What is the recommended treatment for a patient with 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 clinical evidence suggests superiority of any particular agent. 1, 2

Initial Assessment and Red Flags

Before initiating treatment, evaluate for features requiring immediate ophthalmology referral:

• Visual loss, moderate to severe pain, or severe purulent discharge 1
• Corneal involvement or conjunctival scarring 1
• Lack of response after 3-4 days of appropriate therapy 1
• Immunocompromised state or history of HSV eye disease 1
• Neonatal conjunctivitis (requires mandatory hospitalization) 1

For moderate to severe cases with copious purulent discharge, pain, and marked inflammation, obtain conjunctival cultures and Gram staining before initiating treatment, especially if gonococcal infection is suspected. 1, 2

First-Line Antibiotic Selection

For Mild Cases (Typical Community-Acquired)

Choose based on convenience and cost, as efficacy is equivalent among options: 1

• Fluoroquinolones (moxifloxacin, gatifloxacin): Effective against S. aureus, S. pneumoniae, and H. influenzae 1
• Aminoglycosides (tobramycin, gentamicin): Effective against common bacterial pathogens 3, 1
• Polymyxin B/trimethoprim: Alternative broad-spectrum option 1
• Bacitracin ointment: Apply 1-3 times daily directly into conjunctival sac 4

Important caveat: Reserve fluoroquinolones for moderate to severe cases or contact lens wearers at higher risk for Pseudomonas infection to minimize resistance development. 1

For Contact Lens Wearers

Fluoroquinolones are mandatory due to higher risk of Pseudomonas infection. 1

For Suspected MRSA

Fourth-generation fluoroquinolones (moxifloxacin, gatifloxacin) have better gram-positive coverage including some MRSA strains, though fluoroquinolones are generally poorly effective against MRSA ocular isolates. 1 Compounded topical vancomycin may be required for confirmed MRSA, as these organisms are resistant to fluoroquinolones and aminoglycosides but susceptible to vancomycin. 1, 2

Special Situations Requiring Systemic Therapy

Gonococcal Conjunctivitis

Topical antibiotics alone are insufficient. 3, 1

• Adults: Ceftriaxone 1 g IM single dose PLUS azithromycin 1 g orally single dose 1
• Add saline lavage to promote comfort and faster resolution 1
• Daily follow-up until resolution 2
• If corneal involvement present, treat as bacterial keratitis 2

Chlamydial Conjunctivitis

Systemic therapy is required, especially in infants who may have infection at other sites. 3, 1

• Neonates: Erythromycin base or ethylsuccinate 50 mg/kg/day divided into 4 doses for 14 days (clinical cure rate 96%, microbiological cure 97%) 1
• Follow-up evaluation is critical as treatment failure occurs in up to 19% of cases 2
• Consider sexual abuse in children with gonococcal or chlamydial infections 3, 2

Alternative Treatment Options

Povidone-iodine 1.25% ophthalmic solution may be as effective as topical antibiotics and can be considered when access to antibiotics is limited. 3, 1

Treatment Duration and Follow-Up

• Standard duration: 5-7 days of 4 times daily application 3, 1, 2
• Topical antibiotics accelerate clinical and microbiological remission in days 2-5, reduce transmissibility, and allow earlier return to school/work 1, 2
• Return for follow-up if no improvement after 3-4 days 3, 1
• Follow-up should include interval history, visual acuity measurement, and slit-lamp biomicroscopy 3, 1

Critical Pitfalls to Avoid

• Never use topical corticosteroids unless under close ophthalmology supervision, as they may prolong bacterial shedding and worsen infection 3
• Do not prescribe antibiotics for viral conjunctivitis, which promotes unnecessary costs and resistance 1
• Antihistamines provide no benefit in bacterial conjunctivitis, as symptoms are inflammatory rather than histamine-mediated 1
• Increasing bacterial resistance is a major concern, particularly with MRSA 3, 2
• In neonatal ICU settings, gram-negative conjunctivitis is often resistant to gentamicin, particularly in low birth weight infants 1

Infection Control Counseling

Advise patients on: 3, 1

• Frequent hand washing
• Avoiding eye rubbing
• Using separate towels
• Avoiding sharing personal items
• Avoiding close contact during contagious period

Recurrent Infections

Patients with recurrent infections may benefit from decolonization strategies in addition to topical antibiotics, as S. aureus colonization of the nasopharynx, oropharynx, and ocular surface may be the source. 1