BACTERIAL CONJUNCTIVITIS for BSc Optometry

OCULAR MICROBIOLOGY

1. BACTERIAL CONJUNCTIVITIS

2. Definition:  Bacterial conjunctivitis is inflammation of the conjunctiva as a result of bacterial infection. Conjunctivitis, or pink eye , is an irritation or inflammation of the conjunctiva, which covers the white part of the eyeball. It can be caused by allergies or a bacterial or viral infection . Conjunctivitis can be extremely contagious and is spread by contact with eye secretions from someone who is infected.

3. Causative organisms Pathogens responsible for causing bacterial conjunctivitis include Neisseria species, Chlamydial species, Staphylococcus species, Haemophilus species, Streptococcus pneumoniae , and Moraxella species. Acute bacterial conjunctivitis is commonly caused by S. aureus , S. pneumoniae , and Haemophilus species. In children , Streptococcus and Haemophilus infections occur frequently.

4. Predisposing  factors Since these bacteria are usually spread from other infected inviduals , poor hygenic habits may increase the risk of infection  Poor contact lens hygiene , Contaminated cosmetics Crowded living or social conditions such elementary schools, military barracks etc Ocular diseases including dry eye, blepharitis, and anatomic abnormalities of the ocular surface and lids Chronic use of topical medications Immune compromise

5. According to  Mode of infection Exogenous infections may spread: • Directly through close contact, as airborne infections or as waterborne infections • Vector transmission (e.g., flies) • Material transfer such as infected fingers of doctors, nurses, common towels, handkerchiefs, and infected tonometers . 2. Local spread  may occur from neighboring structures such as infected lacrimal sac, lids, and nasopharynx.

6.  3. Endogenous infections may occur very rarely through blood, e.g., gonococcal and meningococcal infections.

7. CLINICAL TYPES OF  BACTERIAL CONJUNCTIVITIS Acute bacterial conjunctivitis, Hyperacute bacterial conjunctivitis, Chronic bacterial conjunctivitis, and Angular bacterial conjunctivitis.

8. Acute bacterial conjunctivitis Acute bacterial conjunctivitis is characterised by marked conjunctival hyperaemia and mucopurulent discharge from the eye. So, clinically, it is called acute mucopurulent conjunctivitis . It is the most common type of bacterial conjunctivitis.   COMPLICATIONS Marginal corneal  ulcer Superficial keratitis Blepharitis or dacryocystitis

9. HYPERACUTE CONJUNCTIVITIS OF ADULTS (GONOCOCCAL  CONJUNCTIVITIS) - Etiology The disease affects adults , predominantly males . Gonococcal infection directly spreads from genitals to eye. Presently, incidence of gonococcal conjunctivitis has markedly decreased. COMPLICATIONS 1 . Corneal involvement  - Diffuse haze and oedema, central necrosis, corneal ulceration or even perforation. 2. Iridocyclitis 3. Systemic complications - Gonorrhoea arthritis, endocarditis and septicaemia.

10. CHRONIC BACTERIAL  CONJUNCTIVITIS Chronic bacterial conjunctivitis is frequently associated with continuous inoculation of bacteria associated with blepharitis . The most common cause of chronic bacterial conjunctivitis is Staphylococcus aureus . Predisposing factors Chronic exposure to dust, smoke, and chemical irritants. Eye strain due to refractive errors, convergence insufficiency. Abuse of alcohol, insomnia and metabolic disorders.

11. ANGULAR BACTERIAL CONJUNCTIVITIS Predisposing  factors are same as for ‘simple chronic conjunctivitis’. Causative organisms Moraxella Axenfield (MA) is the commonest causative organism. MA bacilli are placed end to end, so the disease is also called ‘ diplobacillary conjunctivitis ’. Rarely, staphylococci may also cause angular conjunctivitis

12. TREATMENT Acute bacterial conjunctivitis is empirically treated with a broad-spectrum topical antibiotic . Treatment with a broad-spectrum topical antibiotic for five to seven days is usually effective. Aminoglycosides Gentamicin Tobramycin Chloramphenicol Fluoroquinolone Ciprofloxacin Ofloxacin Levofloxacin Polymyxin B/Neomycin Tetracycline

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