Case ReportCHORIORETINAL BIOPSY FOR THE DIAGNOSIS OF ENDOGENOUS ENDOPHTHALMITIS DUE TO ESCHERICHIA COLICheng, Nicholas M. MBBS, BMedSc*; Chandra, Aman PhD, FRCOphth*; Roufail, Edward PhD, FRANZCO*; Moodie, Jonathan J. FRCOphth*; Yeoh, Jonathan FRANZCO*; Allen, Penelope J. FRANZCO*; Salinas-La Rosa, Cesar M. MD, FRCPA, MAACB†; Matthews, Bryan J. FRCOphth*Author Information *Vitreoretinal Unit, The Royal Victorian Eye and Ear Hospital, Victoria, Australia; and †Department of Anatomical Pathology, St Vincent's Hospital, Victoria, Australia. Reprint requests: Nicholas M. Cheng, MBBS, BMedSc, The Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne 3002, Australia; e-mail: [email protected] Paper presented at The Melbourne Ophthalmic Alumni Meeting, The Royal Victorian Eye and Ear Hospital, Australia, August 16, 2014. None of the authors have any financial/conflicting interests to disclose. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.retinajournal.com). Retinal Cases & Brief Reports: Winter 2017 - Volume 11 - Issue 1 - p 30-33 doi: 10.1097/ICB.0000000000000281 Buy SDC Metrics AbstractIn Brief Purpose: To describe the novel use of a chorioretinal biopsy technique to confirm the microbiological diagnosis of endogenous Escherichia coli (E. coli) endophthalmitis, when other investigations have been proven nondiagnostic. Methods: Case report of an 82-year-old white man with endogenous endophthalmitis without a clearly identifiable source of infection. Results: After systemic cultures and multiple aqueous and vitreous samples were unable to identify a causative organism, chorioretinal biopsy of a subretinal abscess was used to confirm the microbiological diagnosis. This ensured appropriate ophthalmic and systemic treatment of infection. Conclusion: Endogenous E. coli endophthalmitis is a rare and aggressive condition usually seen in patients with insulin-dependent diabetes with concurrent urinary tract infection. This case demonstrates chorioretinal biopsy to be a viable and effective method of establishing a firm microbiological diagnosis in cases of culture-negative endophthalmitis. Endogenous endophthalmitis due to Escherichia coli is a rare and aggressive condition. This case demonstrates chorioretinal biopsy to be a viable and effective method of establishing a firm microbiological diagnosis in cases of culture-negative endophthalmitis. This novel diagnostic approach allowed an appropriate ophthalmic and systemic treatment of infection.