Diagnostic Examination of Human Intestinal Spirochetosis by Fluorescent In Situ Hybridization for Brachyspira aalborgi , Brachyspira pilosicoli , and Other Species of the Genus Brachyspira ( Serpulina )

Abstract

Human intestinal spirochetosis, characterized by end-on attachment of densely packed spirochetes to the epithelial surface of the large intestines as a fringe has been associated with the weakly beta-hemolytic spirochetes Brachyspira aalborgi and Brachyspira (Serpulina) pilosicoli. In this study, fluorescent in situ hybridization with oligonucleotide probes targeting 16S or 23S rRNA of B. aalborgi, B. pilosicoli, and the genus Brachyspira was applied to 40 sections of formalin-fixed, paraffin-embedded intestinal biopsy specimens from 23 Danish and 15 Norwegian patients with histologic evidence of intestinal spirochetosis. Five biopsy specimens from patients without intestinal spirochetosis and three samples from pigs with experimental B. pilosicoli colitis were examined as well. In addition, the 16S ribosomal DNAs of two clinical isolates of B. aalborgi were sequenced, and a PCR procedure was developed for the identification of B. aalborgi in cultures. The genotypic characteristics of the two clinical isolates showed very high (99.5%) similarity with two existing isolates, the type strain of B. aalborgi and a Swedish isolate. Hybridization with the Brachyspira genus-specific probe revealed a brightly fluorescing fringe of spirochetes on the epithelia of 39 biopsy specimens, whereas 1 biopsy specimen was hybridization negative. The spirochetes in biopsy specimens from 13 Danish and 8 Norwegian patients (55.3%) were identified as B. aalborgi. The spirochetes in the biopsy specimens from the other 17 patients hybridized only with the Brachyspira probe, possibly demonstrating the involvement of as-yet-uncharacterized Brachyspira spirochetes in human intestinal spirochetosis.Human intestinal spirochetosis (HIS) is a condition of the large intestinal mucosa microscopically characterized by colonization and extensive end-on attachment of densely packed spirochetes to the epithelial surface (16). The spirochetes are easily demonstrated in hematoxylin-eosin-stained biopsy sections as a diffuse blue fringe 3 to 6 m thick. The colonization is usually associated with no or only minor morphologic and inflammatory reactions in the mucosa (16,17,23,36). Ultrastructurally, spirochetes are attached perpendicular to the epithelial membrane between the microvilli, which appear shorter or depleted (11,17,23,36). However, more severe lesions with spirochetal invasion of the epithelium and the adjacent lamina propria together with purulent discharge may occur (15,27,30,42). HIS is a morphological description based on microscopic examination of biopsy samples. Hence, most reports have outlined histologic and electron microscopic findings, whereas there have been only a few reports of concurrent culturing of spirochetes from the same individuals (11,15,17,36), and two species, Brachyspira aalborgi and Brachyspira (Serpulina) pilosicoli, have been identified (17,36).Recently, the phylogeny of intestinal spirochetes has been studied by multilocus enzyme electrophoresis (20, 21), polyacrylamide gel electrophoresis (7), pulsed-field gel el...

Colonization and risk factors for Brachyspira aalborgi and Brachyspira pilosicoli in humans and dogs on tea estates in Assam, India

“…This is the first study to provide an estimate of the prevalence of B. aalborgi in the general population of a developing country. Unfortunately, there have been no studies on the prevalence of B. aalborgi in developed countries, apart from in selected groups of patients who have undergone colorectal biopsy for underlying complaints of the large bowel [21,[25][26][27][28]. In the absence of this comparative data, it is not possible to determine whether the prevalence of colonization that was detected is unusually high or low, or whether it was influenced by factors peculiar to developing countries.…”

“…To date, B. aalborgi has only been reported to have been isolated from humans in five studies; in three it was grown from colorectal biopsies [1,21,22], and in two it was grown from faeces [23,24]. In recent studies, DNA has been extracted from colorectal biopsies taken from IS patients in Australia, Scandinavia and the United States, and amplified by polymerase chain reaction (PCR) or hybridized with oligonucleotide probes.…”

“…In recent studies, DNA has been extracted from colorectal biopsies taken from IS patients in Australia, Scandinavia and the United States, and amplified by polymerase chain reaction (PCR) or hybridized with oligonucleotide probes. Somewhat unexpectedly, these studies showed that B. aalborgi is much more commonly involved in IS in these developed countries than is B. pilosicoli [21,[25][26][27][28]. Similar studies have not been conducted on patients in developing countries, where B. pilosicoli is known to be common, due to difficulties in accessing suitable samples.…”

Comparison of prevalence and risk factors for faecal carriage of the intestinal spirochaetes Brachyspira aalborgi and Brachyspira pilosicoli in four Australian populations

“…B. aalborgi is difficult to culture due to its fastidious growth requirements and extremely slow growth rate. It is usually detected by polymerase chain reaction (PCR) or gene probe assays, and has only occasionally been isolated [5][6][7]. B. pilosicoli is easier to isolate, and has been cultured from faeces in several developing countries [8][9][10][11], from Australian Aborigines [12,13], migrants to Australia from developing countries [13] and homosexual males [14].…”

Human Intestinal Spirochaetosis in Two Ulcerative Colitis Patients

“…A previous study demonstrated that HIS is associated with various intestinal diseases, including colon carcinoma and colonic polyps (9,10). Previous reports (9, 10) have also shown that HIS can be found in cases of ulcerative colitis.…”