Microbiology Flashcards
What bacteria commonly cause conjunctivitis in neonates
Staph aureus
Neisseria gonorrhoeae
Chlamydia trachomatis
Which bacteria are common causes of conjunctivitis in children and adults
Staph aureus
Strep pneumoniae
Haemophilus influenzae
How do you treat bacterial conjunctivitis
Swab and determine organism
Topical antibiotics - usually chloramphenicol
Drops or ointment
Gentamicin if C isn’t going to work
Which viruses are common causes of conjunctivitis
Adenovirus
Herpes simplex
Herpes zoster
Describe the presentation of chlamydial conjunctivitis
Often a chronic history
Doesn’t respond to normal treatment
Bilateral conjunctivitis in young adults
May or may not have genital symptoms
Which pathogens can cause microbial keratitis
Bacteria
Viruses - herpes/adeno
Fungi
Describe the presentation of bacterial keratitis
Lots of pain Reduced vision Red eye White lesion in the cornea - hypopyon Usually occurs alongside other pathology or contact lens wear
How do you treat bacterial keratitis
Need to be admitted as requires hourly drops
Daily review
Treat other pathology
Quinolones and Gentamicin
Viral keratitis usually occurs alongside another eye pathology -true or false
FALSE
bacterial usually alongside pathology
Viral occurs in an otherwise healthy eye
Describe the presentation of herpetic keratitis
Very painful
Can be recurrent - leads to reduced corneal sensation and visual problems
Do you treat herpetic keratitis with steroids
NO
can lead to corneal melt and perforation of the cornea
Describe the presentation of adenoviral keratitis
Red, watery eye Bilateral Contagious Often occurs after respiratory infection Can slightly affect vision Usually self-limiting
How do you treat adenoviral keratitis
Topical antibiotics
May require steroids to speed up recovery
Which fungi can cause keratitis
Acanthamoeba
Pseudomonas aeruginosa
Who gets fungal keratitis
Contact lens wearers if they clean lenses with tap water
Farmers or gardeners - exposed to the fungi
Fungal keratitis is easy and quick to treat - true or false
False
Takes a long time to heal
Hard to treat
May need corneal transplant
Which organisms are common causes of orbital cellulitis
Staphylococci Streptococci Coliforms Haemophilus influenzae Anaerobes
Describe the presentation of orbital cellulitis
Very painful - especially when moving the eye Red, swollen orbit Proptosis May also have paranasal sinusitis Fever
How do you manage orbital cellulitis
CT scan to look for abscess ENT surgeons will drain pus from orbit Broad spectrum antibiotics Monitoring Cared for by ENT and ophthalmology
What is endophthalmitis
Rare but devastating infection inside of the eye
Can be post-surgery or endogenous
Usually staph epidermidis
Describe the presentation of endophthalmitis
Extremely painful
Decreasing vision - sight threatening
VERY red eye
How do you treat endophthalmitis
Intravitreal amikacin/ ceftazidime/ vancomycin (inject into eye)
+ Topical antibiotics
What can cause chorioretinitis
CMV in AIDS
Toxoplasma gondii
Toxocara canis (worm)
What is toxoplasmosis
Protozoan infection
Comes from cats and raw meat
Causes mild flu like illness and potentially chorioretinitis
Where does toxocara come from
Its a parasitic worm that affects cats and dogs
Unable to replicate in humans so remains as larvae
How does toxocara affect the eye
Form granulomas which can cause irreversible visual loss
List diagnostic tests for eye infection
Swabs for culture - bacteria, viral, chlamydia
Corneal scrapes - keratitis
Aqueous/vitreous samples
Serology - toxoplasma/cara
Describe the use of chloramphenicol
Most common topical antibiotic Comes as ointment or drops Stops bacterial protein production Bactericidal for strep and haem Bacteriostatic for staph
What are the side effects of chloramphenicol
Allergy
Irreversible aplastic anaemia - rare
Which antibiotics inhibit cell wall synthesis
Penicillins
Cephalosporins
(both inhibit the enzyme that makes cell wall)
Which antibiotics inhibit nucleic acid synthesis
Quinolones
Which antivirals are used to treat eye conditions
Aciclovir
Used for dendritic ulcers in the cornea - occurs with herpetic keratitis
Topical and systemic forms
How do you treat chlamydial conjunctivitis
Topical oxytetracycline
Adults may need oral azithromycin for genital infection
Contact tracing
