Toward Improving Therapeutic Regimens forBacillusEndophthalmitis

Abstract

Early intravitreal injection of vancomycin or gatifloxacin improved the therapeutic outcome of B. cereus endophthalmitis. The addition of dexamethasone to antibiotic treatment did not provide a therapeutic benefit over antibiotics alone and appeared to reduce the antibiotic efficacy of vancomycin 6 hours after infection. In this model, delay in treatment past 6 hours significantly reduced the potential for salvaging useful vision.

Unexpected Roles for Toll-Like Receptor 4 and TRIF in Intraocular Infection with Gram-Positive Bacteria

“…Typically, B. cereus endophthalmitis occurs following a penetrating eye injury (posttraumatic) with retained intraocular foreign bodies (7,8) but has also been reported in postoperative patients (9)(10)(11). Fewer than 30% of posttraumatic B. cereus endophthalmitis patients retained useful vision, and out of these, only 9% retained 20/70 vision or better (7,12). Moreover, 48% of B. cereus and other Bacillus species infections required evisceration or enucleation of the eye despite therapeutic intervention (7,12).…”

“…Fewer than 30% of posttraumatic B. cereus endophthalmitis patients retained useful vision, and out of these, only 9% retained 20/70 vision or better (7,12). Moreover, 48% of B. cereus and other Bacillus species infections required evisceration or enucleation of the eye despite therapeutic intervention (7,12). Intraocular inflammation that occurs during B. cereus endophthalmitis interferes with the clarity of the visual axis, contributing to disruptions in vision.…”

“…Characterizing the inflammatory pathways that intensify the infection will help in identifying targets for clinical use. This is especially important as current treatment regimens for B. cereus and other types of endophthalmitis involving the use of corticosteroids are often insufficient in arresting inflammation (12)(13)(14)(15)(16).…”

Efficacy of Vitrectomy in Improving the Outcome of Bacillus Cereus Endophthalmitis

“…Vancomycin is a commonly administered intravitreal antibiotic used for treating intraocular infections, with reported 100% effectiveness against the most common Gram-positive ocular pathogens, including B. cereus (8–10). In an experimental B. cereus endophthalmitis model, vancomycin sterilized infected eyes when intravitreally administered as late as 6 h postinfection (14, 15). However, significant vision was lost if vancomycin was administered after 4 h postinfection in this model, indicating that early treatment was critical for salvaging vision.…”

“…We therefore hypothesized that additional surgical measures to remove offending toxic contents in the vitreous may improve the visual outcome of infection, which is important if treatment is delayed. To this end, we analyzed the therapeutic effectiveness of vitrectomy and intravitreal vancomycin with that of vancomycin alone in a well-established B. cereus endophthalmitis rabbit model (14, 15) to determine whether vitrectomy and antibiotics offered an improved therapeutic benefit over that of antibiotics alone.…”