BI of the Eyes

• Bacteria are generally associated with many types of ocular infections.
• is the inflammation or infection involving the conjunctiva

  Conjunctivitis
• • is the inflammation or infection involving the cornea

  Keratitis
• – is the inflammation or infection involving both the conjunctiva and cornea

  Keratoconjunctivitis
• • is a gram-negative rod shaped (coccobacillus)
  • associated with epidermis of acute, purulent conjunctivitis commonly occur during summer months

  Haemophilus influenzae biogroup Aegyptius (Koch-Weeks bacillus)
• • are gram-positive diplococci, arranged in pairs or short chains and encapsulated.
  • Lancet-shaped cocci
  • Virulence : adhesin, capsule, toxin pneumolysin and IgA protease
  • alpha hemolytic if aerobic; beta hemolytic if anerobic

  Streptococcus pneumoniae
• • gram -negative bacteria and obligate intracellular pathogen
  • cell with high lipid

  Chlamydia trachomatis
• Clinical Findings of Chlamydia trachomatis

  1. Conjunctivitis – “ swimming pool conjunctivitis”; there is mucopurulent eye discharge
  2. Inclusion conjunctivitis (Chlamydial Conjunctivitis, Para trachoma)- In adults, associated with genital infection; In newborn acquired upon passage in birth canal
  3. Trachoma (Chlamydia Keratoconjunctivitis)- aka “chronic keratoconjunctivitis.”
• • a kidney bean–shaped, Gram-negative diplococcus
  • Common cause of STD
  • In neonates- “ophthalmia neonatorum” – acquired upon passage in birth canal.
  • In adults, transmitted through finger-to eye contact involving infectious genital secretions

  Neisseria gonorrhea (gonococcus)
• Infections involving the eyes may be classified as conjunctivitis, keratitis, or keratoconjunctivitis. These infections may be caused by bacteria or viruses.
• Among the bacterial causes are Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus aegypticus, Neisseria gonorrhoeae, and Pseudomonas aeruginosa.
• Viral causes are Enterovirus 70, Coxsackie A24, herpes simplex virus type 1, and measles virus.
• The infections are highly contagious and can be transmitted through: contact with eye and respiratory discharges, contaminated fingers or fomites such as clothing, facial tissues, eye makeup, eye medications, and ophthalmic instruments.
• The common manifestations of eye infections are eye irritation, reddening of the conjunctiva, swelling of the eyelids, watery to mucopurulent discharge, and sensitivity to light (photophobia).
• Chlamydia trachomatis resembles gram-negative bacteria but do not have peptidoglycan in its outer cell wall.
• Trachoma is a form of severe keratoconjunctivits that may lead to blindness.
• N. gonorrhoeae causes ophthalmia neonatorum, acquired by the newborn upon passage through the infected birth canal. The prophylaxis for this infection is called Crede's prophylaxis and involves instilling 1% silver nitrate, erythromycin, or tetracycline to both eyes of the newborn.
• Adenoviruses cause "swimming pool" conjunctivitis, and the source is poorly chlorinated swimming pool water or contaminated ponds.
• Adenovirus is also associated with epidemic keratoconjunctivitis that may lead to residual corneal opacities.
• Herpes simplex virus type 1 can cause severe keratitis which can also lead to blindness.
• Enterovirus 70 and Coxsackie A virus cause a highly contagious eye infection, acute hemorrhagic conjunctivitis.