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Dr. Sadeli Masria, dr., SpMK., MS. Dept. of Microbiology Medical Faculty, Padjadjaran University OCULAR INFECTIONS Ocular bacterial infections viral fungal The normal eye has very effective defenses against infections : - The eyelids & lashes prevent foreign debris from striking the eye - The eyelids wash the tears across the cornea and cleanse the eyes - Tears contain secretory immunoglobulins & lysozymes that help prevent infection - The corneal epithelium and collagenous tissues (Bowman’s layer) act as strong barrier - The eye becomes susceptible to infection only when these defense mechanisms are altered INTRODUCTION The hallmark of an ocular infection is a red eye - The eyelid margins are red in cases of blepharitis - The conjunctiva are injected in bacterial and viral conjunctivitis - The deep blood vessels adjacent to the cornea and sclera are dilated in cases of iritis - Erythema of all ocular structures suggests a severe infection of the entire globe and orbit - (Such as panophthalmitis) - The presence of edema in addition to erythema suggest advanced infection or inflammation An ocular discharge is not normal : - Watery discharge in allergies - Serosanguineous in severe viral conjunctivitis - Purulent in bacterial infections Symptoms of an ocular infection : - The first are a mild sensation of foreign body, tearing and sensitivity to sunlight - More advanced infection causes pain and decreases vision OCULAR BACTERIAL INFECTIONS - Conjunctivitis - Infection of the eyelids and ocular adnexae - Bacterial corneal ulcers - Orbital cellulitis Conjunctivitis - Etiology : - Neisseria - Chlamydia - Hemophilus May cause by normal conjunctival flora Chlamydia : Ch.trachomatis, Ch. Pneumoniae, Ch. psittaci - Are obligate intracellular parasite - Multiply in the cytoplasm of their host cells - Known as elementary body (EB) or reticulate body (RB) - May be found in epithelial cells of conjunctival scraping stain with giemsa or fluorecent antibody Normal conjunctival flora : - Aerobic bacteria : - Staphylococcus epidermidis - Staphylococcus aureus - Streptococcus pneumoniae - Streptococcus sp - Corynebacterium sp - Micrococcus sp - Bacillus sp - Gram-negative rods Staphylococcus : Typical organisms : - Are spherical cells, arranged in irregular cluster - Are gram positive, grow readily on most bacteriologic media under aerobic or microaerophilic conditions - Colonies are round, smooth, raised, glistening Streptococcus : Typical organisms : - Are gram positive, individual cocci are spherical or ovoid arranged in chain - Grow on solid enriched media as discoid colonies, ø 1-2 mm Corynebacterium : - Non-spore-forming gram positive bacilli - C. diphtheriae is the most important of the group - Grow aerobically on most ordinary laboratory media Normal conjunctival flora : - Anaerobic bacteria : - Propionibacterium acnes - Peptostreptococcus sp - Lactobacillus sp - Clostridium sp - Eubacterium sp Normal conjunctival flora : - Fungi : - Candida sp - Aspergillus sp - Rhodotorula sp - Viruses : adenoviruses Clinical manifestations Symptoms & signs of bacterial conjuctivitis : - Symptom : burning, itching, foreign body sensation, pain, photophobia, tearing - Sign : - Preauricular node - Purulent discharge - Marred eyelashes - Conjunctival injections - Eyelids disease - Subconjunctival hemorrhage EPIDEMIC CONJUNCTIVITIS PINKEYE Characterized by an inflamed, bright red conjunctiva with inflammation extending into the cornea It is spread by direct person-toperson contact It is no threat to eyesight Etiological agent : Haemophilus aegypticus Moraxella lacunata Haemophilus Gram-negative coccobacilli Fastidious and require factors X (hemin) and/or V (NAD) Possess LPS in the cell wall but produce no apparent extracellular toxins All Haemophilus species grow more readily in an atmosphere enriched with CO2 Moraxella The mucous membranes of humans and other warm-blooded animals Many species are nonpathogenic M lacunata can be isolated from the eyes and may cause conjunctivitis in humans living under conditions of poor hygiene Cocci that morphologically resemble Neisseria Diagnosis : Clinically in the presence of symptom and sign laboratory diagnosis : - Gram stain are less rewarding - Cultures : ~ also have a poor yield ~ only 30% of patients with clinical ~ bacterial conjunctivitis harbor ~ pathogenic organisms OPHTHALMIA NEONATORUM From a mother with gonorrhea as the fetus passes down the birth canal. Infection does not occur in utero At one time about 10% of all cases of blindness Corneal inflammation is the major clinical sign. Etiological agent : Neisseria gonorrhoeae Neisseriaceae Neisseria spp. Gram-negative diplococci (kidney bean, coffee bean) aerobic, microaerophilic, chocolate agar non-motile, non-spore forming, oxidase positive Acinetobacter spp. Kingella spp. Moraxella spp. Neisseria : N. gonorrhoeae N. meningitidis Typical organisms : is a gram negative non-motile diplococcus individual cocci are kidney-shaped when the organisms occur in pairs, the concave sides are adjacent Growth characteristic : - Grow best under aerobic conditions - Some will grow under anaerobic environment - They have complex growth requirement - In 48 hours on enriched media (Mueller-Hinton, Thayer Martin), Neisseria form convex, glistening, elevated, mucoid colonies, ø 1–5 mm - The colonies are transparant or opaque non pigmented, non hemolytic Infection of the eyelids and ocular adnexae - Infection of the eyelids and ocular adnexae (lacrimal glandm lacrimal ducts, and lacrimal sac) - Infection of the eyelids and adnexae produces redness & swelling of the involved structures - Chronic infection produces permanent changes in the structure and may causes permanent loss of function The sty (hordeolum) : - Is an acute staphylococcal abscess of the oil secreting glands of the eyelids - May occur on the inner lid (internal hordeolum) when the meibomian glands are involved - And on the outer surface of the lids (external hordeolum) when the glands of Zeiss and Moll are infected - Acute localized swelling of the lid with pain erythema - The abscess may point through the skin of the lids - The conjunctiva and remainder of the eye are usually univolved Blepharitis (chronic low-grade infection of oil-secreting glands Etiology : Staphylococcus aureus Staphylococcus epidermidis Produces a vascularized and erythematous lid margin with scale formation, loss of lashes, production of white lashes, misdirection of lashes, and deposits around the base of the eyelashes Dacryocystitis (infection of the lacrimal sac) Etiology : - Staphylococcus aureus - Streptococcus pneumoniae - Hemophilus influenzae Canaliculitis (infection of the lacrimal ducts) Etiology : - Actinomyces - (Fungi) - Other bacteria rarely cause canaliculitis Bacterial corneal ulcers Occurs after trauma to the cornea disrupt the epithelium permits bacterial colonization Etiology : - Pseudomonas - Stephylococcus aureus - Streptococcus pneumoniae - Moraxella These organisms capable of epithelial colonization and penetration can produce spontaneous infection : - Neisseria gonorrhoeae - Corynebacterium diphtheriae - Hemophilus Clinical manifestations : - The hallmark of bacterial corneal ulceration is pus - The stroma becomes opaque and the surface irregular - The underlying stroma becomes soft and mushy; often discolored to a white, yellow or brown color. Laboratory diagnosis : - The specimen (corneal scraping) must be collect by an opthalmologist - Microscopic examinations : - Gram staining, acid-fast or Giemsa - Bacterial culture Orbital cellulitis Is an acute inflammation of the orbital tissue - Produced by spread of an infection from nearby structure or distant foci Etiology : - Hemophilus influenzae - Staphylococcus aureus - Streptococcus group A - Streptococcus pneumoniae Clinical manifestation : - The eye usually protrudes (proptosis) - The lids are usually swollen shut with a discharge - The cornea can become exposed, ulcerated and perforated INCLUSION CONJUNCTIVITIS INCLUSION BLENNORRHEA OF THE NEWBORN SWIMMING POOL CONJUNCTIVITIS During the birth process, when the fetus passes down the birth canal, it can contract an eye infection from the mother's genital flora. If Chlamydia trachomatis of a particular serotype is obtained in this way it can cause an inclusion conjunctivitis after a 512 day incubation period. Etiological agent : Chlamydia trachomatis OCULAR LYMPHOGRANULOMA VENEREUM As in inclusion conjunctivitis, a fetus can contract an eye infection by Chlamydia trachomatis during passage down the birth canal However, if it is of a more virulent serotype than the strain causing inclusion conunctivitis, the presentation can be that of ocular lymphogranuloma venereum This will occur 5-12 days after birth Etiological agent : Chlamydia trachomatis TRACHOMA Trachoma is the most serious of the eye diseases caused by Chlamydia trachomatis There is no genital involvement in this disease; the disease is spread person-to-person via the common use of towels and washcloths Both children and adults can be infected This is the leading cause of blindness in the world Etiological agent : Chlamydia trachomatis Endophthalmitis Inflammation of the aqueous or vitreous humor, occurs most commonly following intraocular lens implantation or trauma or as an extension of an adjacent (endogenous) infection UVEITIS Nonpurulent uveitis seldom involves the entire uveal tract but may occur predominantly in the anterior segment (iritis, iridocyclitis) or the posterior segment (posterior uveitis, retinitis) Etiology (Anterior uveitis) MOST COMMON: Mumps virus Human Herpesvirus 3 (Varicella-Zoster virus) Rubella virus Rubeola virus Human Herpesvirus 1 (Herpes simplex 1 virus) LESS COMMON: Treponema pallidum Neisseria gonorrhoea Brucella sp. Borrelia burgdorferi Rickettsia rickettsii Human immunodeficiency virus Leptospira interrogans Etiology (Posterior uveitis (inflammation of the choroid) Toxoplasma gondii (25% of all cases) Toxocara sp. Cryptococcus neoformans Histoplasma capsulatum Mycobacterium tuberculosis Human Herpesvirus 5 (cytomegalovirus) Human Herpesvirus 1 (Herpes simplex 1 virus) Human immunodeficiency virus OCULAR VIRAL INFECTIONS VIRAL CONJUNCTIVITIS KERATOCONJUNCTIVITIS Etiological agents : Adenovirus, types 3,7 and 8 Human Herpesvirus 1 (Herpes simplex 1 virus) Human Herpesvirus 2 (Herpes simplex 2 virus) Human Herpesvirus 3 (Varicella-Zoster virus) Human Herpesvirus 5 (Cytomegalovirus) ADENOVIRUS INFECTIONS - Produce a simple, mild follicular conjunctivitis - Often unilateral - Associated with pharyngitis, lymphadenopathy, coryza - Sometimes aquired through swimming pool contact ADENOVIRUS INFECTIONS - May cause Epidemic keratoconjunctivitis - The conjunctivitis sometimes mild, but may severe with petechiae or bleeding and even pseudomembran formation - Tends to be bilateral - The keratitis usually begin 2 weeks after the first symptom - Produce subepithelial corneal infiltrates Symptoms : - During the acute phase or adenovirus infection, symptoms may be severe - Pain, redness of the eye, photophobia, uncomfortable to read - The most important fact about epidemickeratoconjunctivitis is that it is frequently spread by the GP or ophthalmologist through unwashed hand or unsterile tonometer HERPES SIMPLEX INFECTION Dendritic keratitis : - As virus infection begins in the cornea, small punctate epithelial spots or tiny vacuoles may appear in the corneal epithelium - Then coalese to form the familiar, branching dendritic figure VARICELLA-ZOSTER INFECTION - The eye involved as severe iridocyclitis - Primary involvement of the cornea may cause corneal ulcers (dendritic ulcers), white corneal scarring - Produce optic neuritis, ophthalmoplegia, and pupillary paralysis OCULAR FUNGAL INFECTIONS Fungal keratitis : Etiology : - Candida - Fusarium - Penicillium - Acremonium - Paecilomyces Symptoms : - Pain, redness, diminished vision, photophobia, tearing & discharge Sign : - The eye appear injected & area of opacification - Slit lamp biomicroscopy shows small oval ulceration with a wide area of stromal infiltrat and edema Fungal retinitis and endophthalmitis Etiology : - Candida - Fusarium - Blastomyces - Aspergillus - Coccidioides Clinical manifestations : - Ocular symptoms are redness, pain & blurred vision Examination : - The eye typically shows hyperemia of the ocular surface and dilatation of the vessels - Fundus examination reveal chorioretinal infiltrate Diagnosis : By culture of the aqueous and vitreous fluids Fungal dacryocystitis & canaliculitis Etiology : - Candida albicans - Aspergillus niger Clinical manifestations : - Typically present with erythema, induration and a sensation of pressure in the medial canthus - The eye may be red & the eyelids edematous - Pain frequently is severe and may localize to the glabelar region Microbiological examination Specimens of the external ocular surface were collected in sterile tubes by calcium alginate swab or by aspiration of the anterior chamber and vitreous The tubes were kept at 4 ºC and transported to the laboratory There was no history of ocular antibiotic drops instillation Collection for Conjunctival Specimens Instructions for Chlamydia trachomatis •If pus or discharge is present, use a sterile, Dacron swab (not provided) to clean the area. Do not scrape the conjunctiva while cleaning the eye(s). •If both eyes are affected, swab the leastaffected eye first. •Thoroughly swab the lower then the upper conjunctiva 2 to 3 times each urethral/conjunctival swab. •Preparation for Transport A portion of each sample was examined microscopically for bacteria and polymorphonuclear leukocytes For bacteriological examination the following media were inoculated: MacConkey's or eosin-methylene blue (Gram-negative bacilli) Blood agar (Gram-positive cocci) Chocolate agar (H. influenzae and N. gonorrhoeae), Thioglycolate broth (anaerobic bacteria) and Mueller-Hinton for antimicrobial susceptibility testing Additional selective media for some bacteria were inoculated as desired by the participating laboratory The swabs were inoculated onto a 5% sheep blood agar plate, chocolate agar plate and MacConkey's medium All sample plates were incubated for 48 hours at 37 ºC in 4% CO2 and some plates to lower the oxidation-reduction potential for anaerobic growth Preliminary identification of suspicious colonies was carried out using standard biochemical and serological tests Antibiotic sensitivity testing was done using a disk diffusion method (Kirby-Bauer)