Pathophysiological study on experimental endophtalmitis due to blood stream infection of Candida albicans

Omuta J 1, Shibuya K 2, Matsuhasi M 1, Uchida K 3, Yamaguchi H 3

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Pathophysiological study on experimental endophtalmitis due to blood stream infection of Candida albicans


Candidial endophthalmitis has been regarded as a part of disseminated candida infection. However, details of correlation between pathophysiology of systemic infection and development of endophthalmitis are still unclear. To go insight into the pathophysiology of endophthalitis, we performed histological and ophthalmoscopic examination for rabbit model of systemic candidasis. 42 rabbits of two experimental groups; with and without treatment of steroid were intravenously injected with 107 Candida albicans. Ocular fundus was observed daily, and their eyes, brain, heart, lungs, liver, spleen, adrenal glands, and kidneys were obtained on the 1st, 3rd, 5th, 7th, 10th, and 14th day after the infection. Paraffin-embedded sections of all organs were prepared and histological examination was carried out. On ophthalmoscopic examination, the initial exudate on fundus was found as white-gray spot in rabbits without treatment of steroid on the 5th day. The exudate enlarged gradually and were clearly bordered. Histologically, pseudohyphae and yeasts of Candida were found in the lesion that comprised packed neutrophils and macrophages. In the kidney, pseudohyphae invaded from tubuli on the 5th day, and abscess was demonstrated in cortical area on the 7th day or later. Response of macrophages over-wrapped after the 10th day. Aggregates of macrophages without neutrophils were demonstrated in the liver. In the steroid-treated group, the initial alteration of ophthalmoscopic examination was found at the same experimental point, but those were many and larger, and rapidly enlarged. On the histological examination, numerous pseudohyphae were demonstrated in dense aggregate of neutrophils in retina. There were two types of enlargement of retinal lesion that one was developed from choroids and protruded into the vitreous, and another was in granular layer and become to involve choroids and erupted at vitreous. In the kidneys, a few fungi were found in tubuli on the 1st day. And the numerous abscesses and granulomatous foci containing many pseudohyphae were developed in both cortex and medulla on the 5th day. On the 7th day after infection, inflammatory lesion increased and enlarged and showed prominent proliferation of fungi. In addition, abscesses were also disseminated in heart, liver, and brain on the 10 th day. From these results, in the early phase of candidemia, it may take the same period to develop the initial lesion in retina, but following acute inflammatory process became prominent in rabbits with corticosteroid. It has been regarded that lesion of endophthalmitis following candidemia starts from the proliferation of yeast settled in choroids. However, from our observation, few were observed fungi in choroids. In the kidney, invasion of fungi occurred earlier and the lesion was severe. Both histological characteristic of lesions in retina and kidney may accurately reflect the state of blood stream infection of candida. As the result, it should be emphasized that the importance of ophthalmoscopic examination to monitor the state of candidemia

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15th Annual Focus on Fungal Infections