We describe the
clinical course and successful treatment of two cases of methicillin-resistant Staphylococcus aureus (MRSA)
keratitis. In case 1, MRSA
keratitis occurred 5 days after
cataract extraction, associated with
endophthalmitis; in case 2, diagnosis was made 19 months after
penetrating keratoplasty. Treatment in both cases consisted of topical fortified
vancomycin and fortified
bacitracin. A third topical
antibiotic,
polymyxin B-
trimethoprim, was added to the therapeutic regimen in case 2, one month into the treatment. Oral
doxycycline was prescribed to reduce
collagenase activity and treat
blepharitis.
Mupirocin nasal
ointment and skin
antiseptics were used to decrease and eliminate potential MRSA colonization. Topical
prednisolone acetate 1% was applied conservatively to mitigate
inflammation in both cases. In case 2, topical
cyclosporine A was also used for similar purposes.
Keratitis may have worsened while on these immune-modulating drops, especially in case 2, and eradication of
infection may have been slowed. Eventually both patients achieved full resolution of
infection. Duration of
keratitis was 3 and 1.5 months, respectively. Polyantimicrobial
therapy is effective in eradicating MRSA-related postoperative
keratitis. Topical fortified
vancomycin and fortified
bacitracin were used in both cases, with a third topical
antibiotic,
polymyxin B-
trimethoprim, also required in case 2. Oral
doxycycline, nasal
mupirocin, and
antiseptic soap may be useful adjuncts in management. Treatment time to achieve full resolution may be prolonged relative to other types of bacterial
keratitis. Alterations in immune status may have lengthened the time of treatment. Our two patients were immune compromised and were also susceptible to
endophthalmitis. It is possible that topical immune-modulating drops such as
prednisolone acetate may potentiate MRSA
infection, and if used, should be only done so with great caution.