Post Pars Plana Vitrectomy Silicone Oil Related Endophthalmitis Caused by Citrobacter Koseri: A Case Report and Literature Review

Abstract

Purpose: To present a rare case of a Citrobateri koseri endophthalmitis after pars plana vitrectomy silicone oil-filled eye. Case Report: A 64-year old male patient presented to our clinic for eye pain and decrease vision in the right eye. He had a history of diabetes mellitus, hypertension, and a cataract surgery in both eyes ten years before and surgery of retinal detachment in RE For a relapse of regmatogenous retinal detachment in RE a pars plana vitrectomy with silicone oil injection was performed. He received topical betamethasone, naphazoline and tetracycline 6 times a day. After one week the patient complained ocular pain and decreased vision. Examination revealed visual acuity deterioration, a severely injected conjunctiva. The cornea was edematous with Descemet’s membrane folds. The anterior chamber was hazy with cells and flare, and hypopyon was observed. A diagnosis of post vitrectomy endophthalmitis was made. Sampling of the aqueous fluid was obtained and he was empirically treated with intravitreal ceftazidime 2.0mg/0,1ml and sub-tenon injection of betamethasone (2mg). The microscopic examination of the aqueous fluid stained with Gram stain revealed the presence of numerous polymorphonuclear cells and of small gram-negative bacteria identified as C. koseri. The strain was susceptible to all the antibiotics tested. A high MIC value (16mg/L) was detected only for tetracycline. The therapy was changed to fortified ceftazidime 5%, fortified tobramycin 0.3%, atropine 1% and prednisone-eye drops administered every 2 hours along with systemic antibiotic (ceftriaxone 2g iv for 5days) and steroid treatment without any improvement. The patient underwent to a new pars plana vitrectomy, removal of the IOL, and silicone oil exchange. In this occasion silicon leakage from previous sclerotomy, pus filled vitreous cavity and some retinal hemorrhages were observed. Vancomycin and ceftazidime according to Endophthalmitis Vitrectomy Study protocol were injected in the vitreous cavity and previous topical and systemic therapy was continued, too. An improvement of visual acuity was obtained. Conclusion: Among cases of culture positive endophthalmitis, Citrobacter spp. is very rare, and this is the first report of a silicone oil related endophthalmitis caused by this microorganism.