Brainscape's Knowledge GenomeTM

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


See full index

OV3017 Eye Disease > 16 - Anti- infective drugs > Flashcards

16 - Anti- infective drugs Flashcards

1
Q

why/how are bacterial cells different to human cells

A
  • unique cell wall
  • diff cell membrane
  • differences in DNA and protein synthesis

differences form the basis for selective toxicity of anti bacterial drugs

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

which drugs affect cell wall synthesis

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

which drugs affect bacterial cell membrane

A
  • polymyxin B
  • propamidine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

which drugs affect bacterial protein synthesis

A
  • aminoglycosides
  • tetracyclines
  • chloramphenicol
  • fusidic acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

which drugs affect bacterial DNA synthesis

A
  • fluoroquinolones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

which drugs affect bacterial metabolism

A
  • sulphonamides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are some general considerations of antibiotics

A
  1. spectrum of cover
    - narrrow vs broad
    - single vs combo
  2. penetrations into the appropriate tissue
    - superficial
  3. route of administration
  4. side effects
    - tolerability
    - pregnancy/lactation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why do we do antibiotic sensitivty testing

A
  • if bacterial infection isnt responding to antibiotic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how is a kirby-bauer A.S test conducted

A

when the bacteria is isolated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

steps of KB antibiotic testing

A
  1. take sample of bacteria (biopsy or swab)
  2. put on agar plate emulsified in saline
  3. spread on plate
  4. paper disc impregnanted with antibiotics placed on top of culture
  5. incubated 37C for 18 hrs

bacteria starting to grow across agar plate
- zone of antibiotic around each plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

anti infectives availible to optoms

A
  • chloramphenicol
  • fusidic acid
  • propamidine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Chloramphenicol POM

A

P for acute bacterial conjunctivitis

  • bacteriostaic
  • broad spectrum (not effective against pseudomanas - can cause severe BK)
    -resistence low
  • good safety profile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

formulations available of chloramphenicol

A
  • CPL 0.5% eye drops
  • CPL 1% ointment
  • CPL minims 0.5%

dose drops - 1 drop every 2 hours for 48 days then every 4 hours or 5 days

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

what is the mode of action of chloramphenicol

A

inhibition of bacterial protein synthesis
- CPL binds to peptidyl transferase on the 50s ribosomal subunit

  • this prevents the incorporation of new amino acids ot the growing peptide chin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what isolates are associated withh bacterial conjunctivitis

A
  • stapha
  • stephe
  • haemop
  • pseudo
  • strep
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

most common isolates associated with bacterial conjunctivitis ?

A

staph

least common: strep

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

Fusidic acid POM - what is it effective against

A
  • gram +ve organisms
    particularly staph A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is fusidic acid lisenced for the treatment of

A

bacterial conjunctivitis

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

is fusidic acid an appropriate agent for acute bacterial conjunctivits in children>
why or why not

A
  • ineffective against gram - H influenza
    -most common causative pathogen in kids
20
Q

formulations of fusidic acid

A

only 1

Fusidic acid 1% modified release eye drops POM
- twice daily

21
Q

Concentration of fusidic acid in tears

A

Overtime, the concentration of fusidic acid in tears decline. the decline is relatively low after instillation

It is an antibiotic that doesnt really penentrate ocular tissues very readily

22
Q

Comparison between chloramphenicol and fusidic acid

A

fusidic acid not really recommended these days BUT advantage is safe for pregancy

expensive

23
Q

Polymyxin B (POM) - what does it do

A
  • PB attatches to and interferes with the functioning of the cell membrane of aerobic gram -ve bacteria
  • bacitracin inhibits synthesis of cell wal in gram +ve bacteria
24
Q

OTC propamidine

A

not an antibiotic! disinfectant

  • active against gram +ve,
  • less active against gram -ve

antifungal properties

  • may be used topically for minor eye conditions such as conj and bleph
25
Q

Fluoroquinolones - what for

A

treatment for BK

26
Q

Fluoroquinolones - how do they work

A
  • inhibit DNA gyrase so prevent DNA synthesis
27
Q

which bacteria are Fluoroquinolones effective against

A

gram negative e.g pseudomonas

28
Q

broad spectrum of Fluoroquinolones

A
  • ofloxacin
  • ciproflaxacin
29
Q

aminoglycosides - effective against?

A
  • both gram + and -
30
Q

how do aminoglycosides work

A
  • inhibit protein synthesis
  • bactericidal
31
Q

side effects of aminoglycosides

A

epithelial toxicity

32
Q

Tetracylines - effective against?

A

both gram + and -

33
Q

how do Tetracylines work

A
  • inhibit bacterial synthesis by blocking the attatchment of the transfer RNA-amino acid to the ribosome
34
Q

how are Tetracylines usually delivered

A
  • systemically - tablets

treatment of meibomiam disease

35
Q

when are Tetracylines used - treatment of __

A
  • lid margin disease

reducing the bacterial load reduces inflammation

36
Q

Azithromycin - lisenced for?

A

trachomatous conjunctivits caused by chlamydial conjunctivitis

  • acute bacterial conj.
37
Q

explainn viral life cycle

A
  • infectious agents only replicate inside living cells
  • once virus binds to target cell, it releases viral DNA that is used to replicate further viruses - which exit from the cell to infect other cells
38
Q

what type of virus is herpes viruses

A
  • DNA viruses
39
Q

VIRAL KERATITIS - hsv

A

HERPES SIMPLEX VIRUS

primary/recurrent/congenital

  • mostly HVS1
  • thin dentritic ulcer
  • contain live virus
40
Q

VIRAL KERATITIS - vzv

A

VARICELLA ZOSTER VIRUS
- ophthalmic shingles
- should be obvious

affects dermatome of branch of trigeminal nerve

41
Q

herpes virus Cytomegalovirus - cmv

A
  • infections with CMV can occur in immunosuppressed inidivualds e.g AIDS, post-transplant
42
Q

what does cmv most commonly present in eye

A
  • viral necrotizing retinitis
43
Q

antiviral drug: acyclovir (discontinued in 2018)

action of drug

A
  • aiclovir enters sell
  • convered to aciclover monophosphate by hsv enzyme Thymidine Kinase (TK)
  • enzymes add 2 more phosphates to form the active drug aciclovir trophosphate
  • aclicover tiphosphate competes with 2- dGTP as a substrate for viral DNA polymerase
44
Q

Antiviral drugs: Ganciclover - replacement for acyclovir

A

available for treatment of HSK

ganclicover eye gel

45
Q

acanthamoeba

A
  • free living amoeba
  • specialised
46
Q

treatment for acanthamoeba keratitis

A

-propamide 0.1%
and (PHMB) 0.02%
or chlorhexidine 0.02%

have acitivity against cyst form

OV3017 Eye Disease (19 decks)

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