What antibiotic is used to treat bacterial eye infections?

Antibiotics for Bacterial Eye Infections

For bacterial eye infections, topical broad-spectrum antibiotics including gentamicin, tetracycline, and ofloxacin are recommended as first-line treatments, with the specific choice depending on the type and severity of infection. 1

Types of Bacterial Eye Infections and Treatment Options

Bacterial Conjunctivitis

• First-line treatment: Topical broad-spectrum antibiotics for 5-7 days 1

  • Gentamicin ophthalmic solution (effective against Staphylococcus aureus, Streptococcus species, Enterobacter, E. coli, Haemophilus influenzae, Klebsiella, Pseudomonas, and other gram-negative bacteria) 2
  • Tetracycline ophthalmic ointment
  • Ofloxacin ophthalmic solution
  • Polymyxin B-trimethoprim ophthalmic solution
  • Moxifloxacin 0.5% ophthalmic solution

• Administration:

  • Apply 1-2 drops every 2-4 hours initially
  • Continue until resolution of discharge, no more matting of eyelids, and reduction in conjunctival injection
  • Ointments may be useful at bedtime but have limited corneal penetration 1

Bacterial Keratitis

• For central/severe keratitis:

  • Topical fluoroquinolones (preferred for most cases) 3
  • Loading dose every 5-15 minutes followed by hourly applications
  • For lesions near limbus, consider additional systemic antibiotics

• For mild/peripheral keratitis:

  • Topical fluoroquinolones with less frequent dosing

Endophthalmitis

• Recommended treatment: 3
  • Intravitreal: ceftazidime plus vancomycin
  • Systemic: ceftriaxone plus vancomycin

Special Considerations

Contact Lens Wearers

• Higher risk for Pseudomonas infections
• Discontinue lens wear until infection resolves 1
• Consider tobramycin for broader coverage against Pseudomonas 4
• Prophylactic antibiotics should be prescribed for contact lens wearers with corneal abrasions 3

Corneal Abrasions

• Broad-spectrum topical antibiotic recommended for any corneal abrasion following trauma 3
• Avoid patching or therapeutic contact lens in contact lens-associated abrasions 3

Neonatal Conjunctivitis

• Requires immediate referral as it may indicate serious infections 1
• For gonococcal conjunctivitis: both systemic (ceftriaxone) and topical therapy
• For chlamydial conjunctivitis: systemic therapy (azithromycin, doxycycline, or levofloxacin)

When to Refer to an Ophthalmologist

• No improvement after 3-4 days of treatment
• Moderate to severe pain
• Decreased vision
• Corneal involvement
• Recurrent episodes
• History of herpes simplex virus eye disease
• Immunocompromised patients 1

Important Cautions

• Antibiotic resistance: Increasing resistance to fluoroquinolones has been reported, particularly in MRSA isolates 1
• Self-limiting nature: 41% of bacterial conjunctivitis cases resolve without antibiotics by days 6-10, but treatment speeds resolution and reduces complications 1
• Hygiene measures: Frequent handwashing, avoiding sharing towels and pillowcases, and proper disinfection of surfaces are essential to prevent spread 1

Pitfalls to Avoid

1. Using fluoroquinolones indiscriminately for mild cases (reserve for severe infections to prevent resistance)
2. Failing to distinguish between viral and bacterial conjunctivitis before starting antibiotics
3. Inadequate treatment duration leading to recurrence
4. Overlooking underlying conditions that may predispose to recurrent infections
5. Not considering local resistance patterns when selecting antibiotics

Remember that bacterial conjunctivitis is often self-limiting, but antibiotic treatment speeds resolution of symptoms and reduces the risk of complications and spread to others.