Microbial Agents of Eye Infections Midterms - L3.2 - PDF

MICROBIOLOGY AND PARASITOLOGY MICROBIAL AGENTS OF EYE INFECTIONS Dr. Ma. Christina Padilla | September 25, 2024 OUTLINE I. ANATOMY OF THE EYE Anatomy of the Eye...

MICROBIOLOGY AND PARASITOLOGY MICROBIAL AGENTS OF EYE INFECTIONS Dr. Ma. Christina Padilla | September 25, 2024 OUTLINE I. ANATOMY OF THE EYE Anatomy of the Eye A. Functions of the eye B. Accessory Structures of the Eyes 1. Eyebrow and Eyelids 2. The Eyeball C. Surface protection of the eye 1. Normal tear flow 2. Lacrimal Gland I 3. Conjunctiva D. Normal Microbiota of the eye E. Invasion of the eye Pathogen 1. Corneal penetration 2. Bacterial Load Anatomy of the Eye 3. Blood-Borne Route Source: Dr. Padilla’s PPT 4. Contact lens 5. Virulence of the organism Eyelids A. Causes of Tearing B. Bacterial Infection of Eyelids 1. Hordeolum (Stye) - External Hordeolum - Internal Hordeolum 2. Blepharitis II C. Viral Infection of Eyelids 1. Herpes Zoster Ophthalmicus (Shingles) Parts of the eye 2. Herpes Simplex of the Lids Dr. Padilla’s PPT 3. Ocular Molluscum D. Parasitic Infection of Eyelids Additional information: 1. Phthiriasis From Dr. MC Padilla’s Lecture: Conjunctiva Conjunctiva - a thin membrane that covers the portion A. Conjunctivitis of the eye. 1. Common Clinical Manifestations → Except for the portion of the cornea of Conjunctivitis Cornea - is the circle with iris that gives pigment/color to 2. Secretions the eye and controls the light that passes into the lens. 3. Symptoms Pupil - normal size is 3-5 mm. 4. Viral conjunctivitis Eyelids - present in both the upper and lower part. - Types of Viral The most common affected portion of the eye is the Conjunctivitis conjunctiva and cornea. They are the ones that are 5. Bacterial Conjunctivitis exposed to the environment. - Acute Bacterial Conjunctivitis III - Hyperacute Bacterial A. FUNCTIONS OF THE EYE conjunctivitis Part of the Function - Chronic Bacterial Conjunctivitis Eye - Gonococcal Ophthalmia Pigmented tissue lying behind the cornea Neonatorum that - Chlamydia Conjunctivitis gives color to the eye, and - Chlamydia Trachomatis controls the amount of light 6. Adult Inclusion conjunctivitis IRIS entering the eye by varying size 7. Neonatal Inclusion conjunctivitis of black pupillary opening; 8. Trachoma - Trachoma Bodies Cornea Separates the anterior chamber from the A. Pseudomonas Keratitis posterior chamber. B. Viral Keratitis Transparent front segment of the eye that IV 1. Herpes Simplex Keratitis covers iris, pupil, and anterior chamber, 2. Herpes Zoster Ophthalmicus CORNEA and provides most of an eye's optical C. Simplex vs Zoster power. V References Variable-sized, circular opening in the VI Review Questions center of the iris; it appears as a black PUPIL circle and it regulates the amount of light that enters the eye. NMD2027  Microbial Agents of Eye Infections Natural lens of eye; transparent intraocular The Eyeball LENS tissue that helps bring rays of light to focus Tunica fibrosa: on the retina. → The outer coat or protective shell, consisting of the The white of the eye; a protective fibrous collagenous cornea and sclera SCLERA outer layer covers all of the eyeball except Tunica vasculosa: for the part covered by the cornea → The middle layer or uvea A muscular ring under the surface of the Tunica nervosa: CILIARY eyeball; helps the eye focus by changing → The inner lining layer of the retina. This tissue BODY the lens’ shape and also produces transforms light radiation into nervous impulses. aqueous humor The vascular layer between the sclera and the retina; the blood vessels in the choroid CHOROID help provide oxygen and nutrients to the eye OPTIC Largest sensory nerve of the eye; carries NERVE impulses for sight from retina to brain Small, specialized central area of the MACULA retina responsible for acute central vision Part of the eye that converts images into electrical impulses sent along the optic The eyeball nerve for transmission back to the brain. Dr. Padilla’s PPT RETINA Consists of many named layers that Additional information: include rods and cones From Dr. Padilla’s Lecture: Eyeball has 3 coverings: B. ACCESSORY STRUCTURES → Tunica Fibrosa OF THE EYE ▪ or the fibrous tunic. This is where sclera is found (white portion) and cornea. Eyebrow and Eyelids → Tunica Vasculosa Eyebrows ▪ or the vascular tunic, where the uvea is found which → Prevent sweat, water and other debris from falling is composed of iris, ciliary body and choroid down into the eye socket → Tunica Nervosa ▪ where the retina is found. Tissue to light radiations. Eyelids (Palpebrae) → Promote moistening and cleansing of the cornea C. SURFACE PROTECTION → Aid in regulating the amount of light reaching the eye OF THE EYE Normal conjunctiva and cornea protected by a triple layered tear film → Outer oily layer from Meibomian glands → Aqueous layer from lacrimal glands → Inner layer of mucin, chiefly from the conjunctival goblet cells Blinking maintains integrity of this layer Functions of Tear Film Protecting the eye from the environment Lubricating the ocular surface Maintaining a smooth surface for light refraction Accessory structure of the eye Preserving the health of the conjunctiva and the avascular Source: Dr. Padilla’s PPT cornea Additional information: From Dr. Padilla’s Lecture: Eyelids are the palpebra. Palpebral > tarsal > Bulbar. → Palpebra - covers the inner part of the eyelid. And it will continue to fornix then to bulbar covering entirely or mostly the eyeball except the cornea → Also responsible for giving moisture to the conjunctiva. → Eyelids also regulate the light. ▪ For instance, if it's too bright or dark in an area, we tend to close our eyes (or close the eyelids). There is a problem in the regulation of light if there are defects in: − Cranial nerve III (oculomotor nerve) for opening Protection of the eye of the eye Source: Dr. Padilla’s PPT − Cranial nerve VII (facial nerve) 2 of 13  Microbial Agents of Eye Infections Additional information: Additional information: From Dr. Padilla’s Lecture: From Dr. Padilla’s Lecture: The surface protection of the eyes is TEARS. Even if we Lacrimal gland - responsible for providing tears. It will are not evidently crying tears are always present. moisten, lubricate and protect the surface of the eye. → We produce tears with an average of 1.2 The space between the bulbar and palpebral is called a microliter/minute. conjunctival sac. Most of the time mucus can be infected. Normal conjunctiva - have 3 (three) protective layer: Most of the time → Oily layer from Meibomian glands - located in the lower eyelid Conjunctiva → Aqueous Layer - the middle part or the watery layer. Palpebral Conjunctiva Produce by lacrimal glands which is a paired almond Bulbar Conjunctiva shape gland → Mucin - the thin inner layer Thin transparent mucous membrane Intermittent blinking - maintain integrity of conjunctiva Translucent but there are tiny blood vessels and cornea. If there is a break in the integrity it will Has glands which secrete mucus and mix with the tears predispose to eye infection. and protect our eye Tears Component: responsible for destroying the cell wall of the bacteria. This is to prevent infection → Immunoglobulin A that will coat bacteria → Lysozyme → Lactoferrin Normal Tear Flow The basal tear flow is 1.2 μL/min. Tears produced by lacrimal gland → High concentration of Immunoglobulin A (IgA) at 0.6 G/L Conjunctiva ▪ IgA coats the bacteria and inactivates bacterial Source: Dr. Padilla’s PPT toxins Additional information: → Lysozyme at 1 G/L From Dr. Padilla’s Lecture: ▪ Antibacterial action Covers the inner surface or the posterior part of the → Lactoferrin at 1.2 G/L eyelid. ▪ Transport iron away from bacteria Membrane lining of the interior part of the eyelid. There is a point that it will change into Bulbar conjunctiva at fornix. D. NORMAL MICROBIOTA OF THE EYE Bacteria ○ Corynebacterium, ○ Staphylococcus Tear flow ○ Simonsiella, Source: Dr. Padilla’s PPT ○ Streptococcus, ○ Propionibacterium, Additional information: ○ Bacillus From Dr. Padilla’s Lecture: This will explain why we have “sipon” or nasal discharges whenever we cry. The tears will drain into the nasolacrimal duct. From superior to inferior canaliculi to lacrimal sac to nasolacrimal sac Causes of Tearing Epiphora → Hypersecretion of tears from the lacrimal gland is caused by infective, chemical, thermal, mechanical, or emotional stimuli → Drainage defect due to stenosis or obstruction of the lacrimal gland Normal Microbiota of the Eye Lacrimal Glands Source: Dr. Padilla’s PPT Network of structures that secrete and drain tears from the surface of the eyeball Moisten, lubricate, and protect surface of the eye Additional information: Continuously secrete tears throughout the day by main From Dr. Padilla’s Lecture: and accessory lacrimal gland Our body organs have different microbiota present like in Almond shape gland under the superior orbital rim which the skin, git, and eye. provides tears 3 of 13  Microbial Agents of Eye Infections The most common is Corynebacterium species especially the Diphtheria/Diphtherium II. EYELIDS Microbiome - are aggregate of not only bacteria and The meibomian glands of the lid prevent over-rapid tear viruses but also fungi and other protozoans. evaporation by secreting an oil film over the watery Normally, the microbiota of the eye involves only the lacrimal gland secretion. conjunctiva and the cornea. Normal microbiota in the eyelid and eyebrows are A. CAUSES OF TEARING usually part of the skin. Based on the pie chart: a study of the American EPIPHORA Academy of ophthalmology. → Hypersecretion of tears from the lacrimal gland is → 80% of bacteria in the surface microbiome. caused by infective, chemical, thermal, mechanical or → Corynebacterium is the most abundant with 63% of emotional stimuli. total. Which is usually found in healthy conjunctiva or → Drainage defect due to stenosis or obstruction of the the patient. lacrimal gland Viruses ○ Torque teno virus (TTV) B. BACTERIAL INFECTION OF EYELIDS ○ Human Papillomavirus (HPV) Hordeolum (Stye) Fungi Staphylococcus aureus ○ Candida albicans Formation of abscess with glands of the eyelids ○ Phylum Localized pain in the lid Ascomycota → External hordeolum Basidiomycota → Internal Hordeolum ○ Genus Aspergillus External Hordeolum Setosphaeria → Bacterial infection of the sweat and sebaceous glands in the lid margin area (Glands of Zeiss and Moll) Malassezia Haematonectria E. INVASION OF THE EYE PATHOGEN Corneal Penetration Facilitated by an epithelial defect or be due to a contaminated contact lens or irrigating solutions, tear film or direct corneal trauma External stye or hordeolum Pseudomonas aeruginosa is adept at invading Source: Dr. Padilla’s PPT compromised epithelium from superficial source Internal Hordeolum Bacterial Load Organism must proliferate to establish enough cells to Infection of the Meibomian glands. overcome host defenses Up to 25% of intraoperative aqueous samples on cataract surgery contain bacteria Blood-Borne Route Considered endophthalmitis (inflammation of the inner coat of the eye) when there is no history of accidental or surgical trauma IV users - more susceptible to develop endophthalmitis → (C. albicans) Internal stye or hordeolum Source: Dr. Padilla’s PPT Contact Lens Acts as a mechanical vector, transferring microbes to corneal epithelium Table 2. Hordeolum (Stye) VS. Chalazion Exacerbated sequestration of tear fluid behind the lens HORDEOLUM CHALAZION Non-infectious Virulence of the Organism meibomian gland Formation of abscess Dictates the outcome of infection occlusion Usually related to the production of lethal toxins, by the Painless bacterium, which are quickly effective at causing tissue necrosis Streptococcus pyogenes → Highly virulent for the eye, producing Exotoxin A and needing only a small inoculum → For as low as 10 cells, to cause necrotizing fasciitis of the lids to fulminant endophthalmitis within 4 hours of cataract surgery 4 of 13  Microbial Agents of Eye Infections Dr. Padilla: Often patients suffer from dandruff. Non-ulcerative Hordeolum Only affects the outside part of the eye a. Painful and itchy Has the tendency to develop into b. Found near or at the eyelash follicle hordeolum. c. Usually triggered by infection Ulceration occurs in the lid margins and d. Can give antibiotics and OTC drugs ULCERATIVE this may be followed by scarring, falling Chalazion BLEPHARITIS out of the eyelashes and distichiasis. a. Painless Inflammation involving the outer angle b. Movable upon palpation ANGULAR of the eyelids c. Far away or further away from the lid margin BLEPHARITIS Staphylococcus and Moraxella spp. d. Blocked gland e. Do not give antibiotics f. Warm compress, surgery or steroids. Blepharitis Source: Dr. Padilla’s PPT Dr. Padilla: Squamous Blepharitis ○ Has the tendency to develop into BLEPHARITIS hordeolum Lid margin inflammations Blepharitis and Hordeolum: Coagulase negative Staphylococcus and Staphylococcus aureus Chronic inflammation of the margins of the eyelid Involve the eyelids, the eyelashes, the conjunctiva and the meibomian glands Characterized by red and pruritic eyelids with formation of dandruff scales on the eyelashes Gritty or burning sensation in their eyes, excessive tearing, itching, red and swollen eyelids, dry eyes or crusting of the eyelids. Dr. Padilla: How to know that it is blepharitis, you can see dandruff TYPES OF BLEPHARITIS Types of Blepharitis Anterior blepharitis occurs at the outside front edge of the eyelid where the eyelashes attach. The eyelid skin, base, and follicles of the eyelashes are affected ANTERIOR Staphylococcal blepharitis BLEPHARITIS Seborrheic blepharitis Blepharitis vs Stye ○ dandruff of the scalp Dr. Padilla’s PPT and eyebrows Less common causes: ○ allergies C. VIRAL INFECTIONS OF EYELIDS ○ mite infestation Posterior blepharitis affects the inner Herpes Zoster Ophthalmicus (Shingles) edge of the eyelid that touches the Varicella-Zoster Virus (VZV) eyeball ○ Occurs when the varicella-zoster virus is Can occur when the glands of the reactivated in the ophthalmic division of POSTERIOR BLEPHARITIS eyelids irregularly produce oil the trigeminal nerve (meibomian blepharitis) ○ Painful herpetic vesicles develop Develop as a result of other skin unilaterally in the skin supplied by the 1st conditions, such as rosacea and branch of the trigeminal nerve (pain will scalp dandruff be felt on the half part of the face) SQUAMOUS Scales develop between the eyelashes ○ The vesicles become crusted and may be BLEPHARITIS and have a tendency for hordeolosis. become secondarily infected 5 of 13  Microbial Agents of Eye Infections ○ This dry, crusted vesicle is highly contagious ○ The patient complains of severe unilateral headache; both skin and corneal sensitivity is reduced ○ Swollen upper lids because of the inflammatory response and swollen lower lid as a result of dependent edema Henderson Patterson Bodies TREATMENT: Analgesics for the pain and can give Dr. Padilla’s PPT antiviral cream for the skin to prevent post herpetic neuralgia (pain) Dr. Padilla Can sometimes cause scarring if not treated Molluscum contagiosum has a characteristic properly histopathologic feature wherein you can see lobular hyperplasia of epidermis into the dermis resulting in a cup-shaped lesion or crater-like nodule. Basal layer usually appear normal but keratinocytes in the stratum malpighi become enlarged and acquire Intracytoplasmic inclusion bodies, containing poxvirus particles called Henderson Patterson Bodies or Molluscum bodies (pointed by black arrow) D. PARASITIC INFECTION Herpes Zoster Opthalmicus Dr. Padilla’s PPT OF THE EYELIDS Herpes Simplex of the Lids Phthiriasis HSV 1: Saliva; HSV 2: sexual Pthirus pubis (pubic or crab louse) Vesicular lesions appear and the lids may be Invasion of the eyelashes by lice swollen Although their primary habitat is pubic hair, these lice are The disease (if limited to the lids) does not cause often found on the hair of the abdomen, thighs and the any complications and no treatment is necessary axilla, and occasionally they may invade the eyebrows and eyelashes Dr. Padilla Sexual contact It can cause prodromal syndrome or tingling sensation that last for 24 hours ➡ vesicle formation ➡ start of Table 4. Head Louse vs Pubic Louse viral infection Head Louse Pubic or Crab Louse Herpes Simplex of the Lids Source: Dr. Padilla’s PPT Ocular Molluscum Molluscum contagiosum (DNA Pox virus family) Small umbilicated pearly lesions appear on the lids and its margins Dome-shaped lesions within central dimple Common viral infection of the children Transmitted by direct (human to human) and indirect contacts (by barbers, use of common towels, swimming pool) Phthiriasis Dr. Padilla’s PPT Ocular Molluscum Dr. Padilla’s PPT HENDERSON PATTERSON BODIES Dr. Padilla → Aka Molluscum bodies This is caused by the infestation of the eyelashes → Intracytoplasmic inclusion bodies, containing poxvirus caused by lice particularly the pubic or crab louse, which particles is usually acquired by sexual contact. → Lobular hyperplasia of epidermis into the dermis Patients complain of eyelid itchiness. → Enlarged keratinocytes of stratum malpighi Eyes become red and watery ▪ Stratum malpighi - contains both the basale and Eggs (nits) and adult lice cling on bases of eyelashes spinosum area 6 of 13  Microbial Agents of Eye Infections III. CONJUNCTIVA Conjunctiva Dr. Padilla’s PPT Secretions in Conjunctivitis A. CONJUNCTIVITIS Source: Dr. Padilla’s PPT Table 5. Common Clinical Manifestations of Conjunctivitis Hyperemia – RED EYE Table 6. Acute and Chronic Conjunctivitis Conjunctival vascular Acute Conjunctivitis Chronic Conjunctivitis dilation - PINK EYE Red eye (conjunctival Red eye (conjunctival hyperemia) hyperemia) Presence of discharge Conjunctival discharge Chemosis Crusting of lid margins Eyelids sticking Foreign body sensation Foreign body sensation CONJUNCTIVAL EDEMA Less than 4 weeks More than 4 weeks Epiphora Dr. Padilla For chronic, the eyelids are sticking because of the INCREASE SECRETION increase in purulent discharge CONJUNCTIVITIS: Symptoms CONJUNCTIVITIS: Agents Discharge Conjunctival reaction Bacteria +/- membranes → Staphylococci Non-specific symptoms: → Streptococci → tearing, irritation, stinging, burning, pain → Pneumococci Foreign body sensation = corneal involvement → Koch-weeks Bacilli Itching = allergic conjunctivitis → Neisseria Photosensitivity → Haemophilus aegyptius → Non pathogenic bacteria are also isolated on occasions: ▪ Diphtheroid ▪ Xerosis bacilli Viruses → Adenovirus → Rubella → Rubeola (measles) virus → Herpesviridae Membrane: Part of Conjunctivitis → Picornavirus Source: Dr. Padilla’s PPT Dr. Padilla Dr. Padilla Most common in viruses – ADENOVIRUS Refer to figure 20: Black arrows are pointed to the MEMBRANE, this should be removed b/c part eto of CONJUNCTIVITIS: Secretions conjunctivitis. Watery VIRAL CONJUNCTIVITIS → Acute Viral Conjunctivitis → Acute Allergic Purulent → Severe acute bacterial Mucopurulent → Mild bacterial → Chlamydial Dr. Padilla Viral Conjunctivitis For conjunctivitis, you will have an idea if the patient has Source: Dr. Padilla’s PPT a viral or bacterial conjunctivitis based on their Adenovirus (most common), Rubella, Rubeola discharges (measles) virus, Herpesviridae, and Picornavirus Watery – VIRAL Highly contagious Purulent – BACTERIAL MOT: spread through hand-to-eye contact Self-limiting 7 of 13  Microbial Agents of Eye Infections VIRAL CONJUNCTIVITIS: Types HYPERACUTE BACTERIAL CONJUNCTIVITIS Pharyngoconjunctival fever Very rare and severe type of conjunctivitis with rapid → commonly caused by infection with adenovirus onset and progression, as well as severe symptoms serotypes 3, 4 and 7 caused by → a syndrome that can produce conjunctivitis as well as a ○ massive exudate, fever and sore throat ○ severe chemosis, Epidemic keratoconjunctivitis ○ eyelid swelling, → commonly caused by infection with adenovirus ○ marked hyperemia, serotypes 8, 19, and 37 ○ pain, → a more severe type of conjunctivitis ○ decreased vision Acute hemorrhagic conjunctivitis Characterized by a copious yellow-green purulent → commonly associated with it include enterovirus 70, discharge that reaccumulates after being wiped coxsackievirus A24, and adenoviruses away → often associated with large epidemics worldwide, especially in the tropical and subtropical regions Neisseria gonorrhoeae or Neisseria meningitidis Can progress to corneal infiltrates, melting and Herpetic keratoconjunctivitis perforation and vision loss if not treated promptly by → herpes simplex virus and blister-like lesions on the skin an ophthalmologist → it may affect only one eye Rubella and rubeola (measles) → conjunctivitis can occur with these viral rash illnesses which are usually accompanied by rash, fever, and cough BACTERIAL CONJUNCTIVITIS Marked grittiness and yellowish mucopurulent Hyperacute Viral Conjunctivitis discharge that may cause the lids to stick together, Source: Dr. Padilla’s PPT especially after sleep. CHRONIC BACTERIAL CONJUNCTIVITIS Defined as symptoms lasting for at least 4 weeks Common causes include by ○ Staphylococcus aureus ○ Moraxella lacunata Often occurs with blepharitis (inflammation of the eyelid), which can cause flaky debris and warmth along the lid People with this condition should see an Bacterial Conjunctivitis ophthalmologist Source: Dr. Padilla’s PPT NEONATAL CONJUNCTIVITIS ACUTE BACTERIAL CONJUNCTIVITIS First 24 hours of life: Chemical causes like silver Haemophilus influenzae nitrate drops from prophylactic medicines, like ○ Gram negative coccobacilli erythromycin drops, gentamicin drops ○ Also known as Koch-weeks bacilli 24 to 48 hours of life: Bacterial causes are most Pink eye conjunctivitis likely (Neisseria gonorrhoeae is the most common ○ Occurs in epidemics cause, Staphylococcus aureus) Most common form of bacterial conjunctivitis among 5 to 14 days of life: Chlamydia trachomatis childrens 6 to 14 days of life: Herpes keratoconjunctivitis In children is often caused by 5 to 18 days of life: Pseudomonas aeruginosa ○ Haemophilus influenzae, Neonates are at higher risk of conjunctivitis due to many ○ Streptococcus pneumoniae predisposing factors: ○ Moraxella catarrhalis Decreased tear production Is typically self-limited within 1–2 weeks, but topical Lack of IgA in tears antibiotic therapy may reduce the duration of Decreased immune function disease Absence of lymphoid tissue in conjunctiva Decreased lysozyme activity GONOCOCCAL OPHTHALMIA NEONATORUM Gonococcal conjunctivitis It is considered in symptomatic neonates after the first day of life, specifically, days 2 to 5, since chemical conjunctivitis (secondary to silver nitrate, antibiotic drops) is often the cause in the first 24 hours Haemophilus aegyptius Source: Dr. Padilla’s PPT Gonococcal Conjunctivitis Source: Dr. Padilla’s PPT 8 of 13  Microbial Agents of Eye Infections Neisseria gonorrhoeae Acquired during passage through infected birth canal The lids are firm, swollen and stuck together by discharge. (Eyelid edema and tenderness) SIGNS/SYMPTOMS ○ Purulent conjunctivitis. ○ Marked conjunctival chemosis ○ Preauricular lymphadenopathy Acute Inclusion Conjunctivitis ○ Pseudomembrane formation Source: Dr. Padilla’s PPT Common cause of blindness Instill eye drops (tetracycline, erythromycin, silver Most patients have a unilateral mucopurulent nitrate) into conjunctival discharge. Treatment for gonococcal ophthalmia neonatorum The tarsal conjunctiva is often more hyperemic than Neonatal Prophylaxis the bulbar conjunctiva. ○ Erythromycin (0.5%) ophthalmic ointment, Characteristically, there is a marked tarsal follicular or response (Follicles in the bulbar conjunctiva and ○ Tetracycline (1%) ophthalmic ointment semilunar folds) Symptomatic or High-Risk Neonate ○ Ceftriaxone (25 mg/k to 50 mg/kg, max 125 mg intravenously (IV) or intramuscularly (IM), single dose, or ○ Cefotaxime (100 mg/kg IV/IM), single dose, which may be preferred if available due to the risk of increasing bilirubin levels associated with ceftriaxone Marked Follicular Hyperplasia Hourly saline lavage Source: Dr. Padilla’s PPT CHLAMYDIAL CONJUNCTIVITIS NEONATAL INCLUSION CONJUNCTIVITIS Acquired by newborn during delivery Table 7. Chlamydial Conjunctivitis Mucopurulent conjunctivitis 7-10 days after delivery Untreated cases may persist as chronic infection Neonates Chlamydial ophthalmia Erythromycin x 14 days or Azithromycin 20 neonatorum Chlamydia mg/kg/day x 3 days is the recommended treatment trachomatis Watery, mucopurulent, or bloody discharge, marked red swelling Sexually active Unilateral with hyperemia and purulent Chlamydia discharge trachomatis subtypes Chlamydial conjunctivitis associated genital D–K infection Neonatal Inclusion Conjunctivitis Unilateral hyperemia Source: Dr. Padilla’s PPT and purulent discharge TRACHOMA Trachoma The leading cause of Most frequent cause of blindness throughout preventable blindness the world Chlamydia Chronic follicular ○ Chlamydia trachomatis A, B, Ba, C trachomatis conjunctivitis ○ Chronic keratoconjunctivitis subtypes Scarring of the inner eye This bacterium causes roughening of inner eyelid ○ (scratch the which causes pain in eye, breakdown of the outer A–C surface of cornea and in severe conditions, often cornea – TRICHIASIS) leads to blindness Table 8. Chronic keratoconjunctivitis Chlamydia trachomatis FIRST STAGE A nonspecific conjunctivitis and Inclusion conjunctivitis – serotypes D and K lymphoid hyperplasia develops. Trachoma - serotypes A, B, Ba & C SECOND STAGE Formation of lymph follicles, ADULT INCLUSION CONJUNCTIVITIS particularly in the superior Chlamydia trachomatis D and K palpebral conjunctiva and fornix, Affect sexually active adolescents and adults with development of gelatinous Asymptomatic granulations of unequal size. Transmission primarily occurs through contact The trachomatous pannus between contaminated genital secretions and the (infiltration of the cornea with eye(s), or via autoinoculation (hand-to-eye blood vessels starts superiorly transmission) and then spreads over the Case reports have documented transmission from cornea from all sides. poorly chlorinated swimming pools or hot tubs. 9 of 13  Microbial Agents of Eye Infections THIRD STAGE Conjunctival fibrosis occurs Neonatal Conjunctivitis, acquired via Vertical Transmission through Delivery, affects the FOURTH STAGE The scars gradually curve the Unilateral area of the eye. If not treated it will lead lower tarsus margin inwards, to Chronic Inclusion Conjunctivitis giving rise to cicatricial entropion Trachoma blindness can be preventable. It not only and trichiasis (rubbing of the affects the conjunctiva but also the cornea lashes against the cornea). in 4th stage Trichiasis (rubbing of the lashes Source: Dr. Padilla’s PPT against cornea) plus Entropion (a condition in which the eyelid is rolled inward against the eyeball, causing the eyelashes to produce friction THE WHO SIMPLIFIED GRADING SCHEME FOR with your conjunctiva causing trichiasis) ASSESSMENT OF TRACHOMA: Trachoma bodies may be identified via biopsy or the blood. Trachoma via blood may be identified via Giemsa Stain IV. CORNEA PSEUDOMONAS KERATITIS Strongly associated with contact lens wear ○ Extended contact lens use allows adhesion of P. aeruginosa (main causative agent) to contact lens surfaces and subsequently the cornea. ○ P. aeruginosa possesses specific virulence factors, including pili, and glycocalyx which allow invasion and adherence into the cornea. Pseudomonas Keratitis Source: Dr. Padilla’s PPT Description/Appearance: ○ Diffuse surrounding corneal edema ○ Thick mucopurulent, yellow-greenish exudates ○ (+) hypopyon formation - a milky white Trachomas Bodies fluid level in the inferior part of the anterior Formerly: Halberstadt-Prowazek inclusion chamber. bodies or Prowazek-Greef bodies Intracytoplasmic form in the conjunctival epithelial Dr. Tina: cells in Acute phase of Trachoma Direct smear: Giemsa stain show dark purple If not treated, the eye (specifically the cornea) will intracytoplasmic inclusions in infected cells (purple be covered by a white fluid that looks like an oyster. caps) In this case, the patient is already blind. Risk factors for contact lens-related infectious keratitis: ○ Overuse of contact lenses ○ Overnight wear ○ Diabetes ○ Trauma ○ Poor hand and lens hygiene Other causes: ○ Staphylococcus aureus Trachoma Bodies ○ Coagulase-negative Staphylococci Source: Dr. Padilla’s PPT Treatment: Dr. Tina: ○ Topical broad-spectrum antibiotics: To identify Adult Inclusion Conjunctivitis, check fluoroquinolones for marked hyperplasia which is found in the Bulbar often combined with fortified Conjunctiva, and Semilunar Folds aminoglycoside or vancomycin should be started promptly 10 of 13  Microbial Agents of Eye Infections VIRAL KERATITIS HERPES ZOSTER OPHTHALMICUS Most commonly after the 6th decade of life Herpes simplex virus Reactivation of the VZV (varicella zoster virus) in Common: 90% human population seropositive Primary infection the trigeminal ganglion In children, through droplet, subclinical Supraorbital and supratrochlear branches of the Recurrence: Immunocompromised frontal nerve are most commonly involved Herpetic eye disease is the most common infectious Hutchinson's sign – vesicles on the tip or on the cause of corneal blindness in developed countries side of the nose, preceding the development of hzo. This classic herpetic lesion consists of a linear This occurs because the nasociliary branch of the branching corneal ulcer (dendritic ulcer) trigeminal nerve innervates both the cornea and the Terminal bulb seen in Viral Keratitis: lateral dorsum of the nose as well as the tip of the nose Herpes Zoster Ophthalmicus Source: Dr. Padilla’s PPT HERPES SIMPLEX KERATITIS Treatment: Symptoms ○ Oral Acyclovir (20 mg/kg four times a day) ○ Eye pain or 500 mg 5 times a day for 1 week ○ Tearing (epiphora) ○ Famcyclovir 300mg TID for 1 week ○ Redness (hyperemia) ○ Valacyclovir 1 gram TID for 1 week ○ Oral antibiotics for secondary bacterial ○ Foreign body sensation infection ○ Sensitivity to bright light Treatment: Antiviral Drugs Dr. Padilla: Prodrome syndrome Usually affects first branch of trigeminal nerve Signs and symptoms: Edema of eyelids, pain, vesicles and ulceration SIMPLEX vs ZOSTER Herpes Simplex Keratitis Source: Dr. Padilla’s PPT Risk factors ○ Frequent recurrent episodes ○ Atopic eye disease ○ Pediatric age group ○ Immunodeficiency or immunosuppression ○ Malnourishment ○ Alcoholism Zoster vs. Simplex ○ Fever Source: Dr. Padilla’s PPT ○ Stress ○ Malaria ACANTHAMOEBA KERATITIS ○ Inappropriate topical steroids may result in Rare but serious infection of the eye that can result geographical ulceration in permanent visual impairment or blindness. Inflame and infects the cornea (keratitis) Dr. Padilla: Acanthamoeba sp. Most common viral keratitis is Herpes simplex ○ Free-living amoeba found in freshwater, virus. tap water, hot tubs (thermophilic) Most common infectious mode of corneal blindness Keratitis is associated with use of contact lenses, in some developed countries. recent eye trauma, or someone exposed to Primary infection and viral keratitis secondary to contaminated water. infection with Herpes simplex virus. Arrow pointing to classic herpetic lesions or dendritic lesions a. branching of corneal ulcerations b. resembles a tree c. green-colored lesion because of immunofluorescence dye Ring-like Acanthamoeba Keratitis From Doc Tina’s PPT 11 of 13  Microbial Agents of Eye Infections Acanthamoeba Keratitis: Symptoms Severe ocular pain & blurring of vision X. FREEDOM WALL Corneal ulceration with progressive corneal infiltration and clouding TRANSPORT SYSTEMS FOR Loss of vision MICROBIOLOGY SPECIMENS Secondary infection may lead to hypopyon formation Cultures System Immunocompromised state may lead to Anaerobic Swab Granulomatous Amebic Encephalitis (GAE) Aerobic Swab Male urethral Swab mini-tip Stromal-like infiltrates in Acanthamoeba keratitis: Urine Sterile screw-capped cup. Sputum Sterile screw-capped cup. Stools Biopsy Sterile screw-capped cup. Add a small amount of sterile non-bacteriostatic saline to the cup. Sterile fluids Sterile tubes Drainage If the fluid will clot, add lithium Bronchial heparin as an anticoagulant. Acanthamoeba Keratitis: Treatment brush Multidrug Tx: Clotrimazole, Pentamidine, Needle Transfer to a sterile tube prior to isethionate, Neosporin aspirate transport to the laboratory. Novel drug: Hexadecy|phosphocholine (Miltefosine) Corneal transplantation (keratoplasty) - therapeutic mainstay of treatment for AK Surgical grafting of the cornea in severe infection V. APA REFERENCES [Padilla, M.C.]. (2024). Microbial Diseases of the Eye [Powerpoint Slides]. College of Medicine, Davao Medical School Foundation, Inc. Dr. Padilla Audio Recording Jawetz, Melnick and Adelberg’s Medical Microbiology (28th ed.). McGrawHill VI. REVIEW QUESTIONS # QUESTION Most common viral conjunctiva? A. Adenovirus 1 B. Herpes Simplex C. Rubella D. Neisseria Common clinical manifestations of conjunctiva, EXCEPT: A. Chemosis 2 B. Hyperemia C. Epiphora D. Distichiasis In meningitis, this infection can cause morbidity in patients, specially if it involves systemic infection A. M. tuberculosis 3 B. H. Influenzae C. E. coli D. N. meningitidis Blepharitis is all of the ff except A. Flaking of the skin around the eyes B. Inflammation of the margins of the eyelid 4 C. Single lump/nodule on a gland D. Involvement of immune damage 5 Most Common causative agent for hordeolum # ANSWER 1 A 2 D 3 A 4 C 5 Staphylococcus aureus 12 of 13 Microbial Agents of Eye Infections APPENDICES 13 of 13