Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Antibiotics > Flashcards

Antibiotics Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
0
Q

Penicillin V

A

Beta-lactam, penicillin
Acid-resistant (can take orally)
Sensitive to penicillinases
Limited spectrum (YES G+, G- cocci, NO G- rods)

Similar: Penicillin VK (+ potassium, more soluble)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Penicillin G

A

“Original” penicillin
Beta-lactam
Acid labile - can’t take orally (only IV, IM)
Sensitive to penicillinases
Limited spectrum (G+ and G- cocci - NOT enteric G- rods)
- Neisseria meningititis
- Treponema pallidum (syphilis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Ampicillin

A

Beta-lactam (penicillin)
Sensitive to penicillinase
Acid stable
Broader spectrum - G- enteric, most G+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Amoxicillin

A

Beta-lactam (penicillin)
Sensitive to penicillinase
Acid stable
Broader spectrum - G- enteric, most G+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Tricarcillin

A 
Beta-lactam (carboxypenicillin)
Sensitive to penicillinase
Acid stable
Extended spectrum
 - effective against G- enteric (including Pseudomonas aeruginosa)
 - less action against G+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Piperacillin

A 
Beta-lactam (ureidopenicillin)
Sensitive to penicillinase
Acid stable
Extended spectrum
 - most effective against Pseudomonas aeruginosa, anaerobic, G-
 - less effective against G+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Methicillin

A 
Beta-lactam (penicillin)
Resistant to penicillinase
Acid labile
Altered spectrum
 - targets Staphylococcus aureus (MRSA = resistant)
 - not effective vs G-
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Oxacillin

A 
Beta-lactam (penicillin)
Resistant to penicillinase
Acid stable (vs methicillin)
Altered spectrum
 - targets Staphylococcus aureus
 - not effective vs G-

Similar: naficillin, dicloxacillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Penicillins

A

Beta-lactam ring + thiazolidine ring + R group
Bacteriocidal but only if cell is growing
Inhibit cell wall synthesis -> lysis

PBP = transpeptidase = penicillin binding protein

Resistance = beta-lactamase (hydrolyzes ring)
- often acquired on plasmid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Cephalosporins

A 
Sim to penicillins - beta lactam
 - bacteriocidal when dividing
Dihydrothiazide ring -> 
More resistant to penicillinases, acid
Can use if penicillin allergy

Broad spectrum - most Gram +, some Gram -

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Cefazolin

A

1st gen cephalosporin (beta lactam)

Most Gram +
Some Gram -
Not pseudomonas aeruginosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Cefuroximide

A

2nd generation cephalosporin (beta lactam)

More Gram -
Fewer Gram +
Not pseudomonas aeruginosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Ceftriaxone

A

3rd generation cephalosporin (beta lactam)

Penetrates blood-brain barrier

Most Gram -

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Ceftazimide

A

3rd generation cephalosporin (beta lactam)

Broad spectrum Gram -
Effective against Pseudomonas aeruginosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Aztreonam

A

Mono-bactam (sim to beta-lactam but resistant to breakdown)

Aerobic Gram -
includes Pseudomonas aeruginosa
Not Gram + or anaerobic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Imipenem

A

Carbapenem (beta lactam)

Broadest spectrum vs Gram -
MRSA variable

Susceptible to renal dipeptidases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Clavulonic acid

A

Beta-lactamase inhibitor

+ amoxicillin = Augmentin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Sulbactam

A

Beta-lactamase inhibitor

+ ampicillin = Unasyn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Vancomycin

A

Glycopeptide - inhibits cell wall synthesis
Blocks transfer of D-Ala-D-Ala
Toxic

Only Gram + (too big for outer membrane porins)
Enterococcus or staphylococcus (ex MRSA)
Oral for C diff
Resistance is possible

25
Q

Cycloserine

A

D-Ala analog -> blocks cell wall synthesis
Toxic

Tuberculosis

26
Q

Bacitracin

A

Blocks phosphatase in murein (cell wall) synthesis
Toxic -> topical only

Only Gram +

27
Q

Polymyxin B

A

Disrupts membrane permeability (-> cidal even without growth)
Toxic -> topical

Gram - enterics (including Pseudomonas)

28
Q

Aminoglycosides

A

Distort 30S subunit -> cidal
Require aerobic conditions, some metabolic activity for entry into cell
Toxic

29
Q

Streptomycin

A

Initial aminoglycoside

Aerobic conditions, metabolic activity, imperfections ->
Entry -> distorts 30S -> misreading -> funny proteins ->
Disrupts membrane -> cidal

Lots of resistance
Toxic
Used for TB

30
Q

Gentamycin

A

Aminoglycoside
Multiple inhibitions to 30S
(less resistance than streptomycin)

Toxic (nerve, renal) - not generally used

31
Q

Tetracyclines

A

also includes doxycicline and monocycline

Block tRNA-30S binding -> static
Broad spectrum
- mycoplasma, rickettsia, chlamydia
- GI microbiome changes

Teratogenic, yellow teeth in kids

32
Q

Erythromycin

A

Macrolide
Blocks 50S chain elongation -> static

Most Gram +
Mycoplasma
Chlamydia

33
Q

Azythromycin

A

Similar to erythromycin (macrolide, blocks chain elongation)

High concentrations at infection site dt macrophages

34
Q

Chloramphenicol

A

Blocks chain elongation -> static

Aplastic anemia - not commonly used

Anaerobes
- Bacteriodes fragilis

35
Q

Clindamycin

A

Blocks peptidyl transfer -> static

Some Gram +
Anaerobes

36
Q

Streptogramins

A 
New class
Binds to 50S -> static

Dalfopristin + quinopristin = Synergin (work synergistically)

MRSA, VRE, etc

37
Q

Oxazolidinones

A

aka linezolid, Zyvox
Blocks tRNA transfer -> static

Gram +
New -> VRE, MRSA, etc
- some resistance already

38
Q

Mupirocin

A

Block isoleucine aminoacyl transferase ->
- static at low, cidal at high

Topical vs MRSA (surgeons)
Impetigo (Staph aureus, Strep pyogenes)

39
Q

Quinolones

A

aka Ciprofloxacin, Moxifloxacin
Inhibits gyrase -> DNA synthesis -> cidal
Inhibits bone growth -> teratogen, kids

Gram + cocci
Enteric Gram - bacilli
 - includes Pseudomonas aeruginosa
Anthrax prophylaxis
No longer MRSA (resistance)
40
Q

Metronidazole

A

Requires anaerobic conditions -> ferredoxin reduces/activates
Fragments DNA -> cidal

Bacteroides
Protozoal - trichomaniasis, amebiasis

41
Q

Rifampin

A

Inhibits RNA synthesis -> cidal

Broad spectrum
Tuberculosis (with isoniazid)
Saliva prophylaxis (Neisseria meningititis)

42
Q

Ethambutol

A

Unknown mechanism
Static

Tuberculosis

43
Q

Isoniazid

A

Blocks InhA enzyme -> mycolic acid -> cell wall -> cidal

Tuberculosis

44
Q

Pyrazinamide

A

Unknown mechanism
Activated by amidase -> cidal

Tuberculosis

45
Q

Reasons to give two drugs

A 
Synergism
Susceptibility pattern
Decreased resistance
Lower dose of toxic drug
Polymicrobial infection
46
Q

Mechanisms of resistance

A

Enzymatic degradation
(Beta-lactam, aminoglycoside, chloramphenicol, erythromycin)
Decreased permeability
(penicillins, chloramphenicol, aminoglycoside)
Active efflux (tetracycline)
Altered targets
(vancomycin, erythromycin, streptomycin, methycillin, sulfonamide, trimethoprim)
Alternative pathway (trimethoprim)

47
Q

Sulfonamide

A

Analog of PABA -> blocks THF production -> static

Wide range
Protozoa
UTI

48
Q

Trimethoprim

A

Blocks DHF reductase -> THF synthesis -> static
(same enzyme in humans but much higher affinity)

UTI (Bactrim = combo with sulfa)

49
Q

Antibiotic sensitivity methods

A

Minimum inhibitory concentration
- Determine via tube dilution -> no growth
Minimum bactericidal concentration
- requires tube -> plate -> no growth after removed
Disc diffusion - simple, simultaneous, doesn’t determine MBC
Betalactamase production - nitrocefin = chromogenic

50
Q

Ideal antibiotic properties

A

Kill bacteria, no toxicity or allergy to host
Should kill faster than it is inhibited
Should kill faster than resistance develops
Should reach bacteria (abcess, brain, inside cells)

Ideal does NOT exist…

51
Q

Major classes of antibiotics

A

Antimetabolites - sulfonamides, trimethoprim, isoniazid
Inhibitors of cell wall synthesis - beta-lactams, glycopeptides
Membrane permeability - polymyxins
Inhibitors of protein synthesis - aminoglysides, macrolides, tetracycline, chloramphenicol
Inhibitors of nucleic acid synthesis - quinolone, rifampin

Microbiology (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions