Microbiology

Question 1

What bacteria commonly cause conjunctivitis in neonates

Answer 1

Staph aureus
Neisseria gonorrhoeae
Chlamydia trachomatis

Question 2

Which bacteria are common causes of conjunctivitis in children and adults

Answer 2

Staph aureus
Strep pneumoniae
Haemophilus influenzae

Question 3

How do you treat bacterial conjunctivitis

Answer 3

Swab and determine organism
Topical antibiotics - usually chloramphenicol
Drops or ointment
Gentamicin if C isn’t going to work

Question 4

Which viruses are common causes of conjunctivitis

Answer 4

Adenovirus
Herpes simplex
Herpes zoster

Question 5

Describe the presentation of chlamydial conjunctivitis

Answer 5

Often a chronic history
Doesn’t respond to normal treatment
Bilateral conjunctivitis in young adults
May or may not have genital symptoms

Question 6

Which pathogens can cause microbial keratitis

Answer 6

Bacteria
Viruses - herpes/adeno
Fungi

Question 7

Describe the presentation of bacterial keratitis

Answer 7

Lots of pain 
Reduced vision 
Red eye 
White lesion in the cornea - hypopyon
Usually occurs alongside other pathology or contact lens wear

Question 8

How do you treat bacterial keratitis

Answer 8

Need to be admitted as requires hourly drops
Daily review
Treat other pathology
Quinolones and Gentamicin

Question 9

Viral keratitis usually occurs alongside another eye pathology -true or false

Answer 9

FALSE
bacterial usually alongside pathology
Viral occurs in an otherwise healthy eye

Question 10

Describe the presentation of herpetic keratitis

Answer 10

Very painful

Can be recurrent - leads to reduced corneal sensation and visual problems

Question 11

Do you treat herpetic keratitis with steroids

Answer 11

NO

can lead to corneal melt and perforation of the cornea

Question 12

Describe the presentation of adenoviral keratitis

Answer 12

Red, watery eye 
Bilateral 
Contagious
Often occurs after respiratory infection 
Can slightly affect vision 
Usually self-limiting

Question 13

How do you treat adenoviral keratitis

Answer 13

Topical antibiotics

May require steroids to speed up recovery

Question 14

Which fungi can cause keratitis

Answer 14

Acanthamoeba

Pseudomonas aeruginosa

Question 15

Who gets fungal keratitis

Answer 15

Contact lens wearers if they clean lenses with tap water

Farmers or gardeners - exposed to the fungi

Question 16

Fungal keratitis is easy and quick to treat - true or false

Answer 16

False
Takes a long time to heal
Hard to treat
May need corneal transplant

Question 17

Which organisms are common causes of orbital cellulitis

Answer 17

Staphylococci
Streptococci
Coliforms
Haemophilus influenzae
Anaerobes

Question 18

Describe the presentation of orbital cellulitis

Answer 18

Very painful - especially when moving the eye 
Red, swollen orbit 
Proptosis 
May also have paranasal sinusitis 
Fever

Question 19

How do you manage orbital cellulitis

Answer 19

CT scan to look for abscess 
ENT surgeons will drain pus from orbit
Broad spectrum antibiotics 
Monitoring 
Cared for by ENT and ophthalmology

Question 20

What is endophthalmitis

Answer 20

Rare but devastating infection inside of the eye
Can be post-surgery or endogenous
Usually staph epidermidis

Question 21

Describe the presentation of endophthalmitis

Answer 21

Extremely painful
Decreasing vision - sight threatening
VERY red eye

Question 22

How do you treat endophthalmitis

Answer 22

Intravitreal amikacin/ ceftazidime/ vancomycin (inject into eye)
+ Topical antibiotics

Question 23

What can cause chorioretinitis

Answer 23

CMV in AIDS
Toxoplasma gondii
Toxocara canis (worm)

Question 24

What is toxoplasmosis

Answer 24

Protozoan infection
Comes from cats and raw meat
Causes mild flu like illness and potentially chorioretinitis

Question 25

Where does toxocara come from

Answer 25

Its a parasitic worm that affects cats and dogs | Unable to replicate in humans so remains as larvae

Question 26

How does toxocara affect the eye

Answer 26

Form granulomas which can cause irreversible visual loss

Question 27

List diagnostic tests for eye infection

Answer 27

Swabs for culture - bacteria, viral, chlamydia Corneal scrapes - keratitis Aqueous/vitreous samples Serology - toxoplasma/cara

Question 28

Describe the use of chloramphenicol

Answer 28

``` Most common topical antibiotic Comes as ointment or drops Stops bacterial protein production Bactericidal for strep and haem Bacteriostatic for staph ```

Question 29

What are the side effects of chloramphenicol

Answer 29

Allergy | Irreversible aplastic anaemia - rare

Question 30

Which antibiotics inhibit cell wall synthesis

Answer 30

Penicillins Cephalosporins (both inhibit the enzyme that makes cell wall)

Question 31

Which antibiotics inhibit nucleic acid synthesis

Answer 31

Quinolones

Question 32

Which antivirals are used to treat eye conditions

Answer 32

Aciclovir Used for dendritic ulcers in the cornea - occurs with herpetic keratitis Topical and systemic forms

Question 33

How do you treat chlamydial conjunctivitis

Answer 33

Topical oxytetracycline Adults may need oral azithromycin for genital infection Contact tracing