Intestinal spirochetosis: first cases reported in Brazil and the use of immunohistochemistry as an aid in histopathological diagnosis

A colonizacao do colo e reto por espiroquetas intestinais foi detectada pela primeira vez no Brasil em 4 de 282 (1,41 por cento) pacientes submetidos a sigmoidoscopia e/ou colonoscopia com o diagnostico histopatologico de colite cronica inespecifica. A frequencia e provavelmente menor que a real, uma vez que especimens cirurgicos nao foram considerados no presente estudo. O diagnostico histopatologico foi feito atraves de coloracoes de rotina, tais como a hematoxilina-eosina, que mostraram franja basofilica de 3u de espessura sobre a borda em escova do epitelio e por impregnacoes pela prata como o metodo de Whartin-Starry. Metodos imunohistoquimicos, usando dois soros primarios policlonais, um contra o Treponema pallidum e outro contra Leptospira interrogans, serovar copenhageni serogrupo...

Intestinal spirochetosis: first cases reported in Brazil and the use of immunohistochemistry as an aid in histopathological diagnosis.

Colonization of the colon and rectum by intestinal spirochetes is detected for the first time in Brazil in 4 of 282 (1.41%) patients who had undergone sigmoidoscopy and/or colonoscopy with a histopathological diagnosis of chronic non specific-colitis. This frequency is probably underestimated, since surgically obtained specimens were not considered in the present study. Histopathological diagnosis was performed using routine stains like hematoxylin-eosin which showed the typical, of 3-microns thick hematoxyphilic fringe on the brush border of the surface epithelium, and by silver stains like the Warthin-Starry stain. Immunohistochemical procedures using two, polyclonal, primary antibodies, one against Treponema pallidum and the other against Leptospira interrogans serovar copenhageni serogroup Icterohaemorrhagiae cross-reacted with spirochetal antigen/s producing a marked contrast of the fringe over the colonic epithelium, preserving the spiral-shaped morphology of the parasite. In one case with marked diarrhea, immunohistochemistry detected spirochetal antigen/s within a cell in an intestinal crypt, thus demonstrating that the infection can be more widely disseminated than suspected using routine stains. Immunohistochemical procedures, thus, greatly facilitate the histological diagnosis of intestinal spirochetosis and may contribute to a better understanding of the pathogenesis of the disease. Transmission and scanning electron microscopy performed in one case showed that the spirochete closely resembled the species designated as Brachyspira aalborgi.