BACTERIAL CONJUNCTIVITIS

There has occurred a relative decrease in the incidence of bacterial conjunctivitis in general and those caused by gonococcus and corynebacterium diphtheriae in particular. However, in developing countries it still continues to be the commonest type of conjunctivitis. It can occur as sporadic cases and as epidemics. Outbreaks of bacterial conjunctivitis epidemics are quite frequent during monsoon season.

Etiology

A. Predisposing factors for bacterial conjunctivitis, especially epidemic forms, are flies, poor hygienic conditions, hot dry climate, poor sanitation and dirty habits. These factors help the infection to establish, as the disease is highly contagious.

B. Causative organisms. It may be caused by a wide range of organisms in the following approximate order of frequency :

• Staphylococcus aureus is the most common cause of bacterial conjunctivitis and blepharoconjunctivitis.
• Staphylococcus epidermidis is an innocuous flora of lid and conjunctiva. It can also produce blepharoconjunctivitis.

• Streptococcus pneumoniae (pneumococcus) produces acute conjunctivitis usually associated with petechial subconjunctival haemorrhages. The disease has a self-limiting course of 9-10 days.
• Streptococcus pyogenes (haemolyticus) is virulent and usually produces pseudomembranous conjunctivitis.
• Haemophilus influenzae (aegyptius, Koch- Weeks bacillus). It classically causes epidemics of mucopurulent conjunctivitis, known as ‘red-eye’ especially in semitropical countries.