716. A Case of Symptomatic Intestinal Spirochetosis

Background Intestinal spirochetosis (IS) is a condition caused by Brachyspira aalborgi and Brachyspira Pilosicoli. Its clinical significance has long been a point of contention with some debating that these spirochetes are simply colonic commensals. It is a condition that is more prevalent in developing nations as well as patients with HIV and the homosexual population. The epidemiology and prevalence of IS has not been studied in the local context. Methods We reviewed a case of a 37-year-old man who presented with a two month history of persistent lower abdominal pain, hematochezia, and increase in mucous discharge per rectum. He is sexually active with multiple male partners, and was previously treated for gonorrhea, chlamydia, and syphilis. His basic laboratory investigations were unremarkable, Venereal Disease Research Laboratory (VDRL) antibody and human immunodeficiency virus (HIV) screen were both non-reactive. Computed tomography of the abdomen was unremarkable. Endoscopic evaluation revealed multiple discrete ulcers measuring 1-2mm seen only in the rectum. Random biopsies of the cecum, ascending colon, transverse colon and descending colon showed mild acute colitis with IS. There was also mild to moderate acute proctitis in the rectum with spirochetes seen. 16s RNA gene sequencing of the biopsy specimen were confirmatory for Brachyspira aalborgi. Investigation findings. A: Discrete Ulcers found in rectum, B: Hemotoxylin and Eosin stained specimen showing proctitis, C: False brush Border appearance D: Spirochetes on Warthin Starry stain Results The patient received a 10 day course of metronidazole with complete resolution of his symptoms. Conclusion This case demonstrates the existence of a treatable condition that can be diagnosed with current available investigations for patients with similar symptoms. Recognising at risk populations can also raise clinical suspicion for this condition. Some studies have found associations between IS with development of colonic polyps and also certain colorectal cancers. Further studies on this treatable condition and its disease burden in the local context should be further explored. Disclosures All Authors: No reported disclosures

Hiding in Plain Sight: Colonic Spirochetosis in Humans

ABSTRACT In 1967, Harland and Lee made a startling discovery: in some humans, the colonic epithelium is covered with a “forest” of spirochetes (W. A. Harlan, and F. D. Lee, Br Med J 3:718–719, 1967, https://doi.org/10.1136/bmj.3.5567.718). In this issue of Journal of Bacteriology, Thorell et al. present a systematic analysis of the prevalence and diversity of the spirochetes Brachyspira aalborgi and Brachyspira pilosicoli in the human colon. These and prior studies provide avenues toward resolving important questions: what bacterial and host parameters contribute to this extensive colonization, and what impact does it have on human health?

Isolates from Colonic Spirochetosis in Humans Show High Genomic Divergence and Potential Pathogenic Features but Are Not Detected Using Standard Primers for the Human Microbiota

ABSTRACT Colonic spirochetosis, diagnosed based on the striking appearance in histological sections, still has an obscure clinical relevance, and only a few bacterial isolates from this condition have been characterized to date. In a randomized, population-based study in Stockholm, Sweden, 745 healthy individuals underwent colonoscopy with biopsy sampling. Of these individuals, 17 (2.3%) had colonic spirochetosis, which was associated with eosinophilic infiltration and a 3-fold-increased risk for irritable bowel syndrome (IBS). We aimed to culture the bacteria and perform whole-genome sequencing of the isolates from this unique representative population sample. From 14 out of 17 individuals with spirochetosis we successfully isolated, cultured, and performed whole-genome sequencing of in total 17 isolates, including the Brachyspira aalborgi type strain, 513A. Also, 16S analysis of the mucosa-associated microbiota was performed in the cases and nonspirochetosis controls. We found one isolate to be of the species Brachyspira pilosicoli; all remaining isolates were of the species Brachyspira aalborgi. Besides displaying extensive genetic heterogeneity, the isolates harbored several mucin-degrading enzymes and other virulence-associated genes that could confer a pathogenic potential in the human colon. We also showed that 16S amplicon sequencing using standard primers for human microbiota studies failed to detect Brachyspira due to primer incompatibility. IMPORTANCE This is the first report of whole-genome analysis of clinical isolates from individuals with colonic spirochetosis. This characterization provides new opportunities in understanding the physiology and potentials of these bacteria that densely colonize the gut in the individuals infected. The observation that standard 16S amplicon primers fail to detect colonic spirochetosis may have major implications for studies searching for associations between members of the microbiota and clinical conditions such as irritable bowel syndrome (IBS) and should be taken into consideration in project design and interpretation of gastrointestinal tract microbiota in population-based and clinical settings.

Isolates from colonic spirochaetosis in humans show high genomic divergence and carry potential pathogenic features but are not detected by 16S amplicon sequencing using standard primers for the human microbiota

Colonic spirochaetosis, diagnosed based on the striking appearance in histological sections, still has an obscure clinical relevance and only few bacterial isolates from this condition have been characterized to date. In a randomized, population-based study in Stockholm, Sweden, 745 healthy individuals underwent colonoscopy with biopsy sampling. In these individuals, 17 (2.3 %) had colonic spirochaetosis, which was associated with eosinophilic infiltration and a three-fold increased risk for irritable bowel syndrome (IBS). We aimed to culture the bacteria and perform whole genome sequencing of the isolates from this unique representative population sample. From 14 out of 17 individuals with spirochaetosis we successfully isolated, cultured and performed whole genome sequencing of in total 17 isolates including theBrachyspira aalborgitype strain 513AT. Also, 16S analysis of the mucosa-associated microbiota was performed in the cases and non-spirochaetosis controls.This is the first report of whole genome analysis of clinical isolates from individuals with colonic spirochaetosis. We found one isolate to be of the speciesBrachyspira pilosicoliand all remaining isolates were of the speciesBrachyspira aalborgi. Besides displaying extensive genetic heterogeneity, the isolates harboured several mucin-degrading enzymes and other virulence-associated genes that could confer a pathogenic potential in the human colon. We also showed that 16S amplicon sequencing using standard primers for human microbiota studies fail to detectBrachyspiradue to primer incompatibility. This failure to detect colonic spirochaetosis should be taken into consideration in project design and interpretation of gastrointestinal tract microbiota in population-based and clinical settings.

Human intestinal spirochaetosis in northern Japan

A histological diagnosis of human intestinal spirochaetosis (HIS) was made in 114 patients during the period 1994–2007. All patients lived in three prefectures in the northern part of Honshu, Japan. Most patients were elderly and male. Twenty-nine patients complained of abdominal pain, bloody stools, diarrhoea or bowel symptoms, but most patients showed no direct symptoms of bowel disease, and occult faecal blood detected at medical check-up was the main reason for colonoscopic examination. There were no homosexual patients and no immunosuppressed patients. HIS was evenly distributed throughout the whole colorectum. PCR analysis of Brachyspira aalborgi and Brachyspira pilosicoli revealed that more patients were infected with B. aalborgi. Follow-up PCR studies confirmed that infestation with B. aalborgi could be repeatedly detected over a 6 year period. This study, involving over 100 patients, identified the characteristic features of HIS in northern Japan. The results suggest that these spirochaetes may be harmless commensals that cause no obvious pathological alterations in infected individuals.

Distribution of the clpX gene in Brachyspira species and reactivity of recombinant Brachyspira pilosicoli ClpX with sera from mice and humans

Previously, a clpX gene encoding a predicted 67 kDa membrane-associated ATPase subunit of the Clp protease (ClpX) was identified in a porcine strain (95/1000) of the intestinal spirochaete Brachyspira pilosicoli. In the current study, the distribution of this large clpX gene was investigated in a collection of strains representing all seven Brachyspira spp. Using PCR with internal primers, an 878 bp portion of the gene was detected in 29 of 35 strains (83 %) of B. pilosicoli, 6 of 24 strains (25 %) of Brachyspira hyodysenteriae, 14 of 16 strains (88 %) of Brachyspira intermedia, 6 of 17 strains (35 %) of Brachyspira innocens, 1 of 6 strains (17 %) of Brachyspira murdochii, 1 of 2 strains (50 %) of Brachyspira aalborgi and not in the single strain of Brachyspira alvinipulli. The whole gene was sequenced from 20 Brachyspira spp. strains and compared with the clpX gene from B. pilosicoli 95/1000 (GenBank accession no. AY466377). The genes had 99.3–99.7 % nucleotide sequence similarity and the predicted products had 99.7–100 % amino acid sequence similarity. The clpX gene from WesB, a human strain of B. pilosicoli, was cloned and expressed as a histidine-tagged fusion protein in Escherichia coli BL21. The purified protein was used to vaccinate mice and their sera were found to recognize the expected ∼67 kDa protein in whole-cell preparations of WesB. Sera from mice vaccinated with formalin-treated whole-cell proteins of WesB reacted with the recombinant protein. These results indicate that ClpX is both conserved and immunogenic and hence might be useful as a subunit vaccine component for Brachyspira spp. infections. Sera from humans with no known exposure to B. pilosicoli reacted with the recombinant ClpX protein, indicating that it is unlikely to be useful as a reagent for serological detection of Brachyspira spp. infections.