbapenems

12

how does augmentin (beta-lactamase inhibitor) help the beta-lactam drugs to be more effective

it deactivates the bacterial beta-lactamase enzymes, so that the bacteria can't fight back against the beta-lactams drugs. normally bacteria with beta-lactamase activity can resist beta-lactam drugs

13

What can be the problem with broad spectrum antimicrobials

they can kill off some of the normal flora, which can lead to the development of superinfections or secondary infections.

14

Which antimicrobial drugs interfere with particular alanine-alanine bridges that link NAM subunits in many gram positives

Vancomycin and Cycloserine

15

Which antimicrobial is topical only and blocks the secretion of NAG and NAM from the cytoplasm

bacitracin

16

which drugs disrupt formation of arabinogalactan-mycolic acid complexes in mycobacterial species

Isoniazid and ethambutol

17

what is the affect of cell wall inhibiting drugs on growing cells, mature cells, animal cells, and plant cells

They destroy growing cells, (don't let peptidoglycan form properly)
They have no effect on mature cells (because they only prevent the peptidoglycan from forming, they don't have any affect on the existing peptidoglycan)
They have no effect on plant or animal cells since those don't have peptidoglycan.

18

Why can drugs that inhibit protein synthesis be harmful in large doses

because animals have mitochondrial ribosomes that are similar to the bacterial ribosomes that are the target of these drugs that inhibit protein synthesis

19

For what type of infection is amphotericin B used

fungal infections

20

what is the mechanism of action of amphotercin B against fungi

it attaches to ergosterol that is found in fungal membranes. This negatively affects the integrity of the fungal membrane by creating pores in the membrane

21

Why can humans be susceptible to Amphotericin B?

because the ergosterol of fungi is similar to the choleterol in humans

22

What is the target of the antibacterial Polymixin

it binds to LPS and disrupts both of the gram negative membranes

23

why are polymixins usually used as a last resort

because they are relatively neurotoxic and nephrotoxic

24

How do the drugs that inhibit metabolic pathways of bacteria work

the drugs are structural analogs that bind to necessary metabolic enzymes and block them from performing their normal function

25

can antimetabolic drugs have an impact on viruses and parasitic worms

yes, they can paralyze the worms, and they can block viral activation

26

Why are sulfa drugs (sulfonamides) and trimethoprim used together (they are combined in bactrim and septra)

they both inhibit bacterial metabolic pathways, but they do it by inactivating different enzymes. so it is more effective when blocking both enzymes

27

What are the drugs that inhibit the metabolism of viruses

amantadine and rimantadine

28

what is the main problem with drugs that are used to inhibit nucleic acid synthesis

there are only a few slight differences between prokaryotic and eukaryotic

29

What are the mechanisms by which drugs that inhibit nucleic acid synthesis work

1. they are nucleoside analogs, so they are inserted into nucleic acids instead of the actual nucleosides
2. or they inhibit necessary enzymes in nucleic acid synthesis

30

What are drugs that inhibit nucleic acid synthesis usually used against

viruses and rapidly dividing cancer cells

31

What are the three most common nucleoside analogs

ribvarin
acyclovir
azidothymine

32

how do quinolones and fluoroquinolones work to inhibit nucleic acid synthesis

they act against prokaryotic DNA gyrase

33

how does rifampin work to inhibit nucleic acid synthesis

it binds to and inhibits RNA polymerase during transcription

34

can prevention of viral attachment be a plausible target of antiviral drugs

yes, there are drugs that do just that

35

name the common antifungal drug groups

polyenes (nystatin, amphotercin)
Azoles (miconazole, ketoconazole, fluconazole)
DNA analogues (Flucytosine)

36

What do the antifungal Azoles do to fight fungi

they inhibit the synthesis of ergosterol

37

What do the antifungal polyenes do to fight fungi

bind to the sterols in the cell membrane, causing leakage and death

38

What are the 6 characteristics of an ideal antimicrobial agent

1. Readily available
2. inexpensive
3. chemically stable
4. easily administered
5. non-toxic, non-allergenic
6. selectively toxic against many pathogens

39

What are the three ways to test the efficacy of antimicrobials

Diffusion susceptibility tests
minimum inhibitory concentration tests
minimum bactericidal concentration tests

40

how is a diffusion susceptibility test performed

you have a plate with growing colonies of your selected microbial, then you put little dabs of different antimicrobials on the plate, and observe which anti-microbials kill the microbial, and how drastically they do so

41

What does the minimum inhibitory concentration test show

it shows the lowest concentration at which an antimicrobial drug will leave no visible bacterial colonies after a night of incubation

42

what does the minimum bactericidal concentration test show

it shows the lowest concentration at which no bacterial colonies grow

43

What is topical administration

external application, applied directly to the infected area

44

What are the four maint types of drug administration

Topical
Oral
Intramuscular
Intravenous

45

What is the difference in relative concentration of the drug over time when given orally, intramuscular, and intravenously

Orally, slow increase, and decrease of a small amount of Drug
Intramuscular. a failry quick increase, of a moderate amount of Drug, followed by a fairly quick decline
Intravenous, Very quick rise or a high concentration of Drug

46

What are the three main side effects of anti-microbials

toxicity
allergies
disruption of normal microbiota

47

Are Drugs fine to take after they expire, why or why not

no, because some can become toxic after expiration

48

how common are allergies caused by anti-microbials

they are rare

49

what are the problems associated with anti-microbials that disrupt the normal microbiota?

1. they can create secondary infections (too much open space for bacteria)
2. they can lead to an overgrowth of normal flora (superinfection)

50

What are the two ways in which bacteria acquire drug resistance

1. New mutations of chromosomal genes
2. Acquisition of R-plasmids from other bacteria

51

What are the four main ways in which microbes resist antibiotics

1. inactivation of the drug
2. altered uptake of the drug
3. modification of the structural target of the drug
4. altered metabolic pathway

52

What are mechanisms by which a microbe can inactivate a drug

cleavage of the drug
phosphorylation, adenylation, methylation

53

What ways does a bacteria alter its uptake up a antibiotic

alters its permeability
uses efflux pumps (after the drug gets in, the bacteria pumps it out)

54

Are resistances to antibiotics passed from one bacteria to another through plasmids

yes

55

How do populations of resistant organisms develop

you start with a population of organisms with only a few resistant organisms. then there is exposure to a drug which kills most of the non-resistant organisms. the few remaining organisms reproduce, leaving a population of mostly drug resistant organisms

56

can a single pathogen be resistant to multiple drugs

yes

57

Where do many of the organisms that are resistant to multiple drugs, or have acquired cross-resistance

in hospitals

58

What is cross-resistance in bacteria

cross-resistance is resistance acquired when a bacteria comes in contact with a substance similar to an antibiotic, and creates a resistance to it, and thus to the antibiotic

59

How do you prevent resistance to antibiotics

1. use high concentrations of a drug, for long periods of time ]
2. take advantage of synergism
3. limit antimicrobials to necesssary cases
4. Develop new drugs

60

what is synergism between antimicrobials

when two drugs used together work better than either of them do on their own.

61

What are CRE's

carbapenem-resistant enterobacteriaceae

62

What's the scary thing about CRE's

these infections are very hard to treat, and have high mortality rates