Microbiota Dynamics in Patients Treated with Fecal Microbiota Transplantation for Recurrent Clostridium difficile Infection

Clostridium difficile causes antibiotic-associated diarrhea and pseudomembraneous colitis and is responsible for a large and increasing fraction of hospital-acquired infections. Fecal microbiota transplantation (FMT) is an alternate treatment option for recurrent C. difficile infection (RCDI) refractory to antibiotic therapy. It has recently been discussed favorably in the clinical and scientific communities and is receiving increasing public attention. However, short- and long-term health consequences of FMT remain a concern, as the effects of the transplanted microbiota on the patient remain unknown. To shed light on microbial events associated with RCDI and treatment by FMT, we performed fecal microbiota analysis by 16S rRNA gene amplicon pyrosequencing of 14 pairs of healthy donors and RCDI patients treated successfully by FMT. Post-FMT patient and healthy donor samples collected up to one year after FMT were studied longitudinally, including one post-FMT patient with antibiotic-associated relapse three months after FMT. This analysis allowed us not only to confirm prior reports that RCDI is associated with reduced diversity and compositional changes in the fecal microbiota, but also to characterize previously undocumented post-FMT microbiota dynamics. Members of the Streptococcaceae, Enterococcaceae, or Enterobacteriaceae were significantly increased and putative butyrate producers, such as Lachnospiraceae and Ruminococcaceae were significantly reduced in samples from RCDI patients before FMT as compared to post-FMT patient and healthy donor samples. RCDI patient samples showed more case-specific variations than post-FMT patient and healthy donor samples. However, none of the bacterial groups were invariably associated with RCDI or successful treatment by FMT. Overall microbiota compositions in post-FMT patients, specifically abundances of the above-mentioned Firmicutes, continued to change for at least 16 weeks after FMT, suggesting that full microbiota recovery from RCDI may take much longer than expected based on the disappearance of diarrheal symptoms immediately after FMT.     

Inhibiting the Initiation of Clostridium difficile Spore Germination using Analogs of Chenodeoxycholic Acid,a Bile Acid

To cause disease, Clostridium difficile spores must germinate in the host gastrointestinal tract. Germination is initiated upon exposure to glycine and certain bile acids, e.g., taurocholate. Chenodeoxycholate, another bile acid, inhibits taurocholate-mediated germination. By applying Michaelis-Menten kinetic analysis to C. difficile spore germination, we found that chenodeoxycholate is a competitive inhibitor of taurocholate-mediated germination and appears to interact with the spores with greater apparent affinity than does taurocholate. We also report that several analogs of chenodeoxycholate are even more effective inhibitors. Some of these compounds resist 7α-dehydroxylation by Clostridium scindens, a core member of the normal human colonic microbiota, suggesting that they are more stable than chenodeoxycholate in the colonic environment.Clostridium difficile is a Gram-positive, spore-forming, anaerobic bacterium that is pathogenic for both humans and animals (33, 44). Infections caused by C. difficile range from mild diarrhea to more life-threatening conditions, such as pseudomembranous colitis (33). In the classic case, prior antibiotic treatment that disrupts the normally protective colonic flora makes patients susceptible to C. difficile infection (CDI) (35, 53). Other antibiotics, such as vancomycin and metronidazole, are the most commonly used treatments for CDI (54). However, because these antibiotics also disrupt the colonic flora, 10 to 40% of patients whose symptoms have been ameliorated suffer from relapsing CDI (15, 24). The annual treatment-associated cost for CDI in the United States is estimated to be between $750 million and $3.2 billion (8, 9, 16, 31). Moreover, the number of fatal cases of CDI has been increasing rapidly (14, 39). Thus, there is an urgent need to find alternative therapies for CDI.C. difficile infection likely is initiated by infection with the spore form of C. difficile (12). C. difficile elicits disease through the actions of two secreted toxins, TcdA and TcdB (48). TcdB was recently shown to be critical for pathogenesis in an animal model of disease (18). Since the toxins are produced by vegetative cells, not by spores (17), germination and outgrowth are prerequisites for pathogenesis.Spore germination is triggered by the interaction of small molecules, called germinants, with receptors within the spore inner membrane. These germinants vary by bacterial species and can include ions, amino acids, sugars, nucleotides, surfactants, or combinations thereof (43). The recognition of germinants triggers irreversible germination, leading to Ca²⁺-dipicolinic acid release, the uptake of water, the degradation of the cortex, and, eventually, the outgrowth of the vegetative bacterium (43). The germination receptors that C. difficile uses to sense the environment have not been identified. Based on homology searches, C. difficile germination receptors must be very different from known germination receptors (42), but they appear to be proteinaceous (13).Taurocholate, a primary bile acid, has been used for approximately 30 years by researchers and clinical microbiologists to increase colony formation by C. difficile spores from patient and environmental samples (3, 49, 51, 52). This suggested that C. difficile spores interact with bile acids along the gastrointestinal (GI) tract and that spores use a host-derived signal to initiate germination.The liver synthesizes the two major primary bile acids, cholate and chenodeoxycholate (40). These compounds are modified by conjugation with either taurine (to give taurocholate or taurochenodeoxycholate) or glycine (producing glycocholate or glycochenodeoxycholate). Upon secretion into the digestive tract, bile aids in the absorption of fat and cholesterol; much of the secreted bile is actively absorbed and recycled back to the liver for reutilization (40). Though efficient, enterohepatic recirculation is not complete; bile enters the cecum of the large intestine at a concentration of approximately 2 mM (30).In the cecum, bile is modified by the normal, benign colonic flora. First, bile salt hydrolases found on the surfaces of many bacterial species remove the conjugated amino acid, producing the deconjugated primary bile acids cholate and chenodeoxycholate (40). These deconjugated primary bile acids are further metabolized by only a few species of intestinal bacteria, including Clostridium scindens. C. scindens actively transports unconjugated primary bile acids into the cytoplasm, where they are 7α-dehydroxylated, converting cholate to deoxycholate and chenodeoxycholate to lithocholate (21, 40). The disruption of the colonic flora by antibiotic treatment abolishes 7α-dehydroxylation activity (41).Building upon the work on Wilson and others (51, 52), we demonstrated that taurocholate and glycine, acting together, trigger the loss of the birefringence of C. difficile spores (45). All cholate derivatives (taurocholate, glycocholate, cholate, and deoxycholate) stimulate the germination of C. difficile spores (45). Recently it was shown that taurocholate binding is prerequisite to glycine binding (37). At physiologically relevant concentrations, chenodeoxycholate inhibits taurocholate-mediated germination (46) and also inhibits C. difficile vegetative growth, as does deoxycholate (45). In fact, C. difficile spores use the relative concentrations of the various bile acids as cues for germination within the host (10).Since chenodeoxycholate is absorbed by the colonic epithelium and metabolized to lithocholate by the colonic flora (25, 40), the use of chenodeoxycholate as a therapy against C. difficile disease might be hindered by its absorption and conversion to lithocholate.Here, we further characterize the interaction of C. difficile spores with various bile acids and demonstrate that chenodeoxycholate is a competitive inhibitor of taurocholate-mediated germination. Further, we identify chemical analogs of chenodeoxycholate that are more potent inhibitors of germination and that resist 7α-dehydroxylation by the colonic flora, potentially increasing their stability and effectiveness as inhibitors of C. difficile spore germination in the colonic environment.     

An Integrated Metabolomic and Microbiome Analysis Identified Specific Gut Microbiota Associated with Fecal Cholesterol and Coprostanol in Clostridium difficile Infection

Clostridium difficile infection (CDI) is characterized by dysbiosis of the intestinal microbiota and a profound derangement in the fecal metabolome. However, the contribution of specific gut microbes to fecal metabolites in C. difficile-associated gut microbiome remains poorly understood. Using gas-chromatography mass spectrometry (GC-MS) and 16S rRNA deep sequencing, we analyzed the metabolome and microbiome of fecal samples obtained longitudinally from subjects with Clostridium difficile infection (n = 7) and healthy controls (n = 6). From 155 fecal metabolites, we identified two sterol metabolites at >95% match to cholesterol and coprostanol that significantly discriminated C. difficile-associated gut microbiome from healthy microbiota. By correlating the levels of cholesterol and coprostanol in fecal extracts with 2,395 bacterial operational taxonomic units (OTUs) determined by 16S rRNA sequencing, we identified 63 OTUs associated with high levels of coprostanol and 2 OTUs correlated with low coprostanol levels. Using indicator species analysis (ISA), 31 of the 63 coprostanol-associated bacteria correlated with health, and two Veillonella species were associated with low coprostanol levels that correlated strongly with CDI. These 65 bacterial taxa could be clustered into 12 sub-communities, with each community containing a consortium of organisms that co-occurred with one another. Our studies identified 63 human gut microbes associated with cholesterol-reducing activities. Given the importance of gut bacteria in reducing and eliminating cholesterol from the GI tract, these results support the recent finding that gut microbiome may play an important role in host lipid metabolism.     

Changes in Amino Acid Composition during Germination of Soybean

As a fundamental approach to the problem of amino acid metabolism in soybean, changes in content of twenty-three free amino acids, two acidic peptides, ammonia, ethanolamine, urea and seventeen total amino acids of cotyledon, hypocotyl and root of soybean during germination were determined with an amino acid analyzer. Glycine Max M. var. T201 (non-nodule-forming) and Glycine Max M. var. T202 (nodule-forming) were used for this experiment. The content and composition of free and total amino acids of cotyledon in both T201 and T202 differ from those of other tissues in any stage of germination. However, no significant difference between these two varieties of soybean has been recognized in patterns of free and total amino acids changes during germination.

In dry bean and initial stage of germination a relatively large unknown peak appeared and disappeared thereafter when the change in free amino acid content during germination of soybean was analyzed with amino acid analyzer. From various tests on the unknown peak, it became obvious that the peak was consisted of two peptides, γ-glutamyl-tyrosine and γ-glutamylphenylalanine, which were discovered in soybean by Thompson et al. in 1962. The content of these peptides did not change during the first 20 hours of germination, but they decreased rapidly thereafter and disappeared after 70 hours.     

Changes in Amino Acid Composition during Germination of Soybean

Malonogalactan, a malonylated polysaccharide (—74° (c=1.6, H₂O)) produced by Penicillium citrinum, consisted of d-galactose and malonic acid in the approximate molar ratio of 3:1. Molecular weight of the demalonylated galactan (-99° (c=4.6, H₂O)) was about 40,000. From the data regarding optical rotation, nuclear magnetic resonance spectrum, infrared spectrum, glycosidase susceptibility, periodate oxidation, Smith degradation, methylation and acid hydrolysis, the possible structure of the Penicillium malonogalactan is deduced as follows: A galactan, 1,5-β-galactofuranoside polymer esterified with malonic acid at the position of 2 or 3.     

Changes in Amino Acid Composition during Germination of Soybean

α- and γ-Glutamylaspartic acids were detected in acidic fraction of soybean seedling. R_F values of both peptides were consistent with those of authentic samples with several solvent systems.     

粪便微生物系移植通过影响炎症因子和肠道菌群结构缓解大鼠实验性结肠炎

炎症性肠病（inflammatory bowel disease,IBD）病因虽未明确,但目前认为,肠道细菌和肠黏膜免疫功能紊乱与IBD的发病密切相关。将40只SD大鼠分为健康对照组、模型组、粪便微生物系移植组（fecal microbiota transplantation,FMT）和柳氮磺胺吡啶组,后3组用2,4,6-三硝基苯磺酸（2,4,6-trinitrobenzene sulfonic acid, TNBS）灌肠造模,造模2 d后分别用粪便悬液和柳氮磺胺吡啶治疗1 w。末次给药后禁食1 d,对大鼠粪便进行菌群成分分析,股动脉取血,对K⁺ 、Na⁺ 、血清白蛋白（ALB）、白细胞计数（WBC）、中性粒细胞百分率（N%）、C-反应蛋白（CRP）、IL-1β、IL-10、IL-12和IL-17 水平进行检测,取结肠行病理学检查。结果发现,通过TNBS灌肠成功建立大鼠实验性结肠炎模型。与模型组比较,FMT组的K⁺和ALB明显升高(P<0.05),WBC、N%和CRP明显降低(P<0.05),IL-1β和IL-17明显降低(P<0.05),IL-10和IL-10/IL-12含量升高(P<0.05)。FMT能显著改善TNBS引起的肠道菌群变化,促进双歧杆菌的增殖而抑制脆弱拟杆菌和大肠杆菌的生长。上述结果证明,FMT可有效治疗炎症性肠病,其机制与其影响血清炎症因子水平和改善肠道菌群有关。     

SleC Is Essential for Germination of Clostridium difficile Spores in Nutrient-Rich Medium Supplemented with the Bile Salt Taurocholate

Clostridium difficile is the major cause of infectious diarrhea and a major burden to health care services. The ability of this organism to form endospores plays a pivotal role in infection and disease transmission. Spores are highly resistant to many forms of disinfection and thus are able to persist on hospital surfaces and disseminate infection. In order to cause disease, the spores must germinate and the organism must grow vegetatively. Spore germination in Bacillus is well understood, and genes important for this process have recently been identified in Clostridium perfringens; however, little is known about C. difficile. Apparent homologues of the spore cortex lytic enzyme genes cwlJ and sleB (Bacillus subtilis) and sleC (C. perfringens) are present in the C. difficile genome, and we describe inactivation of these homologues in C. difficile 630Δerm and a B1/NAP1/027 clinical isolate. Spores of a sleC mutant were unable to form colonies when germination was induced with taurocholate, although decoated sleC spores formed the same number of heat-resistant colonies as the parental control, even in the absence of germinants. This suggests that sleC is absolutely required for conversion of spores to vegetative cells, in contrast to CD3563 (a cwlJ/sleB homologue), inactivation of which had no effect on germination and outgrowth of C. difficile spores under the same conditions. The B1/NAP1/027 strain {"type":"entrez-nucleotide","attrs":{"text":"R20291","term_id":"774925","term_text":"R20291"}}R20291 was found to sporulate more slowly and produce fewer spores than 630Δerm. Furthermore, fewer {"type":"entrez-nucleotide","attrs":{"text":"R20291","term_id":"774925","term_text":"R20291"}}R20291 spores germinated, indicating that there are differences in both sporulation and germination between these epidemic and nonepidemic C. difficile isolates.The Gram-positive anaerobe Clostridium difficile causes diarrheal diseases ranging from asymptomatic carriage to a fulminant, relapsing, and potentially fatal colitis (8, 30). This organism is resistant to various broad-spectrum antibiotics and capitalizes on disruption of the normal intestinal flora to colonize and cause disease symptoms through the action of toxins A and B (16, 40). While these toxins are the principal virulence factors, the ability of the organism to produce endospores is necessary for disease transmission.Clostridial spores are extremely resistant to all kinds of chemical and physical agents and provide the mechanism by which C. difficile can evade the potentially fatal consequences of exposure to heat, oxygen, alcohol, and certain disinfectants (35). Thus, the spores shed in fecal matter are very difficult to eradicate and can persist on contaminated surfaces in health care facilities for extended periods of time (35). This leads to infection or reinfection of cohabitating individuals through inadvertent ingestion of infected material (10, 32). Once in the anaerobic environment of the gut, spores presumably germinate to form toxin-producing vegetative cells and, in susceptible individuals, diarrheal disease.Spore germination is defined as the events that result in the irreversible loss of spore characteristics. However, current mechanistic knowledge of the germination process is based principally on data derived from studying Bacillus subtilis. Little is known about spore germination in clostridia and, in particular, in C. difficile. Germination is initiated when the bacterial spore senses specific effectors, termed germinants. These effectors can include nutrients, cationic surfactants, peptidoglycan, and a 1:1 chelate of pyridine-2,6-dicarboxylic acid (dipicolinic acid) and Ca²⁺ (CaDPA) (23, 34, 36). Spores of B. subtilis can germinate in response to nutrients through the participation of three sensory receptors located in the spore inner membrane, GerA, GerB, and GerK (23). After activation, the events include the release of monovalent cations (H⁺, K⁺, and Na⁺) and CaDPA (accounting for approximately 10% of the spore dry weight) (36). The third major step in germination involves hydrolysis of the spore peptidoglycan (PG) cortex. It is during this hydrolysis that the previously low water content of the spore is restored to the water content of a normal vegetative cell and the core is able to expand, which in turn allows enzyme activity, metabolism, and spore outgrowth (36).CwlJ and SleB are two specific spore cortex-lytic enzymes (SCLEs) involved in Bacillus cortex hydrolysis, which break down PG containing muramic-δ-lactam (28). SleB has been shown to localize in both the inner and outer layers of B. subtilis spores through interaction of the enzyme peptidoglycan-binding motif and the δ-lactam structure of the cortex (7, 19) and in association with YpeB, which is required for sleB expression during sporulation (4, 7). SleB is a lytic transglycosylase muramidase, but so far its mode of activation is unknown (21). CwlJ is localized to the spore coat during sporulation (3) and is required for CaDPA-induced germination in B. subtilis. Activation can be due to either CaDPA released from the spore core at the onset of germination or exogenous CaDPA (22). Neither enzyme is individually essential for complete cortex hydrolysis during nutrient germination, although inactivation of both cwlJ and sleB in B. subtilis results in a spore unable to complete this process (15). The role of SleL has recently been studied in Bacillus anthracis. Mutants unable to produce this enzyme are still able to germinate, but the process is retarded (18).The SCLEs of Clostridium are less well studied than those of Bacillus. The SCLEs SleC (20) and SleM (6) have been identified in Clostridium perfringens, and a recent study demonstrated that SleC is required during germination for complete cortex hydrolysis (26). Although SleM can degrade spore cortex peptidoglycan and inactivation of both sleC and sleM decreased the ability of spores to germinate more than inactivation of sleC alone did, SleM was not essential (26). It has also been shown that the germination-specific serine protease CspB is essential for cortex hydrolysis and converts the inactive pro-SleC found in dormant spores to an active enzyme (24). So far, there has been no detailed study of any gene responsible for spore germination in C. difficile, although genes showing homology to cwlJ and sleB of B. subtilis (CD3563) and sleC of C. perfringens (CD0551) have now been identified in the C. difficile 630 genome (33).With germinant receptors in C. difficile yet to be identified, the mechanism by which the spores sense a suitable environment for germination is unclear. Recent studies have suggested that this process may involve the interaction of C. difficile with bile. Taurocholate has been shown to enhance recovery of C. difficile spores in nutrient-rich medium (42), and it has been proposed that glycine and taurocholate act as cogerminants (38), while chenodeoxycholate inhibits C. difficile spore germination (39).The emergence of C. difficile B1/NAP1/027 strains has increased the burden on health care services worldwide. Such strains have been shown to produce higher levels of toxin in the laboratory than many other types of strains (41), although the mechanism behind this production is not fully understood. However, while the observed higher levels of toxin production is doubtless important, perhaps the recent attention given to B1/NAP1/027 strains has focused too much on toxins. As spores represent the infectious stage of C. difficile, processes such as spore germination may also contribute to the greater virulence of these strains. In this study we evaluated the sporulation and germination efficiencies of an “epidemic” B1/NAP1/027 C. difficile strain ({"type":"entrez-nucleotide","attrs":{"text":"R20291","term_id":"774925","term_text":"R20291"}}R20291, isolated from the Stoke Mandeville outbreak in 2004 and 2005) and the “nonepidemic” strain 630Δerm (14). We then constructed strains with mutations in CD3563 (a cwlJ/sleB homologue) and a sleC homologue to analyze the role of these genes in the germination of C. difficile spores.     

Germination response of spores of the pathogenic bacterium Clostridium perfringens and Clostridium difficile to cultured human epithelial cells

Spores of pathogenic Clostridium perfringens and Clostridium difficile must germinate in the food vehicle and/or host's intestinal tract to cause disease. In this work, we examined the germination response of spores of C. perfringens and C. difficile upon incubation with cultured human epithelial cell lines (Caco-2, HeLa and HT-29). C. perfringens spores of various sources were able to germinate to different extents; while spores of a non-food-borne isolate germinated very well, spores of food-borne and animal isolates germinated poorly in human epithelial cells. In contrast, no detectable spore germination (i.e., loss of spore heat resistance) was observed upon incubation of C. difficile spores with epithelial cells; instead, there was a significant (p?相似文献   

Fungal Trans-kingdom Dynamics Linked to Responsiveness to Fecal Microbiota Transplantation (FMT) Therapy in Ulcerative Colitis

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Fecal IgA Levels Are Determined by Strain-Level Differences in Bacteroides ovatus and Are Modifiable by Gut Microbiota Manipulation

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The Effect of Sampling and Storage on the Fecal Microbiota Composition in Healthy and Diseased Subjects

Large-scale cohort studies are currently being designed to investigate the human microbiome in health and disease. Adequate sampling strategies are required to limit bias due to shifts in microbial communities during sampling and storage. Therefore, we examined the impact of different sampling and storage conditions on the stability of fecal microbial communities in healthy and diseased subjects. Fecal samples from 10 healthy controls, 10 irritable bowel syndrome and 8 inflammatory bowel disease patients were collected on site, aliquoted immediately after defecation and stored at -80°C, -20°C for 1 week, at +4°C or room temperature for 24 hours. Fecal transport swabs (FecalSwab, Copan) were collected and stored for 48-72 hours at room temperature. We used pyrosequencing of the 16S gene to investigate the stability of microbial communities. Alpha diversity did not differ between all storage methods and -80°C, except for the fecal swabs. UPGMA clustering and principal coordinate analysis showed significant clustering by test subject (p<0.001) but not by storage method. Bray-Curtis dissimilarity and (un)weighted UniFrac showed a significant higher distance between fecal swabs and -80°C versus the other methods and -80°C samples (p<0.009). The relative abundance of Ruminococcus and Enterobacteriaceae did not differ between the storage methods versus -80°C, but was higher in fecal swabs (p<0.05). Storage up to 24 hours (at +4°C or room temperature) or freezing at -20°C did not significantly alter the fecal microbial community structure compared to direct freezing of samples from healthy subjects and patients with gastrointestinal disorders.     

Variation in Taxonomic Composition of the Fecal Microbiota in an Inbred Mouse Strain across Individuals and Time

Genetics, diet, and other environmental exposures are thought to be major factors in the development and composition of the intestinal microbiota of animals. However, the relative contributions of these factors in adult animals, as well as variation with time in a variety of important settings, are still not fully understood. We studied a population of inbred, female mice fed the same diet and housed under the same conditions. We collected fecal samples from 46 individual mice over two weeks, sampling four of these mice for periods as long as 236 days for a total of 190 samples, and determined the phylogenetic composition of their microbial communities after analyzing 1,849,990 high-quality pyrosequencing reads of the 16S rRNA gene V3 region. Even under these controlled conditions, we found significant inter-individual variation in community composition, as well as variation within an individual over time, including increases in alpha diversity during the first 2 months of co-habitation. Some variation was explained by mouse membership in different cage and vendor shipment groups. The differences among individual mice from the same shipment group and cage were still significant. Overall, we found that 23% of the variation in intestinal microbiota composition was explained by changes within the fecal microbiota of a mouse over time, 12% was explained by persistent differences among individual mice, 14% by cage, and 18% by shipment group. Our findings suggest that the microbiota of controlled populations of inbred laboratory animals may not be as uniform as previously thought, that animal rearing and handling may account for some variation, and that as yet unidentified factors may explain additional components of variation in the composition of the microbiota within populations and individuals over time. These findings have implications for the design and interpretation of experiments involving laboratory animals.     

Changes in Lipid Composition and Carbohydrate Composition of Aspergillus niger Conidia during Germination

Data on the lipid composition and carbohydrate composition of Aspergillus niger conidia make it possible to characterize the individual germination stages and differentiate between the conidia capable of germination and those that lost the germination capacity. The following criteria are proposed: the ratio of phosphatidylcholine and phosphatidylethanolamine, the ratio of mannitol and arabitol, and the levels of sterols and free fatty acids. The role of these compounds in the biochemical background of cell transition from dormancy to active metabolism and their use as indices of the quality of inocula in biotechnological processes are discussed.     

Levan Enhances Associated Growth of Bacteroides,Escherichia, Streptococcus and Faecalibacterium in Fecal Microbiota

The role of dietary fiber in supporting healthy gut microbiota and overall well-being of the host has been revealed in several studies. Here, we show the effect of a bacterial polyfructan levan on the growth dynamics and metabolism of fecal microbiota in vitro by using isothermal microcalorimetry. Eleven fecal samples from healthy donors were incubated in phosphate-buffered defined medium with or without levan supplementation and varying presence of amino acids. The generation of heat, changes in pH and microbiota composition, concentrations of produced and consumed metabolites during the growth were determined. The composition of fecal microbiota and profile of metabolites changed in response to substrate (levan and amino acids) availability. The main products of levan metabolism were acetic, lactic, butyric, propionic and succinic acids and carbon dioxide. Associated growth of levan-degrading (e.g. Bacteroides) and butyric acid-producing (e.g. Faecalibacterium) taxa was observed in levan-supplemented media. The study shows that the capacity of levan and possibly also other dietary fibers/prebiotics to modulate the composition and function of colon microbiota can be predicted by using isothermal microcalorimetry of fecal samples linked to metabolite and consortia analyses.     

Low Level Engraftment and Improvement following a Single Colonoscopic Administration of Fecal Microbiota to Patients with Ulcerative Colitis

Objective

Fecal microbiota transplantation (FMT) is an investigational treatment for diseases thought to involve alterations in the intestinal microbiota including ulcerative colitis (UC). Case reports have described therapeutic benefit of FMT in patients with UC, possibly due to changes in the microbiota. We measured the degree to which the transplanted microbiota engraft following FMT in patients with UC using a donor similarity index (DSI).

Methods

Seven patients with mild to moderate UC (UC disease activity index scores 3–10) received a single colonoscopic administration of FMT. Metagenomic sequence data from stool were analyzed using an alignment-free comparison tool, to measure the DSI, and a phylogenetic analysis tool, to characterize taxonomic changes. Clinical, endoscopic, histologic, and fecal calprotectin outcome measures were also collected.

Results

One of 5 patients from whom sequencing data were available achieved the primary endpoint of 50% donor similarity at week 4; an additional 2 patients achieved 40% donor similarity. One patient with 40% donor similarity achieved clinical and histologic remission 1 month after FMT. However, these were lost by 2−3 months, and loss correlated with a decrease in DSI. The remaining patients did not demonstrate clinical response or remission. Histology scores improved in all but 1 patient. No patients remained in remission at 3 months after FMT.

Conclusions

Following a single colonoscopic fecal transplant, a DSI of 40-50% is achieved in about two-thirds of recipients. This level of engraftment correlated with a temporary clinical improvement in only 1/5 patients. Larger sample sizes could further validate this method for measuring engraftment, and changes in transplant frequency or method might improve microbiota engraftment and efficacy.

Trial Registration

ClinicalTrials.gov NCT01742754     

Changes in Resistance to Radiation and Heat During Sporulation and Germination of Clostridium botulinum 33A

During sporulation, Clostridium botulinum 33A developed resistance to ultraviolet and gamma rays about 2 hr prior to its development of heat resistance. During germination, loss of resistance to heat, ultraviolet radiation, and gamma radiation occurred essentially simultaneously.