What are the treatment guidelines for bacterial conjunctivitis in a general adult population?

Treatment Guidelines for Bacterial Conjunctivitis

First-Line Treatment Recommendation

For uncomplicated bacterial conjunctivitis in adults, prescribe topical moxifloxacin 0.5% three times daily for 5-7 days, which provides superior gram-positive coverage including activity against some MRSA strains and covers all common pathogens. 1, 2

Treatment Algorithm by Clinical Presentation

Mild Bacterial Conjunctivitis (Minimal discharge, mild injection)

• Topical moxifloxacin 0.5% one drop three times daily for 5-7 days 1, 2
• Alternative options if moxifloxacin unavailable:
  • Gatifloxacin 0.3% 1, 3
  • Ofloxacin 0.3% four times daily 1
  • Polymyxin B/trimethoprim four times daily 4
• Note: Mild bacterial conjunctivitis is self-limited and resolves spontaneously in 64% of cases by days 6-10, but topical antibiotics provide earlier clinical remission (68.2% cure rate vs 55.5% placebo by days 4-9) and allow faster return to work/school 1, 4

Moderate to Severe Bacterial Conjunctivitis (Copious purulent discharge, marked inflammation, pain)

• Obtain conjunctival cultures and Gram staining BEFORE initiating treatment 1, 4, 5
• Start topical moxifloxacin 0.5% three times daily while awaiting culture results 1, 2
• Consider MRSA if patient is from nursing home or has community-acquired infection 1
• If no improvement in 48-72 hours and MRSA suspected, switch to compounded topical vancomycin 1, 4

Special Pathogens Requiring Systemic Therapy

Gonococcal Conjunctivitis:

• Ceftriaxone 250 mg IM single dose PLUS azithromycin 1 g oral single dose 1, 4
• Add topical therapy and saline lavage 4
• Daily monitoring until resolution is mandatory 1
• Obtain cultures before treatment 1, 5
• Screen for concurrent genital infections and treat sexual partners 1

Chlamydial Conjunctivitis:

• Azithromycin 1 g oral single dose OR doxycycline 100 mg oral twice daily for 7 days 1, 4
• Topical therapy provides no additional benefit 4
• Screen for concurrent genital infections and treat sexual partners 1
• In pregnancy, use azithromycin or erythromycin (avoid doxycycline) 1

Antibiotic Selection Rationale

Fourth-generation fluoroquinolones (moxifloxacin, gatifloxacin) are preferred because:

• Superior gram-positive coverage including some MRSA strains 1, 4
• Effective against S. aureus, S. pneumoniae, H. influenzae, and Chlamydia trachomatis 1, 2
• Three times daily dosing improves compliance compared to older agents 2
• Microbiological eradication rates of 84-94% 1

No single antibiotic demonstrates superiority over others for uncomplicated cases, so choice can be based on dosing convenience, cost, and local resistance patterns 1, 4

Critical Red Flags Requiring Immediate Ophthalmology Referral

• Visual loss 1, 4, 5
• Moderate to severe pain 1, 4, 5
• Severe purulent discharge 1, 4, 5
• Corneal involvement (infiltrate, ulcer, opacity) 1, 4, 5
• Conjunctival scarring 1, 4
• No improvement after 3-4 days of appropriate therapy 1, 4, 5
• History of HSV eye disease 1, 5
• Immunocompromised state 1, 4
• Suspected gonococcal or chlamydial infection 1, 4

Important Clinical Pitfalls to Avoid

Do NOT use topical antibiotics for viral conjunctivitis:

• Viral conjunctivitis is the most common cause of infectious conjunctivitis overall 6
• Antibiotics provide no benefit and contribute to resistance 1, 6
• Viral conjunctivitis requires only supportive care with artificial tears and cold compresses 1, 5

Do NOT use topical corticosteroids without ophthalmology supervision:

• Corticosteroids prolong adenoviral infections 1
• Corticosteroids potentiate HSV infection and are absolutely contraindicated in HSV conjunctivitis without antiviral coverage 1, 5
• If used for severe adenoviral complications, monitor intraocular pressure and for cataract formation 1

Do NOT use oral antibiotics for routine bacterial conjunctivitis:

• Oral antibiotics are reserved exclusively for gonococcal and chlamydial conjunctivitis 1, 4
• Unnecessary systemic exposure promotes resistance and causes adverse effects 1

Consider sexual abuse in children with gonococcal or chlamydial conjunctivitis 1, 4, 5

Infection Control Measures

• Strict hand hygiene with soap and water 1, 4
• Avoid close contact for 7-14 days in viral conjunctivitis 1
• Discard multiple-dose eyedrop containers to avoid cross-contamination 1
• Advise patients to avoid sharing towels and avoid eye rubbing 4
• Do NOT wear contact lenses during treatment 1, 2

Follow-Up Protocol

• Return in 3-4 days if no improvement 1, 4, 5
• At follow-up: perform visual acuity measurement and slit-lamp biomicroscopy 4, 5
• Signs of positive response include reduced pain/discharge, lessened eyelid edema, and decreased conjunctival injection 1, 4

Geographic Resistance Considerations

Be aware that resistance patterns vary significantly by region:

• In southern India, Pseudomonas aeruginosa resistance to moxifloxacin increased from 19% to 52% between 2007-2009 1
• MRSA isolates show 42% concurrent resistance to fluoroquinolones 1
• Individual risk factors for fluoroquinolone resistance include recent fluoroquinolone use, hospitalization, advanced age, and recent ocular surgery 1