antibiotics med chem Flashcards

(97 cards)

1
Q

mutualistic relationship

A

both organisms benefit

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2
Q

opportunistic relationship

A

under normal conditions the microbe does not cause disease, but can if certain conditions are met

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3
Q

features of gram positive bacteria

A
  • Outer peptidoglycan layer

- stains purple

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4
Q

features of gram negative bacteria

A
  • out lipopolysaccharide layer
  • porins provide channels through LPS
  • stains pink
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5
Q

antibiotics that are from manmade sources

A

sulfa drugs
fluoroquinolones
linezolid

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6
Q

bacteriocidal

A
kills bacteria
(technically all antibiotics are bacteriocidal at high doses)
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7
Q

bacteriostatic

A

inhibits growth of bacteria

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8
Q

sugar with the peptide attached for cross linking in peptidoglycan

A

NAM

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9
Q

amino acids needed to form cross-link

A
  • D-Ala D-Ala on NAM

- pentaglycine chains linking the NAMs

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10
Q

steps of forming peptidoglycan cross-link

A

in cytoplasm

  1. synthesize NAM
  2. attach NAG and prenyl
  3. add peptide side chain
  4. flipping into periplasm

in periplasm
5. form crosslink

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11
Q

enzyme that makes crosslinks

A

transpeptidase

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12
Q

what facilitates transport of NAG and NAM into periplasm

A

bactoprenol

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13
Q

how does transpeptidation take place?

A
  1. penicillin binding protein has an active Ser that attacks the non-terminal D-Ala forming an ester bond
  2. Ester bond can be attacked by an amine in the pentaglycine chain via transpeptidation, forming a cross link
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14
Q

beta-lactam MoA

A

mimic D-Ala D-Ala to form a bond with PBP and prevent it from being used to make cross links, thus opening the cells wall

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15
Q

definition of a lactam ring

A

an intramolecular ring with an amine and a carboxylic acid linked with varying amounts of carbons (alpha=1, beta=2, and so on)

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16
Q

what part of beta-lactams mimics the D-Ala D-Ala peptide

A

the acidic withdrawing group on the lactam ring

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17
Q

Problems with beta lactams

A
  • degraded by water and stomach acid due to its instability

- resistance via beta-lactamase, penicillinase, and other mechanisms

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18
Q

beta-lactamase function

A

hydrolysis of penicillins

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19
Q

location of beta-lactamase in gram positive bacteria

A

outside the peptidoglycan

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20
Q

location of beta-lactamase in gram negative bacteria

A

periplasmic space, between LPS and cytoplasmic membraine

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21
Q

general SAR of penicillins

A
  • required S in ring
  • ring system
  • no substitution on ring
  • “west end” has amide linkage
  • aromatic or cyclic function in “west end” R group
  • dimethyl on east end
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22
Q

penicillin G features

A
  • early penicillin
  • very Gm+ (no staph)
  • little Gm-
  • unstable when given orally
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23
Q

penicillin V features

A
  • early penicillin
  • very Gm+ (no staph)
  • little Gm-
  • given orally b/c of ether electron withdrawing group
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24
Q

early penicillins

A

Pen G

Pen V

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25
methicillin features
- ortho groups prevent beta-lactamase attack - ok GM+ - little GM- - given IV
26
nafcillin features
- ortho groups prevent beta-lactamase attack - ok GM+ (staph) - little GM- - given IV
27
oxacillins feature
- ortho groups prevent beta-lactamase attack - ok GM+ (staph) - little GM- - given oral
28
penicillinase-resistant penicillins
- methicillin - nafcillin - oxacillins (oxacillin, cloxacillin, dicloxacillin)
29
ampicillin/amoxicillin features
- amino group good for passing through porins - good Gm- - good Gm+ - good substrate for beta-lactamase - ineffective against pseudomonas - given orally
30
broad-spectrum penicillins
ampicillin | amoxicillin
31
broad-spectrum penicillins for pseudomonas
carbenicillin | ticarcillin
32
carbenicillin features
- has alpha-acidic group - broad Gm- - reduced Gm+ - useful against pseudomonas - given IV
33
ticarcillin features
- has alpha-acidic group - broad Gm- - reduced Gm+ - useful against pseudomonas - given orally
34
broad spectrum ureido penicillin
piperacillin
35
piperacillin features
- has urea-like group linker - piperazine ring gives great Gm- penetration - resistant to Gm- beta-lactamases - susceptible to Staph beta-lactamase - given IV - good for pseudomonas and anaerobes
36
clavulanic acid features
- similar structure to penicillins, except has O in place of S and unsaturated C-2 - given with other beta-lactams to deal with beta-lactamase resisitance
37
clavulanic acid MoA
irreversible inhibitor of beta-lactamase
38
penem drugs
thienamycin imipenem meropenem ertapenem
39
penem features
- very broad Gm- - PBP binder - no S or O in lactam ring - long N and S based chain from ring - anaerobes - pseudomonas
40
cilastatin features
- taken with imipenem to prevent degradation | - don't give w/ drugs that have methyl on lactam ring
41
monobactam drug
aztreonam
42
aztreonam features
- no intramolecular ring attached to lactam - sulfate EWG group - PBP binder - good Gm- - pseudomonas - given IV
43
features of cephalosporins
- 6 member ring attached to lactam - "west end" like penicillin - leaving group attached to 6 mem ring - acidic group required on 6 mem ring
44
1st gen cephalosporin drugs
cefalexin | cefazolin
45
cefalexin features
- broad Gm+ - limited Gm- - none for MRSA - given orally, ampicillin like side chain
46
cefazolin features
- broad Gm+ - limited Gm- - none for MRSA - given IV/IM
47
2nd gen cephalosporin drugs
cefuroxime cefoxitin cefotetan
48
cefuroxime features
- broad Gm+ - ok Gm- - some beta lactamase resistance - prodrug required for oral, IV
49
cefoxitin features
- broad Gm+ - ok Gm- - some beta lactamase resistance - anaerobes - has methoxy to protect from beta lactam - IV
50
cefotetan features
- broad Gm+ - ok Gm- - some beta lactamase resistance - anaerobes - toxic tetrazole group that can case BLEEDING
51
drug that can cause bleeding
cefotetan
52
3rd gen cephalosporin drugs
cefdinir cefixime ceftriaxone ceftazidime
53
cefdinir features
- good Gm+ - broadest Gm- of cephalosporins - some beta-lactamase resistance - poor leaving group (double bonded C's) makes it good for oral
54
cefixime features
- good Gm+ - broadest Gm- of cephalosporins - some beta-lactamase resistance - poor leaving group (double bonded C's) makes it good for oral
55
ceftriaxone features
- good Gm+ - broadest Gm- of cephalosporins - some beta-lactamase resistance - no pseudomonas - IV
56
ceftazidime features
- poor Gm+ - broadest Gm- of cephalosporins, including pseudomonas - some beta-lactamase resistance - given with avibactam - IV
57
avibactam
suicide inhibitor of beta-lactamase, given with ceftazidime
58
why is MRSA resistant
uses PBP2a instead of usual PBP
59
ceftaroline fosamil features
- 5th gen cephalosporin | - active against PBP2a MRSA
60
fosfomycin features
- similar to phosphoenolpyruvate - inhibits enolpyruvyl transferase which makes NAM sugar - broad spectrum - uses a Cys residue to work
61
how to get resistance to fosfomycin
change Cys to an Asp in enolpyruvyl transferase
62
2 subunits that make up the prokaryotic ribosome
30S and 50S 70S together
63
activity sites in ribosome
EPA
64
2 subunits that make up the eukaryotic robosome
40S and 60S 80S together
65
aminoglycosides MoA
bind to 30S subunit of the ribosome, blocking initiation of translation or promoting misreading of the code
66
nonsense mutation
mutation that stops function of the gene
67
aminoglycosides use
broad spectrum, but mostly Gm- including pseudomonas
68
aminoglycoside side effects
- ototoxicity (organ of corti; irreversible) - kidney toxicity (proximal tubule; reversible) * small therapeutic window*
69
aminoglycoside general structure
amine sugar that does not have an O in the ring; | is attached to a sugar
70
aminoglycoside drugs
streptomycin gentamicin tobramycin amikacin
71
streptomycin use
- Gm- - tuberculosis and plague - lots of resistance - oral
72
gentamicin use
- Gm- - UTI - bone/joint infection
73
gentamicin unique feature
can be given with beta-lactams, but they cannot be in the same solution or they will inactivate each other
74
tobramycin use
Gm- | pseudomonas
75
amikacin use
Gm- pseudomonas tuberculosis (only aerobic infections)
76
quinolones MoA
inhibit DNA gyrase
77
quinolone structure features
- double ring, must have a double bond and ketone on right side - can't give with multivitamins or Ca because of chelation
78
quinolone drugs
nalidixic acid ciprofloxacin levofloxacin moxifloxacin
79
nalidixic acid use
Gm- UTI not very potent so high doses are needed leading to AEs like rash and GI
80
ciprofloxacin use
- Gm- - pseudomonas - atypicals - PO/IV
81
ciprofloxacin side effects
- possibly erosion of joints - damaging in 1st trimester of pregnancy - CNS effects b/c of GABA activity
82
levofloxacin use
- broad, improved Gm+ over other quinolones - pseudomonas - once a day dosing - PO/IV
83
two targets in folate synthesis inhibition
- dihydropteroate synthesis (unique in bacteria) | - tetrahydrofolate reductase inhibitors
84
role of folates
used for methylation of nucleosides and synthesis of purines and AAs
85
sulfonamide MoA
inhibit dihydropteroate synthase
86
sulfonamides in pregnancy
avoid near term because of neonatal jaundice
87
general sulfonamide adverse effects
- crystalluria - agranulocytosis - aplastic anemia - stevens johnson - skin rashes
88
trimethoprim MoA
dihydrofolate reductase inhibitor
89
trimethoprim use
given with sulfamethoxazole because of their different targets in folate synthesis and similar half lives (11 hr)
90
Bactrim
sulfamethoxazole and trimethoprim | -used for Gm+ and Gm-
91
imiprenem and meropenem use
- Gm+ - Gm- - pseudomonas - anaerobes
92
what should we never treat enterococcus with
carbapenems or cephalosporins
93
ertapenem lacks what activity
pseudomonas acinetobacter enterococcus
94
Cefipime features
- Gm+ - Gm- - psuedomonas - no anaerobes (preferred over zosyn when none present) - IV
95
ceftaroline features
- Gm+ - Gm- (no pseudomonas) - MRSA - IV
96
TMP/SMZ combo use
- Gm+ - Gm- - MRSA
97
TMP/SMZ side effects
- GI - rash - hyperkalemia