[674] Histologic Characteristic of Human Intestinal Spirochetosis Is Evident Only Where Colonic Surface Epithelium Has Microvilli.

Sho Ogata, Ichiyou Ohara, Kimiya Sato, Junichi Matsuzaki, Masaaki Higashiyama, Kuniaki Nakanishi, Toshiaki Kawai. National Defense Medical College, Tokorozawa, Saitama, Japan; Japan Self Defense Forces Hospital Yokosuka, Yokosuka, Kanagawa, Japan; Japan Self Defense Forces Central Hospital, Setagaya, Tokyo, Japan

Background: Human intestinal spirochetosis (HIS) is a colorectal infectious disease caused by Brachyspira species bacteria. Its histologic characteristic is the so-called fringe formation of spirochetes on the colonic surface epithelium, while its cytologic one is spiral organisms floating within the mucus. Previously, we demonstrated that for the detection of spirochetes, imprint cytology was more powerful than histology (Hum Pathol 2010).
Design: We compared these two methods by a large-scale trial of their routine practice (435 endoscopy cases). We investigated the microvillus-spirochete relationship ultrastructurally in 16 HIS cases.
Results: Fifty-eight cases (13.3 %) were histology-positive (fringe formation). Seventy-seven (17.7 %) were cytology-positive (spiral organisms), of which 22 (5.1 % of the 435 cases) were histology-negative. The two major ultrastructural findings were: 1) a single spirochete was frequently surrounded and enclosed by several microvilli, and 2) when microvilli were sparse, spirochetes attached to the cell surface only where microvilli were present.
Conclusions: In the present large-scale study, histologic diagnosis of HIS was difficult in some cases. Since our ultrastructural study suggests that robust microvilli must be present on the epithelial surface for spirochetal attachment, the density of microvilli may determine whether a fringe formation is seen under the light microscope.
Category: Gastrointestinal

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 22, Wednesday Morning

 

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