Microbiology Flashcards
Treatment of bacterial conjunctivitis
Chloramphenicol Fusidic acid (Staph) Gentamicin (Pseudomonas)
How is bottle contamination stopped?
Preservative - keeps for 4 weeks
Common contaminant
Pseudomonas
Causes of contact lens conjunctivitis/keratitis
Acanthamoeba
Pseudomonas
Causes of viral conjunctivitis
Adenovirus Herpes simplex (white vesicles) Herpes zoster (Hutchison Robinson sign)
Chlamydial conjunctivitis symptoms/signs
Young, bilateral
Follicles
Subtarsal scarring
Urethritis, vaginitis
Hypopyon
Level of WBCs/inflammatory cells in anterior chamber
Bacterial keratitis cause
Usually in association with other corneal pathology, e.g. abrasion/dry/contacts
Treatment of bacterial keratitis
Admit for hourly drops 1st 48 hours - Ofloxacin, Gentamicin
Corneal scrape
Adenoviral keratitis features
Follows URTI
Bilateral, contagious, may affect vision
Subepithelial infiltrates
Treatment of adenoviral keratitis
Chloramphenicol to prevent secondary infectoin
Steroid (if you know its not herpetic)
Herpetic keratitis features
Very painful
Branching ulcers
Reduced corneal sensation
Treatment of herpetic keratitis
NOT STEROIDS = corneal melt
Acyclovir
Fungal keratitis features
More indolent, slower
History of trauma from vegetation (farmers)
Takes long time to heal
Features of orbital cellulitis
Young kids
Very painful (especially on eye movements)
Proptosis, pyrexia, sight threatening
Often due to paranasal sinusitis/chalazion
Investigation for orbital cellulitis
CT to identify orbital abscess
Treatment for orbital cellulitis
Antibiotics, scan, drain
Causes of orbital cellulitis
Staph, Strep, Coliforms, Haemi influenzae, Anaerobes
Endopthalmitis
Infection of whole eye, sight threatening
Extremely painful, red, decreasing vision, systemically unwell
Casuses of endophthalmitis
Commensals
Staph epidermidis
Treatment of endophthalmitis
Intravitreal antibiotics
Causes of chorioretinitis
CMV (in AIDS)
Toxoplasma gondii
Toxocara canis (worm)
CMV chorioretinitis
Fast onset blindness
Treat with intravitreal injections
Toxoplasma gondii chorioretinitis
Protozoan infection (tick bites)
Flu-like
Can reactivate
Systemic treatment if sight threatening
Toxocara canis chorioretinitis
Parasitic nematode (roundworm) Often self limiting (cannot replicate in human) Seed in eye, form granulomas = irreversible vision loss
Diagnosis of eye infections
Swab for culture (chlamydial needs patient permission)
Corneal scrape (bacterial keratitis)
Microscopy/culture (acanthamoeba)
Serology (toxoplasma/toxicara)
Antibiotic that inhibits bacterial protein synthesis
Chloramphenicol- inhibits peptidyl transferase
Is chloramphenicol bactericidal or bacteriostatic?
Bactericidal for Strep and Haemophilus
Bacteriostatic for Staph
Side effects of chloramphenicol
Aplastic anaemia
Grey baby syndrome
Antibiotics that inhibit cell wall synthesis
Penicillins and Cephalosporins (B lactam ring = inhibits enzyme)
Flucloxacillin and Fluoroquinolone for bacterial cellulitis
Antibiotics that inhibit nucleic acid synthesis
Quinolones, e.g. ofloxacin (inhibits gyase = no supercoils)
Treatment of chlamydial conjunctivitis
Oxytetracycline
Azithromycin for genital infection
Contact tracing
Dacrocystitis
Infection of lacrimal sac
