What are the guidelines for treating antibiotic-resistant bacterial conjunctivitis?

Treatment Guidelines for Antibiotic-Resistant Bacterial Conjunctivitis

For antibiotic-resistant bacterial conjunctivitis, combination fortified-antibiotic therapy is recommended, especially for severe infections and eyes unresponsive to initial treatment. 1

Identification of Resistant Organisms

• Methicillin-resistant Staphylococcus aureus (MRSA): Increasingly common in bacterial conjunctivitis

  • Fluoroquinolones are generally poorly effective against MRSA ocular isolates 1
  • MRSA isolates are typically susceptible to vancomycin 1

• Resistant Pseudomonas aeruginosa: Associated with high morbidity

  • Increasing resistance to moxifloxacin (from 19% in 2007 to 52% in 2009 in southern India) 1
  • A 20-year study in San Francisco found increasing overall resistance to moxifloxacin from 1996 to 2015 1

Treatment Algorithm for Antibiotic-Resistant Bacterial Conjunctivitis

1. For MRSA Conjunctivitis:

• First-line: Topical vancomycin (fortified)

  • MRSA isolates are generally susceptible to vancomycin 1
  • Should be prepared by an accredited compounding pharmacy (Pharmacy Compounding Accreditation Board member designated by FDA as 503A/503B facility) 1

• For vancomycin-resistant enterococcus:

  • Topical linezolid can be used with no ocular surface toxicity 1

2. For Resistant Pseudomonas aeruginosa:

• Consider: Topical colistin 0.19% 1

3. For Recurrent Bacterial Conjunctivitis:

• More likely to be caused by S. aureus 1
• Consider treatments to decolonize S. aureus from nasopharynx, oropharynx, and ocular surface 1

4. For Moraxella Conjunctivitis:

• Usually susceptible to fluoroquinolones and aminoglycosides
• Requires more prolonged treatment duration (mean 41.9 days) 1

Monitoring and Follow-up

• Severe cases should be followed daily initially until stable or clinical improvement is confirmed 1
• Treatment should continue until resolution of discharge, no more matting of eyelids in the morning, and reduction in conjunctival injection 2

Important Considerations and Pitfalls

Pitfall #1: Inappropriate Fluoroquinolone Selection

• Despite widespread use, fourth-generation fluoroquinolones (moxifloxacin, gatifloxacin) are not FDA-approved for bacterial keratitis 1
• Besifloxacin 0.6% has been established as a potent treatment for bacterial conjunctivitis with potency against ocular pathogens similar to fourth-generation agents 1, 3
• Besifloxacin may have better coverage over ciprofloxacin and methicillin-resistant staphylococci than other fluoroquinolones 1

Pitfall #2: Inadequate Preparation of Fortified Antibiotics

• Fortified antibiotics should be prepared by an accredited compounding pharmacy 1
• Improper preparation can lead to treatment failure or toxicity

Pitfall #3: Failure to Consider Systemic Antibiotics When Needed

• Systemic antibiotics are rarely needed but may be considered in severe cases where:
  • Infection has extended to adjacent tissues (e.g., sclera)
  • Impending or frank perforation of the cornea exists
  • Gonococcal infection is present (systemic therapy is necessary) 1

Pitfall #4: Inappropriate Use of Corticosteroids

• Topical corticosteroid therapy may have a beneficial role in some cases of microbial keratitis
• However, potential disadvantages include recurrence of infection, local immunosuppression, inhibition of collagen synthesis predisposing to corneal melting, and increased intraocular pressure 1
• Should be used with caution and only after appropriate antibiotic coverage is established

By following these guidelines and considering the specific resistant organism, clinicians can effectively manage antibiotic-resistant bacterial conjunctivitis while minimizing complications and improving outcomes.