Eye, Ear, Nose, Mouth Infections

Eye

Anatomy of the Eye:

• The eye external structures are: eyelids,

conjunctiva, sclera, and cornea.

• Conjunctiva is a mucous membrane, lines

each eyelid and extends onto the surface of

the eye itself.

Resident Microbial Flora

• S. epidermids and Lactobacillus spp are the most common flora of the eye.

• S. aureus (30%)*

• H. influenzae (0.4% - 25%)*

• Morroxella catarrhalis*

• S. pyogenes*

• S. pneumoniae*

• Various GNR*

• Skin flora may be present

Defense mechanisms

• Eyelashes

• The lids blinks 15-20 times per minute

,accompanied with secretion of lacrimal

glands, wash away foreign matter.

• Lysozyme and IgA.

Infections:

Blepharitis:

• Is the inflammation of the eyelid.

• S. aureus and S. epidermidis are the most common causative agents.

• Burning, itching sensation of a foreign body , and crusting of the eyelids are the most common symptoms.

Conjunctivitis

• Is the most common type of ocular infection.

• Is the inflammation of conjunctiva, called red eye or pinkeye.

• The most common causative agent of this condition are:

– N. gononrrhae (ophthalmia neonatorum)

– C. trachomatis ( trachoma) leading cause of blindness

– H. influenzae (subsp. aegyptius)

– S. aureus

– S. pneumoniae

– Moraxella. catarrhalis

• The use of contact lenses has increased the

incidence of eye infections.

• Pseudomonads can cause conjunctivitis with

serious eye damage.

Keratitis

• Is corneal infection

• Various of agent can cause this condition, usually only after some type of trauma produces a defect in the ocular surface.

• Bacteria account for 65 – 90 % of corneal infections.

• S. aureus, S. pneumoniae, and P. aeruginosa account for more than 80% of all bacterial corneal ulcer.

• Some fungi, such as Apergillus spp and Candida spp can cause keratitis.

Anatomy of the Ear

• The ear consists of the external, middle, and inner ear.

• Middle ear is connected to nares, naspharynx, and auditory tube, all of which are lined with respiratory epithelium.

Resident Microbial Flora

• The normal flora of the external ear is similar

to flora of the conjunctiva except for S.

pneumoniae.

• P. aeruginosa is found on occasions.

• Candida spp. (non- C. albican) are also

common.

Otitis Externa (swimmer’s ear)

• External ear infection is similar to skin infections elsewhere.

• Acute localized disease (pustule or furuncle) is caused by S. aureus.

• Erysipelas caused by GAS may involve the

external ear canal.

• P. aeroginosa causes a sever, hemorrhagic

external otitis, which is difficult to treat and

has been associated with hot tub use.

Otitis media

• Is the inflammation of the middle ear.

• The formed pus expresses pressure against the eardrum and causes it to become inflamed and painful.

• Otitis media is more common in childhood because auditory tube is small and more horizontal than in adults and so is more likely to be blocked by infection.

• The most commonly isolated pathogen is : – S. pneumoniae (about 35% of cases)

– Nonencapsolated H. influenzae (20%-30%)

– Moraxella catarrhalis (10% - 15%)

– S. pyogenes (8%-10%)

– S. aureus (1%-2%)

• Mastoiditis is a complication of chronic otitis

media in which organisms find their way into

the mastoid sinuses.

Anatomy of Sinuses

• The sinuses, like mastoids, are air-filled

cavities within the head, and are lined with

respiratory epithelium.

• The sinuses are normally sterile.

Paranasal sinuses

Sinusitis

Acute sinusitis:

• usually develops during the course of a cold or influenzal illness and tend to be self-limited, lasting 1-3 weeks.

– Purulent nasal and postnasal discharge

– Feeling of pressure over sinus areas of the face

– Cough

– Nasal quality to the voice

– Fever may be present.

• Thought to be bacterial complications of viral cold

• Acute maxillary sinus infection is dental source.

• S. pneumoniae, Haemophilus influenzae, GAS, and M. catarrhalis are the major bacterial pathogens for acute sinusitis.

Dental caries (tooth Decay)

• Because teeth do not shed surface cells, microorganisms and their products can accumulate, causing dental plaque.

• Dental plaque are a type of biofilm and involved in dental caries.

• Probably, the most important cariogenic (caries causing) bacterium is Streptococcus mutans, which is capable of metabolizing a wide range of carbohydrates.

Periodontal diseases

Gingivitis( اللثة التهاب ):

• Is the inflammation of the gum or gingiva.

• Characterized by bleeding of the gum while the

teeth are being brushed.

• An assortment of streptococci, actinomycetes,

and anaerobic gram-negative bacteria

predominate in these infections.

Periodonitis:

• Is a chronic gingivitis.

– The gum is inflamed and bleed easily.

– Pus sometimes forms in periodontal pockets.

– Bone and tissue that support the teeth are destroyed, leading to loosening or loss of the teeth.

– Porphyromonas spp is important agent found in these conditions.

Acute necrotizing ulcerative gingivitis:

• Is also termed Vincent’s disease or trench mouth

• Is one of the more common serious mouth infection

• The normal chewing is difficult, and there is foul smell.

• Up to 24% of the cases are associated with prevotella intermedia (anaerobic GNR)

Thrush (oral Candida infection)

• Candida spp. can invade the oral mucosa.

• Immunocompromized patients may develop candidiasis.

• Thrush is suspected if whitish patches of exudate on an area of inflammation are observed on buccal (cheek) mucosa, tongue, or oropharynx.