[752] Molecular, Histologic and Clinical Features of Persistent Intestinal Spirochetosis

Kirsten Threlkeld, Thomas Trainer, Christine Adamson, Mark Evans, Rebecca Wilcox. University of Vermont, Burlington, VT

Background: Although human intestinal spirochetosis(IS) is a well-documented entity, its clinical significance remains controversial. Brachyspira aalborgi and pilosicoli are the species most commonly associated with human IS. We performed a retrospective analysis of colorectal biopsies in patients found to have persistent IS with the goal of highlighting molecular,histologic and clinical features.
Design: We identified all pts diagnosed with IS in our institution over the last 11yrs. Of these pts, those with at least one additional lower GI specimen in our database were defined as study patients. Retrospective exam of study slides(documenting IS,associated histology,recognition of IS in SP reports) and clinical data(reason to biopsy,symptoms,additional diagnoses,immune status) was performed. Primary molecular detection was achieved by amplifying species-specific portion of 16S ribosomal RNA. Non-amplfied cases were tested for viable DNA using β-globin.
Results: 29 pts (70 biopsies) had persistent(2mo-14yr) IS(66% male:35-91yrs;mean57.9yrs). In 32/70 biopsies(46%), IS was identified by H&E on retrospective review only(not documented in SP report). 8/29 pts had a history of immunosuppression(treated IBD, carcinoma,lymphoma). Reason to biopsy, associated histology and causative species are summarized in Table 1. The 9 samples(17%) positive for IS on H&E but not amplified by PCR all had additional biopsies that speciated as B. aalborgi. 27 additional pts had “non-persistent” IS (IS at one point in time with negative prior or subsequent colorectal biopsies). These cases all typed as B. aalborgi with an exception of one B. pilosicoli. The pt with B. pilosicoli was a homosexual male with diarrhea and active colitis.

Findings in 29 Patients (70 biopsies) With Persistent IS
Reason to BiopsyHistology∗Species
Screening72%WDA59%B. aalborgi83%
Diarrhea;R/O Microscopic Colitis7%Polyp: HP33%Non-Amplified17%
Heme + Stool6%Polyp: TA9%  
Unknown5%Active Colitis6%  
IBD Surveillance3%Polyp: SSA4%  
Hx of Colitis3%Polyp: TVA1%  
Other3%Chronic Active Colitis1%  
∗Refers to area directly involved by IS

Conclusions: In our 29 pts with persistent IS, the overwhelming majority were asymptomatic/non-immunocompromised. In fact,5 of the 8 immunocomprimised pts were found to have IS in biopsies prior to their immunocompromised state. B. aalborgi was the only species isolated in all persistent IS cases. In this study population, B. aalborgi appears to be a colonizer rather than a pathogen and may be more common than reported as it is often found in asymptomatic “low-power diagnoses”(e.g. HPs in screening colonoscopies).
Category: Gastrointestinal

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 127, Tuesday Afternoon


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