What is the recommended treatment for bacterial conjunctivitis?

Treatment of Bacterial Conjunctivitis

For mild bacterial conjunctivitis, prescribe a 5-7 day course of broad-spectrum topical antibiotic applied 4 times daily, with the most convenient or least expensive option being appropriate as no specific antibiotic has proven superiority. 1, 2

Treatment Algorithm Based on Severity

Mild Bacterial Conjunctivitis

Topical antibiotics are recommended even for mild cases because they accelerate clinical and microbiological remission by days 2-5, reduce transmissibility, and allow earlier return to school or work. 1, 2 While mild bacterial conjunctivitis is self-limited and may resolve spontaneously in immunocompetent adults, the shortened morbidity associated with antibiotic use justifies treatment. 3, 2

Recommended antibiotic options include:

• Fluoroquinolones (moxifloxacin, gatifloxacin) - effective against common pathogens 1, 4
• Aminoglycosides (tobramycin, gentamicin) 1, 4
• Polymyxin B/trimethoprim 1
• Azithromycin ophthalmic solution - dosed twice daily for 2 days, then once daily for 5 days 5

Alternative when antibiotic access is limited: Povidone-iodine 1.25% ophthalmic solution may be as effective as topical antibiotics. 1, 2

Moderate to Severe Bacterial Conjunctivitis

Obtain conjunctival cultures and Gram staining before initiating treatment, especially if gonococcal infection is suspected based on copious purulent discharge, pain, and marked inflammation. 3, 1, 4 The choice of antibiotic should be guided by laboratory results. 3, 2

Critical consideration: Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly isolated from bacterial conjunctivitis and is resistant to many commercially available topical antibiotics. 3, 2 Microbiology testing may guide therapy, which may require compounded topical vancomycin. 3, 1

Special Pathogen-Specific Treatment

Gonococcal Conjunctivitis

Systemic antibiotic therapy is mandatory - topical treatment alone is insufficient. 3, 1, 4 Initiate systemic therapy when there is high clinical suspicion, even before obtaining culture results. 3

Additional management:

• Saline lavage promotes comfort and faster resolution 3, 1
• If corneal involvement is present, treat topically as for bacterial keratitis 3, 2
• Daily follow-up until resolution is required 3, 2
• Eliminate N. meningitidis as causative organism before concluding N. gonorrhoeae is responsible 3
• Evaluate and treat sexual contacts; consider sexual abuse in children 3, 4

Chlamydial Conjunctivitis

Systemic antibiotic therapy is required because more than 50% of infants with chlamydial conjunctivitis may have infection at other sites (nasopharynx, genital tract, lungs). 3, 1 There is no evidence supporting additional topical therapy beyond systemic treatment. 3, 1

For neonates: Erythromycin base or ethylsuccinate 50 mg/kg/day divided into four doses daily for 14 days, with clinical cure rates of 96% and microbiological cure rates of 97%. 1

Important caveat: Treatment failure can occur in up to 19% of cases, so re-evaluation following treatment is essential. 3, 2 Evaluate and treat sexual contacts; consider sexual abuse in children. 3, 4

Follow-Up and Monitoring

Advise patients to return in 3-4 days if no improvement is noted. 3, 1, 4 Follow-up visits should include interval history, visual acuity measurement, and slit-lamp biomicroscopy. 3, 4

When to Refer to Ophthalmology

Immediate referral is indicated for:

• Visual loss 1, 4
• Moderate or severe pain 1, 4
• Severe purulent discharge 1, 4
• Corneal involvement 1, 4
• Conjunctival scarring 1, 4
• Lack of response to therapy 1, 4
• Recurrent episodes 1, 4

Hospitalization may be necessary for severe gonococcal conjunctivitis and is mandatory for neonatal conjunctivitis. 1

Critical Pitfalls to Avoid

Bacterial resistance is a growing concern, particularly with MRSA infections, and poor adherence to frequent administration regimens contributes to treatment failure. 1, 2 To prevent antibiotic resistance, avoid prolonged continuous use and consider intermittent treatment with different antibiotics having different mechanisms of action. 1

Avoid contaminating the applicator tip by not allowing it to touch the eye, fingers, or other sources. 5

Do not use topical corticosteroids unless under close ophthalmologic supervision, as they may prolong bacterial shedding and worsen infection. 4

Advise patients not to wear contact lenses if they have signs or symptoms of bacterial conjunctivitis. 5