Antibacterials 2 Flashcards

(43 cards)

1
Q

what two antibacterials target the cell envelope

A

beta-lactams and glycopeptides

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2
Q

what do beta-lactams consist of

A

beta lactam ring

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3
Q

what do beta-lactams compete with

A

d-ala d-alanine

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4
Q

what does the serine in b-lactams cause

A

breaking down of d-ala d-ala

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5
Q

what does b-lactam bind to and what does it cause

A

to the active site so transpeptidation cannot occur

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6
Q

After b-lactam is bound to the active site so transpeptidation cannot occur what does this result in

A

cross-links cannot form resulting in a weak cell wall and lysing of the cell

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7
Q

What are the three types of beta-lactam

A

penicilin (penicillin G), cephlasporins and carbapenems

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8
Q

What are carbapenems used for

A

last port of call for gram negative that are multidrug resistant

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9
Q

what is penicillin G used to treat

A

pneumonia, syphillis and gonorrhea

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10
Q

three glycopeptides

A

Vancomycin, Polymyxins B and E, daptomycin

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11
Q

what is the prime mode of action of vancomycin

A

transglycoylation

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12
Q

what does vancomycin bind to

A

d-ala d-ala

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13
Q

is vancomycin active against gram negative

A

no

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14
Q

why might vancomycin be used

A

if the patient cannot have b-lactam because of resistance or hypersensitivity

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15
Q

what is vancomycin used to treat

A

serious MRSA and other gram positives

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16
Q

adverse side effects of vancomycin (5)

A
'Red man'
Histamine release
Ototoxic 
Neutropenia
Thrombocytopenia
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17
Q

are polymyxins active for gram positives

A

no

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18
Q

what do polymyxins interact with

A

liposaccharide leaflet of -VE, penetrating outer membrane

19
Q

what are polymyxins used to treat

A

cystic fibrosis, decontamination of gut and burns infections

20
Q

toxicity of polymyxins

A

potential neurotoxicity and nephro due to accumulation on kidneys

21
Q

how does daptomycin work

A

by interaction with membrane via acyl chain integration , causing integration, aggregation and membrane depolarisation causing leakagr and cell death

22
Q

are daptomycins used for gram negative

23
Q

what are daptomycins used to treat

A

soft tissue infections

24
Q

what two drugs target nucleic acids and nucleic acid biosynthesis

A

Sulfa drugs and trimethoprim

25
how do drugs that target nucleic acids and their biosynthesis work
inhibiting dihydropteroate synthase ( DHPS)
26
how do sulfa drugs work
they are structural analogues of the substrates for DHPS
27
what are the substrates for DHPS
p-aminobenzoic acid
28
what happens when sulfa binds to DHPS
forms a dead end complex and therefore no tetrahydrofolate
29
what is trimethoprim formed of
2 pyridimes joined together
30
how does trimethoprim work
inhibiting dihydrofolic reductase catalysing the reduction of dihydrofolic acid to tetrahydrofolic acid
31
what are both sulfa and trimethoprim used to treat
short term respiratory, urinary and digestive tract infections
32
what are sulfa and trimethoprim used to treat in HIV patients
pneumonia
33
what two drugs are involved in targeting the synthesis of DNA-pre-existing DNA
Quinolones and fluoroquinolones
34
what do all quinolones and fluoroquinolones drugs end in
-floaxacin
35
how do quinolones and fluoroqunolones work (2 things)
1. they interfere with enzymes responsible for bacterial topology 2. they catalyse ATP dependant DNA double strand breakages
36
what two enzymes do quinolones and fluoroquinolones target
DNA gyrase and DNA topoisomerase IV
37
how do nitroheterocyclic drugs work
targeting obligate anaerobes to cause DNA damage
38
two examples of nitroheterocyclic drugs
Metronidazole and Tinidazole
39
are nitroheterocyclic bacteriostatic or cidal
cidal
40
what drug works by targeting RNA synthetase
Rifamycin
41
how does Rifamycin stop rNA synthetase
blocks RNA exit channel, RNA knocks into rifamycin and spontaneously dissociates
42
is rifamycin bacteriostatic or cidal
cidal
43
what is rifamycin used to treat
TB, leprosy, penicillin resistant s.pneumoniae