Endogenous Endophthalmitis Due to Streptococcus agalactiae With a Suspected Urinary Source in a Patient Without Systemic Symptoms at Presentation: A Case Report

Group B Streptococcus (GBS, Streptococcus agalactiae) increasingly causes invasive infection in older adults, and endogenous endophthalmitis due to GBS carries a poor visual prognosis.Urinary tract infection in older adults may present without urinary or systemic symptoms, so the source is difficult to recognize when endophthalmitis is the presenting feature.An 82-year-old man with diabetes mellitus and a bladder tumor under evaluation developed blurred vision and pain in the left eye.Uveitis was initially suspected at a referring hospital; hypopyon appeared the next day, intravitreal vancomycin 1.0 mg and ceftazidime 2.0 mg were given, and he was referred.At presentation, visual acuity was light perception and intraocular pressure was 48 mmHg, with marked corneal opacity, hypopyon, and only mild vitreous opacity on B-scan ultrasonography.He was afebrile without urinary symptoms, yet the white blood cell count was 12,600/µL, C-reactive protein was 7.75 mg/dL, and procalcitonin was 1.05 ng/mL; shivering appeared about 12 hours later.Lens extraction and pars plana vitrectomy were performed the same day.Aqueous humor smear showed phagocytosed chain-forming cocci and culture grew S. agalactiae; the undiluted vitreous specimen, taken about 24 hours after the intravitreal injection, was smear-and culture-negative.Midstream urine grew S. agalactiae at 10⁵ CFU/mL or more with pyuria, and the two isolates had identical susceptibility profiles across 11 agents.Blood cultures were not obtained at presentation.CT showed focal areas of reduced parenchymal enhancement in the right kidney; echocardiography showed no findings supporting infective endocarditis.Systemic therapy totaled 46 days, with two intracameral injections of vancomycin and ceftazidime.An iatrogenic retinal break occurred during the initial surgery, and silicone oil tamponade was required at a second vitrectomy.Two months later, the eye was free of pain, inflammation, and recurrence, but the retina remained detached and visual acuity was no light perception.No evidence of an exogenous source was identified; bacteremia was not documented, and the urinary source remained a presumption.The case shows how narrow the window is in which the route and source of infection can still be established microbiologically.