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Multisystem 1st Half > antibiotics 1 > Flashcards

antibiotics 1 Flashcards

1
Q

4 classes of beta-lactams

what do they all target?

A

penicillins
cephalosporins
carbecephams
monobactams

–all target cell wall biosynthesis

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2
Q

what two types of drugs target cell wall biosynthesis?

A

beta lactams and glycopeptides

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3
Q

what class of drugs target membrane potential?

A

lipopeptides

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4
Q

what class of drugs target cell membrane disruption?

A

polymyxins

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5
Q

sulfonamides target…?

A

nucleic acid biosynthesis

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6
Q

trimethoprim targets…?

A

nucleic acid biosynthesis

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7
Q

What do fluoroquinolones target?

A

DNA replication/transcription

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8
Q

bacteriostatic

A

inhibits bacterial growth without causing cell death

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9
Q

MIC vs MBC

A

MIC - lowest {} that inhibits growth after 18-24 hrs in vitro
MBC - lowest [] at which 99.9% of culture is killed after 18-24 hours in vitro

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10
Q

PAE

A

post antibiotic effect

suppression of bacterial growth continues after [ ] falls below MIC

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11
Q

gram + stains ___?

gram negative stains ____?

A

+ blue

- pink

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12
Q

3 aerobic gram + cocci

A

staphylococci
streptococcus
enterococcus

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13
Q

3 aerobic gram + bacilli

A

bacillus
cornyebacterium
listeria monocytogenes

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14
Q

3 aerobic gram - cocci

A

acinetobacter
moraxella catarhallis
neisseria

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15
Q

aerobic gram - bacilli

A 
acinetobacter
citrobacter
enterobacter
helicobacter
e coli
H. influenzae
klebsiella
proteus
pseudomonas
salmonella
shigella
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16
Q

gram - spirochetes

A

borrelia burgdorfera

treponema pallidum

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17
Q

above diaphragm anaerobe

A

peptostreptocuccus

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18
Q

below diaphragm anaerobes

A

gram + clostridium perfringens, tetani, and dificile

gram - bacterioides and fusobacterium

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19
Q

acid fast bacteria

A

mycobacterium and nocardia species that produce myolic acid = stain purple

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20
Q

do human cells have cell walls?

A

no…this is why we can target them

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21
Q

B lactams mechanism

A

inhibit peptidoglycan layer of cell wall synthesis

  • inhibits crosslinks between disaccharide units
  • can inhibit transpeptidase or PBPs
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22
Q

how to overcome penicillinase resistance?

A

combine penicillin with an inhibitor of B lactamase

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23
Q

side effects of beta lactams except monobactams

A

diarrhea
CV overload due to increased salts (v overload)
in renal failure –> hallucinations/convulsions
coagulation defects d/t inhibition of platelet activation and conversion of fibrinogen to fibrin

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24
Q

are penicillins and cephalosporins antigenic?

A

no, but their polymers and metabolites can react with bacterial or tissue proteins to form antigenic conjugates –> causing allergic reactions

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25
Q

penicillins structure

3 roles of the beta lactam ring

A

beta lactam ring + thiazolide ring = 6 aminopenicillanic acid

beta-lactam ring: 1) the active center of abx, 2) site of action for bacterial enzymes, and 3) site of formation of antigenic determinants

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26
Q

B lactamases and penicillinases

A

bacterial enzymes that allow resistance against penicillins

27
Q

do penicillins have good solubility?

A

no; they are ionized free acids at physiological pH so to improve solubility they are given as Na or K salts

28
Q

do peniciliins enter csf?

A

no, only during inflammation

29
Q

penicillin G and penicillin V

A

natural penicillins - made from the fungus penicillium

broad gram + bacteria (non penicillinase)

30
Q

penicillin G

A 
acid labile (not stable in acid)
only a third of dose is absorbed
31
Q

penicillin V

A

acid stable form

better oral absorption than penicillin G

broad spectrum gram +

32
Q

penicilin G vs V coverage

A

G is more active against neisseria and some anaerobes

33
Q

two ways to prolong penicillin G blood levels?

A

1) delay absorption by adding organic base like procaine or benzathine –> poorly soluble form
2) delay elimination by adding probenacid (blocks tubular secretion)

34
Q

penicillinase resistant penicillins (5)

use when bacteria are resistant to penicillin

A 
"i met nasty oxen"
methicillin
nafcillin
oxacillin
cloxacilin
dicloxacillin
35
Q

i met nasty oxen (penicillinase resistant penicillins) are not active against

A

NOT active against gram -

36
Q

MRSA

A

methicillin resistant related to failure to bind penicillin binding proteins (PBPs)

37
Q

first line treatment for B lactamase producing staph?

A

penicillinase resistant penicillins

  • methacillin
  • nafcillin
  • oacillin, cloxacillin, dicloxacillin
38
Q

extended range penicillins

A

ampicillin
amoxicillin
“am” extended

first penicillins effective against gram - (better penetration of outer membrane)

less susceptibility to to gram - penicillinases but more suseptibility to gram + penicillinases

39
Q

amoxicillin or ampicillin: which extended penicillin is more completely absorbed orally?

A

amoxicillin

40
Q

amoxicillin and ampicillin are active against which specific 6 orgs?

A 
e coli
p mirabilis
h influenzae
salmonella
shigella
neisseria
41
Q

anti pseudomonal penicillins

A

–carboxylated derivatives (ticarcillin)

extend the range of ampicillin to P aeruginosa, indole-positive proteus and enterobacter

42
Q

ticarcillin

A

used with pulmonary infections

extends ampicillin range from 6 gram - (epnssh)

and adds p aeruginosa
proteus
and enterobacter

43
Q

cephalosporins

A

similar structure and mechanism as penicillins

wider activity range

4 generations

44
Q

side effects of cephalosporins

A

GI issues and

BLEEDING

45
Q

1st gen cephalosporins

A

cephalexin
cefazolin

  • narrow spectrum (staph and strep) (gram + >gram -)
  • use for SURG prophylaxis; -NOT for active infection
  • dont penetrate CNS
  • not effective against MRSA
46
Q

what is recommended for mild foot infections in diabetics?

A

first gen cephalosporin –> cephalexin

47
Q

second gen cephalosporin

A

cefoxitin

used for B fragilis and other anerobics

prophylaxis for abdominal surgery

48
Q

prophylaxis for abdominal surgery?

A

cefoxitin (2G cephalosporin)

49
Q

3rd gen cephalosporins

A

ceftriaxone and ceftazidime

broad; penetrates CNS

highly active against gram - enteric orgs

50
Q

ceftriaxone used for what 3 bacteria?

A

–> N gonorrheae, N meningitis, and B burgdorferi

51
Q

ceftazidime used for what?

A

–> multidrug resistant gram - infections (like P aeruginosa)

52
Q

what is the first B lactam approved for MRSA infections?

A

ceftaroline fosamil

a 3G cephalosporin

53
Q

cefepime

A

4G cephalosporin
similar to ceftazidime against P aeruginosa and other gram -

better than 3g against gram + due to resistant to chromosomally encoded B lactamases

54
Q

ertapenem

A

a carbapenem

resistant to B lactamases, but
NOT resistant to metallo B lactamases

BROAD ( +, -, and anaerobics)

CNS and renal toxicity

55
Q

aztreonam

A

a monobactam

gram -

can be inhaled; little cross allergenicity with other B lactam abx

56
Q

vancomycin

A

a glycopeptide abx that prevents d-ala attachment to cell wall (binds substrate)

must give by IV; no cross-allergenicity!

bactericidal against gram + rods (including penicillinase producers and MRSA)

LAST resort for c dificile

57
Q

when can vancomycin be given orally?

A

abx-resistant pseudomembranous colitis and staph enterocolitis

58
Q

what resistance canbe developed against vancomycin?

A

van HAX genes

replaces D-ala with D lactate

59
Q

vancomycin side effects

A

“Red man syndrome” – hypersensitivity skin flushing or rash

tissue necrosis if given IM

neutropenia and nephrotoxicity

60
Q

daptomycin

A

lipopeptide; inhibits cell membrane potential by forming ca-dep membrane channels

used for skin infections and endocarditis by aerobic, gram +
works against resistant strains (VRSA, MRSA)

61
Q

vancomycin and daptomycin: can they be given IM?

A

no –> they cause tissue necrosis!

62
Q

polymyxins

A

polymyxins A and B (colistin)

cationic detergents that disrupt cell membrane

used topically or in eye/ear drops

NEPHROTOXIC

63
Q

what drug is used for acinetobacter from middle east

A

polymyxins (colistin)

Multisystem 1st Half (23 decks)

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