Intrastromal Antibiotic Injection in Polymicrobial Keratitis: Case Report and Literature Review

Abstract

Bacterial keratitis (corneal infection) caused by more than one organism is rare and exceedingly difficult to treat due to variable antibiotic susceptibilities. Intrastromal injections of antibiotics may be necessary to achieve higher drug concentrations at the site of infection, particularly in the case of deep stromal disease refractory to topical therapy. However, while this approach is increasingly used for fungal keratitis, there is a paucity of the literature regarding the use of intrastromal antibiotics bacterial keratitis. In the current case, an 86-year-old patient presented with a left corneal ulcer with corresponding microbiologic cultures positive for <i>Staphylococcus epidermidis</i>, <i>Staphylococcus aureus</i>, and <i>Achromobacter</i> species. The ulcer continued to progress despite maximal topical antibiotic treatment yet demonstrated marked improvement after two intrastromal injections of moxifloxacin administered 2 weeks apart. Polymicrobial keratitis can be particularly challenging to eradicate despite maximal topical antibiotic therapeutics. Intrastromal corneal injections provide a mechanism for drug delivery directly to the site of infection and thus may represent an important alternative in refractory cases.

Alternative Treatment Approaches in Bacterial Keratitis

“…When topical treatment failed to treat the keratitis, a new strategy was used and 0.2 mL of 0.5% moxifloxacin was administered intrastromally, precisely at the edge of the infiltrate. The study explained that the complete remission of the keratitis was accomplished with the first dose at the initial and the second dose after 2 weeks [24].…”

Intrastromal Injections in the Management of Infectious Keratitis

“…After six months, the keratitis became dormant, and five years later, there was no sign of a recurrence [27]. Pak et al recently described for the first time in the literature a triplebacterial keratitis caused by penicillin-resistant S. aureus, pan-sensitive S. epidermidis, and Achromobactin species with unknown antibiotic sensitivities treated successfully with intrastromal antibiotic injection [30]. When topical treatment failed to treat the keratitis, a new strategy was used and 0.2 mL of 0.5% moxifloxacin was administered intrastromally, precisely at the edge of the infiltrate.…”

“…When topical treatment failed to treat the keratitis, a new strategy was used and 0.2 mL of 0.5% moxifloxacin was administered intrastromally, precisely at the edge of the infiltrate. Five days after the first injection, there was some improvement, but unsatisfactory, so it was decided to administer the second injection with the same dose 2 weeks later, resulting in complete remission of the keratitis [30].…”