Intestinal spirochetosis due to Brachyspira pilosicoli: endoscopic and radiographic features

Mucosal eosinophilic infiltration may be a characteristic of human intestinal spirochetosis

Background

Human intestinal spirochetosis (HIS) is an infectious disease of large intestines caused by Brachyspira species, and most HIS cases are asymptomatic or exhibit mild intestinal symptoms. The host reaction to HIS remains unclear, and we examined HIS-related mucosal inflammatory features histologically.

Methods

From the archival HIS cases in a single medical center, 24 endoscopically taken specimens from 14 HIS cases (male:female = 10:4; 28–73 yrs) were selected as not containing polypoid or neoplastic lesions. Stromal neutrophils, eosinophils, and mast cells, and intraepithelial neutrophils and eosinophils, (sNeu, sEo, sMast, iNeu, and iEo, respectively) were counted, and the presence or absence of lymphoid follicles/aggregates (LFs) was also examined. Association of the above inflammation parameters and spirochetal infection parameters (such as degrees of characteristic fringe distribution, of spirochetal cryptal invasion, and of spirochetal intraepithelial invasion) were also analysed.

Results

iNeu was observed in 29.2%, iEo in 58.3%, and LFs in 50.0% of the specimens. Maximal counts of sNeu, sEo, sMast, iNeu, and iEo averaged 8.4, 21.5, 6.0, 0.5 and 1.5, respectively. Strong correlation between the maximum counts of iNeu and iEo (p < 0.001, r = 0.81), and correlations between those of iEo and sNeu (p = 0.0012, r = 0.62) and between those of iEo and sEo (p = 0.026, r = 0.45) were observed. iNeu was influenced by fringe formation (p < 0.05) and spirochetal crypt involvement (p < 0.05).

Conclusions

HIS was accompanied by inflammatory reactions, and among these, mucosal eosinophilic infiltration may be a central indicator and host reaction of HIS.

Human intestinal spirochetosis, a sexually transmissible infection? Review of six cases from two sexually transmitted infection centres in Barcelona

Human intestinal spirochetosis (HIS) is a possible cause of chronic diarrhoea and affects mainly men who have sex with men (MSM) and people living with HIV. Diagnosis is based on colon biopsy, where spirochetes can be observed on the luminal surface, especially with the Warthin-Starry stain or similar silver stains. We conducted a retrospective descriptive study of all HIS cases diagnosed in two sexually transmitted infections (STI) centres in Barcelona from 2009 until 2018. The medical histories were reviewed to gather epidemiological, clinical, and diagnostic variables. Six patients were diagnosed with HIS. All the individuals were MSM, with a median age of 31.5 years (interquartile range [IQR] 29.5;49.25) and half of them were living with HIV. Five patients reported condomless anal intercourse and 4 patients had practised oro-anal sex previously. Concomitantly, two of them had rectal gonorrhoea, one had rectal Chlamydia trachomatis and none of them had syphilis. The predominant clinical symptom was diarrhoea (5 patients). All cases were diagnosed by a Warthin-Starry stain on a colon biopsy specimen, and mild inflammatory changes were found in 5 cases. Five patients were treated with metronidazole and one with benzathine penicillin G. Treatment was successful in all the patients. HIS should be considered in patients with chronic diarrhoea who report risky sexual practices and/or concomitant STI. HIS may also be sexually transmitted according to the context.

Pneumatosis cystoides intestinalis accompanied by intestinal spirochetosis

Pneumatosis cystoides intestinalis (PCI) is a rare but well-recognized entity characterized by multiple gas-filled cysts in the intestinal wall. Although the pathogenesis of PCI remains unclear, several theories, including a bacterial theory, have been postulated. Intestinal spirochetosis (IS) is an uncommon condition defined by the presence of spirochetes attached to the surface of the colonic epithelium. The nature of IS as a commensal or pathogenic process remains debatable. However, recent evidence supports the idea that IS can be invasive and highly pathogenic in both immunocompromised and immunocompetent individuals. We present the case of a 35-year-old asymptomatic and immunocompetent man who underwent colonoscopy because of a positive fecal blood test. Multiple submucosal cystic lesions were detected accompanied by erythematous areas along the ascending colon. Computed tomography-colonography and biopsy specimens from the erythematous areas confirmed coexisting PCI and IS. Both PCI and IS recovered completely 3 months after administration of metronidazole. To the best of our knowledge, this case represents only the second report of the extremely rare concurrence of PCI with IS. Taking into account the published literature, we also discuss the possibility that the development of PCI may be related to IS.

Severe Colitis with Portal Venous Gas Caused by Brachyspira pilosicoli Infection

We herein report a case of Brachyspira pilosicoli-caused severe colitis presenting with portal venous gas. A 75-year-old man was admitted because of a fever, severe abdominal pain and bloody diarrhea. He was negative for anti-HIV antibodies. He had been in close contact with a dog earlier. Abdominal computed tomography detected severe wall-thickening and fat-stranding of the entire colon accompanied by portal venous gas. A smear examination of his stool showed many Gram-negative spiral rods, suggesting intestinal spirochetosis. A polymerase chain reaction assay using stool samples detected an amplified band specific for B. pilosicoli. He responded well to antimicrobial agents including metronidazole.

The comparison of the intensity of human intestinal spirochetes between Brachyspira pilosicoli and Brachyspira aalborgi infections

The agglutination titers of Brachyspira pilosicoli (B. pilosicoli) and Brachyspira aalborgi (B. aalborgi) were examined in colitis patients with human intestinal spirochetes. Among three cases of colitis patients, the titer of B. pilosicoli was extremely high in two cases while the titer of B. aalborgi was extremely high in one case. These three cases had symptoms of colitis, such as watery diarrhea, and we diagnosed the case as Brachyspira- related colitis. These findings suggest that the agglutination titers of Brachyspira may be useful in cases of Brachyspira- related colitis. Severe symptoms, such as abdominal pain and diarrhea, were observed in cases with high antibody titer of B. aalborgi, as well as B. pilosicoli, indicating that B. aalborgi could also cause symptomatic colitis.

The Spirochete Brachyspira pilosicoli, Enteric Pathogen of Animals and Humans

Brachyspira pilosicoli is a slow-growing anaerobic spirochete that colonizes the large intestine. Colonization occurs commonly in pigs and adult chickens, causing colitis/typhlitis, diarrhea, poor growth rates, and reduced production. Colonization of humans also is common in some populations (individuals living in village and peri-urban settings in developing countries, recent immigrants from developing countries, homosexual males, and HIV-positive patients), but the spirochete rarely is investigated as a potential human enteric pathogen. In part this is due to its slow growth and specialized growth requirements, meaning that it is not detectable in human fecal samples using routine diagnostic methods. Nevertheless, it has been identified histologically attached to the colon and rectum in patients with conditions such as chronic diarrhea, rectal bleeding, and/or nonspecific abdominal discomfort, and one survey of Australian Aboriginal children showed that colonization was significantly associated with failure to thrive. B. pilosicoli has been detected in the bloodstream of elderly patients or individuals with chronic conditions such as alcoholism and malignancies. This review describes the spirochete and associated diseases. It aims to encourage clinicians and clinical microbiologists to consider B. pilosicoli in their differential diagnoses and to develop and use appropriate diagnostic protocols to identify the spirochete in clinical specimens.

Colonic Spirochetosis in a 60-Year-Old Immunocompetent Patient: Case Report and Review

Spirochetes, a genetically and morphologically distinct group of bacteria, are thin, spiral-shaped, and highly motile. They are known causes of several human diseases such as syphilis, Lyme disease, relapsing fever, and leptospirosis. We report a case of colonic spirochetosis in a healthy patient presenting for surveillance colonoscopy. The diagnosis of intestinal spirochetosis was made accidentally during the histological examination of colonic polyps, which were removed during colonoscopy. We also performed an extensive review on intestinal spirochetosis with a focus on clinical presentation and outcomes of reported cases from the past two decades.

Intestinal spirochetosis: an enigmatic disease

INTRODUCTION

Intestinal spirochetosis (IS) is a condition in which colonic and appendiceal epithelial cells are colonized by one of two anaerobic spirochetes, either the Brachyspira aalborgi or Brachyspira pilosicoli. There is much debate in the literature as to whether IS is a pathogen or a commensal inhabitant. A recent case of IS at our institution prompted a retrospective database search and review of the literature.

METHODS

A pathology database search for IS was performed at Carolinas Medical Center from 2003 through 2007. After patient identification, a retrospective review of the endoscopic record and the pathology report was performed. Pathology slides were reviewed for accuracy and special silver stains and/or immunostains were performed if needed. The following data were collected for each patient when available: age, gender, nationality, HIV status, and other co-morbid conditions when noted. We attempted to determine whether patients were treated for spirochetosis and if so, the treatment regimen used as well as the results.

RESULTS

The database search detected 29 patients with biopsies showing IS. Three patients were subsequently removed due to incorrect identification. A total of 26 patients with an average age of 45 years were reviewed. The most common symptoms were abdominal pain, diarrhea, and rectal bleeding. Most patients did not exhibit inflammatory changes despite the presence of spirochetosis. Pathologic examination revealed a relative increase in intra-epithelial lymphocytes in a subset of cases, a non-specific finding. Acute colitis or architectural distortion was not seen in any of the study cases. We were only able to obtain follow-up of two patients after treatment with metronidazole and both responded to therapy.

CONCLUSIONS

To date, our study is the largest case series that includes both endoscopic and pathologic descriptions and confirms the "bland" nature of the condition. In <20 % of our patients inflammation was present microscopically and it did not correlate well with endoscopic appearance. Symptoms reported by our patients were similar to those reported in previous studies, although our lack of endoscopic changes was different from one previous paper. There is no established standard of care for the treatment of IS and our study, reflects the enigmatic nature of IS as a disease process. In the absence of rigorous literature, physicians will need to use a logical and pragmatic approach to the evaluation and treatment of IS.

Intestinal spirochetosis in children: five new cases and a 20-year review of the literature

Intestinal spirochetosis (IS) is an unusual infection in children, one with no standard therapeutic options. This article reports the findings on 5 new cases in conjunction with a 20-year review of the pediatric literature. The diagnosis of IS in children requires a high degree of suspicion by the physician, as many cases present with abdominal pain, chronic diarrhea, and/or hematochezia associated with a normal endoscopic examination. Silver stains (Dieterle or Whartin-Starry) are the preferred confirmatory stains on tissue sections. Giemsa (Diff-Quik) and periodic acid-Schiff stains may also be of value. Current literature favors the use of metronidazole in adult patients with IS, yet little information is available regarding treatment options in pediatric cases. This review indicates that a macrolide antibiotic with or without metronidazole may represent the best therapeutic choice for children. Further investigations are needed to determine the correlation between IS and coexisting gastrointestinal diseases and/or immunodeficiencies.