Methanobrevibacter Smithii Research Articles

192 Abundance of rumen methanogens did not differ in cattle that differed in residual feed intake

Abstract Methane represents an energetic loss, and it has been proposed that its reduction may be associated with improved feed efficiency. Rumen methanogens produce most of the methane. Forty-nine crossbred heifers were individually fed a ration that consisted of 67.75% rolled corn, 20% wet distillers grain with solubles, 8% chopped alfalfa and 4.25% mineral/vitamin/rumensin mix for 84 d. Residual feed intake was the residual of the observed – predicted FI for the multivariate regression of FI on ADG and mid-metabolic BW for the population. Six heifers with the greatest RFI (1.75 ± 0.31 kg DM/d) and 6 with least RFI (-1.48 ± 0.31 kg DM/d) were selected. Rumen fluid was sampled from a tube passed through the mouth into the rumen. Rumen fluid was flash frozen in liquid N2 and stored at -80°C. After the first collection, heifers with greater RFI were pair fed to the less RFI heifers and rumen fluid was sampled 5 wk later. DNA was isolated from the rumen fluid and primer sets targeting total methanogens, Methanomicrobiales, Methanobacteriales, Methanosarcina, Methanobacterium, Methanobrevibacter ruminantium + Mbb. Cuticularis, and Methanobrevibacter smithii + Mbb. wolinii + Mbb. thaueri + Mbb. gottschalkii + Mbb. Woesei were amplified with real-time quantitative PCR (qPCR). Standard curves were generated to quantify copy number. There were no differences in copy number for the interaction of RFI classifications and sample period for all primer sets (P > 0.18). There were no differences in (P > 0.15) in RFI classification for all qPCR primer sets. There were fewer copies for the Methanobrevibacter ruminantium + Mbb. Cuticularis qPCR for samples collected in the first week compared to the 5 wk sample (P = 0.03); however, there were no difference for collection week for the other qPCR assays (P > 0.16). USDA is an equal opportunity provider and employer.

Detection of Methanobrevobacter smithii and Methanobrevibacter oralis in Lower Respiratory Tract Microbiota.

Methanogens, the sole microbes producing methane, are archaea commonly found in human anaerobic microbiota. Methanogens are emerging as opportunistic pathogens associated with dysbiosis and are also detected and cultured in anaerobic abscesses. Their presence in the respiratory tract is yet unknown. As a preliminary answer, prospective investigation of 908 respiratory tract samples using polyphasic approach combining PCR-sequencing, real-time PCR, fluorescent in situ hybridization (FISH), and methanogens culture was carried out. Methanobrevibacter smithii and Methanobrevibacter oralis DNA sequences, were detected in 21/527 (3.9%) sputum samples, 2/188 (1.06%) bronchoalveolar lavages, and none of 193 tracheo-bronchial aspirations. Further, fluorescence in situ hybridization detected methanogens in three sputum investigated specimens with stick morphology suggesting M. oralis and in another one bronchoalveolar lavage sample investigated, diplococal morphology suggesting M. smithii. These observations extend the known territory of methanogens to the respiratory tract and lay the foundations for further interpretation of their detection as pathogens in any future cases of isolation from bronchoalveolar lavages and the lungs.

Structure/activity virtual screening and in vitro testing of small molecule inhibitors of 8-hydroxy-5-deazaflavin:NADPH oxidoreductase from gut methanogenic bacteria

Virtual screening techniques and in vitro binding/inhibitory assays were used to search within a set of more than 8,000 naturally occurring small ligands for candidate inhibitors of 8-hydroxy-5-deazaflavin:NADPH oxidoreductase (FNO) from Methanobrevibacter smithii, the enzyme that catalyses the bidirectional electron transfer between NADP+ and F420H2 during the intestinal production of CH4 from CO2. In silico screening using molecular docking classified the ligand-enzyme complexes in the range between − 4.9 and − 10.5 kcal/mol. Molecular flexibility, the number of H-bond acceptors and donors, the extent of hydrophobic interactions, and the exposure to the solvent were the major discriminants in determining the affinity of the ligands for FNO. In vitro studies on a group of these ligands selected from the most populated/representative clusters provided quantitative kinetic, equilibrium, and structural information on ligands’ behaviour, in optimal agreement with the predictive computational results.

Methanobrevibacter smithii Archaemia in Febrile Patients With Bacteremia, Including Those With Endocarditis.

The spectrum of infections caused by methanogens remains to be described. We searched for methanogens in the blood of febrile patients using specific tools. Blood culture samples routinely collected in patients with fever were prospectively screened by specific PCR assays for methanogens. Positive samples were observed by autofluorescence and electron microscopy, analyzed by metagenomics and cultured using previously developed methods. Blood culture bottles experimentally inoculated were used as controls. The presence of methanogens in vascular and cardiac tissues was assessed by indirect immunofluorescence, fluorescent in situ hybridization and PCR-based investigations. PCR detection attempted in 7,716 blood samples, was negative in all 1,312 aerobic bottles and 810 bacterial culture-negative anaerobic bottles. PCRs were positive in 27/5,594 (0.5%) bacterial culture-positive anaerobic bottles collected from 26 patients. Sequencing confirmed Methanobrevibacter smithii associated with staphylococci in 14 patients, Enterobacteriaceae in nine patients and streptococci in three patients. Metagenomics confirmed M. smithii in five samples, and M. smithii was isolated in broth from two samples; the genomes of these two isolates were sequenced. Blood cultures experimentally inoculated with Enterobacteriaceae, Staphylococcus epidermidis or Staphylococcus hominis yielded hydrogen, but no methane, authentifying observational data. Three patients diagnosed with infectious mitral endocarditis, were indisputably diagnosed by microscopy, PCR-based detections and culture: we showed M. smithii microscopically and by a specific PCR followed by sequencing method in two of three cardiovascular tissues. Using appropriate laboratory methods, M. smithii is demonstrated as causing archaemia and endocarditis in febrile patients who are coinfected by bacteria.

Prevalence and abundance of traditional and host-associated fecal indicators in urban estuarine sediments: Potential implications for estuarine water quality monitoring

This study aimed to determine the prevalence and abundance of sewage and animal fecal contamination of sediment at seven estuarine locations in Sydney, NSW, Australia. Sediment samples were tested for the occurrence of microbial targets including molecular marker genes of enterococci (ENT), Bacteroides HF183 (HF183), Methanobrevibacter smithii (nifH), human adenovirus (HAdV) and emerging sewage-associated marker genes crAssphage (CPQ_056) and Lachnospiraceae (Lachno3) and animal feces-associated marker genes, including avian feces-associated Helicobacter spp. (GFD), canine-feces associated Bacteroides (DogBact), cattle-feces associated (cowM2) and horse feces-associated Bacteroides (HoF597). Results from this study showed that urban estuarine sediment can act as a reservoir of fecal indicator bacteria (FIB) and several microbial source tracking (MST) marker genes, including previously unreported Lachno3. The sewage-associated marker gene CPQ_056 was most prevalent, in 63.8% of sediment samples, while the avian associated marker gene GFD had the highest mean abundance. The GFD marker gene was highly abundant and widely detected in sediment samples from all seven locations compared to the other animal feces-associated marker genes. In all, 31 (44.9%) sediment samples were positive for at least two sewage-associated marker genes. However, the non-quantifiable detection of the HAdV marker gene did not always align with the detection of two or more sewage-associated marker genes. In addition, the most frequent wet weather overflow exposure occurred at locations that did not have a consistent pattern of detection of the sewage-associated marker genes, suggesting sediments may not be a suitable measure of recent sewage contamination. To assist water quality and public health managers better understand past microbial contamination of estuarine sediment, further studies seem justified to explore the role of decay of MST marker genes in sediment. Further work is also needed on the role of resuspension of MST marker genes from sediment during storm events to the water column as a source of contamination for both the GFD and sewage-associated marker genes.

Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome - An Update.

Small intestinal bacterial overgrowth (SIBO) is one manifestation of gut microbiome dysbiosis and is highly prevalent in IBS (Irritable Bowel Syndrome). SIBO can be diagnosed either by a small bowel aspirate culture showing ≥103 colony-forming units (CFU) per mL of aspirate, or a positive hydrogen lactulose or glucose breath test. Numerous pathogenic organisms have been shown to be increased in subjects with SIBO and IBS, including but not limited to Enterococcus, Escherichia coli, and Klebsiella. In addition, Methanobrevibacter smithii, the causal organism in a positive methane breath test, has been linked to constipation predominant irritable bowel syndrome (IBS-C). As M. smithii is an archaeon and can overgrow in areas outside of the small intestine, it was recently proposed that the term intestinal methanogen overgrowth (IMO) is more appropriate for the overgrowth of these organisms. Due to gut microbiome dysbiosis, patients with IBS may have increased intestinal permeability, dysmotility, chronic inflammation, autoimmunity, decreased absorption of bile salts, and even altered enteral and central neuronal activity. As a consequence, SIBO and IBS share a myriad of symptoms including abdominal pain, distention, diarrhea, and bloating. Furthermore, gut microbiome dysbiosis may be associated with select neuropsychological symptoms, although more research is needed to confirm this connection. This review will focus on the role of the gut microbiome and SIBO in IBS, as well as novel innovations that may help better characterize intestinal overgrowth and microbial dysbiosis.

Long-term evaluation of bioaugmentation to alleviate ammonia inhibition during anaerobic digestion: Process monitoring, microbial community response, and methanogenic pathway modeling

The effect of different bioaugmentation strategies on anaerobic digestion related to the alleviation of ammonia inhibition was investigated in a long-term operation. The long-term operation confirmed that bioaugmentation is a stable method. A 35% increase in methane production (MP) was observed in bottles bioaugmented with Methanosarcina barkeri (MSB) or Syntrophaceticu schinkii (SS) + Methanobrevibacter smithii (MBS), and a 49% increment was obtained from the bottles bioaugmented with Methanosaeta harundinacea (MSH) + SS + MBS. Results suggest that the enhancement in both aceticlastic and hydrogenotrophic methanogenic pathways should be considered, and bioaugmentation strain should be properly selected to achieve a synergistic effect. The microbial community analysis indicated Methanosarcina spp. was the dominant archaea. Combined with specific methanogenic activity and carbon isotope fractionation analysis, it was suggested that Methanosarcina spp. performed differently in methanogenic pathways in different bottles. The abundance of COG and total enzymes in the bottles with high MP (MSB and MSH + SS + MBS) was higher than that in the other bottles. The ratio of the functional enzyme tetrahydromethanopterin S-methyltransferase subunit H (EC 2.1.1.86) to formylmethanofuran dehydrogenase subunit E (EC 1.2.99.5) and the relative abundance of enolase (EC 1.2.1.2) confirmed the aceticlastic methanogenic pathway of MSB in Group 1 and the pathway enhancement balance in MSH + SS + MBS. The modified Anaerobic Digestion Model No.1 including syntrophic acetate oxidation was used for simulation with R2 > 0.96. Simulated contribution rate data indicated that the hydrogenotrophic methanogenic pathway was dominant while both two pathways got strengthened, which is consistent with the findings of the microbial analysis.

Associations of plasma trimethylamine N-oxide, choline, carnitine, and betaine with inflammatory and cardiometabolic risk biomarkers and the fecal microbiome in the Multiethnic Cohort Adiposity Phenotype Study

Trimethylamine N-oxide (TMAO), a compound derived from diet and metabolism by the gut microbiome, has been associated with several chronic diseases, although the mechanisms of action are not well understood and few human studies have investigated microbes involved in its production. Our study aims were 1) to investigate associations of TMAO and its precursors (choline, carnitine, and betaine) with inflammatory and cardiometabolic risk biomarkers; and 2) to identify fecal microbiome profiles associated with TMAO. We conducted a cross-sectional analysis using data collected from 1653 participants (826 men and 827 women, aged 60-77 y) in the Multiethnic Cohort Study. Plasma concentrations of TMAO and its precursors were measured by LC-tandem MS. We also analyzed fasting blood for markers of inflammation, glucose and insulin, cholesterol, and triglycerides (TGs), and further measured blood pressure. Fecal microbiome composition was evaluated by sequencing the 16S ribosomal RNA gene V1-V3 region. Associations of TMAO and its precursors with disease risk biomarkers were assessed by multivariable linear regression, whereas associations between TMAO and the fecal microbiome were assessed by permutational multivariate ANOVA and hurdle regression models using the negative binomial distribution. Median (IQR) concentration of plasma TMAO was 3.05 μmol/L (2.10-4.60 μmol/L). Higher concentrations of TMAO and carnitine, and lower concentrations of betaine, were associated with greater insulin resistance (all P<0.02). Choline was associated with higher systolic blood pressure, TGs, lipopolysaccharide-binding protein, and lower HDL cholesterol (P ranging from <0.001 to 0.03), reflecting an adverse cardiometabolic risk profile. TMAO was associated with abundance of 13 genera (false discovery rate<0.05), including Prevotella, Mitsuokella, Fusobacterium, Desulfovibrio, and bacteria belonging to the families Ruminococcaceae and Lachnospiraceae, as well as the methanogen Methanobrevibacter smithii. Plasma TMAO concentrations were associated with a number of trimethylamine-producing bacterial taxa, and, along with its precursors, may contribute to inflammatory and cardiometabolic risk pathways.

Profile of the gut microbiota of adults with obesity: a systematic review.

Recently, relationship between gut microbiota composition and development of obesity has been pointed. However, the gut microbiota composition of individual with obesity is not known yet. Therefore, this systematic review aimed to evaluate differences in profile of gut microbiota between individuals with obesity and individuals with normal weight. A search performed on August 2019 in the databases Pubmed, Scopus, Web of Science, Cochrane library, Lilacs and gray literature using the terms: "microbiota", "microbiome", "obesity", "obesity morbid", and "humans". Studies assessing the gut microbiota composition in adults with obesity and lean were included. Quality assessment was performed by Newcastle-Ottawa Quality Assessment Scale. Of the 12,496 studies, 32 were eligible and included in this review. Individuals with obesity have a greater Firmicutes/Bacteroidetes ratio, Firmicutes, Fusobacteria, Proteobacteria, Mollicutes, Lactobacillus (reuteri), and less Verrucomicrobia (Akkermansia muciniphila), Faecalibacterium (prausnitzii), Bacteroidetes, Methanobrevibacter smithii, Lactobacillus plantarum and paracasei. In addition, some bacteria had positive correlation and others negative correlation with obesity. Individuals with obesity showed profile of gut microbiota different than individual lean. These results may help in advances of the diagnosis and treatment of obesity.

Altered Gut Microbial Fermentation and Colonization with Methanobrevibacter smithii in Renal Transplant Recipients.

Renal transplant recipients (RTRs) often suffer from posttransplant diarrhea. The observed dysbiosis in RTR may influence the fermentation processes in the gut. In this study, we aimed to investigate whether fermentation differs between RTRs and healthy controls (HCs), by measuring breath H2 and CH4 concentrations. Additionally, we determined the fecal presence of the methanogen Methanobrevibacter smithii (M. smithii), which plays a main role in the process of methanogenesis. Data from the TransplantLines Biobank and Cohort Study (NCT03272841) was used. A total of 142 RTRs and 77 HCs were included. Breath H2 concentrations in RTRs were not significantly different from HCs. Breath CH4 concentrations in RTRs were significantly lower compared with HCs (median [interquartile range (IQR)] 7.5 [3.9–10.6] ppm vs. 16.0 [8.0–45.5] ppm, p < 0.001). M. smithii was less frequently present in the feces of RTRs compared to HCs (28.6% vs. 86.4% resp., p < 0.001). Our findings regarding the altered methanogenesis in the gut of RTRs show similarities with previous results in inflammatory bowel disease patients. These findings provide novel insight into the alterations of fermentation after renal transplantation, which may contribute to understanding the occurrence of posttransplant diarrhea.

Structural and Functional Characterization of the Gut Microbiota in Elderly Women With Migraine.

Migraine is a very common, multifactorial, and recurrent central nervous system disorder that causes throbbing headache, photophobia, phonophobia, nausea, and disability. Migraine occurs more often in females, and its complex physiopathology is not yet fully understood. An increasing number of gastrointestinal disorders have been linked to the occurrence of migraine suggesting that gut microbiota might play a pivotal role in migraine through the gut–brain axis. In the present work, we performed a metagenome-wide association study (MWAS) to determine the relationship between gut microbiota and migraine by analyzing 108 shotgun-sequenced fecal samples obtained from elderly women who suffer from migraine and matched healthy controls. Notably, the alpha diversity was significantly decreased in the migraine group at species, genus, and Kyoto Encyclopedia of Genes and Genomes (KEGG) orthologous levels. Firmicutes, especially the “unfriendly” Clostridium spp., were significantly enriched in the migraine group. Conversely, the healthy controls held more beneficial microorganisms, such as Faecalibacterium prausnitzii, Bifidobacterium adolescentis, and Methanobrevibacter smithii. For functional modules, the migraine group was enriched in gut–brain modules (GBMs) including kynurenine degradation and γ-aminobutyric acid (GABA) synthesis. However, the healthy controls held higher gut metabolic modules (GMMs) including glycolysis, homoacetogenesis, and GBMs including quinolinic acid degradation and S-adenosyl methionine (SAM) synthesis. The differences in gut microbiota composition and function between the migraine and healthy groups provided new information as well as novel therapeutic targets and strategies for migraine treatment, which could help to improve the early diagnosis of the disease, as well as the long-term prognosis and the life quality of patients suffering from migraine.

P846 Comparative study of faecal microbiota in Crohn’s disease patients in remission with and without surgical resection

Abstract Background Inflammatory bowel disease (IBD) is defined as a group of autoimmune diseases that affects the digestive tract by causing chronic inflammatory processes. Crohn’s disease (CD) is one of the major types of IBD. Although there are several efficient drugs for its treatment, almost 80% of patients will require an intestinal resection throughout their lives. Some bacterial species found in faecal samples can be used as indicators to diagnose and monitor activity in CD patients. However, this methodology has not yet been tested in patients that underwent an intestinal resection. The aim of this study was to investigate the changes in the abundance of these species associated with total or partial intestinal resection. Methods In this study, we used 30 faecal samples from patients diagnosed with CD in remission withdrawn from the Biobank of the Hospital Universitari Dr. Josep Trueta of Girona. Fifteen samples corresponded to patients who underwent an intestinal resection. The following markers were quantified by qPCR: Faecalibacterium prausnitzii (Fpra), F. prausnitzii phylogroup I (PHG-I), F. prausnitzii phylogrup II (PHG-II), Escherichia coli (Eco), Akkermansia muciniphila (Akk), Ruminococcus sp. (Rum), Bacteroidetes (Bac) and Methanobrevibacter smithii (Msm). Results The abundances of Fpra, PHG-I, PHG-II, Rum, and Msm were significantly lower (p &amp;lt; 0.05) in resected CD patients, whereas Eco was significantly more abundant in those patients. No significant differences were observed in the abundances of Akk and Bac. Conclusion In resected CD patients, beneficial butyrate-producing bacteria are underrepresented, whereas pro-inflammatory species are overpopulated. Any quantitative relationship of these indicators with the relapse probability would help to stratify these patients for a better orientation of therapeutic strategies.

P835 Correlation between microbial markers and faecal calprotectin in IBD patients

Abstract Background Crohn disease (CD) and Ulcerative colitis (UC) are characterised by episodes of exacerbations and remissions. Monitoring disease activity based on intestinal lesion is mandatory prior to any change in the therapeutic strategy. Colonoscopy is the gold standard technique to monitor the disease activity in IBD patients, but it is usually discarded because of costs and risk issues. The concentration of Faecal Calprotectin (FC) is widely used as a non-invasive marker of inflammation of the intestinal mucosa, allowing the assessment of the disease activity. Recently, different studies have demonstrated that certain microbial species, part of intestinal microbiota which can be detected in stool samples, are capable of correlating with disease activity in CD and UC patients. The purpose of this study was to analyse the correlation between these microbial indicators and the FC to monitor the disease activity in CD and UC patients. Methods FC levels were used to define inflammatory disease activity, the predetermined cut-off of 250 μg/g of faeces was used, higher values indicated an active inflammation and lower values indicated disease in remission. Two cohorts consisting of 61 patients of CD (25 with active inflammation and 36 with remission) and 90 of UC (42 with active inflammation and 48 with remission) were recruited by the Gastroenterology department of 4 Catalan hospitals. A sample of faeces was collected from each patient. FC and the following markers were quantified by qPCR: Faecalibacterium prausnitzii (Fpra), Escherichia coli (Eco), Akkermansia muciniphila (Akk), Ruminococcus sp. (Rum), Bacteroidetes (Bac) and Methanobrevibacter smithii (Msm) for each sample. Results The bacterial markers presented different behaviour depending on the disease analysed. The abundances of Eco and Bac were higher in CD with active inflammation compared with CD with remission. In contrast, no significant differences were found for Fpra, Akk, Rum, and Msm. Besides, a significant positive correlation between Eco abundance and FC levels (0.280, p = 0.029) and a significant negative correlation between Msm and FC levels (−0.299, p = 0.021) were observed. According UC patients, while the abundance of Eco was higher in patients with active inflammation, the abundance of Rum was significantly less abundant. No significant differences were found for Fpra, Akk, Bac, and Msm. Moreover, we also observed a significant negative correlation between Rum and FC levels (−0.308, p = 0.003, respectively). Conclusion The abundance of Eco and Msm in CD patients and the abundance of Rum in UC patients correlate to FC in order to determine inflammatory disease activity. So, these markers can also be an accurate discriminator of active disease in CD and UC patients.

A Comprehensive Analysis of the Global Human Gut Archaeome from a Thousand Genome Catalogue

The human gut microbiome plays an important role in health and disease, but the archaeal diversity therein remains largely unexplored. Here we report the pioneering analysis of 1167 non-redundant archaeal genomes recovered from diverse human gastrointestinal tract microbiomes. We identified 15 novel species including 52 previously unknown archaeal strains. Based on distinct genomic features, we warrant the split of the Methanobrevibacter smithii clade into two separate species. Patterns derived from 1.8 million proteins coded in these genomes showed substantial correlation with socio-demographic characteristics such as age and lifestyle. We infer that archaea are actively replicating in the human gut and are characterized by specific genomic and functional adaptations to the host. The archaeome carries a complex virome, with some species showing unexpected host flexibility. Our work furthers our current understanding of the human archaeome, and provides a large genome catalogue for future analyses to decipher its impact on human physiology.

Hydrogenotrophic methanogens of the mammalian gut: Functionally similar, thermodynamically different-A modelling approach.

Methanogenic archaea occupy a functionally important niche in the gut microbial ecosystem of mammals. Our purpose was to quantitatively characterize the dynamics of methanogenesis by integrating microbiology, thermodynamics and mathematical modelling. For that, in vitro growth experiments were performed with pure cultures of key methanogens from the human and ruminant gut, namely Methanobrevibacter smithii, Methanobrevibacter ruminantium and Methanobacterium formicium. Microcalorimetric experiments were performed to quantify the methanogenesis heat flux. We constructed an energetic-based mathematical model of methanogenesis. Our model captured efficiently the dynamics of methanogenesis with average concordance correlation coefficients of 0.95 for CO2, 0.98 for H2 and 0.97 for CH4. Together, experimental data and model enabled us to quantify metabolism kinetics and energetic patterns that were specific and distinct for each species despite their use of analogous methane-producing pathways. Then, we tested in silico the interactions between these methanogens under an in vivo simulation scenario using a theoretical modelling exercise. In silico simulations suggest that the classical competitive exclusion principle is inapplicable to gut ecosystems and that kinetic information alone cannot explain gut ecological aspects such as microbial coexistence. We suggest that ecological models of gut ecosystems require the integration of microbial kinetics with nonlinear behaviours related to spatial and temporal variations taking place in mammalian guts. Our work provides novel information on the thermodynamics and dynamics of methanogens. This understanding will be useful to construct new gut models with enhanced prediction capabilities and could have practical applications for promoting gut health in mammals and mitigating ruminant methane emissions.

Culture of Methanogenic Archaea from Human Colostrum and Milk

Archaeal sequences have been detected in human colostrum and milk, but no studies have determined whether living archaea are present in either of these fluids. Methanogenic archaea are neglected since they are not detected by usual molecular and culture methods. By using improved DNA detection protocols and microbial culture techniques associated with antioxidants previously developed in our center, we investigated the presence of methanogenic archaea using culture and specific Methanobrevibacter smithii and Methanobrevibacter oralis real-time PCR in human colostrum and milk. M. smithii was isolated from 3 colostrum and 5 milk (day 10) samples. M. oralis was isolated from 1 milk sample. For 2 strains, the genome was sequenced, and the rhizome was similar to that of strains previously isolated from the human mouth and gut. M. smithii was detected in the colostrum or milk of 5/13 (38%) and 37/127 (29%) mothers by culture and qPCR, respectively. The different distribution of maternal body mass index according to the detection of M. smithii suggested an association with maternal metabolic phenotype. M. oralis was not detected by molecular methods. Our results suggest that breastfeeding may contribute to the vertical transmission of these microorganisms and may be essential to seed the infant’s microbiota with these neglected critical commensals from the first hour of life.

Culture of salivary methanogens assisted by chemically produced hydrogen

Methanogen cultures require hydrogen produced by fermentative bacteria such as Bacteroides thetaiotaomicron (biological method). We developed an alternative method for hydrogen production using iron filings and acetic acid with the aim of cultivating methanogens more efficiently and more quickly (chemical method). We developed this new method with a reference strain of Methanobrevibacter oralis, compared the method to the biological reference method with a reference strain of Methanobrevibacter smithii and finally applied the method to 50 saliva samples. Methanogen colonies counted using ImageJ software were identified using epifluorescence optical microscopy, real-time PCR and PCR sequencing. For cultures containing pure strains of M. oralis and M. smithii, colonies appeared three days postinoculation with the chemical method versus nine days with the biological method. The average number of M. smithii colonies was significantly higher with the chemical method than with the biological method. There was no difference in the delay of observation of the first colonies in the saliva samples between the two methods. However, the average number of colonies was significantly higher with the biological method than with the chemical method at six days and nine days postinoculation (Student’s test, p = 0.005 and p = 0.04, respectively). The chemical method made it possible to isolate four strains of M. oralis and three strains of M. smithii from the 50 saliva samples. Establishing the chemical method will ease the routine isolation and culture of methanogens.

Mutual Metabolic Interactions in Co-cultures of the Intestinal Anaerostipes rhamnosivorans With an Acetogen, Methanogen, or Pectin-Degrader Affecting Butyrate Production.

The human intestinal tract harbors diverse and complex microbial communities that have a vast metabolic capacity including the breakdown of complex carbohydrates into short chain fatty acids, acetate, propionate, and butyrate. As butyrate is beneficial for gut health there is much attention on butyrogenic bacteria and their role in the colonic anaerobic food chain. However, our understanding how production of butyrate by gut microorganisms is controlled by interactions between different species and environmental nutrient availability is very limited. To address this, we set up experimental in vitro co-culture systems to study the metabolic interactions of Anaerostipes rhamnosivorans, a butyrate producer with each of its partners; Blautia hydrogenotrophica, an acetogen; Methanobrevibacter smithii, a methanogen and Bacteroides thetaiotaomicron, a versatile degrader of plant cell wall pectins; through corresponding specific cross-feeding. In all co-cultures, A. rhamnosivorans was able to benefit from its partner for enhanced butyrate formation compared to monocultures. Interspecies transfer of hydrogen or formate from A. rhamnosivorans to the acetogen B. hydrogenotrophica and in turn of acetate from the acetogen to the butyrogen were essential for butyrate formation. A. rhamnosivorans grown on glucose supported growth of M. smithii via interspecies formate/hydrogen transfer enhancing butyrate formation. In the co-culture with pectin, lactate was released by B. thetaiotaomicron which was concomitantly used by A. rhamnosivorans for the production of butyrate. Our findings indicate enhanced butyrate formation through microbe-microbe interactions between A. rhamnosivorans and an acetogen, a methanogen or a pectin-degrader. Such microbial interactions enhancing butyrate formation may be beneficial for colonic health.

First characterization of methanogens in oral cavity in Malian patients with oral cavity pathologies

BackgroundThe oral cavity of humans is inhabited by several hundreds of bacterial species and other microorganisms such as fungi and archaeal methanogens. Regarding methanogens, data have been obtained from oral cavity samples collected in Europe, America and Asia. There is no study published on the presence of methanogens in the oral cavity in persons living in Africa. The objective of our study was to bring new knowledge on the distribution of oral methanogens in persons living in Mali, Africa.MethodsA total of 31 patients were included in the study during a 15-day collection period in September. Bacterial investigations consisted in culturing the bacteria in 5% sheep blood–enriched Columbia agar and PolyViteX agar plates. For archaeal research, we used various methods including culture, molecular biology and fluorescent in situ hybridization (FISH).ResultsEight of 31 (26%) oral samples collected in eight patients consulting for stomatology diseases tested positive in polymerase chain-reaction (PCR)-based assays for methanogens including five cases of Methanobrevibacter oralis and one case each of Methanobrevibacter smithii, Methanobrevibacter massiliense and co-infection Methanobrevibacter oralis and Methanobrevibacter massiliense.ConclusionsIn this pilot study, we are reporting here the first characterization of methanogens in the oral cavity in eight patients in Mali. These methanogen species have already been documented in oral specimens collected from individuals in Europe, Asia, North America and Brazil.

Anthropogenic markers for source tracking of fecal contamination in Bayou Lafourche: a major drinking water source in Southeast Louisiana, USA

Abstract Bayou Lafourche, which is the sole drinking water source for 300,000 people in Louisiana, has failed to consistently meet its designated use criteria set by the Louisiana Department of Environmental Quality (LDEQ). This resulted in a total maximum daily load to be imposed on the Bayou by the Environmental Protection Agency (EPA). These designated use water quality criteria include fecal coliform (FC) levels for drinking water source, primary contact recreation, and secondary contact recreation. The goal of this study was to identify and enumerate anthropogenic nonpoint source FC contamination from malfunctioning home sewage systems in the Bayou's watershed. Thirty-four sites along the Bayou were selected for the study. Samples were analyzed for optical brightener ratios, FC CFU/100 mL (mFC), Escherichia coli, and three human markers, including human polyomavirus BK, the Archaeon Methanobrevibacter smithii, and the human-associated Brevibacterioides HF 183 eubacteria. Frequencies of sites with all three anthropogenic molecular markers are considered positive for human fecal contamination. This study provided data to address the problem of malfunctioning on-site sewage systems in the Bayou Lafourche watershed.