Microbiota composition and mucosal immunity in patients with asymptomatic diverticulosis and controls

INTRODUCTION

The etiology of diverticulosis is still poorly understood. However, in patients with diverticulitis, markers of mucosal inflammation and microbiota alterations have been found. The aim of this study was to evaluate potential differences of the gut microbiota composition and mucosal immunity between patients with asymptomatic diverticulosis and controls.

METHODS

We performed a prospective study on patients who underwent routine colonoscopy for causes not related to diverticular disease or inflammatory bowel disease. Participants were grouped based on the presence or absence of diverticula. Mucosal biopsies were obtained from the sigmoid and transverse colon. Microbiota composition was analyzed with IS-pro, a 16S-23S based bacterial profiling technique. To predict if patients belonged to the asymptomatic diverticulosis or control group a partial least squares discriminant analysis (PLS-DA) regression model was used. Inflammation was assessed by neutrophil and lymphocyte counts within the taken biopsies.

RESULTS

Forty-three patients were enrolled. Intestinal microbiota profiles were highly similar within individuals for all phyla. Between individuals, microbiota profiles differed substantially but regardless of the presence (n = 19) of absence (n = 24) of diverticula. Microbiota diversity in both sigmoid and transverse colon was similar in all participants. We were not able to differentiate between diverticulosis patients and controls with a PLS-DA model. Mucosal lymphocyte counts were comparable among both groups; no neutrophils were detected in any of the studied biopsies.

CONCLUSIONS

Microbiota composition and inflammatory markers were comparable among asymptomatic diverticulosis patients and controls. This suggests that the gut microbiota and mucosal inflammation do not play a major role in the pathogenesis of diverticula formation.

Intestinal Barrier Breakdown and Mucosal Microbiota Disturbance in Neuromyelitis Optical Spectrum Disorders

Background and Purpose

The mechanism underlying the pathology of neuromyelitis optica spectrum disorders (NMOSD) remains unclear even though antibodies to the water channel protein aquaporin-4 (AQP4) on astrocytes play important roles. Our previous study showed that dysbiosis occurred in the fecal microbiota of NMOSD patients. In this study, we further investigated whether the intestinal barrier and mucosal flora balance are also interrupted in NMOSD patients.

Methods

Sigmoid mucosal biopsies were collected by endoscopy from six patients with NMOSD and compared with samples from five healthy control (HC) individuals. These samples were processed for electron microscopy and immunohistochemistry to investigate changes in ultrastructure and in the number and size of intestinal inflammatory cells. Changes in mucosal flora were also analyzed by high-throughput 16S ribosomal RNA gene amplicon sequencing.

Results

The results from bacterial rRNA gene sequencing showed that bacterial diversity was decreased, but Streptococcus and Granulicatella were abundant in the colonic mucosa specimens of NMOSD patients compared to the HC individuals. The intercellular space between epithelia of the colonic mucosa was wider in NMOSD patients compared to the HC subjects (p < 0.01), and the expression of tight junction proteins [occludin, claudin-1 and zonula occludens-1 (ZO-1)] in NMOSD patients significantly decreased compared to that in the HC subjects. We also found numerous activated macrophages with many inclusions within the cytoplasm, mast cells with many particles in their cytoplasm, and enlarged plasma cells with rich developed rough endoplasmic reticulum in the lamina propria of the mucosa of the patients with NMOSD. Quantitative analysis showed that the percentages of small CD38+ and CD138+ cells (plasma cells) were lower, but the percentage of larger plasma cells was higher in NMOSD patients.

Conclusion

The present study demonstrated that the intestinal barrier was disrupted in the patients with NMOSD, accompanied by dysbiosis and inflammatory activation of the gut. The mucosal microbiota imbalance and inflammatory responses might allow pathogens to cross the damaged intestinal barrier and participate in pathological process in NMOSD. However, further study on the pathological mechanism of NMOSD underlying gut dysbiosis is warranted in the future.

MRSA peritonitis secondary to perforation of sigmoid diverticulitis

The occurrence of methicillin-resistant Staphylococcus aureus (MRSA) is well documented, but the pathology is usually associated with post surgical infections or long-term peritoneal dialysis. We report the case of a 50-year-old Caucasian man who presented with a one week history of left lower quadrant abdominal pain, poor appetite and nausea due to MRSA peritonitis secondary to perforated sigmoid diverticulitis. Despite a thorough search of the medical literature, we could not find that this problem has been previously described. We report this case to demonstrate the robust nature of MRSA, which has generally not been considered to be a normal colonizing bacterium of the sigmoid colon.

A case of perforative peritonitis caused by a piece of bamboo in a patient on peritoneal dialysis

We report a case of peritonitis resulting from colon perforation caused by ingestion of a rare foreign body in a patient on peritoneal dialysis (PD). A 72-year-old woman on PD was hospitalized with abdominal pain and cloudy PD fluid (PDF). Although conventional antibiotic therapy was started because of a diagnosis of infectious peritonitis, low-grade fever, abdominal pain and a high number of white blood cells in PDF persisted. On day 3, anaerobic bacteria were recognized on bacterial culture of PDF, suggesting a gastrointestinal etiology. During exploratory laparotomy, sigmoidal perforation by a piece of bamboo, probably resulting from ingestion of contaminated food, was found.

Dihydroxy bile acids increase mucosal permeability and bacterial uptake in human colon biopsies

OBJECTIVE

Bile acids in mM concentrations are known to increase chloride secretion and alter mucosal permeability in animal colon. Increased mucosal permeability is believed to play an important role in the development of intestinal inflammation. The aim of this study was to investigate the influence of microM concentrations of dihydroxy bile acids on permeability and bacterial uptake in the normal human colon.

MATERIAL AND METHODS

Endoscopic biopsies from the sigmoid colon of 18 subjects with normal colonic histology were mounted in modified Ussing chambers. Chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA) were added to the mucosal compartment. Short-circuit current (Isc) and transepithelial resistance (TER) were studied for 120 min. Cr-EDTA and horseradish peroxidase (HRP) were used to assess paracellular and transcellular permeability, respectively. The transmucosal passage of chemically killed Escherichia coli was quantified and investigated using confocal microscopy.

RESULTS

A significant decrease in TER was seen after 60 min of exposure to 1000 micromol/l CDCA and DCA. The combination of E. coli and 100 micromol/l CDCA gave a decrease in TER compared to controls (p = 0.06). DCA showed a dose-related increase in Cr-EDTA permeability, which was most pronounced at 1000 micromol/l (p = 0.02). Increased E. coli uptake was induced by 500 micromol/l (p = 0.01) and 1000 micromol/l CDCA (p = 0.04). Bacterial uptake was increased at 100 micromol/l by exposure to DCA (p = 0.03). Confocal microscopy revealed the presence of E. coli bacteria in the lamina propria after 15 min of exposure to 1000 micromol/l CDCA and DCA.

CONCLUSIONS

Our study suggests that dihydroxy bile acids in microM concentrations alter barrier function in normal human colon biopsies, causing increased antigen and bacterial uptake; thereby bile acids may contribute to the development of intestinal inflammation.

Severe large bowel obstruction secondary to infection with Actinomyces israelii

Abdomino-pelvic actinomycosis is a rare disease, which usually follows a chronic course. However, bowel obstruction may reveal an acute clinical picture. We report on a 38-y-old female with abdomino-pelvic actinomycosis, characterized by a 10 cm long filiform stenosis of the sigmoid colon and bilateral ovarian abscesses. She developed acute ileus that required emergency surgery.

[Severe diarrhoea with invasive intestinal spirochaetosis]

A 38-year-old heterosexual male presented with a 6 to 7 week history of severe diarrhoea but no other complaints. In routine faecal cultures and routine parasitological investigations no pathogenic micro-organisms were observed. Colonoscopy revealed a normal mucosa. Multiple biopsies were obtained. The histological diagnosis was invasive intestinal spirochaetosis. The immunostain for Borrelia burgdorferi cross-reacted with the spirochetes of the intestinal spirochaetosis. After two weeks of incubation under strict anaerobic conditions a spirochaete was cultured from a biopsy of the sigmoid mucosa. The 16SrDNA sequence was consistent with Brachyspira aalborgi. The HIV and syphilis results were negative. The patient was treated first with metronidazole and then by clindamycin. The diarrhoea subsided after the second course of treatment and the cause was presumed to have been the invasive intestinal spirochaetosis. Intestinal spirochaetosis is usually found coincidentally at histological examination of colon biopsies. There is no general consensus that intestinal spirochaetosis is the cause of the diarrhoea. There is however an association between the presence of symptoms and the invasivity of spirochaetes, morphological colon epithelial changes and evidence of immune response. The literature reports patients who improve symptomatically without specific treatment. Treatment may be given to patients with severe symptoms.

Molecular analysis of jejunal, ileal, caecal and recto-sigmoidal human colonic microbiota using 16S rRNA gene libraries and terminal restriction fragment length polymorphism

Microbiota in gut contents of jejunum, ileum, caecum and recto-sigmoid colon obtained from three elderly individuals at autopsy were compared using 16S rRNA gene libraries and terminal restriction fragment length polymorphism (T-RFLP). Random clones of 16S rRNA gene sequences were isolated after PCR amplification with universal primer sets of total genomic DNA extracted from each sample of gut contents. An average of 90 randomly selected clones were partially sequenced (about 500 bp). T-RFLP analysis was performed using the 16S rRNA gene amplified from each sample. The lengths of the terminal restriction fragments were analysed after digestion with HhaI and MspI. The jejunal and ileal microbiota consisted of simple microbial communities of streptococci, lactobacilli, 'Gammaproteobacteria', the Enterococcus group and the Bacteroides group. Most of the species were facultative anaerobes or aerobes. The Clostridium coccoides group and the Clostridium leptum subgroup, which are the most predominant groups in human faeces, were not detected in samples from the upper gastrointestinal tract. The caecal microbiota was more complex than the jejunal and ileal microbiota. The C. coccoides group, the C. leptum subgroup and the Bacteroides group were detected in the caecum. The recto-sigmoidal colonic microbiota consisted of complex microbial communities, with numerous species that belonged to the C. coccoides group, the C. leptum subgroup, the Bacteroides group, 'Gammaproteobacteria', the Bifidobacterium group, streptococci and lactobacilli, and included more than 26 operational taxonomic units. The results showed marked individual differences in the composition of microbiota in each region.

Spatial organization and composition of the mucosal flora in patients with inflammatory bowel disease

The composition and spatial organization of the mucosal flora in biopsy specimens from patients with inflammatory bowel disease (IBD; either Crohn's disease or ulcerative colitis), self-limiting colitis, irritable-bowel syndrome (IBS), and healthy controls were investigated by using a broad range of fluorescent bacterial group-specific rRNA-targeted oligonucleotide probes. Each group included 20 subjects. Ten patients who had IBD and who were being treated with antibiotics were also studied. Use of nonaqueous Carnoy fixative to preserve the mucus layer was crucial for detection of bacteria adherent to the mucosal surface (mucosal bacteria). No biofilm was detectable in formalin-fixed biopsy specimens. Mucosal bacteria were found at concentrations greater than 10(9)/ml in 90 to 95% of IBD patients, 95% of patients with self-limiting colitis, 65% of IBS patients, and 35% of healthy controls. The mean density of the mucosal biofilm was 2 powers higher in IBD patients than in patients with IBS or controls, and bacteria were mostly adherent. Bacteroides fragilis was responsible for >60% of the biofilm mass in patients with IBD but for only 30% of the biofilm mass in patients with self-limiting colitis and <15% of the biofilm mass in patients with IBS. In contrast, bacteria which positively hybridized with the probe specific for Eubacterium rectale-Clostridium coccoides accounted for >40% of the biofilm in IBS patients but for <15% of the biofilm in IBD patients. In patients treated with (5-ASA) or antibiotics, the biofilm could be detected with 4,6-diamidino-2-phenylindole but did not hybridize with fluorescence in situ hybridization probes. A Bacteroides fragilis biofilm is the main feature of IBD. This was not previously recognized due to a lack of appropriate tissue fixation. Both 5-ASA and antibiotics suppress but do not eliminate the adherent biofilm.

Difficult hernia repair in the elderly. A particular case

A particular clinical case personally observed is described. On the basis of this case it is evaluated if it can be correct to implant a mesh in potentially contaminated areas, if preperitoneal repair is the best approach in recurrent or difficult hernia repair and if there are specific contraindications in operating elderly patients.

Female genital coccidioidomycosis (FGC), Addison's disease and sigmoid loop abscess due to Coccidioides immites; case report and review of literature on FGC

We describe a woman with unusual complications of infection with Coccidioides immitis--infection of the genital tract and adrenal insufficiency. The patient also had intestinal coccidioidomycosis (cocci) in conjunction with presumed pulmonary, and asymptomatic central nervous system cocci. To our knowledge, concurrent FGC, intestinal and adrenal cocci have not been reported previously. A MEDLINE review from 1966-1997 revealed only 1 case of adrenal insufficiency due to cocci. FGC is rare; we identified 12 reported cases since 1929. No combination of investigations or clinical features is sensitive enough to predict FGC. Diagnosis is usually made after microscopy of surgical specimens. FGC presents either as tubo-ovarian disease or endometritis. Treatment generally involves surgical excision and antifungal agents. We hypothesize that an initial trial of antifungals may obviate the need for surgery.

Gastrointestinal basidiobolomycosis. Morphologic findings in a cluster of six cases

We describe the histopathologic features of 6 cases of gastrointestinal basidiobolomycosis examined at 4 Phoenix, AZ, area hospitals during the last 4 years. Resected stomach and intestinal specimens were characterized by marked mural thickening with fibrosis, prominent tissue eosinophil infiltration and palisading granulomatous inflammation around pale fungal hyphae. In 2 cases, there was colonic perforation. Basidiobolus ranarum hyphae (associated with spore-like spherules in 4 cases) were identified within tissue sections; the irregularly branched, thin-walled, occasionally septated hyphae were typically surrounded by a thick eosinophilic cuff (Splendore-Hoeppli phenomenon). Although the histologic features of B ranarum are well described in the skin and subcutaneous tissue, gastrointestinal involvement has presented considerable diagnostic difficulty. Before the occurrence of this cluster of cases, intra-abdominal B ranarum infection has been reported only rarely.

[The colonization resistance of the mucous membrane of the large intestine in patients with rheumatoid arthritis in a period of exacerbation]

Specific and quantitative compositions of the colon mucous microflora in 36 patients with rheumatic arthritis (RA) in the remission period were studied. The mucous membrane of healthy people is colonized by bifidobacteria, lactobacilli, Bacteroides, Escherichia and enterococci. The mucous membrane in such people is mainly colonized by aerobic opportunistic conventionally pathogenic enterobacteria (enteropathogenic Escherichia, Citrobacter [correction of cytobacter], Enterobacter, Klebsiella, etc.), staphylococci, enterococci and anaerobic bacteria (Bacteroides, peptococci, peptostreptococci, etc.). Taking into account significant changes of colonization resistance in the colon mucous membrane in remission period of RA, it is necessary to apply bacteriotherapy, using bacterial drugs containing bifidobacteria and lactobacteria.

Diversion-related experimental colitis in rats

PURPOSE

Diversion-related colitis is an inflammatory process that affects the colon and/or rectum distal to a colostomy. Its mechanisms are unknown, and many hypotheses have been considered. The aim of the present study was to create an experimental model of diversion-related colitis in rats, so in the future it will be possible to test different hypotheses.

METHODS

Three groups of ten male Wistar rats were used for the study. Two groups underwent a colostomy and were kept alive for 6 or 17 weeks. One group of rats was killed at the onset of the experiment. Specimens were taken in bypassed segments in the rats who had had a colostomy and in the sigmoid colon for the control group. Histologic analysis using standard coloration, histochemical techniques, and bacterial preparation was used to find histologic or changes of colonic histology or flora.

RESULTS

Exclusion was associated with vascular congestion, a decrease in length of glandular crypts (P < 0.01), and an erosion of surface epithelium; inflammation of the mucosa was absent in all control animals and present in all test animals. In contrast, the number of goblet cells was not changed by the procedure. There was also a significant change in distribution and intensity of sulfomucins and sialomucins and quantitative and qualitative changes of the colonic flora.

CONCLUSION

This experimental model of diversion colitis is characterized by histologic and bacteriologic modifications comparable with those reported in humans but with different histochemical changes.

Candida carriage in the alimentary tract of liver transplant candidates

Thirty randomly selected patients with advanced chronic liver disease, which had been evaluated for possible liver transplantation, were sampled endoscopically at 7 alimentary tract locations to assess the frequency and amount of Candida carriage. Eighty-one percent (127/156) of the samples obtained contained Candida and 53% (82/156) yielded high counts (> 300 CFU/ml). The most predominant Candida species isolated at each site was Candida albicans, which accounted for 103 (64%) of the 160 fungal isolates. The other Candida species isolated included C tropicalis 30 (19%), C krusei 16 (10%), and C glabrata 11 (7%). Although the number of sites at which yeast was present and the quantities of yeast at each site varied widely among the patients studied, 100% of the patients had Candida in at least one site of the gastrointestinal tract. Eighty-six percent (24/28) of the duodenal aspirates contained Candida and 50% (14/28) of the duodenal samples contained greater than 300 CFU/ml. A positive culture from the stomach was a reliable predictor of the presence of Candida in the duodenum (P = 0.0001), but a positive culture at no other site readily predicted the presence of Candida at yet another site. Importantly, there was no correlation between the presence or absence of Candida in either oral or rectal swabs and colonization at other anatomic sites within the gastrointestinal tract. These findings are important in liver transplantation, particularly in those cases in which the bowel has been opened to create a choledochojejunostomy anastomosis. The operative attempts to reduce gastrointestinal fungal carriage using oral antifungal agents may be justified before liver transplantation in an effort to lower the risk of posttransplantation fungal infections, particularly in those patients expected to have a Roux-en-Y choledochojejunostomy biliary reconstruction.

[Scanning electron microscopy of intestinal mucosa after enteric preparation in patients with carcinoma of large bowel]

In this study, 6 patients were randomly divided into three groups, receiving different intestinal preparations. Colonic mucosa were biopsied for S-520 scanning electron microscopy. Of them, only a tiny minority of bacteria were found in the specimen of the first group. Bacteria weren't discovered in the other two groups. Therefore, three conventional enteric preparations are equally effective and efficient in eliminating intestinal flora. The causes of postoperative incisional infection are many and varied.

Bacterial flora of the sigmoid neovagina

The bacterial microbiota of 15 sigmoid neovaginas, created in patients with congenital vaginal aplasia or male transsexualism, was studied. No specimen was sterile, and only normal inhabitants of the colon were cultured. The total counts of bacteria were lower than those reported for healthy sigmoid colons.

Isolation of Chlamydia trachomatis from the lower digestive tract

Chlamydia trachomatis was isolated from ten of 188 biopsies (5.3%) obtained from different parts of the lower digestive tract. Patients (mean age 37.0 years) presented with ulcerative proctitis, Crohn's disease, mild colitis or ulcerative colitis. Seven rectal biopsies, two biopsies from the sigmoid flexure and one caecal biopsy were positive for chlamydial isolation whereas all biopsies taken from the colon ascendens, transversum or descendens and from the terminal ileum were negative. We conclude that isolation of C. trachomatis is most effective from rectal and sigmoidal biopsies and is a rare event from other sites of the lower digestive tract.

[A case of actinomycosis of the sigmoid in a 41-year-old woman with a clinical appearance of cancer]

A case of sigmoid actinomycosis is described in a women aged 41 years in whom clinical and intraoperative diagnosis was that of carcinoma. Laparotomy was performed with resection of the sigmoid with the tumour.

Ammoniagenic coma following ureterosigmoidostomy

Ammoniagenic coma or episodic stupor is a rare complication of ureterosigmoidostomy. We report a case with the unusual features of normal liver function and normal liver biopsy. With extremely rare exception, ammoniagenic coma will not occur in the presence of normal ornithine-urea cycle synthesis in the liver.

Interactions of serotypes A and B of Candida albicans in mice

Candida albicans serotypes A and B were mixed in different proportions and administered orally to white mice receiving a protein-free diet. Recoveries of the serotype from the stomach and rectosigmoid showed that the relative proportion of serotype A was consistently higher than in the inoculating suspension. No modification of serotype was observed in mice given only one serotype, and there was no change in proportions of serotypes coincubated in vitro. These observations indicate that host factors must be involved in selective colonization by the serotypes in vivo.

[Study of various factors affecting the colonization of the digestive tract in white mice by Candida albicans]

This paper deals with the quantitative localization of Candida albicans in different parts of white micr gastrointestinal tract after oral inoculation of the yeast. Animals are previously treated with ampicillin, cortisone, or estradiol. Female pregnant and normal adult mice are also used. Our results show that the number of yeasts increases respectively in small intestine, stomach, caecum, and sigmoid. As compared with normal adult mice, C. albicans is more abundant in mice treated wtih ampicillin or cortisone whereas the yeast growth is lower in pregnant animals or in mice receiving estradiol. Moreover, male animals ordinarily show higher values than those found in female mice.