EYE EAR CULTURES ANATOMY OF THE EAR Tympanic

EYE & EAR CULTURES

ANATOMY OF THE EAR Tympanic membrane Inner ear Middle ear Eustachian tube

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

OTITIS MEDIA 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 F

OTITIS MEDIA: TYMPANIC MEMBRANE Bulging tympanic membrane

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)

SWIMMERS EAR – OTITIS EXTERNA 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 F

OTITIS EXTERNA Infection and irritation in the outer ear

OTITIS EXTERNA 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 F

OBTAINING A SPECIMEN FOR CULTURING THE OUTER EAR

EAR CULTURES F Set-ups: – CAP (H. influenzae) “chocolate Agar plates” – BAP ( Blood Agar Plates) – Mac. C 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

EYE ANATOMY

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)

EYE PATHOGENS F Truly invasive organisms – N. gonorrhoeae and meningitidis – Streptococcus pneumoniae – Listeria monocytogenes – Corynebacterium diptheriae – Staphylococcus aureus – Pseudomonas aeruginosa

EYE INFECTIONS 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 F

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

CONJUNCTIVITIS OR “PINK EYE”

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

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)

CONJUNCTIVITIS AGENT EXUDATE & CELLS LIDS SWELL NODES INVOLVED Bacteria Pus, PMNs, clear Viruses Monos, clear Allergy Eos. , clear Moderate No No Minimal No Yes Moderate No to severe ITCH Intense

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

CONJUNCTIVITIS Set-ups – CAP (H. influenzae and N. gonorrhoeae) – BAP – Smear F Special techniques required for Chlamydia trachomatis, viruses, parasites F

KERATITIS 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 F

KERATITIS F Keratitis is a condition in which the eye's cornea is inflamed.

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

KERATITIS F Common vectors – Contact lenses!!! – Latent viruses – Contaminated soil and water – Damage out doors from trees and sand

KERATITIS 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 F

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

Congenital cataracts F Result of mother with rubella

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 F Other causes include penetrating trauma and retained intraocular foreign bodies

ENDOPHTHALMITIS 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 F

ENDOPHTHALMITIS

ENDOPHTHALMITIS F Set-ups: – CAP – BAP – Anaerobic BAP – All purpose fungal medium – Broth medium – Smear – Extra samples held for viral and chlamydial work-ups