An outbreak of endogenous fungal endophthalmitis in immunocompetent individuals caused by presumed intravenous infusion contamination

Background: An outbreak of endogenous fungal endophthalmitis (EFE) caused by contaminated intravenous infusion was identified in immunocompetent individuals. We aimed to describe its clinical characteristics and outcomes. Methods: This retrospective case series included all patients referred with EFE and had a history of intravenous infusions at the same rural clinic, between May 1st, 2024 and November 30th, 2024, to Ophthalmology Department of Ningde Municipal Hospital. Demographic and clinical data were collected. Whole-genome sequencing (WGS) and SNP-based phylogenetic analysis were performed on 7 culture-positive Candida albicans vitreous isolates. Results: The inclusion criteria were met in 26 eyes of 17 patients. All were healthy and immunocompetent. On average, patients presented after 24.3 days of symptoms. Presenting best corrected visual acuity (BCVA) ranged from 20/25 to no light perception (NLP). All patients were initially treated with pars plana vitrectomy (PPV) and intravitreal voriconazole injection followed by systemic voriconazole therapy. Vitreous cultures obtained during PPV were positive in 19 eyes, all showing growth of Candida albicans. Three months after treatment, patients' BCVA improved significantly from a mean of 20/100 to 20/50 (p = 0.00011). All sequenced isolates clustered tightly in SNP-based phylogenetic analysis, supporting a clonal outbreak. Two patients with a final BCVA of NLP were initially misdiagnosed with noninfectious uveitis and treated with an intravitreal steroid injection at other hospitals. Since the closure of the rural clinic, no new cases have been reported. Conclusions: Primary PPV followed by systemic and intravitreal antifungal therapy and an epidemiological investigation could be effective in finding the infectious source of an EFE outbreak and achieving favorable visual outcomes. Misuse of intravitreal steroids due to incorrect diagnosis could lead to severe vision loss in individuals with EFE.