ENDOPHTHALMITIS CAUSED BY SERRATIA MARCESCENS: Clinical Features, Antibiotic Susceptibilities, and Treatment Outcomes.

Purpose: To report the clinical features, antibiotic sensitivities, and visual outcomes associated with endophthalmitis caused by Serratia marcescens. Methods: A consecutive case series of patients with vitreous culture-positive endophthalmitis caused by S. marcescens from July 1, 1993, to June 30, 2012, at a large university referral center. Findings from this study were compared with those of a previous study (January 1980-June 1993) from our institution. Results: Of the 10 study patients who were identified, clinical settings included trabeculectomy bleb-associated (n = 3), post-cataract surgery (n = 2), post-penetrating keratoplasty (n = 2), post-scleral buckle (n = 1), glaucoma drainage implant-associated (n = 1), and post-keratoprosthesis (n = 1). Clinical features included pain (n = 10) and hypopyon (n = 5). Presenting visual acuity was hand motions or worse in seven cases. All isolates were sensitive to gentamicin, ceftazidime, imipenem, and levofloxacin. The MIC 90s of isolates for antibiotics tested in the current period compared with isolates from January 1980 to June 1993 were unchanged. All isolates were resistant to vancomycin. Initial treatment strategies were vitreous tap and intravitreal antibiotic injection (n = 8), pars plana vitrectomy with intravitreal antibiotic injection (n = 1), and evisceration (n = 1). When repeat vitreous fluid was obtained, persistent positive cultures were present in 1 (10%) of 10 patients in this study, compared with 5 (50%) of 10 patients in the previous study. Final visual acuity was no light perception in 6 of 10 patients (60%). Conclusion: Outcomes were generally poor with a high rate of complete visual loss in the affected eye.