Experimental hematogenous Candida endophthalmitis: diagnostic approaches

Abstract

Anterior chamber aspiration and vitreous aspiration were evaluated as diagnostic procedures for establishing a specific microbiological diagnosis in the rabbit model of hematogenous Candida endophthalmitis. Vitreous aspiration was the most successful procedure, confirming the diagnosis of hematogenous Candida endophthalmitis in 62% of eyes with documented intraocular infection. When animals with only the most severe clinical endophthalmitis were considered, vitreous aspiration confirmed the diagnosis in 89% of eyes evaluated. Vitreous aspiration correlated well with the extent of clinical endophthalmitis, as well as with postmortem, whole-vitreous cultures. Gram staining of the aspirate was additive to culture results in confirming the diagnosis. Anterior chamber aspiration was positive in only 1 of 58 eyes evaluated (1.7%). Additionally, muscle biospy was evaluated in this study as a tool for establishing a microbiological diagnosis in the rabbit model of disseminated candidiasis. Only 2 of 131 biospy specimens contained detectable Candida. Although vitreous aspiration may be associated with ocular complications, in certain clinical settings this procedure may be valuable in establishing the definitive microbiological diagnosis of hematogenous Candida endophthalmitis.

Histopathological Study on Experimental Endophthalmitis Induced by Bloodstream Infection with <i>Candida albicans</i>

“…In 1961, Hoffmann et al established an experimental rabbit model of EFE by intravenous administration of C. albicans. They documented that the experimental EFE was started with the settlement of yeast cells in the choroid membrane followed by PMN infiltration (12)(13)(14)(15)(16).…”

“…Furthermore, fungemia develops 6 to 58 days after catheterization and visual symptoms appear 3 to 15 days after blood cultures of the patients turn positive (35,36). Many researchers noted that Candida was observed in the kidneys, brain, liver, and spleen, but not in the eyeballs (13)(14)(15)(16)(37)(38)(39). However, only a few reported the time of onset of the initial event or a comparative histopathological examination of the ocular lesion and those in other organs.…”

“…In patients with EFE, fungi, usually pathogenic yeasts, may disseminate and spread via the bloodstream, and settle in the choroid. Infection of the choroid has been regarded as the initial event leading to endophthalmitis (12)(13)(14)(15). Many experiments have been performed on animal models of EFE, but there have been no studies on immunocompromised EFE.…”

“…Many experiments have been performed on animal models of EFE, but there have been no studies on immunocompromised EFE. A few studies have been done on the pathophysiology, ophthalmoscopic findings, and histology of retinal lesions (12)(13)(14)(15)(16)(17)(18)(19)(20). Although EFE has been recognized as a clinical manifestation of a generalized infection (10), the relationship between a generalized infection and endophthalmitis, in magnitude and/or under immunocompromised conditions, has not been clarified.…”

Systemic Candida albicans Infection in Mice Causes Endogenous Endophthalmitis via Breaching the Outer Blood-Retinal Barrier

“…Most studies related to Candida endophthalmitis are classified as clinical and epidemiological, where the focus of the study is to describe the risk factors (parenteral nutrition; immunosuppression; intravenous drug use; recent central venous catheters, including peripherally inserted central catheters; race; and age) involved in the pathogenesis ( 1 , 7 , 12 , 13 , 17 ). Surprisingly, the few experimental studies available ( 13 , 18 – 21 ) have an emphasis on evaluating the efficacy of antifungal drugs and comparing the infectivity of different Candida species. Previously, we have established a murine model of Aspergillus and Candida endophthalmitis to characterize the retinal innate immune response and its pathogenesis ( 4 , 22 ).…”