Systemic proinflammation after Mycobacterium tuberculosis infection was correlated to the gut microbiome in HIV-uninfected humans.

BACKGROUND: The dysbiosis of gut microbiome and interaction with host immunity after Mycobacterium tuberculosis (MTB) infection are under investigation. We had found fatigue symptom concurrent with dysbiosis by decreasing the ratio of Firmicutes to Bacteroidetes (F/B ratio) in active tuberculosis (TB). The study aims to assess the inflammatory biomarkers and their interaction with gut microbiome in active TB and latent TB infection before starting anti-TB regimens. MATERIALS AND METHOD: Interleukin-1 beta (IL-1B), IL-4, IL-6, IL-10, CD3+, CD4+, CD8+ T cells and interferon-gamma (IFN-γ) releasing assay (IGRA) were measured in 25 active TB patients, 32 LTBI subjects and 23 healthy controls (HC). Gut microbiome profiles were obtained using 16S rRNA MiSeq sequencing method. RESULTS: The leucocytosis (7032 ± 387 cell/cum, P < 0.05), increase in IL-6 (229.7 ± 104 µg/dL, P < 0.05), and decrease in IL-4 (0.27 µg/dL ± 0.1, P < 0.05) were presented in active TB. The proportion of polymorphic neutrophil (PMN) in peripheral blood was positively related to the relative abundance of Bacteroidetes in LTBI and active TB (R2  = 0.23, P < 0.05). The F/B ratio was positively related to the detectable IL-1B in TB (R2  = 0.97, P < 0.01) and to the IL-4 in LTBI (R2  = 0.27, P < 0.05). In LTBI, the relative abundances of Coriobacteriaceae were positively related to the secretion of IFN-gamma against MTB-antigens more likely associated with of CD4+ T cell (R2  = 0.42, P < 0.05). CONCLUSION: In active TB, dysbiosis with higher relative abundances of Bacteroidetes in stool and low F/B ratio was related to systemic proinflammation. In LTBI, dose-response relationship between peripheral PMN and relative abundances of Bacteroidetes was remained but not leads to systemic inflammation.

Interactions Between Facultative Symbionts Hamiltonella and Cardinium in Bemisia tabaci (Hemiptera: Aleyrodoidea): Cooperation or Conflict?

Maternally-inherited facultative symbionts are widespread in most insect species, and it is common that several symbionts coexist in the same host individual. Hence, the symbionts may compete or share for the limited resources and space in the host. The whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodoidea), harbors a diverse array of facultative symbionts, among which Hamiltonella sp. and Cardinium sp. are abundant species. Hamiltonella alone increases host fitness, while Cardinium alone confers lower fitness. Locking those different partners together creates ideal situations for the evolution of interactions between symbionts. In this study, we compared the fitness effects of whiteflies infected with only Hamiltonella to Hamiltonella-Cardnium co-infected whiteflies and measured the density of Hamiltonella and Cardinium during host aging, aiming to explore Hamiltonella-Cardinium interactions in B. tabaci. Our results illustrated that Hamiltonella-Cardinium coinfection induced lower fecundity, egg hatchability and number of female offspring, leading to a male-biased sex ratio in offspring, while there is no evidence for reproductive incompatibility between the infections. We also found an antagonistic interaction between Hamiltonella and Cardinium given that the density of the latter increased across time and led to a decrease of Hamiltonella density, which may be the underlying causes of the fitness cost in double-infected B. tabaci. Exploring the ecological consequences of co-infections of these different symbionts helps us to understand the nature of host-symbiont interactions in this species and potential for evolutionary conflict.

Gut microbiota dysbiosis is associated with Henoch-Schönlein Purpura in children.

BACKGROUND: Alterations in the intestinal microbiota have been associated with the development of allergic diseases, such as asthma and food allergies. However, there is no report detailing the role of microbiota alterations in Henoch-Schönlein Purpura (HSP) development. METHOD: A total of 85 children with HSP and 70 healthy children were recruited for this study. Intestinal microbiota composition was analyzed by 16S rRNA gene-based pyrosequencing. Fecal microbial diversity and composition were compared. RESULT: We compared the gut microbiota of 155 subjects and found that children with HSP exhibited gut microbial dysbiosis. Lower microbial diversity and richness were found in HSP patients when compared to the control group. Based on an analysis of similarities, the composition of the microbiota in HSP patients was also different from that of the control group (r = 0.306, P = 0.001). The relative abundance of the bacterial genera Dialister (P < 0.0001), Roseburia (P < 0.0001), and Parasutterella (P < 0.0001) was significantly decreased in HSP children, while the relative abundance of Parabacteroides (P < 0.006) and Enterococcus (P < 0.0001) in these children was significantly increased. Based on Spearman correlation analysis, the LOS showed a significant negative (P < 0.05) correlation with the genera Paraprevotella and Roseburia. Meanwhile, IgA levels exhibited a significant negative (P < 0.01) correlation with the genus Bifidobacterium. CONCLUSIONS: Our results indicate that HSP is associated with significant compositional and structural changes in the gut microbiota. These results enhance the potential for future microbial-based therapies to improve the clinical outcome of HSP in children.

Bacteroidales recruit IL-6-producing intraepithelial lymphocytes in the colon to promote barrier integrity.

Interactions between the microbiota and distal gut are important for the maintenance of a healthy intestinal barrier; dysbiosis of intestinal microbial communities has emerged as a likely contributor to diseases that arise at the level of the mucosa. Intraepithelial lymphocytes (IELs) are positioned within the epithelial barrier, and in the small intestine they function to maintain epithelial homeostasis. We hypothesized that colon IELs promote epithelial barrier function through the expression of cytokines in response to interactions with commensal bacteria. Profiling of bacterial 16S ribosomal RNA revealed that candidate bacteria in the order Bacteroidales are sufficient to promote IEL presence in the colon that in turn produce interleukin-6 (IL-6) in a MyD88 (myeloid differentiation primary response 88)-dependent manner. IEL-derived IL-6 is functionally important in the maintenance of the epithelial barrier as IL-6-/- mice were noted to have increased paracellular permeability, decreased claudin-1 expression, and a thinner mucus gel layer, all of which were reversed by transfer of IL-6+/+ IELs, leading to protection of mice in response to Citrobacter rodentium infection. Therefore, we conclude that microbiota provide a homeostatic role for epithelial barrier function through regulation of IEL-derived IL-6.

Comprehensive evaluation of the bactericidal activities of free bile acids in the large intestine of humans and rodents.

In addition to functioning as detergents that aid digestion of dietary lipids in the intestine, some bile acids have been shown to exhibit antimicrobial activity. However, detailed information on the bactericidal activities of the diverse molecular species of bile acid in humans and rodents is largely unknown. Here, we investigated the toxicity of 14 typical human and rodent free bile acids (FBAs) by monitoring intracellular pH, membrane integrity, and viability of a human intestinal bacterium, Bifidobacterium breve Japan Collection of Microorganisms (JCM) 1192T, upon exposure to these FBAs. Of all FBAs evaluated, deoxycholic acid (DCA) and chenodeoxycholic acid displayed the highest toxicities. Nine FBAs common to humans and rodents demonstrated that α-hydroxy-type bile acids are more toxic than their oxo-derivatives and ß-hydroxy-type epimers. In five rodent-specific FBAs, ß-muricholic acid and hyodeoxycholic acid showed comparable toxicities at a level close to DCA. Similar trends were observed for the membrane-damaging effects and bactericidal activities to Blautia coccoides JCM 1395T and Bacteroides thetaiotaomicron DSM 2079T, commonly represented in the human and rodent gut microbiota. These findings will help us to determine the fundamental properties of FBAs and better understand the role of FBAs in the regulation of gut microbiota composition.

Cospeciation of gut microbiota with hominids.

The evolutionary origins of the bacterial lineages that populate the human gut are unknown. Here we show that multiple lineages of the predominant bacterial taxa in the gut arose via cospeciation with humans, chimpanzees, bonobos, and gorillas over the past 15 million years. Analyses of strain-level bacterial diversity within hominid gut microbiomes revealed that clades of Bacteroidaceae and Bifidobacteriaceae have been maintained exclusively within host lineages across hundreds of thousands of host generations. Divergence times of these cospeciating gut bacteria are congruent with those of hominids, indicating that nuclear, mitochondrial, and gut bacterial genomes diversified in concert during hominid evolution. This study identifies human gut bacteria descended from ancient symbionts that speciated simultaneously with humans and the African apes.

Colonisation of gingival epithelia by subgingival biofilms in vitro: role of "red complex" bacteria.

OBJECTIVES: Biofilm formation on tooth surface results in colonisation and invasion of the juxtaposed gingival tissue, eliciting strong inflammatory responses that lead to periodontal disease. This in vitro study investigated the colonisation of human gingival multi-layered epithelium by multi-species subgingival biofilms, and evaluated the relative effects of the "red complex" species (Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola). METHODS: The grown biofilm consisted of Fusobacterium nucleatum, Campylobacter rectus, Veillonella dispar, P. gingivalis, Prevotella intermedia, T. forsythia, T. denticola, Actinomyces oris, Streptococcus anginosus and Streptococcus oralis, or its variant lacking the "red complex". After 48h in co-culture with the gingival epithelia, the bacterial species in the biofilm were quantified, whereas their localisation on the cell surface was investigated by combining confocal-laser scanning microscopy (CLSM) and fluorescence in situ hybridisation (FISH), as well as by scanning electron microscopy (SEM). RESULTS: Exclusion of the "red complex" quantitatively affected S. oralis, but not other species. The "red-complex" species were all able to colonise the gingival epithelial cells. A co-localisation trend was observed between P. gingivalis and T. denticola, as determined by FISH. However, in the absence of all three "red complex" bacteria from the biofilm, an immense colonisation of streptococci (potentially S. oralis) was observed on the gingival epithelia, as confirmed by both CLSM and SEM. CONCLUSIONS: While the "red complex" species synergise in colonizing gingival epithelia, their absence from the biofilm enhances streptococcal colonisation. This antagonism with streptococci reveals that the "red complex" may regulate biofilm virulence, with potential implications in periodontal pathogenesis.

Intestinal microbiota containing Barnesiella species cures vancomycin-resistant Enterococcus faecium colonization.

Bacteria causing infections in hospitalized patients are increasingly antibiotic resistant. Classical infection control practices are only partially effective at preventing spread of antibiotic-resistant bacteria within hospitals. Because the density of intestinal colonization by the highly antibiotic-resistant bacterium vancomycin-resistant Enterococcus (VRE) can exceed 10(9) organisms per gram of feces, even optimally implemented hygiene protocols often fail. Decreasing the density of intestinal colonization, therefore, represents an important approach to limit VRE transmission. We demonstrate that reintroduction of a diverse intestinal microbiota to densely VRE-colonized mice eliminates VRE from the intestinal tract. While oxygen-tolerant members of the microbiota are ineffective at eliminating VRE, administration of obligate anaerobic commensal bacteria to mice results in a billionfold reduction in the density of intestinal VRE colonization. 16S rRNA gene sequence analysis of intestinal bacterial populations isolated from mice that cleared VRE following microbiota reconstitution revealed that recolonization with a microbiota that contains Barnesiella correlates with VRE elimination. Characterization of the fecal microbiota of patients undergoing allogeneic hematopoietic stem cell transplantation demonstrated that intestinal colonization with Barnesiella confers resistance to intestinal domination and bloodstream infection with VRE. Our studies indicate that obligate anaerobic bacteria belonging to the Barnesiella genus enable clearance of intestinal VRE colonization and may provide novel approaches to prevent the spread of highly antibiotic-resistant bacteria.

Discrimination of viable and dead fecal Bacteroidales bacteria by quantitative PCR with propidium monoazide.

Propidium monoazide (PMA) was optimized to discriminate between viable and dead Bacteroides fragilis cells and extracellular DNA at different concentrations of solids using quantitative PCR. Conditions of 100 microM PMA and a 10-min light exposure also excluded DNA from heat-treated cells of nonculturable Bacteroidales in human feces and wastewater influent and effluent.

Alendronate augments interleukin-1beta release from macrophages infected with periodontal pathogenic bacteria through activation of caspase-1.

Nitrogen-containing bisphosphonates (NBPs) are anti-bone-resorptive drugs with inflammatory side effects that include osteomyelitis and osteonecrosis of the jaw. Oral bacteria have been considered to be a trigger for these NBP-associated jaw bone diseases. The present study examined the effects of alendronate (a typical NBP) and clodronate (a non-NBP) on the production of proinflammatory cytokines by macrophages infected with Porphyromonas gingivalis and Tannerella forsythia, which are important pathogens of periodontal diseases. Pretreatment with alendronate augmented IL-1beta, but not TNFalpha, production by macrophages infected with P. gingivalis or T. forsythia. This augmentation of IL-1beta production was inhibited by clodronate. Furthermore, caspase-1, a promoter of IL-1beta production, was activated by treatment with alendronate, and caspase-1 inhibitor reduced the production of IL-1beta induced by alendronate and P. gingivalis. These results suggest that NBPs augment periodontal pathogenic bacteria-induced IL-1beta release via caspase-1 activation, and this phenomenon may contribute to the development of NBP-associated inflammatory side effects including jaw osteomyelitis. Co-treatment with clodronate may prevent and/or reduce these inflammatory effects induced by NBPs.

Endosymbiotic Bacteroidales bacteria of the flagellated protist Pseudotrichonympha grassii in the gut of the termite Coptotermes formosanus.

A unique lineage of bacteria belonging to the order Bacteroidales was identified as an intracellular endosymbiont of the protist Pseudotrichonympha grassii (Parabasalia, Hypermastigea) in the gut of the termite Coptotermes formosanus. We identified the 16S rRNA, gyrB, elongation factor Tu, and groEL gene sequences in the endosymbiont and detected a very low level of sequence divergence (<0.9% of the nucleotides) in the endosymbiont population within and among protist cells. The Bacteroidales endosymbiont sequence was affiliated with a cluster comprising only sequences from termite gut bacteria and was not closely related to sequences identified for members of the Bacteroidales attached to the cell surfaces of other gut protists. Transmission electron microscopy showed that there were numerous rod-shaped bacteria in the cytoplasm of the host protist, and we detected the endosymbiont by fluorescence in situ hybridization (FISH) with an oligonucleotide probe specific for the 16S rRNA gene identified. Quantification of the abundance of the Bacteroidales endosymbiont by sequence-specific cleavage of rRNA with RNase H and FISH cell counting revealed, surprisingly, that the endosymbiont accounted for 82% of the total bacterial rRNA and 71% of the total bacterial cells in the gut community. The genetically nearly homogeneous endosymbionts of Pseudotrichonympha were very abundant in the gut symbiotic community of the termite.

A bacterial symbiont in the Bacteroidetes induces cytoplasmic incompatibility in the parasitoid wasp Encarsia pergandiella.

Vertically transmitted symbionts of arthropods have been implicated in several reproductive manipulations of their hosts. These include cytoplasmic incompatibility (CI), parthenogenesis induction in haplodiploid species (PI), feminization and male killing. One symbiont lineage in the alpha-Proteobacteria, Wolbachia, is the only bacterium known to cause all of these effects, and has been thought to be unique in causing CI, in which the fecundity of uninfected females is reduced after mating with infected males. Here, we provide evidence that an undescribed symbiont in the Bacteroidetes group causes CI in a sexual population of the parasitic wasp Encarsia pergandiella. Wasps were crossed in all four possible combinations of infected and uninfected individuals. In the cross predicted to be incompatible, infected (I) males x uninfected (U) females, progeny production was severely reduced, with these females producing only 12.6% of the number of progeny in other crosses. The incompatibility observed in this haplodiploid species was the female mortality type; dissections showed that most progeny from the incompatible cross died as eggs. The 16S rDNA sequence of this symbiont is 99% identical to a parthenogenesis-inducing symbiont in other Encarsia, and 96% identical to a feminizing symbiont in haplodiploid Brevipalpus mites. Thus, this recently discovered symbiont lineage is capable of inducing three of the four principal manipulations of host reproduction known to be caused by Wolbachia.

Roles of mucosal bacteria and succinic acid in colitis caused by dextran sulfate sodium in mice.

Intestines of mice with colitis caused by dextran sulfate sodium (DSS) contain more Bacteroidaceae cells than untreated controls. We investigated the roles of intestinal bacteria and succinic acid, a by-product of Bacteroidaceae metabolism, in this model of colitis. CBA/J mice were given 3% DSS in water for 14 days. After mice were anesthetized and killed, concentrations of organic acids in stools from the cecum and colon were measured. The resected rectum and colon were washed with sterile saline; some specimens were incubated with imipenem in saline for 1 h to kill bacteria on the surfaces and others were not. Their homogenates were cultured anaerobically and aerobically. Separately, 1 mL of 20 mM succinic acid was infused into the rectum of mice, whose anal verge was glued. Animals were anesthetized and killed the next day. The rectum and colon were examined histologically. Concentrations of succinate were higher everywhere in the colon of mice with colitis than in controls. Mice with colitis had more Bacteroidaceae cells, especially B. caccae, than controls. Mice given succinate enemas had focal erosions of the mucosa and edema of the submucosa. Succinic acid, produced abundantly by members of the family Bacteroidaceae, especially B. caccae, may be the ulcerogenic agent in DSS colitis.

Adherence of oral microorganisms to guided tissue membranes: an in vitro study.

Microorganisms can adhere and colonize on an exposed guided tissue regeneration (GTR) membrane thus developing a nidus of infection. The purpose of this study was to compare early bacterial adhesion to three different GTR membranes. Expanded polytetrafluoroethylene, polyglactin 910, and collagen were used as the test membranes. In part I of this study 15 different oral microbes were used to compare their relative ability to adhere to the membranes. Six of the most strongly adherent bacteria (Actinomyces viscosus, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Streptococcus mutans, Fusobacterium nucleatum, and Selenomonas sputigena) were selected for part II of this study. The membranes were placed in tubes containing broth cultures containing identical concentrations (1 x 10(8) cells/ml) of these bacteria at 37 degrees C. Membranes were placed in tubes of media without bacteria as controls. At 4, 6, 12, and 24 hours, the bacterial cultures were decanted and the membranes in the tubes were agitated gently in reduced transfer fluid (RTF) 4 times to remove non-adherent bacteria. Each tube was then sonicated for 30 seconds in 10 ml RTF to detach adherent bacteria. The detached adherent bacteria were counted using a Petroff-Hausser chamber. Data were analyzed by using the SAS program. Analysis of variance was used to test for differences between multiple means. Results showed S. mutans had the strongest attachment to the collagen membrane at 4 and 6 hours. Selenomonas sputigena had the lowest adherence capability to all test membranes. Polyglactin 910 had significantly (P < 0.05) lower S. mutants adherence than either the ePTFE or the collagen membrane at 4 and 6 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

The surface structure of Leptotrichia buccalis.

Leptotrichia buccalis shows a mosaic of surface structure on its outer membrane consisting of curved ridges 35 mm high and 22 nm apart, and erect on that surface. Fimbriae (common pili) are not present and nor is an S layer. The flap-like ridges consist of strings of macromolecules radiating from the cell surface. This ridge structure is not soluble in any of the usual chaotropes and can only be released when the outer membrane has been damaged or dispersed by extracting envelope preparations with 0.5% SDS at room temperature. The ridge is then found to be attached firmly to the peptidoglycan sacculus, which may be the point of origin of the structure. When so prepared the macromolecules forming the ridge can be removed from the sacculus by treatment with 6 M guanidine HCl, and SDS-PAGE analysis of the extract reveals a 210-kDa polypeptide as a major component and a 15-kDa minor component. The latter is probably a peptidoglycan-associated protein and much of it remains with the sacculus. Each string forming the ridge is of a volume consistent with being made of three elongated 210-kDa molecules, which are united in series by strong hydrophobic association and laterally with neighboring strings by slightly weaker forces. We confirm that L. buccalis causes haemagglutination and the bacteria are known to attach to various tissue cells. Human group A red blood corpuscles remove both of the proteins from solution, which supports the hypothesis that the ridges are adhesin structures. It is likely but not proven that the 210-kDa molecule is the adhesin.

[Recent bacteriologic data: from physiopathology to treatment]. / Données bactériologiques récentes: de la physiopathologie au traitement.

Bacterial vaginosis is characterized by a change in the vaginal ecosystem in which Lactobacillus spp, the dominant members of the normal flora, are replaced by an association of various bacterial species including Gardnerella vaginalis, anaerobes (Bacteroides spp, Prevotella spp, Porphyromonas spp, Peptostreptococcus spp and Mobiluncus spp) and Mycoplasma hominis. The reasons for this imbalance are unknown, although the loss of lactobacilli that produce hydrogen peroxide (which is toxic for G. vaginalis and numerous anaerobes) may be an essential element. The introduction of one or several of these species into the vagina (they can occasionally be isolated in small numbers even in the absence of vaginosis) following intercourse or from the intestinal tract may also play a role. G. vaginalis itself is not considered to cause vaginosis, but is almost always present and multiplies rapidly; in addition, it has a high capacity for adherence to epithelial cells both in vivo and in vitro. It is now agreed that the concomitant growth of one or several anaerobic species is required for bacterial vaginosis to develop. Our knowledge of the bacteriology of bacterial vaginosis has implications for diagnosis and treatment. It is now possible to obtain a precise bacteriologic diagnosis, not by culturing G. vaginalis (a costly and low-yield procedure), but by direct examination of the vaginal flora after Gram staining, which shows the replacement of lactobacilli by a characteristic polymorphic flora. Therapy is based on the use of antibiotics such as the imidazoles, which are active against G. vaginalis and anaerobes, but not against the commensal lactobacilli.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial activities of black-pigmented gram-negative anaerobes.

The antimicrobial activities of Prevotella intermedia and Porphyromonas gingivalis isolates were tested against other species of Gram-positive and Gram-negative anaerobes as well as against each other. Generally, Pr. intermedia possessed significantly higher antimicrobial activity than P. gingivalis. The strongest activity of P. gingivalis towards Gram-negative anaerobes was directed against Pr. intermedia. Cross-sensitivity between both species was observed with strains from different lesions. Antimicrobial activity towards strains of the same species was detected only with Pr. intermedia. No correlations were found between plasmid content and antimicrobial activity. It was concluded that the inhibitory potency of Pr. intermedia could be one reason for the high proportion of black-pigmented Gram-negative anaerobes in the subgingival flora of periodontitis lesions.

DNA base composition, aerotolerance and enzyme patterns of Leptotrichia buccalis.

The guanine plus cytosine content of the DNA of Leptotrichia buccalis varied from 28.4 to 29.5 mol% (three strains). Eleven strains examined grew well under anaerobic and microaerobic conditions, but slowly in air in the presence of CO2. When examined for preformed enzymes in the APIZYM Complete Research Kit, positive reactions were obtained for several glucosidases and carboxylic ester hydrolases, and for a few peptidases.