Anti infectives

Question 1

What is the difference between antimicrobials and antibiotics?

Answer 1

Antimicrobials is an umbrella term for any substance that fights against micro-organisms
Antibiotics refers to substances that are derived from or produced by micro-organisms which destroy bacteria or inhibit their growth

Question 2

How do bacterial spores form?

Answer 2

Via spormulation inside the cell, release on bursting of the cell

Question 3

How can anti-bacterial resistance occur?

Answer 3

Spontaneous mutation
Reduced drug affinity to the bacterial binding site
Bacterial enzymes able to deactivate drug

Question 4

When does anti-bacterial resistance occur?

Answer 4

When not all micro-organisms are destroyed, allowing them to overcome the drug

Question 5

How should bacteria be identified?

Answer 5

Signs and sxs
Subculture (microscope or staining)
Test antibiotic sensitivity

Question 6

What colour does gram positive bacteria stain?

Answer 6

Purple

Question 7

What colour does gram negative bacteria stain?

Answer 7

Pink/red

Question 8

What type of bacteria tends to have a more serious infection and why?

Answer 8

Gram negative
Due to extra outer membrane, it’s more resistant to immune defence and drugs

Question 9

What are the types of bacterial infections commonly seen in practice?

Answer 9

Blepharitis
Bacterial conjunctivitis
Stye
Chalazion
Corneal ulcer
Keratitis
Orbital cellulitis
Dacrocystitis

Question 10

Is Staphylococcus Aureus gram positive or negative?

Answer 10

Gram positive

Question 11

Give some examples of Staphylococcus Aureus infections

Answer 11

Blepharitis
Central and marginal coreal ulcers
Mucopurulent conjunctivitis
Stye
Dacrocystitis
Orbital cellulitis

Question 12

Is Streptococcus gram positive or negative?

Answer 12

Gram positive

Question 13

Give examples of a Streptococcus infection

Answer 13

Mucopurulent conjunctivitis
Dacrocystitis
Central corneal ulcers
Orbital cellulitis

Question 14

Is Pseudomonas Aeruginosa gram positive or negative?

Answer 14

Gram negative

Question 15

When are you likely to pick up an Pseudomonas Aeruginosa infection?

Answer 15

From plants, soil and water - it’s opportunistic

Question 16

What could happen with a Pseudomonas Aeruginosa infection?

Answer 16

Sight loss

Question 17

Give examples of a Pseudomonas Aeruginosa infection

Answer 17

Endophthalmitis
Central corneal ulcers

Question 18

Is Moraxella Lacunata gram positive or negative?

Answer 18

Gram negative

Question 19

Give examples of a Moraxella Lacunata infection

Answer 19

Conjunctivitis
Central/peripheral corneal ulcers

Question 20

Are E-coli, neisseria, salmonella and haemophilus influenzae gram positive or negative?

Answer 20

Gram negative

Question 21

Give examples of infections that E-coli, neisseria, salmonella and haemophilus influenzae would cause

Answer 21

Conjunctivitis
Central corneal ulcers

Question 22

What are the two bacteria most likely to cause bacterial conjunctivitis?

Answer 22

Staphylococcus and streptococcus

Question 23

How should a bacterial infection be treated?

Answer 23

1. Identify bacteria with clinical/lab diagnosis
2. Select effective antibacterial
3. Use antibacterial at an effective dose for long enough in the right place to fight infection
4. Use other non-pharma treatments to aid symptoms (e.g. hot compress)

Question 24

What are the types of antibacterial drugs?

Answer 24

Chloramphenicol
Tetracyclines
Fusidic Acid
Penicillins
Polymixin
Aminoglyosides
Fluoroquinalones
Isetionates

Question 25

How can antibacterial drugs work? i.e. what are the possible mechanisms?

Answer 25

Inhibit protein synthesis Inhibit nucleic acid synthesis Inhibit bacterial cell wall synthesis Disrupt bacterial cell plasma membrane

Question 26

Which drugs inhibit protein synthesis?

Answer 26

Chloramphenicol Fusidic acid Propamidine isetionate Aminoglycosides Tetracyclines

Question 27

How does protein synthesis inhibition work?

Answer 27

Ribosomal subunits selectively targeted, preventing assembly of new proteins within the bacterial cell by toxicity from the drug

Question 28

When can chloramphenicol be given?

Answer 28

With a signed order as a POM As a P OTC as long as px is over 2, is used to treat acute bacterial conjunctivitis for a max of 5 days

Question 29

Which ribosomal subunit is chloramphenicol toxic to?

Answer 29

50S

Question 30

What bacteria is chloramphenicol effective against?

Answer 30

Gram positive and negative Some funghi

Question 31

What forms is chloramphenicol available in? How should it be stored?

Answer 31

0.5% drops and minims 1% ointment Must be kept in fridge

Question 32

What cautions do you need to be aware of with chloramphenicol?

Answer 32

If using systemically: aplastic anaemia or grey baby syndrome can occur Most Pseudomonas aeruginosas resistant Refrain from use unless infection not clearing up (after 72 hours with lid hygiene advice)

Question 33

When would chloramphenicol be indicated?

Answer 33

Superficial eye infections

Question 34

Is chloramphenicol bacteriostatic or bacteriocidal?

Answer 34

Bacteriostatic

Question 35

Is Fusidic acid bacteriostatic or bacteriocidal?

Answer 35

Bacteriostatic (mostly) Can be bacteriocidal if conc high enough

Question 36

What is fusidic acid available as?

Answer 36

1% modified-release eye drops: ophthalmic gel (liquifies on contact) 2x daily POM

Question 37

When is fusidic acid indicated?

Answer 37

Bacterial conjunctivitis

Question 38

What bacteria is fusidic acid effective against?

Answer 38

Gram positive cocci

Question 39

What is the mode of action for propamidine isetionate and diprompropamidine isetionate?

Answer 39

Bacteriostatic Not fully clear - modify protein/DNA synthesis

Question 40

When is propamidine isetionate and diprompropamidine isetionate indicated?

Answer 40

Acanthamoeba keratitis Effective against staph and strep

Question 41

What is resistant to propamidine isetionate and diprompropamidine isetionate?

Answer 41

Pseudomonas aeruginosa

Question 42

What is propamidine isetionate and diprompropamidine isetionate available as?

Answer 42

Drops 0.1% (propamidine) Ointment 0.15% (diprompropmidine)

Question 43

What type of antibiotic is Gentamicin?

Answer 43

Aminoglycoside

Question 44

What is Gentamicin effective against?

Answer 44

Pseudomonas aeruginosa!! Many other bacteria (gram positive and negative)

Question 45

Which is Gentamicin's mode of action?

Answer 45

Inhibits protein synthesis by targeting 30S subunit

Question 46

Who can prescribe Gentamicin?

Answer 46

IP OOs and ophthalmologists

Question 47

What is gentamicin used to treat?

Answer 47

Conjunctivitis Serious bleph infections

Question 48

What is Gentamicin available as?

Answer 48

0.3% drops, sometimes with BK chloride

Question 49

What's the dose for Gentamicin?

Answer 49

1 drop every 2 hours initially, reduce dose until 48 hours after healing

Question 50

Name another aminoglycoside

Answer 50

Framycetin

Question 51

What is Polymixin B's mode of action?

Answer 51

Bactericidal, disrupting on the cell plasma membrane of gram negative bacteria

Question 52

When is Polymixin B indicated?

Answer 52

Superficial bacterial infections (conjunctivitis, blepharitis)

Question 53

What is Polymixin B available as?

Answer 53

Maxitrol drops or ointment (with dexamethasone and neomycin)

Question 54

What drugs prevent cell wall synthesis?

Answer 54

Penicillins Vancomycin

Question 55

Who can prescribe Polymixin B?

Answer 55

IP OOs

Question 56

What should you do with a fungal infection?

Answer 56

Refer, no drugs available to OOs

Question 57

Whats the difference between moulds and yeasts?

Answer 57

Moulds - multicellular, spore to reproduce, infection usually trauma related Yeasts - unicellular, bud to reproduce, infection usually due to chronic/systemic causes

Question 58

What are the RFs for fungal infections?

Answer 58

Exposure (e.g. gardening) Immunocompromised Hot/humid climate Increased Age

Question 59

Give an example of a fungi

Answer 59

Candida albicans

Question 60

Give an example of a fungal infection

Answer 60

Fungal keratitis Endophthalmitis

Question 61

Give an example of an antifungal

Answer 61

Nystatin Amphotericin Fluctyosine

Question 62

What is used to treat Chlamydiae?

Answer 62

Tetracyclines

Question 63

How do tetracyclines work?

Answer 63

Prevent protein synthesis by binding to ribosomal subunit 30S

Question 64

When are tetracyclines contraindicated?

Answer 64

<12 year olds bc deposits in teeth and bones

Question 65

How do modern antivirals work?

Answer 65

Utilise chemical signals specific to target virus - strengthens drug activity and minimises effect on host cells

Question 66

What are some types of viral infection?

Answer 66

HSV 1 - dendritic ulcers, keratoconjunctivis and cold cores Herpes zoster - chicken pox, shingles Adenovirus - epidemic keratoconjunctivitis HIV Rubella - congenital cataracts and microphthalmos

Question 67

What ophthalmic effects can shingles have?

Answer 67

Corneal oedema and inflammation Reduced corneal sensitivity Corneal ulcers and scarring

Question 68

What does Aciclovir treat?

Answer 68

HSV (local and systemic) Herpes zoster (systemic)

Question 69

How does Aciclovir work?

Answer 69

Prevents viral DNA replication Inactive form until activated by thymidine kinase

Question 70

What is Aciclovir available as?

Answer 70

3% ointment Systemic tablets (or if ocular infection stromal or deeper)

Question 71

What does Ganciclovir treat?

Answer 71

Herpetic keratitis CMV for AIDs pxs

Question 72

How does Ganciclovir work?

Answer 72

Stops viral DNA replication

Question 73

What is Ganciclovir available as?

Answer 73

0.15% gel with BK chloride

Question 74

What's the dose for Ganciclovir?

Answer 74

5x daily until epithelium healed, then 3x daily for 7 days

Question 75

Who can prescribe Ganciclovir?

Answer 75

IP OOs if infection is unilateral and epithelial only

Question 76

When is it ideal to treat acanthamoeba keratitis?

Answer 76

Before formation of cysts

Question 77

What is acanthamoeba keratitis treated with?

Answer 77

Aggressive combination therapy (polyhexanide or chlorhexidine and propamidine)