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Bacterial Conjunctivitis - Causes, Routes of Transmission, Symptoms, and Management

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Bacterial conjunctivitis is the most common and challenging disorder affecting the eye. Read about bacterial conjunctivitis and its empiric therapy below.

Written by

Dr. A. Srividya

Medically reviewed by

Dr. Prashant Koranmath

Published At December 9, 2022
Reviewed AtJune 9, 2023


Conjunctivitis or pink eye is inflammation and infection of the eye's conjunctiva. Conjunctiva is the thin transparent layer inside the eye covering the eye's white opaque (sclera). It consists of two parts; the bulbar conjunctiva and the palpebral conjunctiva. Bulbar conjunctiva covers the visible part of the sclera, and palpebral conjunctiva lines the inside of the eyelids. Conjunctivitis is viral, allergic, or bacterial in origin. Bacterial conjunctivitis is the most common infectious disease affecting children and is associated with raised morbidity. General practitioners encounter around one to four percent of patients suffering from conjunctivitis.

What Causes Bacterial Conjunctivitis?

Bacterial conjunctivitis is linked to several bacterial organisms. Children suffering from bacterial conjunctivitis are affected by Haemophilus influenzae. Bacterial conjunctivitis in adults is caused by Haemophilus influenzae and Streptococcus species. Recently, Methicillin-resistant Staphylococcus aureus-induced conjunctivitis has been on the rise. Neonates suffer from conjunctivitis induced by Neisseria gonorrhoeae and Chlamydia trachomatis. In addition, Pseudomonas aeruginosa causes conjunctivitis in hospitalized patients.

Bacterial conjunctivitis is formed due to the bacteria's direct invasion of the eye's conjunctival layer. Bacterial invasion and compromise of the host's immunity lead to the dilation of the blood vessels of the conjunctiva. Hence, this causes swelling and redness of the conjunctiva.

What Are the Routes of Transmission of the Bacteria Causing Conjunctivitis?

The transfer of the bacteria from an infected person to the unaffected occurs through the following routes -

  • Direct transfer from infected persons.

  • Inanimate objects.

  • Sexual transmission.

  • Mother to child.

What Are the Most Common Risk Factors That Aggravate the Spread of Bacterial Conjunctivitis?

There are several risk factors linked to bacterial conjunctivitis spread. The factors include the following -

  • Lack of tears.

  • Immunocompromised people.

  • Adnexal structure trauma (trauma to structures supporting and protecting eyes).

What Are the Different Types of Bacterial Conjunctivitis?

Based on the time of onset, bacterial conjunctivitis is of three types:

  • Hyperacute - This type is commonly found in patients affected by N. Gonorrhea. The infection onset is rapid and affected patients experience an exaggerated form of purulent discharge and conjunctival infection.

  • Acute - It is the most common type of bacterial conjunctivitis. The most common bacteria causing acute bacterial conjunctivitis include Streptococcus pneumoniae, Staphylococcus aureus, Chlamydia trachomatis, and Hemophilus influenzae.

  • Chronic - It is characterized by red eye with discharge persisting for a few weeks. It is generally caused by Chlamydia trachomatis.

What Are the Signs and Symptoms of Bacterial Conjunctivitis?

The onset of bacterial conjunctivitis's clinical signs and symptoms occurs within seven to ten days of exposure to the bacteria.

The typical clinical features presented by patients suffering from bacterial conjunctivitis are:

  • Red-eyes.

  • Pain loss.

  • Sensitivity to light.

  • Purulent discharge.

  • Glued eyelids.

  • Crustation.

  • Ear infections (otitis syndrome) are present in children with bacterial conjunctivitis.

A few clinical features are specific to particular organisms.

  • Chlamydial conjunctivitis patients present with redness of the eye. Genital lesions, mucous discharge, and the formation of lymphoid follicles also accompany the eye infection.

  • Gonococcal conjunctivitis is related to hyperacute conjunctivitis in neonates and sexually active adolescents. Eye swelling, tenderness, a copious discharge, and decreased vision characterize hyperacute conjunctivitis.

  • Chlamydia trachoma species cause trachoma conjunctivitis. It is one of the leading causes of blindness. Patients present with mucopurulent discharge and ocular discomfort. In later stages, there is scarring of the eyes.

How Are Patients With Bacterial Conjunctivitis Diagnosed?

The diagnosis of bacterial conjunctivitis mainly depends on detailed history and clinical examination.

  • Detailed history, like the duration of the lesion, its onset, and the presence of any other associated symptoms, specifically otic symptoms in children, is acquired to form a proper diagnosis of bacterial conjunctivitis.

  • Lab tests and radiography have limited use in diagnosing bacterial conjunctivitis.

  • The conjunctival discharge culture helps distinguish the organism, especially in recurrent lesions.

When Is the Right Time to Consult a Specialist?

Patients should consult a specialist if there is the persistence of the following signs and symptoms:

  • Vision loss.

  • Recurrent infections.

  • Severe pain.

  • Corneal involvement.

How Are the Treatment Options for Bacterial Conjunctivitis?

The natural course of the condition gets resolved within a week without any specific treatment. However, managing bacterial conjunctivitis involves empirical management approaches and organism-specific management of the disease.

Empirical Management of Bacterial Conjunctivitis:

  • Bacterial conjunctivitis is usually treated with antibiotic eye drops or ointments.

  • Broad-spectrum antibiotics are preferred and known to reduce the transmission rate, decrease symptoms and hasten the resolution of the lesion.

  • Topical antibiotics are prescribed in acute cases, such as Erythromycin, Aminoglycosides, Fluoroquinolones, and Polymyxin B.

  • Oral antibiotics are prescribed in children with associated otitis symptoms and adults with Chlamydia infections.

Organ-Specific Treatment of Bacterial Conjunctivitis:

  • Conjunctivitis caused by Hemophilus influenza, Staphylococcus aureus, and Streptococcus pneumonia is treated with topical antibiotics like Erythromycin, Polymyxin B, Gatifloxacin, Azithromycin, and Ciprofloxacin drops, two to four times per day for a week.

  • Gonococcal conjunctivitis is treated with a single dose of Ceftriaxone injection.

  • Chlamydial infections mainly affect newborns. Therefore, newborns and those at risk of contact are treated systemically with Erythromycin and Doxycyclin tablets for a week.

Bacterial conjunctivitis can be managed by following a wait-and-watch approach or treating it with antibiotic therapy. Situations that warrant the use of antibiotic therapy for treating bacterial conjunctivitis include:

  • Mucopurulent (thick and cloudy) discharge.

  • Contact lens wearers.

  • Immunocompromised patients.

  • Chlamydial and gonococcal infections.

Most bacterial conjunctivitis cases resolve spontaneously or after antibiotic therapy without adverse effects.

How to Prevent Bacterial Conjunctivitis?

The team effort of healthcare professionals for patient education can prevent the condition.

  • Patients are educated about the disease and its complications.

  • Patients are instructed about maintaining good hands and sexual hygiene to avoid spreading the disease.

  • Regular follow-up after a lack of progress after the treatment is a must.

  • Interprofessional cooperation in prompt diagnosis and referral will help the earlier management of the condition.

What Are the Conditions That Mimic Bacterial Conjunctivitis?

Conditions that are to be considered before forming a conclusive diagnosis of bacterial conjunctivitis are:

  • Allergic Conjunctivitis - Allergic conjunctivitis is the inflammation of the eyes due to an allergy to substances such as pollens.

  • Viral Conjunctivitis - Adenovirus causes this eye infection.

  • Keratitis - It is the inflammation of the cornea, the clear tissue in the front of the eye.

  • Iridocyclitis - This condition is the inflammation of two parts of the eye called the iris and ciliary body occurs.

The main feature differentiating bacterial conjunctivitis from others is the lack of clear discharge and a history of itching. Itching and clear discharge are features of viral and allergic conjunctivitis.

What Are the Complications Associated With Bacterial Conjunctivitis?

Bacterial conjunctivitis rarely is associated with complications of the eye. However, some severe infections can lead to the following complications:

  • Keratitis.

  • Perforations in the cornea.

  • Ulcerations in the cornea.

  • Chronic irritation, redness, and discharge from the eyes.

  • Blindness.


Bacterial conjunctivitis is the most common eye infection, often proving a challenge to physicians in treating the condition. The rampant use of antibiotics and antibiotic-resistant forms further complicates the disease's treatment protocol. Early diagnosis and referral to the specialist will help rapidly resolve the condition.

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Dr. Prashant Koranmath
Dr. Prashant Koranmath

Ophthalmology (Eye Care)


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