Eye Infections and Microbial Agents

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Questions and Answers

Which of the following is NOT a risk factor for contact lens-related infectious keratitis?

Wearing glasses instead of contacts (correct)

Diabetes

Overuse of contact lenses

Poor hand and lens hygiene

What is a common bacterial cause of infectious keratitis mentioned?

Bacillus cereus

Pseudomonas aeruginosa

Staphylococcus aureus (correct)

Escherichia coli

Which risk factor significantly increases the likelihood of developing infectious keratitis from contact lenses?

Wearing contact lenses for a shorter duration

Using daily disposable lenses

Overnight wear of contact lenses (correct)

Regular eye examinations

Which of the following is NOT considered a risk factor for infectious keratitis?

Good hygiene practices Signup and view all the answers

Which of the following is a key factor contributing to the risk of infection in contact lens wearers?

Inconsistent cleaning of lenses Signup and view all the answers

What type of infection is hordeolum commonly known as?

Stye Signup and view all the answers

Which bacterium is primarily associated with external hordeolum?

Staphylococcus aureus Signup and view all the answers

What is the consequence of a compromised corneal epithelium?

Corneal penetration by pathogens Signup and view all the answers

Which of the following fungi is associated with infections of the eyelids?

Candida albicans Signup and view all the answers

Which condition occurs when the Meibomian glands become infected?

Internal hordeolum Signup and view all the answers

What percentage of intraoperative aqueous samples on cataract surgery typically contain bacteria?

25% Signup and view all the answers

What is endophthalmitis associated with?

IV drug use Signup and view all the answers

Which organism is known to invade compromised epithelium effectively?

Pseudomonas aeruginosa Signup and view all the answers

What is the primary characteristic that differentiates a hordeolum from a chalazion?

A hordeolum is associated with infection while a chalazion is non-infectious. Signup and view all the answers

Which organism is noted for its high virulence related to eye infections?

Streptococcus pyogenes Signup and view all the answers

What role do contact lenses play in eye infections?

They act as a mechanical vector, transferring microbes. Signup and view all the answers

How many Streptococcus pyogenes cells are needed to potentially cause necrotizing fasciitis?

10 cells Signup and view all the answers

What is a common symptom of a hordeolum?

Itching and pain Signup and view all the answers

What typically happens at the site of a hordeolum?

Formation of an abscess Signup and view all the answers

What complication can arise from inadequately managed hordeolum?

Formation of a chalazion Signup and view all the answers

What is the typical location for a hordeolum to develop?

On the eyelid margin Signup and view all the answers

What type of discharge is typically associated with viral conjunctivitis?

Watery Signup and view all the answers

Which viral pathogen is most commonly associated with pharyngoconjunctival fever?

Adenovirus Signup and view all the answers

What is a hallmark symptom of hyperacute bacterial conjunctivitis?

Massive exudate Signup and view all the answers

Which of the following types of conjunctivitis is characterized by severe chemosis?

Acute hemorrhagic conjunctivitis Signup and view all the answers

What type of conjunctivitis is caused by herpes simplex virus?

Herpetic keratoconjunctivitis Signup and view all the answers

Which of the following is NOT a symptom of bacterial conjunctivitis?

Blister-like lesions Signup and view all the answers

Which viral infection is most commonly associated with acute hemorrhagic conjunctivitis?

Enterovirus 70 Signup and view all the answers

How is bacterial conjunctivitis primarily transmitted?

Hand-to-eye contact Signup and view all the answers

Among these options, which symptom is associated with rubella and rubeola infections?

Conjunctivitis with rash Signup and view all the answers

What is a common characteristic of epidemic keratoconjunctivitis?

Caused by adenovirus serotype 8, 19, and 37 Signup and view all the answers

What is considered chronic bacterial conjunctivitis?

Symptoms lasting for at least 4 weeks Signup and view all the answers

Which bacterium is NOT a common cause of acute bacterial conjunctivitis?

Escherichia coli Signup and view all the answers

What is a typical symptomatic association with chronic bacterial conjunctivitis?

Flaky debris and warmth along the lid Signup and view all the answers

What is the most common bacterial cause of neonatal conjunctivitis occurring between 24 to 48 hours of life?

Neisseria gonorrhoeae Signup and view all the answers

Which factor is NOT considered a predisposing factor for conjunctivitis in neonates?

Increased lymphoid tissue in conjunctiva Signup and view all the answers

What is the potential outcome of untreated bacterial conjunctivitis in children?

Self-limited resolution within 1–2 weeks Signup and view all the answers

What is the primary treatment recommendation for chronic bacterial conjunctivitis?

Topical antibiotic therapy Signup and view all the answers

Gonococcal conjunctivitis is considered in neonates during which days after birth?

Days 2 to 5 Signup and view all the answers

Which of the following statements about blepharitis is true?

It can lead to flaky debris along the eyelid. Signup and view all the answers

Which of the following conditions is associated with acute bacterial conjunctivitis but not with chronic?

High prevalence in children Signup and view all the answers

Study Notes

Eye Infections

Microbial agents:
- Viruses: Torque teno virus (TTV), Human Papillomavirus (HPV)
- Fungi: Candida albicans, Phylum (Ascomycota, Basidiomycota), Genus (Aspergillus, Setosphaeria, Malassezia, Haematonectria)
Corneal Penetration:
- Can occur due to epithelial defect, contaminated contact lenses, irrigating solutions, tear film, or direct corneal trauma
- Pseudomonas aeruginosa thrives in compromised epithelium from superficial sources
Bacterial Load:
- Bacteria must multiply to overcome host defenses
- 25% of aqueous samples during cataract surgery contain bacteria
Blood-Borne Route:
- Can lead to endophthalmitis (inflammation of eye's inner layer) if no history of trauma or surgery
- IV drug users are more susceptible to endophthalmitis due to C. albicans
Contact Lens:
- Act as a mechanical vector, transferring microbes to the cornea
- Trapped tear fluid behind the lens exacerbates the problem
Virulence of the Organism:
- Determines the outcome of the infection
- Related to production of lethal toxins, causing tissue necrosis
- Streptococcus pyogenes is highly virulent for the eye, produces Exotoxin A, and requires only a small amount to cause severe damage.
Hordeolum (Stye) vs Chalazion:
- Hordeolum:
  - Infectious (Staphylococcus aureus) abscess formation in the eyelid's glands
  - Causes localized pain in the lid
  - External Hordeolum: affects glands of Zeiss and Moll,
  - Internal Hordeolum: affects Meibomian glands
- Chalazion:
  - Non-infectious, painless meibomian gland occlusion
  - No abscess formation

Conjunctivitis

Causes:
- Viral: Adenovirus, Rubella, Rubeola (measles) virus, Herpesviridae, Picornavirus
- Bacterial: Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, Staphylococcus aureus, Moraxella lacunata, Neisseria gonorrhoeae, Neisseria meningitidis
Symptoms:
- Viral: Watery discharge, highly contagious, self-limiting
- Bacterial: Purulent discharge, marked grittiness
Types of Viral Conjunctivitis:
- Pharyngoconjunctival fever: Caused by adenovirus serotypes 3, 4, and 7, causing fever and sore throat
- Epidemic keratoconjunctivitis: Caused by adenovirus serotypes 8, 19, and 37, more severe than other forms
- Acute hemorrhagic conjunctivitis: Associated with enterovirus 70, coxsackievirus A24, and adenoviruses, causing large epidemics
- Herpetic keratoconjunctivitis: Caused by herpes simplex virus, leads to blister-like lesions
- Rubella and rubeola (measles): Can cause conjunctivitis as part of a rash illness
Types of Bacterial Conjunctivitis:
- Acute Bacterial Conjunctivitis: Most common, often caused by Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis
- Chronic Bacterial Conjunctivitis: Symptoms last for at least 4 weeks, often caused by Staphylococcus aureus, Moraxella lacunata, and associated with blepharitis
- Hyperacute Bacterial Conjunctivitis: Rare and severe, characterized by massive exudate, severe chemosis, eyelid swelling, marked hyperemia, pain, and decreased vision, often caused by Neisseria gonorrhoeae or Neisseria meningitidis
- Neonatal Conjunctivitis:
  - First 24 hours: Often chemical conjunctivitis from prophylactic medications like silver nitrate or antibiotic drops
  - 24 to 48 hours: Most likely bacterial cause, with Neisseria gonorrhoeae being the most common
  - 5 to 14 days: Likely caused by Chlamydia trachomatis
  - 6 to 14 days: Possible Herpes keratoconjunctivitis
  - 5 to 18 days: Possible Pseudomonas aeruginosa
- Gonococcal Ophthalmia Neonatorum: Gonococcal conjunctivitis, most likely to develop within days 2-5
Risk Factors for Contact Lens-Related Infectious Keratitis:
- Overuse of contact lenses
- Overnight wear
- Diabetes
- Trauma
- Poor hand and lens hygiene

Trachoma

Cause: Chlamydia trachomatis
Symptoms: Trachoma bodies
Complications: Can lead to blindness if untreated

Other Important Info

Source: Dr. Padilla's PPT
Treatment: Varies depending on the cause, but often includes topical antibiotics or antiviral medications.
Prevention: Proper hygiene, including good handwashing, and avoiding contact with infected individuals.

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Description

This quiz focuses on the various microbial agents responsible for eye infections, including viruses, fungi, and bacteria. It also addresses how factors like corneal penetration and contact lens usage contribute to these infections. Test your knowledge on the mechanisms and implications of eye-related infections.