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EYE & EAR CULTURES. ANATOMY OF THE EAR Tympanic membrane Middle ear Eustachian tube Inner ear

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Text of EYE & EAR CULTURES. ANATOMY OF THE EAR Tympanic membrane Middle ear Eustachian tube Inner ear

  • Slide 1
  • EYE & EAR CULTURES
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  • ANATOMY OF THE EAR Tympanic membrane Middle ear Eustachian tube Inner ear
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  • EAR INFECTIONS & CULTURES F Otitis media Most common infection in young children 1/3 rd of all pediatric visits due to infection of middle ear Often the result of viral or bacterial infections of the respiratory tract Clearance mechanism of Eustachian tubes impaired; tubes shorter in children than adults Cultures required only infrequently
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  • OTITIS MEDIA F Specimen collection by typanocentesis F Symptoms Fever and irritability (may be only symptom) Tugging at affected ear Ear pain and red, bulging tympanic membrane Drainage of purulent secretions into ear canal
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  • OTITIS MEDIA: TYMPANIC MEMBRANE Bulging tympanic membrane
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  • OTITIS MEDIA F Causative agents *Streptococcus pneumoniae *Haemophilus influenzae Streptococcus pyogenes Moraxella catarrhalis (in children) Staphylococcus aureus Gram negative bacilli (following antibiotics) Group B beta streptococci (newborns)
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  • SWIMMERS EAR OTITIS EXTERNA F Maceration of outer ear from swimming, hot and humid weather, or hot tub use F Pools with high coliform counts increase risks F Symptoms Irritation and itch Swelling and pain
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  • OTITIS EXTERNA Infection and irritation in the outer ear
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  • OTITIS EXTERNA F Specimen collection - insertion of sterile swab into ear F Causative agents Pseudomonas spp. (most common) Enterobacteriaceae spp., including E. coli and Proteus spp. F Prevent through complete drying of ears using acidic alcohol (vodka and vinegar?) F Rx with antibiotic containing otic drops
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  • OBTAINING A SPECIMEN FOR CULTURING THE OUTER EAR
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  • EAR CULTURES F Set-ups: CAP (H. influenzae) chocolate Agar plates BAP ( Blood Agar Plates) MacC or EMB CNA? u nalidixic acid and colistin in Columbia Blood Agar the growth of most gram-negative bacteria, including Klebsiella, Proteus and Pseudomonas species Thioglycollate broth (middle ear sources only) Smear
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  • EYE ANATOMY
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  • EYE INFECTIONS & CULTURES F Conjunctiva and cornea invaded by few organisms if barrier is intact Lysozyme (gram positives) Immunoglobulins Filters (lashes) Other anatomic features (density of tissues)
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  • EYE PATHOGENS F Truly invasive organisms N. gonorrhoeae and meningitidis Streptococcus pneumoniae Listeria monocytogenes Corynebacterium diptheriae Staphylococcus aureus Pseudomonas aeruginosa
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  • EYE INFECTIONS F Normal flora *Coagulase negative staphylococci *Propionibacterium spp. Corynebacterium spp. Staphylococcus aureus Haemophilus influenzae Streptococci pneumoniae F NF usually protects eye from invasion by more harmful organisms
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  • CONJUNCTIVITIS (pink eye) F Causative agents Adults u Staphylococcus aureus (warmer climes) u Streptococcus pneumoniae (cooler climes) Infants & children u Haemophilus influenzae u Staph. aureus u Streptococcus spp. u Enterobacteriaceae
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  • CONJUNCTIVITIS OR PINK EYE
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  • CONJUNCTIVITIS F Causative agents Neonates u Neisseria gonorrhoeae (large volume of exudate) u Neisseria meningitidis (large volume of exudate) u Chlamydia trachomatis (requires special culturing or diagnostic techniques) Viruses, fungi, and parasites Allergies
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  • CONJUNCTIVITIS F Common means of infection Birth canal (eg., Chlamydia trachomatis & Neisseria gonorrhoeae) Hand-eye contact (N. gonorrhoeae, Staph. aureus, H. influenzae) Contaminated cosmetics and medications (Staph. aureus, gram negative bacilli)
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  • CONJUNCTIVITIS AGENTEXUDATE & CELLS LIDS SWELL NODES INVOLVED ITCH BacteriaPus,PMNs, clear ModerateNo VirusesMonos, clear MinimalYesNo AllergyEos., clear Moderate to severe NoIntense
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  • CONJUCTIVITIS F Specimen collection Dacron (not cotton) swabs (cotton has oils with antimicrobial properties) Conjunctival scrapings or expressed fluids Often collected by opthalmologist When possible, inoculate directly onto media
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  • CONJUNCTIVITIS F Set-ups CAP (H. influenzae and N. gonorrhoeae) BAP Smear F Special techniques required for Chlamydia trachomatis, viruses, parasites
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  • KERATITIS F Ocular emergency F Causative agents Extremely critical cases due to rapidly acting (24/48 hrs) enzyme-mediated corneal melt u Pseudomonas aeruginosa u Staphylococcus aureus
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  • KERATITIS F Keratitis is a condition in which the eye's cornea is inflamed.
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  • KERATITIS Frequently isolated gram negatives u Serratia marcescens - common H 2 O microbe u Proteus mirabilis u Haemophilus influenzae u Moraxella spp. Frequently isolated gram positives u Streptococcus pneumoniae u Viridans streptococci u Coagulase negative staphylococci Mycobacterium other than tb. (MOTT) Viruses, fungi, parasite
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  • KERATITIS F Common vectors Contact lenses!!! Latent viruses Contaminated soil and water Damage out doors from trees and sand
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  • KERATITIS F Specimen collection same as conjunctivitis F Set-ups: CAP BAP Thioglycollate broth Anaerobic BAP? All purpose fungal medium? Smear F Special techniques required for Chlamydia, viruses, parasites
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  • KERATITIS F Limulus lysate test may be rapidly diagnostic for infections with g- bacilli Hemolymph from horseshoe crab plus microbe (LPS?) Clot Only useful for detection of gram negatives Does not differentiate between gram negatives
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  • Congenital cataracts F Result of mother with rubella
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  • Endophthalmitis F Endophthalmitis is an inflammation of the internal coats of the eye. F It is a dreaded complication of all intraocular surgeries, particularly cataract surgery, with possible loss of vision and the eye itself. F Other causes include penetrating trauma and retained intraocular foreign bodies
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  • ENDOPHTHALMITIS F Nosocomial sequellae of eye surgery F Sight threatening F Samples are aspirates of anterior chamber or vitreous humor fluids F Common isolates Coagulase negative staphylococci Viridans streptococci Enterococci Gram negative bacilli Other organisms associated with conjunctivitis & keratitis
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  • ENDOPHTHALMITIS
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  • F Set-ups: CAP BAP Anaerobic BAP All purpose fungal medium Broth medium Smear Extra samples held for viral and chlamydial work-ups