Infections of the Eyes and Bacterial Agents
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Questions and Answers

What is a common manifestation of bacterial conjunctivitis?

  • Increased intraocular pressure
  • Mucopurulent discharge (correct)
  • Severe eye pain
  • Blurred vision

Which of the following is a mode of transmission for bacterial conjunctivitis?

  • Insect bites
  • Viral exposure
  • Direct contact with eye discharges (correct)
  • Airborne particles

Which bacterium is associated with epidemics of acute, purulent conjunctivitis?

  • Pseudomonas aeruginosa
  • Haemophilus influenzae biogroup aegypticus (correct)
  • Chlamydia trachomatis
  • Staphylococcus aureus

What structural characteristic distinguishes Streptococcus pneumoniae?

<p>Lancet-shaped appearance (D)</p> Signup and view all the answers

Which pathogen is NOT a common cause of bacterial conjunctivitis?

<p>Escherichia coli (D)</p> Signup and view all the answers

Which bacterium lacks peptidoglycan in its outer wall?

<p>Chlamydia trachomatis (A)</p> Signup and view all the answers

Which symptom is least likely to be associated with keratitis?

<p>Swelling of the eyelids (A)</p> Signup and view all the answers

What is a potential mechanical route of transmission for bacterial conjunctivitis?

<p>Gnats or other flying insects (C)</p> Signup and view all the answers

What characteristic feature do C. trachomatis possess that indicates their dependence on a host?

<p>Round vacuolar inclusions filled with glycogen (B)</p> Signup and view all the answers

What is a common cause of conjunctivitis resulting from C. trachomatis?

<p>Poorly chlorinated swimming pool waters (C)</p> Signup and view all the answers

Which clinical feature distinguishes viral conjunctivitis from bacterial conjunctivitis?

<p>Clear or watery discharge (D)</p> Signup and view all the answers

What is a notable feature of adenoviruses related to their structure?

<p>Penton base acting as hemagglutinin (B)</p> Signup and view all the answers

What type of conjunctivitis is specifically associated with poorly chlorinated swimming pools?

<p>Conjunctivitis due to <em>C. trachomatis</em> (A)</p> Signup and view all the answers

Which serotypes of adenoviruses most commonly cause epidemic keratoconjunctivitis?

<p>Adenovirus types 8, 19, and 23 (C)</p> Signup and view all the answers

What symptom may accompany conjunctivitis caused by adenoviruses?

<p>Pharyngitis (B)</p> Signup and view all the answers

What is the typical outcome of an epidemic keratoconjunctivitis infection?

<p>Long-lasting sub-epithelial opacities in the cornea (A)</p> Signup and view all the answers

Flashcards

Bacterial Conjunctivitis

A highly contagious eye infection that causes inflammation of the conjunctiva, often referred to as "pink eye".

Haemophilus influenzae biogroup aegypticus

Gram-negative rod bacteria associated with epidemics of acute, purulent conjunctivitis. It's commonly spread through direct contact, such as touch.

Streptococcus pneumoniae

Gram-positive diplococci, arranged in pairs or short chains, known for causing various infections, including pneumonia and conjunctivitis.

Keratitis

Inflammation or infection involving the cornea, the clear outer layer of the eye. It can cause blurry vision and pain.

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Keratoconjunctivitis

Inflammation or infection involving both the conjunctiva and the cornea.

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Conjunctivitis

Inflammation or infection involving the conjunctiva, the transparent membrane that lines the inner surface of the eyelids and covers the white part of the eye.

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Chlamydia trachomatis

A bacterium that resembles gram-negative bacteria but lacks peptidoglycan in its outer wall. It is known for causing trachoma, a serious eye infection.

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Fomites

The transmission of infection through inanimate objects, such as clothing, facial tissues, or instruments.

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Obligate Intracellular Parasite

A parasitic bacteria that relies on its host's energy production for survival, typically residing within host cells. It lacks the means to produce its own energy (ATP).

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Chlamydial Conjunctivitis

A specific type of eye infection characterized by a mucopurulent discharge and often occurs concurrently with other chlamydial infections, such as nasopharyngitis or pneumonia.

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Swimming Pool Conjunctivitis

A common type of eye infection caused by adenoviruses, usually acquired from poorly chlorinated swimming pools or ponds, often accompanied by a sore throat.

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Adenoviruses

Double-stranded DNA viruses that infect the mucous epithelium. They are known for their penton base protein, which acts as a hemagglutinin, prompting the virus to bind to the mucous membranes.

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Epidemic Keratoconjunctivitis (EKC)

A more severe eye infection caused by adenoviruses, mainly types 8, 19, and 23. This infection is often observed in adults and can result in corneal opacities.

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Viral Conjunctivitis

A type of viral eye infection often spreading through the air through sneezing or coughing. Characterized by swelling of the conjunctiva, but unlike bacterial conjunctivitis, it doesn't exhibit a purulent discharge.

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Study Notes

Infections of the Eyes

  • Eye infections can involve the conjunctiva (conjunctivitis), cornea (keratitis), or both (keratoconjunctivitis)
  • Infections can be caused by bacteria or viruses
  • Bacterial conjunctivitis (pink eye) is highly contagious
  • Transmission occurs through human-to-human contact, contaminated surfaces, and fomites
  • Bacterial conjunctivitis can be caused by various bacteria like Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa

Bacterial Infections

  • Streptococcus pneumoniae: Gram-positive diplococci, alpha/beta hemolytic, with virulence factors like capsule, pneumolysin, and IgA protease
  • Staphylococcus aureus: Gram-positive cocci; virulence factors are associated with adherence and toxin production
  • Pseudomonas aeruginosa: Gram-negative rod; virulence factors include mechanisms for resisting host defenses
  • Chlamydia trachomatis: Obligate intracellular parasite, lacks peptidoglycan but high lipid content; causes conjunctivitis, inclusion conjunctivitis, and trachoma; frequently associated with swimming pools
  • Trachoma is a chronic keratoconjunctivitis often transmitted through direct contact, flies, and contaminated objects.

Viral Infections

  • Viral eye infections can manifest as conjunctivitis and keratoconjunctivitis
  • Viral conjunctivitis, unlike bacterial, does not have purulent discharge
  • Viral infections are often spread through airborne means such as sneezing and coughing

Viral Etiologic Agents

  • Adenoviruses: Double-stranded DNA viruses; cause mild (swimming pool conjunctivitis) to severe (epidemic keratoconjunctivitis) infections. Serotypes 3 and 7 are common causes of swimming pool conjunctivitis, while serotypes 8, 19, and 23 are linked to epidemic keratoconjunctivitis.
  • Herpes simplex virus (HSV-1): herpes simplex virus type 1 causes severe keratoconjunctivitis, often with corneal ulcers and potentially blindness.
  • Enterovirus 70 and Coxsackie A24 Virus: Cause acute hemorrhagic conjunctivitis; characterized by conjunctival congestion, vascular dilatation, and edema.

Other Important Infections

  • Measles Virus: Conjunctivitis is a common symptom during measles, along with photophobia (sensitivity to light).
  • Neisseria gonorrhoeae: Sexually transmitted infection, often causing ophthalmia neonatorum (eye infection in newborns) acquired during passage through the infected birth canal. Treatment is important to prevent blindness.

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Related Documents

Infections of the Eye PDF

Description

This quiz explores eye infections such as conjunctivitis and keratitis, focusing on their bacterial causes. Participants will learn about the major bacteria involved, their virulence factors, and transmission methods. Test your knowledge on the infection mechanisms and bacterial species affecting ocular health.

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