Colonic spirochetosis in animals and humans

Identification of Terminal βGlcNAc on Brachyspira Species in Human Intestinal Spirochetosis

Human intestinal spirochetosis (HIS) is a colorectal bacterial infection caused by the Brachyspira species. Griffonia simplicifolia-II (GS-II) is a lectin specific to terminal α/βGlcNAc residues. Here, we investigated terminal βGlcNAc residues in the context of HIS infection using GS-II-horseradish peroxidase staining and HIK1083 immunostaining specific to terminal αGlcNAc residues. Fourteen of 15 HIS cases were GS-II-positive on the bacterial body. No cases showed HIK1083 positivity. The percentage of bacterial bodies staining positively for GS-II based on comparison with anti-Treponema immunostaining was ≤30% in seven cases, 30-70% in two, and >70% in six. Of 15 HIS cases analyzed, none were comorbid with tubular adenomas, and three were comorbid with sessile serrated lesions (SSLs). To determine the species of spirochete infected, the B. aalborgi-specific or B. pilosicoli-specific NADPH oxidase genes were amplified by PCR. After direct sequencing of the PCR products, all nine cases in which PCR products were observed were found to be infected with B. aalborgi alone. These results indicate that the HIS bacterial body, especially of B. aalborgi, is characterized by terminal βGlcNAc and also indicate that terminal βGlcNAc on the HIS bacterial body is associated with HIS preference for SSLs.

Clinical and Pathologic Factors Associated With Colonic Spirochete (Brachyspira pilosicoli and Brachyspira aalborgi) Infection: A Comprehensive Systematic Review and Pooled Analysis

OBJECTIVES

This study aims to determine what pathologic and clinical factors differentiate Brachyspira species that may be useful to clinicians and pathologists.

METHODS

We identified 21 studies of Brachyspira infection with individual patient information (n = 113) and conducted a pooled analysis comparing each species.

RESULTS

There were differences in the pathologic and clinical profiles of each Brachyspira species. Patients infected with Brachyspira pilosicoli infection were more likely to have diarrhea, fever, HIV, and immunocompromised conditions. Those patients infected with Brachyspira aalborgi were more likely to have lamina propria inflammation.

CONCLUSIONS

Our novel data provide potential insights into the pathogenic mechanism(s) and the specific risk factor profile of Brachyspira species. This may be clinically useful when assessing and managing patients.

Assembly of novel microbial genomes from gut metagenomes of rhesus macaque (Macaca mulatta)

Rhesus macaque (RM, Macaca mulatta), as an important model animal, commonly suffers from chronic diarrheal disease, challenging the breeding of RMs. Gut microbiomes play key roles in maintaining intestinal health of RMs. However, it is still unclear about more features of gut microbiome as responsible for intestinal health of RMs. In this study, we performed de novo assembly of metagenome-assembled genomes (MAGs) based on fecal metagenomes from chronic diarrheal RMs and asymptomatic individuals. In total of 731 non-redundant MAGs with at least 80% completeness were reconstructed in this study. More than 97% MAGs were novel genomes compared with more than 250,000 reference genomes. MAGs of Campylobacter and Helicobacteraceae from RM guts mainly carried flagella-associated virulence genes and chemotaxis-associated virulence genes, which might mediate motility and adhesion of bacteria. Comparing to MAGs of Campylobacter from humans, distributions and functions of these MAGs of Campylobacter from RMs exhibited significant differences. Most members of Bacteroidota, Spirochaetota, Helicobacteraceae, Lactobacillaceae and Anaerovibrio significantly decreased in guts of chronic diarrhea RMs. More than 92% MAGs in this study were not contained in 2,985 MAGs previously reported from other 22 non-human primates (NHPs), expanding the microbial diversity in guts of NHPs. The distributions and functions of gut microbiome were prominently influenced by host phylogeny of NHPs. Our results could help to more clearly understand about the diversity and function of RMs gut microbiome.

Evidence of homologous recombination as a driver of diversity in Brachyspira pilosicoli

The enteric, pathogenic spirochaete Brachyspira pilosicoli colonizes and infects a variety of birds and mammals, including humans. However, there is a paucity of genomic data available for this organism. This study introduces 12 newly sequenced draft genome assemblies, boosting the cohort of examined isolates by fourfold and cataloguing the intraspecific genomic diversity of the organism more comprehensively. We used several in silico techniques to define a core genome of 1751 genes and qualitatively and quantitatively examined the intraspecific species boundary using phylogenetic analysis and average nucleotide identity, before contextualizing this diversity against other members of the genus Brachyspira. Our study revealed that an additional isolate that was unable to be species typed against any other Brachyspira lacked putative virulence factors present in all other isolates. Finally, we quantified that homologous recombination has as great an effect on the evolution of the core genome of the B. pilosicoli as random mutation (r/m=1.02). Comparative genomics has informed Brachyspira diversity, population structure, host specificity and virulence. The data presented here can be used to contribute to developing advanced screening methods, diagnostic assays and prophylactic vaccines against this zoonotic pathogen.

An uncommon cause of chronic abdominal pain and diarrhea

The intestinal spirochaetosis is defined as the presence of spirochetes on the colonic surface. We present the case of a 57-years-old male, with a history of 4-5 months of diffuse abdominal pain, watery diarrhoea due to this infection. The colonoscopy revealed a serpiginous ulcer in the cecum. The biopsy was positive for intestinal spirochaetosis. It is rare infection, more common among immunocompromised patients and HIV, with a faecal-oral transmission. Most cases are incidental findings in the endoscopic screening. In symptomatic patients the watery diarrhoea and non-specific abdominal pain are the most common symptoms. The macroscopic appearance on the colonoscopy is often normal or non-specific lesions can be identified. The diagnosis is based on the biopsy with haematoxylin and eosin and the confirmation can be made with a Warthin-Starry stain. In symptomatic patients the metronidazole is the preferred treatment option. Although it is rare infection, clinicians should be aware of it in patients with common gastrointestinal symptoms.

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

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.

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.

[Immunohistochemical diagnosis of colonic spirochetosis with anti-treponema antibody in patients consulting for chronic diarrhea. Results of a prospective study conducted in 137 patients]

AIM

To assess the incidence of colonic spirochetosis, diagnosed by immunohistochemical stain with anti-Treponema pallidum antibody, in a prospective study of colonic biopsies of patients presenting with chronic diarrhea.

MATERIAL AND METHODS

From March 2017 to March 2018 the colonic biopsies of patients presenting with chronic diarrhea were stained with Hematoxylin Eosin and anti-Treponema pallidum antibody. The positive cases were also stained with Steiner stain.

RESULTS

A total of 137 colonic biopsies were assessed and 3 cases were positive for immunohistochemical stain with anti-Treponema pallidum antibody (2% of the patients). One case was easy to diagnose with HE stain but the 2 other cases were not. The bacteria were stained with Steiner stain, but less easily seen than with the immunohistochemical stain. No patient was treated with antibiotics.

DISCUSSION AND CONCLUSION

The colonic spirochetosis can be easily diagnosed by pathologists with immunohistochemical stain with anti-Treponema pallidum antibody. The bacteria are more easily diagnosed with immunohistochemical stain than with HE stain or Steiner stain. However, colonic spirochetosis is rarely diagnosed on colonic biopsies of patients presenting with chronic diarrhea (2% of the patients in our study). Due to the rarity of the entity, and the cost of immunohistochemical stain and the weak benefit for the patient (no patient in our study was treated with antibiotics for colonic spirochetosis) we cannot advise to perform systematic immunohistochemical stain with anti-Treponema pallidum antibody in all the colonic biopsies of patients presenting with chronic diarrhea.

Prevalence, distribution and risk factors of farmer reported swine influenza infection in Guangdong Province, China

A cross-sectional study was undertaken to better understand the husbandry, management and biosecurity practices of pig farms in Guangdong Province (GD), China to identify risk factors for farmer reported swine influenza (SI) on their farms. Questionnaires were administered to 153 owners/managers of piggeries (average of 7 from each of the 21 prefectures in GD). Univariable and multivariable logistic regression analyses were used to identify risk factors for farmer reported SI in piggeries during the six months preceding the questionnaire administration. The ability of wild birds to enter piggeries (OR 2.50, 95% CI: 1.01-6.16), the presence of poultry on a pig-farm (OR 3.24, 95% CI: 1.52-6.94) and no biosecurity measures applied to workers before entry to the piggery (OR 2.65, 95% CI: 1.04-6.78) were found to increase the likelihood of SI being reported by farmers in a multivariable logistic regression model. The findings of this study highlight the importance of understanding the local pig industry and the practices adopted when developing control measures to reduce the risk of SI to pig farms.

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.

Intestinal Spirochetosis in an Immunocompetent Patient

Intestinal spirochetosis (IS) is an infestation defined by the presence of spirochetes on the surface of the colonic mucosa. The implicated organisms can be Brachyspiraaalborgior Brachyspirapilosicoli. We present the case of a 66-year-old man with a past medical history of diabetes mellitus, hypertension, morbid obesity, and gastroesophageal reflux. The patient was sent to the gastroenterology clinic for a screening colonoscopy due to a prior history of colonic polyps. The patient was completely asymptomatic as he denies any abdominal pain, diarrhea, melena, or hematochezia. A colonoscopy was done showing colitis in the cecum and at the ileocecal valve, for which random biopsies were taken in the terminal ileum, cecum, and ascending colon. The histopathology result was positive for spirochetosis. Due to this finding, the patient was referred to the infectious diseases clinic, where a rapid plasma reagin (RPR) and human immunodeficiency virus (HIV) tests were found to be negative. Since the patient was immunocompetent and asymptomatic, it was decided to monitor and not initiate antibiotic treatment. Human IS are not related to non-intestinal spirochetes like Treponema pallidum. An infection of T. pallidum leads to a malignant picture called syphilitic proctitis and appears in the setting of an immunocompromised patient. The treatment of IS is based on the clinical presentation, severity of symptoms, and immune status. The purpose of this case is to emphasize the correct antibiotic indication in patients with IS.

Treponema pallidum Immunohistochemistry is positive in human intestinal Spirochetosis

BACKGROUND

Human intestinal spirochetosis (IS) has been recognized for decades, but whether it represents commensalism or a pathogenic process remains controversial. IS is diagnosed on routine stains with confirmation by silver stains but these stains are labor intensive and slow to read. We evaluated the Treponema pallidum immunostain as a diagnostic adjunct for IS.

METHODS

We retrieved biopsies from 33 patients with IS for this study. Each case was tested by Warthin-Starry (WS) and T. pallidum immunohistochemistry (IHC). Species specific genotyping was performed in 3 cases.

RESULTS

Patients with IS ranged from 22 to 82 years without gender predilection. IS involved normal (n = 15), and inflamed (n = 5) mucosa and colonic polyps (n = 13). Warthin-Starry and T. pallidum IHC were positive in all cases including both species of Brachyspira. Six (18%) symptomatic patients were treated for IS, and experienced resolution. In patients diagnosed with incidental IS on cancer screening (n = 5), follow up biopsies, without therapy, were negative for IS. T. pallidum IHC required 75 min less hands-on time than WS for performance and was faster to interpret.

CONCLUSIONS

T. pallidum IHC can be used to confirm the diagnosis of IS and is easier to perform and faster to interpret than WS.

Human intestinal spirochetosis in Japanese patients aged less than 20 years: Histological analysis of colorectal biopsy and surgical specimens obtained from 479 patients

Human intestinal spirochetosis (HIS) is a condition in which spirochetes attach to and colonize the colorectal epithelium. To our knowledge, no comprehensive studies of HIS in young patient have been published in a developed country. This study aimed to determine the incidence and clinicopathological manifestations of HIS in Japanese patients aged less than 20 years. We retrospectively reviewed 3605 biopsy and 92 surgical specimens obtained from 479 patients admitted to Shinshu University Hospital between 1997 and 2014. All slides were reviewed independently by two pathologists to confirm the histological presence of spirochetes. Among 387 patients who underwent biopsy, the most common pathologic diagnosis was ulcerative colitis (12.6%, n = 49). Additionally, about half of the biopsy specimens showed non-specific, mildly inflamed mucosa (50.6%, n = 196); only one of these cases was HIS. On the other hand, among the surgical specimens, we found no cases of HIS. We concluded that the incidence of HIS in Japanese young patients was 0.2% (1/479 cases). The incidence of HIS in Japanese young patients was very low, and one HIS case was associated with colitis with abdominal pain.

Clinicopathologic study of intestinal spirochetosis in Japan with special reference to human immunodeficiency virus infection status and species types: analysis of 5265 consecutive colorectal biopsies

Background

Previous studies reported that the incidence of intestinal spirochetosis was high in homosexual men, especially those with Human Immunodeficiency Virus infection. The aim of the present study was to clarify the clinicopathological features of intestinal spirochetosis in Japan with special reference to Human Immunodeficiency Virus infection status and species types.

Methods

A pathology database search for intestinal spirochetosis was performed at Tokyo Metropolitan Cancer and Infectious Disease Center Komagome Hospital between January 2008 and October 2011, and included 5265 consecutive colorectal biopsies from 4254 patients. After patient identification, a retrospective review of endoscopic records and clinical information was performed. All pathology slides were reviewed by two pathologists. The length of the spirochetes was measured using a digital microscope. Causative species were identified by polymerase chain reaction.

Results

Intestinal spirochetosis was diagnosed in 3 out of 55 Human Immunodeficiency Virus-positive patients (5.5%). The mean length of intestinal spirochetes was 8.5 μm (range 7–11). Brachyspira pilosicoli was detected by polymerase chain reaction in all 3 patients. Intestinal spirochetosis was also diagnosed in 73 out of 4199 Human Immunodeficiency Virus-negative patients (1.7%). The mean length of intestinal spirochetes was 3.5 μm (range 2–8). The species of intestinal spirochetosis was identified by polymerase chain reaction in 31 Human Immunodeficiency Virus-negative patients. Brachyspira aalborgi was detected in 24 cases (78%) and Brachyspira pilosicoli in 6 cases (19%). Both Brachyspira aalborgi and Brachyspira pilosicoli were detected in only one Human Immunodeficiency Virus-negative patient (3%). The mean length of Brachyspira aalborgi was 3.8 μm, while that of Brachyspira pilosicoli was 5.5 μm. The length of Brachyspira pilosicoli was significantly longer than that of Brachyspira aalborgi (p < 0.01). The lengths of intestinal spirochetes were significantly longer in Human Immunodeficiency Virus-positive patients than in Human Immunodeficiency Virus-negative patients (p < 0.05).

Conclusions

The incidence of intestinal spirochetosis was slightly higher in Human Immunodeficiency Virus-positive patients than in Human Immunodeficiency Virus-negative patients. However, no relationship was found between the Human Immunodeficiency Virus status and intestinal spirochetosis in Japan. Brachyspira pilosicoli infection may be more common in Human Immunodeficiency Virus-positive patients with intestinal spirochetosis than in Human Immunodeficiency Virus-negative patients with intestinal spirochetosis.

Human intestinal spirochetosis is significantly associated with sessile serrated adenomas/polyps

It remains unclear whether or not human intestinal spirochetosis (HIS) has any associated symptoms or lesions. In this study, we assessed the prevalence of HIS in sessile serrated adenomas/polyps (SSA/Ps) and their possible association. Following identification of early cecal cancer with SSA/P accompanied by a colonization of HIS, we went on to conduct a retrospective case-control study using endoscopically resected SSA/P specimens to examine the frequency of HIS infection in SSA/Ps. Nineteen SSA/P cases and 172 controls were obtained. The rate of HIS infection was significantly higher at 52.6% (10/19) in the SSA/P cases compared to the controls at 8.1% (14/172). Our SSA/P series were associated with a remarkably higher rate of HIS than controls or than previously reported. This is the first report to provide evidence for potential association between HIS and SSA/Ps.

Human intestinal spirochaetosis in two ulcerative colitis patients

A histological examination of colonic biopsies of the longitudinal and irregularly-shaped ulcerative lesions of a 37-year-old man and 61-year-old man with ulcerative colitis showed so-called "fringe formation," a typical finding of Brachyspira infection. The antibody titer to Brachyspira aalborgi showed marked elevation in both cases, and the patients were each treated with 1,000 mg of metronidazole for 14 days. Colonoscopy performed after treatment showed an improvement in the ulcerative lesions in both patients. These results indicate the possibility that intestinal spirochaetosis infection should be considered as an infectious complication in patients with ulcerative colitis receiving long-term steroid therapy.

Comparative genomics of Brachyspira pilosicoli strains: genome rearrangements, reductions and correlation of genetic compliment with phenotypic diversity

Background

The anaerobic spirochaete Brachyspira pilosicoli causes enteric disease in avian, porcine and human hosts, amongst others. To date, the only available genome sequence of B. pilosicoli is that of strain 95/1000, a porcine isolate. In the first intra-species genome comparison within the Brachyspira genus, we report the whole genome sequence of B. pilosicoli B2904, an avian isolate, the incomplete genome sequence of B. pilosicoli WesB, a human isolate, and the comparisons with B. pilosicoli 95/1000. We also draw on incomplete genome sequences from three other Brachyspira species. Finally we report the first application of the high-throughput Biolog phenotype screening tool on the B. pilosicoli strains for detailed comparisons between genotype and phenotype.

Results

Feature and sequence genome comparisons revealed a high degree of similarity between the three B. pilosicoli strains, although the genomes of B2904 and WesB were larger than that of 95/1000 (~2,765, 2.890 and 2.596 Mb, respectively). Genome rearrangements were observed which correlated largely with the positions of mobile genetic elements. Through comparison of the B2904 and WesB genomes with the 95/1000 genome, features that we propose are non-essential due to their absence from 95/1000 include a peptidase, glycine reductase complex components and transposases. Novel bacteriophages were detected in the newly-sequenced genomes, which appeared to have involvement in intra- and inter-species horizontal gene transfer. Phenotypic differences predicted from genome analysis, such as the lack of genes for glucuronate catabolism in 95/1000, were confirmed by phenotyping.

Conclusions

The availability of multiple B. pilosicoli genome sequences has allowed us to demonstrate the substantial genomic variation that exists between these strains, and provides an insight into genetic events that are shaping the species. In addition, phenotype screening allowed determination of how genotypic differences translated to phenotype. Further application of such comparisons will improve understanding of the metabolic capabilities of Brachyspira species.

Occurrence of viable Brachyspira spp. on carcasses of spent laying hens from supermarkets

Brachyspira spp. are frequent inhabitants of the chicken's intestine and some have been associated with enteric disease in humans. We studied contamination with Brachyspira spp. of carcasses of spent laying hens as a possible source of infections for humans and animals that may eat this meat. Eleven batches of hen carcasses, for a total of 110 carcasses, were bought in Belgian supermarkets during 2009-2010. Carcass rinse samples were examined for the presence of Brachyspira. Brachyspira spp. were cultured from some carcass in all batches. Besides presumably non-pathogenic species such as Brachyspira murdochii and Brachyspira innocens, the poultry pathogen Brachyspira intermedia and the poultry and suspected human pathogen Brachyspira pilosicoli were identified in 7/11 and 1/11 carcass batches, respectively, at high numbers, as shown using quantitative polymerase chain reactions. Multilocus sequence typing (MLST) demonstrated the presence of 2 and 13 MLST types of B. pilosicoli and B. intermedia, respectively, with all strains belonging to novel MLST types. The findings show that carcasses of spent laying hens are commonly contaminated with high numbers of Brachyspira spp., including the suspected zoonotic agent B. pilosicoli.

Bloodstream infection due to Brachyspira pilosicoli in a patient with multiorgan failure

Brachyspira pilosicoli is an etiological agent of human intestinal spirochetosis. Bloodstream infection due to this microorganism is rare. We report a case of B. pilosicoli bacteremia in a 70-year-old patient who presented with multiorgan failure.

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.

In vitro antagonistic activities of Lactobacillus spp. against Brachyspira hyodysenteriae and Brachyspira pilosicoli

The sensitivity of Brachyspira hyodysenteriae and Brachyspira pilosicoli, respectively the causative agents of Swine Dysentery and Porcine Intestinal Spirochaetosis to two probiotic Lactobacillus strains, L. rhamnosus CNCM-I-3698 and L. farciminis CNCM-I-3699 was studied through viability, motility and coaggregation assays. The cell-free supernatant of these lactobacilli contains lactic acid, that is stressful for Brachyspira (leading to the formation of spherical bodies), and lethal. It was demonstrated for the first time the in vitro coaggregation properties of two probiotic Lactobacillus strains (active or heat-treated) with two pathogenic strains of Brachyspira, leading to (1) trapping of spirochaetal cells in a physical network as demonstrated by SEM; (2) inhibition of the motility of Brachyspira. Such in vitro studies should encourage in vivo studies in animal model to evaluate the potential of the use of probiotic lactobacilli through a feeding strategy for the prevention of B. hyodysenteriae and B. pilosicoli.

Occurrence of human intestinal spirochetosis in comparison with infections by other enteropathogenic agents in an area of the Northern Italy

The aim of this study was to investigate the occurrence of human intestinal spirochetosis (IS) by a 16S rRNA restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) in a selected group (234) of patients with gastrointestinal complaints and/or potential risk factors for IS in comparison with the occurrence of infections by other enteropathogenic agents. By using 16S rRNA RFLP-PCR, 16 patients (6.8%) with IS were found (11 infected by Brachyspira aalborgi, 3 by Brachyspira pilosicoli, and 2 by both species); moreover, 10 patients with gastroenteric viruses (4.2%), 13 with enteropathogenic bacteria other than intestinal spirochetes (5.5%), and 24 with intestinal parasites (10.2%) were found. This study provides an enhancement of the knowledge about the distribution of IS, suggesting that it may be more frequent than suspected and that clinicians should consider IS when patients present with long-standing diarrhea. Moreover, 16S rRNA RFLP-PCR might be a powerful tool not only for diagnostic purpose but also to investigate the occurrence of IS just on fecal samples, not requiring invasive diagnostic techniques.

Symptomatic colonic spirochaetosis in an immunocompetent patient

Spirochaetes are organisms that can infect the colon of people with normal or compromised immune systems. Infected patients can present with a variety of gastrointestinal symptoms, including diarrhoea and rectal bleeding. However, some report a lack of association between specific symptoms and the presence of spirochaetes. It is therefore unclear whether the spirochaetes colonising the colon are true pathogens. Diagnosis is typically made by histological examination, with the biopsy specimen showing a band-like growth of spirochaetes adherent to the colonic luminal surface, giving an accentuated brush-border appearance. A course of metronidazole can eliminate the spirochaetes, but treatment might not lead to improvement of symptoms. Owing to the lack of a definite association between symptoms and the presence of spirochaetes, observation without specific antibiotic treatment can be pursued in most patients.