What is the recommended treatment for a patient with bacterial conjunctivitis?

Treatment of Bacterial Conjunctivitis

For bacterial conjunctivitis, initiate a 5-7 day course of broad-spectrum topical antibiotic applied 4 times daily, with fluoroquinolones (moxifloxacin, gatifloxacin) or aminoglycosides (tobramycin) as first-line options for typical community-acquired cases. 1, 2

Severity-Based Treatment Algorithm

Mild Bacterial Conjunctivitis

• Mild cases are self-limited but topical antibiotics accelerate clinical and microbiological remission in days 2-5, reduce transmissibility, and allow earlier return to school/work 1, 2, 3
• Choose the most convenient or least expensive broad-spectrum antibiotic for 5-7 days, as no clinical evidence suggests superiority of any particular agent in uncomplicated cases 1, 3
• Acceptable first-line options include:
  • Fluoroquinolones (moxifloxacin 0.5%, gatifloxacin 0.5%) - superior gram-positive coverage including some MRSA strains 2, 3
  • Aminoglycosides (tobramycin 0.3%) - effective against common pathogens 2, 3, 4
  • Azithromycin 1.5% - convenient twice-daily dosing for 3 days (total 6 drops) with non-inferior efficacy to tobramycin 5, 6, 7
  • Polymyxin B/trimethoprim - cost-effective alternative 3
• Povidone-iodine 1.25% ophthalmic solution may be as effective as topical antibiotics when access to antibiotics is limited 1, 3

Moderate to Severe Bacterial Conjunctivitis

• Characterized by copious purulent discharge, pain, and marked inflammation 1, 2
• Obtain conjunctival cultures and Gram staining BEFORE initiating treatment, especially if gonococcal infection is suspected 1, 2, 3
• Initiate empiric broad-spectrum fluoroquinolone therapy while awaiting culture results 3
• Fourth-generation fluoroquinolones (moxifloxacin, gatifloxacin) have superior gram-positive coverage including some MRSA strains 3

Special Populations and Circumstances

Contact Lens Wearers

• Reserve fluoroquinolones (ofloxacin, ciprofloxacin, moxifloxacin) for contact lens wearers due to higher risk of Pseudomonas infection 3

MRSA Conjunctivitis

• MRSA isolates are increasingly common and resistant to most commercially available topical antibiotics including aminoglycosides and fluoroquinolones 1, 3
• May require compounded topical vancomycin, as MRSA is generally susceptible to vancomycin 3
• Consider decolonization strategies for patients with recurrent infections, as S. aureus colonization of nasopharynx and ocular surface may be the source 3

Gonococcal Conjunctivitis

• Requires systemic antibiotic therapy, NOT topical treatment alone 1, 2, 3
• Adults: Ceftriaxone 1 g IM single dose PLUS azithromycin 1 g orally single dose 1, 3
• Add saline lavage to promote comfort and faster resolution of inflammation 3
• Children weighing ≤45 kg: Ceftriaxone 25-50 mg/kg IV or IM, single dose, not to exceed 250 mg 1
• Consider sexual abuse in preadolescent children with gonococcal infection 1, 3

Chlamydial Conjunctivitis

• Requires systemic antibiotic therapy, NOT topical treatment alone 1, 2, 3
• Adults: Azithromycin 1 g orally single dose OR doxycycline 100 mg orally twice daily for 7 days 1
• Neonates: Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into 4 doses for 14 days 1
• Monitor infants treated with erythromycin for signs of infantile hypertrophic pyloric stenosis 1
• Children ≥8 years: Azithromycin 1 g orally single dose OR doxycycline 100 mg orally twice daily for 7 days 1

Neonatal Conjunctivitis (Ophthalmia Neonatorum)

• Gonococcal: Ceftriaxone 25-50 mg/kg IV or IM, single dose, not to exceed 250 mg 1
• Chlamydial: Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into 4 doses for 14 days 1
• Ocular prophylaxis at birth: Erythromycin 0.5% ophthalmic ointment in each eye in single application 1

Administration and Compliance

Dosing Regimens

• Standard regimen: 1 drop 4 times daily for 5-7 days 1, 2, 3
• Azithromycin 1.5%: 1 drop twice daily (8-12 hours apart) for 2 days, then once daily for 5 days 5, 6, 7
• Do NOT taper doses below 3-4 times daily, as subtherapeutic doses increase antibiotic resistance risk 3

Patient Instructions

• Wash hands before instillation 5
• Avoid contaminating the applicator tip by not allowing it to touch the eye, fingers, or other surfaces 5
• Do NOT wear contact lenses during treatment 5
• Complete the full course even if symptoms improve to prevent resistance development 5

Infection Control Measures

• Counsel on strict hand hygiene and frequent hand washing 2, 3, 8
• Avoid sharing towels, pillowcases, and makeup 8
• Avoid eye rubbing and close contact during contagious period 3
• Use separate towels from family members 2

Follow-Up and Monitoring

Return Visit Criteria

• Advise patients to return if no improvement after 3-4 days of treatment 1, 2, 3, 8
• Follow-up should include interval history, visual acuity measurement, and slit-lamp biomicroscopy 2, 3, 8

Red Flags Requiring Immediate Ophthalmology Referral

• Visual loss 2, 3
• Moderate to severe pain 2, 3
• Severe purulent discharge 2, 3
• Corneal involvement 2, 3
• Conjunctival scarring 2, 3
• Lack of response to therapy after 3-4 days 2, 3
• Recurrent episodes 2, 3
• Immunocompromised state 3

Critical Pitfalls to Avoid

Corticosteroid Use

• Avoid topical corticosteroids unless under close ophthalmology supervision, as they may prolong bacterial shedding and worsen infection 2, 8
• If severe inflammation with marked chemosis or eyelid swelling requires corticosteroids, perform baseline and periodic intraocular pressure measurements 3

Antibiotic Resistance

• Avoid prescribing antibiotics for viral conjunctivitis, which promotes unnecessary resistance 3
• Bacterial resistance is increasing, particularly with MRSA 1, 3, 9
• Poor adherence to frequent administration regimens contributes to treatment failure and resistance 3, 9

Misdiagnosis

• Do NOT use antihistamines for bacterial conjunctivitis, as burning and itching are inflammatory symptoms from infection, not histamine-mediated allergic responses 3
• Distinguish from viral conjunctivitis, which does not require antibiotics 3