Probiotic/synbiotic therapy for treating critically ill patients from a gut microbiota perspective.

The gut is an important target organ for stress caused by severe insults such as sepsis, trauma, burn, shock, bleeding and infection. Severe insult to the gut is considered to have an important role in promoting infectious complications and multiple organ dysfunction syndrome. These are sequelae of interactions between deteriorated intestinal epithelium, the immune system and commensal bacteria. The gut is the "motor" of multiple organ failure, and now it is recognized that gut dysfunction is a causative factor in disease progression. The gut flora and environment are significantly altered in critically ill patients, and the number of obligate anaerobes is associated with prognosis. Synbiotic therapy is a combination of probiotics and prebiotics. Probiotic, prebiotic and synbiotic treatment has been shown to be a promising therapy to maintain and repair the gut microbiota and gut environment. In the critically ill, such as major abdominal surgery, trauma and ICU patients, synbiotic therapy has been shown to significantly reduce septic complications. Further basic and clinical research would clarify the underlying mechanisms of the therapeutic effect of probiotic/synbiotic treatment and define the appropriate conditions for use.

Prognostic impact of fecal pH in critically ill patients.

INTRODUCTION: We have reported that altered gut flora is associated with septic complications and eventual death in critically ill patients with systemic inflammatory response syndrome. It is unclear how fecal pH affects these patients. We sought to determine whether fecal pH can be used as an assessment tool for the clinical course of critically ill patients. METHODS: Four hundred ninety-one fecal samples were collected from 138 patients who were admitted to the Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, Japan. These patients were treated in the intensive care unit for more than 2 days. Fecal pH, fecal organic acids, and fecal bacteria counts were measured and compared by survived group and nonsurvived group, or nonbacteremia group and bacteremia group. Logistic regression was used to estimate relations between fecal pH, age, sex, or APACHE II score and mortality, and incidence of bacteremia. Differences in fecal organic acids or fecal bacteria counts among acidic, neutral, and alkaline feces were analyzed. RESULTS: The increase of fecal pH 6.6 was significantly associated with the increased mortality (odds ratio, 2.46; 95% confidence interval, 1.25 to 4.82) or incidence of bacteremia (3.25; 1.67 to 6.30). Total organic acid was increased in acidic feces and decreased in alkaline feces. Lactic acid, succinic acid, and formic acid were the main contributors to acidity in acidic feces. In alkaline feces, acetic acid was significantly decreased. Propionic acid was markedly decreased in both acidic and alkaline feces compared with neutral feces. No differences were noted among the groups in bacterial counts. CONCLUSIONS: The data presented here demonstrate that the fecal pH range that extended beyond the normal range was associated with the clinical course and prognosis of critically ill patients.

CO2 -dependent growth of Succinatimonas hippei YIT 12066T isolated from human feces.

Succinatimonas hippei is a new bacterial species isolated from human feces. Here we report that the growth of S. hippei YIT 12066(T) depends on CO(2) or bicarbonate and the headspace gas produced by microbiota. Genetic defect for carbonic anhydrase in this bacterium suggested a reason for the syntrophic property of CO(2) dependency and may suggest an adaptation to its habitat.

Description of Christensenella minuta gen. nov., sp. nov., isolated from human faeces, which forms a distinct branch in the order Clostridiales, and proposal of Christensenellaceae fam. nov.

A novel, strictly anaerobic, non-motile, non-spore-forming, Gram-negative, short, straight rod with tapered ends, designated YIT 12065(T), was isolated from human faeces. Strain YIT 12065(T) was saccharolytic and negative for catalase, oxidase and urease, hydrolysis of aesculin and gelatin, nitrate reduction and indole production. The end products of glucose fermentation were acetic acid and a small amount of butyric acid. The DNA G+C content was 51.3 mol%. The predominant fatty acids were iso-C(15:0), C(16:0) and C(14:0). Respiratory quinones were not detected. The cell wall contained glutamic acid, serine, alanine and ll-diaminopimelic acid. The whole-cell sugars were ribose, rhamnose, galactose and glucose. Phylogenetic analyses based on 16S rRNA gene sequences using three treeing algorithms revealed that the strain formed a novel family-level lineage within the phylum Firmicutes, class Clostridia, order Clostridiales. Caldicoprobacter oshimai JW/HY-331(T) was shown to be the closest named relative on the basis of 16S rRNA gene sequence similarity (86.9%), followed by Tindallia californiensis DSM 14871(T) (86.3%) and Clostridium ganghwense JCM 13193(T) (86.1%). Similar 16S rRNA gene sequences (98.6-96.7%) were found amongst faecal uncultured clones of human and dugong (Dugong dugon). They clustered with strain YIT 12065(T) in a distinct and deep evolutionary lineage of descent in the order Clostridiales. The distinct phylogenetic position supports the proposal of Christensenella gen. nov., with the type species Christensenella minuta sp. nov. (type strain YIT 12065(T) =DSM 22607(T) =JCM 16072(T)). A new family Christensenellaceae fam. nov. is also proposed.

Characterization of Phascolarctobacterium succinatutens sp. nov., an asaccharolytic, succinate-utilizing bacterium isolated from human feces.

Isolation, cultivation, and characterization of the intestinal microorganisms are important for understanding the comprehensive physiology of the human gastrointestinal (GI) tract microbiota. Here, we isolated two novel bacterial strains, YIT 12067(T) and YIT 12068, from the feces of healthy human adults. Phylogenetic analysis indicated that they belonged to the same species and were most closely related to Phascolarctobacterium faecium ACM 3679(T), with 91.4% to 91.5% 16S rRNA gene sequence similarities, respectively. Substrate availability tests revealed that the isolates used only succinate; they did not ferment any other short-chain fatty acids or carbohydrates tested. When these strains were cocultured with the xylan-utilizing and succinate-producing bacterium Paraprevotella xylaniphila YIT 11841(T), in medium supplemented with xylan but not succinate, their cell numbers became 2 to 3 orders of magnitude higher than those of the monoculture; succinate became undetectable, and propionate was formed. Database analysis revealed that over 200 uncultured bacterial clones from the feces of humans and other mammals showed high sequence identity (>98.7%) to YIT 12067(T). Real-time PCR analysis also revealed that YIT 12067(T)-like bacteria were present in 21% of human fecal samples, at an average level of 3.34 × 10(8) cells/g feces. These results indicate that YIT 12067(T)-like bacteria are distributed broadly in the GI tract as subdominant members that may adapt to the intestinal environment by specializing to utilize the succinate generated by other bacterial species. The phylogenetic and physiological properties of YIT 12067(T) and YIT 12068 suggest that these strains represent a novel species, which we have designated Phascolarctobacterium succinatutens sp. nov.

Altered gut flora are associated with septic complications and death in critically ill patients with systemic inflammatory response syndrome.

BACKGROUND: Gut under severe insult is considered to have an important role in promoting infection and multiple organ dysfunction syndrome from the viewpoint of altered intestinal epithelium, immune system and commensal bacteria. There are few reports, however, about the relationship between gut flora and septic complications. METHODS: We analyzed gut flora in patients with systemic inflammatory response syndrome (SIRS) and evaluated key bacteria and their cutoff values for infectious complications and mortality by using classification and regression trees (CART). Eighty-one SIRS patients with a serum C-reactive protein level higher than 10 mg/dL treated in the intensive care unit (ICU) for more than 2 days were included for the study. We quantitatively evaluated nine types of bacteria in fecal samples by plate or tube technique. Two hundred seventy-one samples were analyzed using CART and logistic regression. RESULTS: The dominant factors for complication of enteritis were the minimum number of total obligate anaerobes and the maximum number of Staphylococcus and Enterococcus. The dominant factors for complication of bacteremia were the minimum numbers of total obligate anaerobes and total facultative anaerobes. The dominant factors for mortality were the numbers of total obligate anaerobes and total facultative anaerobes and age. CONCLUSIONS: A decrease in total obligate anaerobes and an increase in pathogenic bacteria in the gut are associated with septic complications and mortality in patients with SIRS. The altered gut flora may be a potential prognostic marker in SIRS patients.

Patterns of Gram-stained fecal flora as a quick diagnostic marker in patients with severe SIRS.

BACKGROUND: The gut is an important target organ of injury during critically ill conditions. Although Gram staining is a common and quick method for identifying bacteria, its clinical application has not been fully evaluated in critically ill conditions. AIMS: This study's aims were to identify patterns of Gram-stained fecal flora and compare them to cultured bacterial counts and to investigate the association between the patterns and septic complications in patients with severe systemic inflammatory response syndrome (SIRS). METHODS: Fifty-two patients with SIRS were included whose Gram-stained fecal flora was classified into three patterns. In a diverse pattern, large numbers of multiple kinds of bacteria completely covered the field. In a single pattern, one specific kind of bacteria or fungi predominantly covered the field. In a depleted pattern, most bacteria were diminished in the field. RESULTS: In the analysis of fecal flora, the numbers of total obligate anaerobes in the depleted pattern was significantly lower than those in the diverse pattern and single pattern (p < 0.05). The concentrations of total organic acids, acetic acid, and propionic acid in the depleted pattern were significantly lower than those in diverse pattern and single pattern (p < 0.05). Mortality due to multiple organ dysfunction syndrome for the single pattern (52%) and the depleted pattern (64%) was significantly higher than that for the diverse pattern (6%) (p < 0.05). CONCLUSIONS: Gram-stained fecal flora can be classified into three patterns and are associated with both cultured bacterial counts and clinical information. Gram-stained fecal bacteria can be used as a quick bedside diagnostic marker for severe SIRS patients.

Parasutterella secunda sp. nov., isolated from human faeces and proposal of Sutterellaceae fam. nov. in the order Burkholderiales.

A novel, strictly anaerobic, non-spore-forming, Gram-reaction-negative coccobacillus bacterium, designated strain YIT 12071(T), was isolated from human faeces. Biochemically, this strain was largely unreactive and asaccharolytic. Growth of this strain in peptone-yeast-extract broth was weak, producing no visible turbidity, and no short-chain fatty acids were detected as an end product of metabolism. Following 16S rRNA gene sequence analysis, strain YIT 12071(T) was found to be most closely related to Parasutterella excrementihominis (90  % sequence similarity) and phylogenetically distinct from other known genera belonging to the order Burkholderiales. Biochemical data supported the affiliation of this strain with the genus Parasutterella. Strain YIT 12071(T), therefore, represents a novel species of the genus Parasutterella, for which the name Parasutterella secunda sp. nov. is proposed. The type strain is YIT 12071(T) (=DSM 22575(T) =JCM 16078(T)). On the basis of 16S rRNA gene sequence analysis, species of the genera Sutterella and Parasutterella form a distinct and deep evolutionary lineage of descent in the order Burkholderiales. This lineage could not be associated with any of the four known families of the order Burkholderiales. The distinct phylogenetic position and the unusual combination of chemotaxonomic characteristics shared by these genera, such as the predominant quinones and cellular fatty acid compositions, suggest that they constitute a novel family in the order Burkholderiales, for which the name Sutterellaceae fam. nov. is proposed to accommodate the genera Sutterella and Parasutterella.

[Altered gut bacterial flora and organic acids in feces of patients undergoing autologous stem cell transplantation with quinolone-based antibacterial prophylaxis].

Gastrointestinal toxicity and various infections are serious problems associated with high-dose chemotherapy. Antibacterial chemoprophylaxis reduces the incidence of gram-negative bacterial infection; however, it may affect the normal intestinal flora and induce drug resistance in organisms. We evaluated the chronological changes in fecal bacteria and organic acids in 6 patients undergoing autologous stem cell transplantation with quinolone-based chemoprophylaxis. All patients developed grade 2-3 diarrhea. Four patients developed grade 3 febrile neutropenia. The total count of obligatory anaerobic bacteria was significantly decreased on Day 7, but total facultative anaerobic bacterial count did not change throughout transplantation. However, Enterobacteriaceae and Lactobacillus were decreased on Day 7 and Staphylococcus was increased after transplantation. Total organic acid concentration and short-chain fatty acids were decreased on Day 7. The bacterial flora and organic acids in the gut were significantly altered in patients who underwent autologous stem cell transplantation with quinolonebased chemoprophylaxis. These changes may contribute to gastrointestinal toxicity and infections.

Bifidobacterium septicemia associated with postoperative probiotic therapy in a neonate with omphalocele.

We report the one case of sepsis caused by Bifidobacterium breve administered as probiotic therapy. Probiotics can be a potential cause of an invasive disease and should be used with care in vulnerable patients.

Slackia piriformis sp. nov. and Collinsella tanakaei sp. nov., new members of the family Coriobacteriaceae, isolated from human faeces.

Three Gram-positive, strictly anaerobic, non-spore-forming, rod-shaped organisms (strains YIT 12062(T), YIT 12063(T) and YIT 12064) were isolated from human faeces. Strain YIT 12062(T) was asaccharolytic and possessed a DNA G+C content of 58.3 mol%. Cells of strain YIT 12062(T) were negative for catalase, oxidase, urease, hydrolysis of aesculin and gelatin, nitrate reduction and indole production. Based on 16S rRNA gene sequence analysis, strain YIT 12062(T) was assigned to the genus Slackia (91.7-96.0 % sequence similarities to type strains of Slackia species). Biochemical data showed that the isolate was phenotypically distinct from all recognized species of the genus Slackia. Strain YIT 12062(T) therefore represents a novel species in the genus Slackia, for which the name Slackia piriformis sp. nov. is proposed. The type strain is YIT 12062(T) (=DSM 22477(T)=JCM 16070(T)). Following 16S rRNA gene sequence analysis, strains YIT 12063(T) and YIT 12064, which were isolated from different subjects, were shown to be most closely related to species of the genus Collinsella (93.8-95.1 % similarities to type strains). Although their phenotypic characteristics were very similar and they shared >99 % 16S rRNA gene sequence similarity and >97±1.8 % DNA-DNA relatedness, the two isolates could be discriminated by RAPD fingerprints. The DNA G+C contents of strains YIT 12063(T) and YIT 12064 were 60.8 and 61.0 mol%, respectively. They were saccharolytic in API test systems, positive for aesculin hydrolysis and negative for catalase, oxidase, urease, indole production, nitrate reduction and gelatin hydrolysis. The major end products of glucose fermentation of these strains were lactate, acetate and formate. Biochemical data supported the affiliation of strains YIT 12063(T) and YIT 12064 to the genus Collinsella and showed that they were phenotypically distinct from all recognized species of the genus Collinsella. Strains YIT 12063(T) and YIT 12064 therefore represent a novel species of the genus Collinsella, for which the name Collinsella tanakaei sp. nov. is proposed. The type strain is YIT 12063(T) (=DSM 22478(T)=JCM 16071(T)).

Alistipes indistinctus sp. nov. and Odoribacter laneus sp. nov., common members of the human intestinal microbiota isolated from faeces.

Two anaerobic, non-spore-forming, non-motile, Gram-negative-staining bacteria, strains YIT 12060(T) and YIT 12061(T), were isolated from human faeces. Cells of strain YIT 12060(T) were coccoid to rod-shaped with round ends, positive for catalase, negative for indole and oxidase production, produced succinic and acetic acids as end products of glucose metabolism in peptone/yeast extract/glucose medium and had a DNA G+C content of 55.2 mol%. The main respiratory quinones were MK-10 (40%) and MK-11 (57%). Fatty acid analysis demonstrated the presence of a high concentration of iso-C(15 : 0) (56%). Following 16S rRNA gene sequence analysis, this strain was found to be most closely related to species of the genus Alistipes, with 90.9-92.6% gene sequence similarities to type strains of this species. Phylogenetic analysis and biochemical data supported the affiliation of strain YIT 12060(T) to the genus Alistipes of the family 'Rikenellaceae'. Strain YIT 12060(T) therefore represents a novel species of the genus Alistipes for which the name Alistipes indistinctus sp. nov. is proposed; the type strain is YIT 12060(T) (=DSM 22520(T)=JCM 16068(T)). Cells of the other isolate, strain YIT 12061(T), were pleomorphic rods that were asaccharolytic, catalase- and oxidase-negative, positive for gelatin hydrolysis and indole production, produced small amounts of succinic, acetic and iso-valeric acids as end products of metabolism in peptone/yeast extract medium and had a DNA G+C content of approximately 42.4 mol%. On the basis of 16S rRNA gene sequence similarity values, this strain was shown to belong to the family 'Porphyromonadaceae' and related to the type strains of Odoribacter splanchnicus (89.6%) and Odoribacter denticanis (86.2%); similarity values with strains of recognized species within the family 'Porphyromonadaceae' were less than 84 %. Biochemical data supported the affiliation of strain YIT 12061(T) to the genus Odoribacter. Strain YIT 12061(T) therefore represents a novel species for which the name Odoribacter laneus sp. nov. is proposed; the type strain is YIT 12061(T) (=DSM 22474(T)=JCM 16069(T)).

Early use of probiotics is important therapy in infants with severe congenital anomaly.

BACKGROUND: Infants with severe congenital anomaly often need to undergo operation followed by antibiotic therapy. As a result they inevitably acquire abnormal intestinal microbiota, which cause severe infections such as necrotizing enterocolitis. Also, intestinal function deteriorates and their nutritional state is very poor. In order to prevent these situations probiotic therapy is proposed as an effective supporting treatment. Probiotic therapy were therefore applied to infants with severe congenital anomaly as early as possible to ascertain its efficacy. METHODS: As probiotics, two bacteria were used: Bifidobacterium breve Yakult and Lactobacillus casei Shirota. Probiotic therapy was used in four infants with severe congenital anomaly as early as possible after surgery. Their intestinal microbiota and physical growth were followed through the treatment course. RESULTS: Two patients suffered from meconium peritonitis with ileal atresia. One patient was born with complex anomalies (omphalocele, bladder exstrophy, myelomeningocele). The fourth patient suffered from complete urorectal septum malformation. The intestinal microbiota of these four patients was first induced to be probiotic dominant and finally changed to commensal anaerobe dominant that was similar to normal intestinal microbiota. Pathogenic bacteria were seldom detected. The patients' physical growth was excellent despite short bowel and pulmonary hypoplasia. CONCLUSION: Probiotic therapy was effective in inducing probiotic dominant intestinal microbiota and normal intestinal microbiota in infants with severe congenital anomalies. As a result their intestinal absorptive functions were activated and severe infections were completely prevented. All of the infants grew well despite their physical disadvantages.

Succinatimonas hippei gen. nov., sp. nov., isolated from human faeces.

A novel strictly anaerobic, non-spore-forming, non-motile, non-flagellated, rod-shaped, Gram-negative bacterium (YIT 12066T) was isolated from human faeces. The isolate was negative for catalase, oxidase, urease, hydrolysis of aesculin and gelatin, nitrate reduction and indole production. The major end products of glucose metabolism were succinate and acetate. The major cellular fatty acids (>10%) were C14:0, C18:1omega7c, C18:1omega9c, C16:1omega7c and C16:0. The G+C content of the DNA was 40.3 mol%. 16S rRNA gene sequence analysis showed that strain YIT 12066T was most closely related to members of the family Succinivibrionaceae, with sequence similarity of 92-87%. However, some phenotypic characteristics such as cellular morphology and the major fatty acid profile of strain YIT 12066T were markedly different from those of other members of the family Succinivibrionaceae. On the basis of both phylogenetic and phenotypic evidence, it is suggested that strain YIT 12066T represents a novel species in a new genus, for which the name Succinatimonas hippei gen. nov., sp. nov. is proposed; the type strain of Succinatimonas hippei is YIT 12066T (=DSM 22608T =JCM 16073T).

Bacteroides clarus sp. nov., Bacteroides fluxus sp. nov. and Bacteroides oleiciplenus sp. nov., isolated from human faeces.

Three Gram-stain-negative, obligately anaerobic, non-spore-forming, rod-shaped bacteria (strains YIT 12056T, YIT 12057T and YIT 12058T) were isolated from human faeces. These strains were characterized by phylogenetic analyses based on 16S rRNA gene sequence and phenotypic tests. 16S rRNA gene sequence analyses revealed that strains YIT 12056T, YIT 12057T and YIT 12058T were most closely related to the type strains of Bacteroides gallinarum, Bacteroides uniformis and Bacteroides intestinalis with approximate similarity values of 96.6, 95.0 and 96.7%, respectively. The DNA G+C contents of the novel strains were 45.3 (YIT 12056T), 45.2 (YIT 12057T) and 43.6 mol% (YIT 12058T) and the major respiratory quinones of all three isolates were menaquinones MK-10 and MK-11. These properties were typical for members of the genus Bacteroides. The results of the other phenotypic analyses also supported the affiliation of these strains to the genus Bacteroides. The 16S rRNA gene sequence analysis, analysis of the major cellular fatty acids and other biochemical tests enabled the genotypic and phenotypic differentiation of the three new strains. Based on these data, three novel species, Bacteroides clarus sp. nov., Bacteroides fluxus sp. nov. and Bacteroides oleiciplenus sp. nov. are proposed. The type strains of B. clarus, B. fluxus and B. oleiciplenus are YIT 12056T (=JCM 16067T=DSM 22519T), YIT 12057T (=JCM 16101T=DSM 22534T) and YIT 12058T (=JCM 16102T=DSM 22535T), respectively.

Paraprevotella clara gen. nov., sp. nov. and Paraprevotella xylaniphila sp. nov., members of the family 'Prevotellaceae' isolated from human faeces.

Two anaerobic, non-spore-forming, pleomorphic, Gram-negative rods, designated YIT 11840T and YIT 11841T, were isolated from human faeces. The organisms were catalase-negative, produced succinic and acetic acids as end products of glucose metabolism and had DNA G+C contents of approximately 48-49 mol%. Although the phenotypic characteristics of these two strains were very similar, analysis of their 16S rRNA gene sequences showed that they are only distantly related (93.8%), indicating that they represent two different species. A comparative sequence analysis revealed that these two species are members of the family 'Prevotellaceae' but are phylogenetically distant (<88% sequence similarity) from the known genera belonging to this family, including Prevotella, Hallela and Xylanibacter. On the basis of the phylogenetic analysis and physiological tests, strains YIT 11840T and YIT 11841T represent two novel species of a new genus, for which the names Paraprevotella clara gen. nov., sp. nov. (type strain YIT 11840T=JCM 14859T=DSM 19731T), the type species, and Paraprevotella xylaniphila sp. nov. (type strain YIT 11841T=JCM 14860T=DSM 19681T) are proposed.

Parasutterella excrementihominis gen. nov., sp. nov., a member of the family Alcaligenaceae isolated from human faeces.

A novel, strictly anaerobic, non-spore-forming, Gram-negative coccobacillus (strain YIT 11859(T)) was isolated from human faeces. Biochemically, this strain was largely unreactive and was asaccharolytic. Growth of strain YIT 11859(T) in peptone-yeast extract broth produced no visible turbidity, and a trace amount of propionate was detected as an end product of metabolism. 16S rRNA gene sequence analysis showed that strain YIT 11859(T) was related most closely to the type strains of Sutterella species, with 90.8-88.0 % sequence similarity. Phylogenetic analysis of these and other related sequences confirmed that strain YIT 11859(T) was phylogenetically most closely associated with Sutterella species, but formed a separate cluster, indicating that strain YIT 11859(T) represents a novel member of the family Alcaligenaceae. Fatty acid analysis demonstrated the presence of a high concentration of C(18 : 1)omega9c (75 % of the total). The main respiratory quinones were menaquinone (MK-6) and methylated menaquinone (MMK-6). The G+C content of the DNA was 49.8 mol%. These results suggest that strain YIT 11859(T) represents a novel species of a new genus, for which the name Parasutterella excrementihominis gen. nov., sp. nov. is proposed. The type strain of Parasutterella excrementihominis is YIT 11859(T) (=DSM 21040(T) =JCM 15078(T)).

Synbiotics decrease the incidence of septic complications in patients with severe SIRS: a preliminary report.

The purpose of this study was to evaluate if synbiotic therapy can correct the deteriorated gut flora and environment in patients with severe systemic inflammatory response syndrome (SIRS). Twenty-nine SIRS patients, who fulfilled a serum C-reactive protein (CRP) level >10 mg/dl, received synbiotics (Bifidobacterium breve, Lactobacillus casei, and galactooligosaccharides) (S group) and were compared with previous observations in 26 patients without synbiotics (NS group). Analysis of fecal flora confirmed that patients in the S group had significantly greater levels of beneficial Bifidobacterium, Lactobacillus, and total organic acids (particularly short-chain fatty acids) than those in the NS group. The incidence of infectious complications such as enteritis, pneumonia, and bacteremia was significantly lower in the S group than in the NS group. Synbiotics maintain the gut flora and environment and decrease the incidence of septic complications in patients with severe SIRS. Further randomized controlled study is necessary to determine the effects of synbiotics.

Dialister succinatiphilus sp. nov. and Barnesiella intestinihominis sp. nov., isolated from human faeces.

Two anaerobic, non-spore-forming, bacteria (YIT 11850(T) and YIT 11860(T)) that stained Gram-negative, were isolated from human faeces. Cells of strain YIT 11850(T) were coccobacilli, asaccharolytic and largely unreactive, with only traces of lactate and propionate as metabolic end products; however, strain YIT 11850(T) was able to decarboxylate succinate to propionate. The DNA G+C content of strain YIT 11850(T) was 51.9 mol%. Following 16S rRNA gene sequence analysis, this strain was found to be most closely related to Dialister propionicifaciens, with 95.1 % sequence similarity between the two taxa. Biochemical data supported the affiliation of strain YIT 11850(T) to the genus Dialister. Strain YIT 11850(T) therefore represents a novel species for which the name Dialister succinatiphilus sp. nov. is proposed; the type strain is YIT 11850(T) (=DSM 21274(T)=JCM 15077(T)). Cells of the other isolate, strain YIT 11860(T), were non-motile, rod-shaped, positive for aesculin hydrolysis, negative for indole production, produced succinic and acetic acids as end products of glucose metabolism and possessed a DNA G+C content of 45.5 mol%. On the basis of 16S rRNA gene sequence similarity values, this strain was shown to belong to the family 'Porphyromonadaceae' related to Barnesiella viscericola (96.0 %); similarity values with species within the family 'Porphyromonadaceae' with validly published names were less than 86 %. Biochemical data supported the affiliation of strain YIT 11860(T) to the genus Barnesiella. Strain YIT 11860(T) therefore represents a novel species for which the name Barnesiella intestinihominis sp. nov. is proposed; the type strain is YIT 11860(T) (=DSM 21032(T)=JCM 15079(T)).

Relationship between the in vitro response of dendritic cells to Lactobacillus and prevention of tumorigenesis in the mouse.

BACKGROUND: Some strains of lactobacilli stimulate immune cells, yet little is known about their potency in cancer prevention. We have previously reported that Lactobacillus casei Shirota (LcS) suppresses murine tumorigenesis through immune modulation. In this study, differences were compared among six representative strains of lactobacilli in regard to their ability to stimulate bone marrow cell-derived dendritic cells (BMDCs) in vitro and tumor suppression in vivo. METHODS: BM-DCs were cocultured with a Lactobacillus strain in vitro, and the interleukin (IL)-12 released into the culture supernatant was measured by enzyme-linked immunosorbent assay. Tumors were chemically induced by a single subcutaneous injection of 3-methylcholanthrene (MC) in BALB/c mice. The test diets containing Lactobacillus were given from the day of the MC injection, and the tumor incidences were monitored. Peyer's patches were dissected from Lactobacillus-fed mice, and the status of c-Src, a regulator of DCs, in Peyer's patch cells was examined by Western blotting. RESULTS: In the coculture system, L. fermentum FERM P-13857 and LcS potently elicited IL-12 production. LcS but not the other strains of lactobacilli showed tumor suppression. The inactive form of c-Src, phosphorylated at Tyr527, was dominantly detected in Peyer's patches resected from L. fermentum FERM P-13857-fed mice compared with LcS-fed mice. CONCLUSIONS: The responses of DCs may be associated with tumor suppression by an ingested Lactobacillus strain.