Bacterial 16S Ribosomal DNA Research Articles

Assessing the microbiota of the snail intermediate host of trematodes, Galba truncatula

BackgroundThe microbiome is known to play key roles in health and disease, including host susceptibility to parasite infections. The freshwater snail Galba truncatula is the intermediate host for many trematode species, including the liver and rumen flukes Fasciola hepatica and Calicophoron daubneyi, respectively. The snail-parasite system has previously been investigated. However, the specific interaction between the snail-associated microbiota and intra-snail developmental stages of trematodes has yet to be explored.MethodsGalba truncatula snails were collected from farms in Northern Ireland and trematode infection was diagnosed using PCR. High-throughput sequencing analysis of the bacterial 16S ribosomal DNA V3-V4 hypervariable regions was subsequently applied to characterise the microbiota of both uninfected and infected snails.Results We first showed that the snail harboured microbiota that was distinct for its environment. The microbiota of infected snails was found to differ significantly from that of uninfected snails. In particular, the bacterial genera Mycoplasma and Methylotenera were significantly more abundant in infected snails, while genera Sphingomonas and Nocardioides were predominantly associated with uninfected snails. ConclusionThese findings pave the way to future studies on the functional roles of bacteria in host-parasite relationships.Graphical

Pulp Regenerative Therapy Using Autologous Dental Pulp Stem Cells in a Mature Tooth with Apical Periodontitis: A Case Report

The utility and feasibility of pulp regenerative therapy with autologous dental pulp stem cells (DPSCs) in mature teeth with irreversible pulpitis were clinically demonstrated. On the other hand, there is no evidence of the utility of DPSCs in mature teeth with apical periodontitis. The aim of this case report was to describe the potential utility of regenerative cell therapy in mature teeth with apical periodontitis. A 44-year-old man was referred for pulp regeneration due to a periapical lesion in his maxillary first premolar. Root canal disinfection was performed by irrigation and intracanal medication by nanobubbles with levofloxacin and amphotericin B in addition to conventional irrigation. Autologous DPSCs isolated from an extracted third molar were transplanted into the root canal after residual bacteria and fungi were below the detection level by polymerase chain reaction assay using universal genes to amplify specific regions within bacterial 16S ribosomal DNA and fungal ribosomal DNA (ITS1), respectively. There were no adverse events or systemic toxicity assessed for clinical evaluations during the 79-week-follow-up period and laboratory evaluations after 4 weeks. The affected tooth was responsive to the electric pulp test. Cone-beam computed tomographic imaging revealed a reduced lesion size, remission of the periapical tissue, and mineralized tissue formation in the apical part of the canal after 79 weeks. The signal intensity on magnetic resonance imaging of the regenerated tissue in the affected tooth was comparable to that of the normal pulp in the adjacent teeth after 24 weeks. This case report demonstrated the potential use of DPSCs for pulp regenerative therapy in mature teeth with apical periodontitis.

Characterizing ruminal acidosis risk: A multiherd, multicountry study

A multicenter observational study was conducted on early lactation Holstein cows (n = 261) from 32 herds from 3 regions (Australia, AU; California, CA; and Canada, CAN) to characterize their risk of acidosis into 3 groups (high, medium, or low) using a discriminant analysis model previously developed. Diets ranged from pasture supplemented with concentrates to total mixed ration (nonfiber carbohydrates = 17 to 47 and neutral detergent fiber = 27 to 58% of dry matter). Rumen fluid samples were collected <3 h after feeding and analyzed for pH, and ammonia, d- and l-lactate, and volatile fatty acid (VFA) concentrations. Eigenvectors were produced using cluster and discriminant analysis from a combination of rumen pH, and ammonia, d-lactate, and individual VFA concentrations and were used to calculate the probability of the risk of ruminal acidosis based on proximity to the centroid of 3 clusters. Bacterial 16S ribosomal DNA sequence data were analyzed to characterize bacteria. Individual cow milk volume, fat, protein, and somatic cell count values were obtained from the closest herd test to the rumen sampling date (median = 1 d before rumen sampling). Mixed model analyses were performed on the markers of rumen fermentation, production characteristics, and the probability of acidosis. A total of 26.1% of the cows were classified as high risk for acidosis, 26.8% as medium risk, and 47.1% as low risk. Acidosis risk differed among regions with AU (37.2%) and CA (39.2%) having similar prevalence of high-risk cows and CAN only 5.2%. The high-risk group had rumen phyla, fermentation, and production characteristics consistent with a model of acidosis that reflected a rapid rate of carbohydrate fermentation. Namely, acetate to propionate ratio (1.98 ± 0.11), concentrations of valerate (2.93 ± 0.14 mM), milk fat to protein ratio (1.11 ± 0.047), and a positive association with abundance of phylum Firmicutes. The medium-risk group contains cows that may be inappetant or that had not eaten recently or were in recovery from acidosis. The low-risk group may represent cattle that are well fed with a stable rumen and a slower rumen fermentation of carbohydrates. The high risk for acidosis group had lower diversity of bacteria than the other groups, whereas CAN had a greater diversity than AU and CA. Rumen fermentation profile, abundance of ruminal bacterial phyla, and production characteristics of early lactation dairy cattle from 3 regions were successfully categorized in 3 different acidosis risk states, with characteristics differing between acidosis risk groups. The prevalence of acidosis risk also differed between regions.

Altered gut microbiota is associated with different immunologic responses to antiretroviral therapy in HIV-infected men who have sex with men.

The association between gut microbiota and immunologic nonresponse among people living with HIV (PLHIV) on antiretroviral therapy (ART) is not well documented. This study aimed to characterize gut microbiota among HIV-infected men who have sex with men (MSM) with different immunologic responses. We recruited HIV-infected MSM and HIV-uninfected MSM (healthy controls, HC) in Guangzhou, June-October 2021. HIV-infected MSM were grouped into good immunological responders (GIR) (CD4 + T cell count ≥ 350 cells/μL) and poor immunological responders (PIR) (<350 cells/μL). Blood and stool samples were collected. Microbial translocation in serum was performed using enzyme-linked immunosorbent assay (ELISA). Bacterial 16S ribosomal DNA sequencing was performed on stool samples, and microbial metabolites were obtained through gas chromatography-mass spectrometry. 56 GIR, 41 PIR, and 51 HC were included. Microbial translocation marker soluble cluster of differentiation 14 (sCD14) in both GIR and PIR groups was significantly higher than that in HC. Compared with PIR or HC groups, the genera of Coprococcus, Blautia, Clostridium, and SMB53 were decreased, whereas Megamonas and Megasphaera were more abundant in GIR group. Compared with GIR or PIR groups, Bifidobacterium, Collinsella, Faecalibacterium, Oscillospira, and Roseburia were more abundant, whereas Escherichia was decreased in HC group. The levels of benzenoids, imidazoles, phenylpropanoic acids, phenylpropanoids, and pyridines showed strongly significant correlations between differential genera. This study presented a comprehensive landscape of gut microbiota in PLHIV with different treatment outcomes. Megamonas, Coprococcus and Blautia were the major genera correlated with different immunologic responses in PLHIV.

Heterosis in root microbiota inhibits growth of soil-borne fungal pathogens in hybrid rice.

In nature, plants are colonized by various microbes that play essential roles in their growth and health. Heterosis is a natural genetic phenomenon whereby first-generation hybrids exhibit superior phenotypic performance relative to their parents. It remains unclear whether this concept can be extended to the "hybridization" of microbiota from two parents in their descendants and what benefits the hybrid microbiota might convey. Here, we investigated the structure and function of the root microbiota from three hybrid rice varieties and their parents through amplicon sequencing analysis of bacterial 16S ribosomal DNA (rDNA) and fungal internal transcribed spacer (ITS) regions. We show that the bacterial and fungal root microbiota of the varieties are distinct from those of their parental lines and exhibit potential heterosis features in diversity and composition. Moreover, the root bacterial microbiota of hybrid variety LYP9 protects rice against soil-borne fungal pathogens. Systematic analysis of the protective capabilities of individual strains from a 30-member bacterial synthetic community derived from LYP9 roots indicated that community members have additive protective roles. Global transcription profiling analyses suggested that LYP9 root bacterial microbiota activate rice reactive oxygen species production and cell wall biogenesis, contributing to heterosis for protection. In addition, we demonstrate that the protection conferred by the LYP9 root microbiota is transferable to neighboring plants, potentially explaining the observed hybrid-mediated superior effects of mixed planting. Our findings suggest that some hybrids exhibit heterosis in their microbiota composition that promotes plant health, highlighting the potential for microbiota heterosis in breeding hybrid crops.

Basophil Depletion Alters Host Immunity, Intestinal Permeability, and Mammalian Host-to-Mosquito Transmission in Malaria.

Malaria-induced bacteremia has been shown to result from intestinal mast cell (MC) activation. The appearance of MCs in the ileum and increased intestinal permeability to enteric bacteria are preceded by an early Th2-biased host immune response to infection, characterized by the appearance of IL-4, IL-10, mast cell protease (Mcpt)1 and Mcpt4, and increased circulating basophils and eosinophils. Given the functional similarities of basophils and MCs in the context of allergic inflammation and the capacity of basophils to produce large amounts of IL-4, we sought to define the role of basophils in increased intestinal permeability, in MC influx, and in the development of bacteremia in the context of malaria. Upon infection with nonlethal Plasmodium yoelii yoelii 17XNL, Basoph8 × ROSA-DTα mice or baso (-) mice that lack basophils exhibited increased intestinal permeability and increased ileal MC numbers, without any increase in bacterial 16S ribosomal DNA copy numbers in the blood, relative to baso (+) mice. Analysis of cytokines, chemokines, and MC-associated factors in the ileum revealed significantly increased TNF-α and IL-13 at day 6 postinfection in baso (-) mice compared with baso (+) mice. Moreover, network analysis of significantly correlated host immune factors revealed profound differences between baso (-) and baso (+) mice following infection in both systemic and ileal responses to parasites and translocated bacteria. Finally, basophil depletion was associated with significantly increased gametocytemia and parasite transmission to Anopheles mosquitoes, suggesting that basophils play a previously undescribed role in controlling gametocytemia and, in turn, mammalian host-to-mosquito parasite transmission.

Basophil depletion alters host immunity, intestinal permeability and mammalian host-to-mosquito transmission in malaria.

Abstract Malaria-induced bacteremia has been shown to result from intestinal mast cell (MC) activation (Chau et al. 2013, Potts et al. 2016, Céspedes et al. 2020). The appearance of MCs in the ileum and increased permeability to enteric bacteria are preceded by an early Th2-biased host immune response to infection, characterized by the appearance of IL-4, IL-10, mast cell protease (Mcpt)1 and Mcpt4, and an increase in circulating basophils and eosinophils. Given the functional similarities of basophils and MCs in the context of allergic inflammation and the capacity of basophils to produce IL-4 in large amounts, we sought to define the role of basophils in the development of increased intestinal permeability and in MC influx and the development of bacteremia in the context of malaria. Upon infection with non-lethal Plasmodium yoelii yoelii 17XNL, mice that lack basophils exhibited increased intestinal permeability and increased ileal MC numbers, without any increase in bacterial 16S ribosomal DNA copy numbers in the blood, relative to non-depleted mice. Analysis of cytokines, chemokines and MC-associated factors in the ileum revealed significantly increased TNFα and IL-13 at day 6 post infection (PI) in basophil-depleted mice compared to non-depleted mice. Moreover, network analysis revealed profound differences between depleted and non-depleted mice over time following infection in both systemic and local immune responses to parasites and translocated bacteria. Finally, basophil depletion was associated with significantly increased gametocytemia and parasite transmission to mosquitoes, suggesting that basophils play a previously undescribed role in controlling gametocytemia and in turn, mammalian host-to-mosquito transmission. This work was supported by NIH NIAID RO1 AI131609 to Shirley Luckhart.

Blood microbiome is associated with changes in portal hypertension after successful direct-acting antiviral therapy in patients with HCV-related cirrhosis

Patients with a significant decrease in hepatic venous pressure gradient (HVPG) have a considerable reduction of liver complications and higher survival after HCV eradication. To evaluate the association between the baseline blood microbiome and the changes in HVPG after successful direct-acting antiviral (DAA) therapy in patients with HCV-related cirrhosis. We performed a prospective study in 32 cirrhotic patients (21 HIV positive) with clinically significant portal hypertension (HVPG ≥10 mmHg). Patients were assessed at baseline and 48 weeks after HCV treatment completion. The clinical endpoint was a decrease in HVPG of ≥20% or HVPG <12 mmHg at the end of follow-up. Bacterial 16S ribosomal DNA was sequenced using MiSeq Illumina technology, inflammatory plasma biomarkers were investigated using ProcartaPlex immunoassays and the metabolome was investigated using GC-MS. During the follow-up, 47% of patients reached the clinical endpoint. At baseline, those patients had a higher relative abundance of Corynebacteriales and Diplorickettsiales order, Diplorickettsiaceae family, Corynebacterium and Aquicella genus and Undibacterium parvum species organisms and a lower relative abundance of Oceanospirillales and Rhodospirillales order, Halomonadaceae family and Massilia genus organisms compared with those who did not achieve the clinical endpoint according to the LEfSe algorithm. Corynebacteriales and Massilia were consistently found within the 10 bacterial taxa with the highest differential abundance between groups. Additionally, the relative abundance of the Corynebacteriales order was inversely correlated with IFN-γ, IL-17A and TNF-α levels and the Massilia genus with glycerol and lauric acid. Baseline-specific bacterial taxa are related to an HVPG decrease in patients with HCV-related cirrhosis after successful DAA therapy.

Gaseous and Particulate Content of Laser Tattoo Removal Plume.

There is increasing awareness of the potential hazards of surgical plumes. The plume associated with laser tattoo removal remains uncharacterized. To determine the gaseous, particulate, and microbiological content of the laser tattoo removal plume. Air sampling was performed during laser tattoo removal from pig skin and from patients. Measurement of metals, volatile organic compounds (VOCs), carbon monoxide (CO), hydrogen sulfide (HS), and ultrafine particulates (UPs) as well as bacterial 16S ribosomal DNA sequencing were performed. Metals were identified in the plume from both pig and human skin. Volatile organic compounds were found at similar levels within and outside the treatment room. Several bacterial phyla were detected in the treatment room, but not outside. High levels of UPs were measured throughout the treatment room during tattoo removal from pig skin. Ultrafine particulates were detected at low levels in the room periphery during tattoo removal from human skin, but at higher levels in the immediate treatment zone. HS and CO were not detected. Metals, VOCs, HS, and CO were found at levels below applicable occupational exposure limits. The presence of bacteria is of uncertain significance, but may be hazardous. High levels of UPs require further investigation.

Hepatic microbiome in healthy lean and obese humans

Background & AimsDysbiosis of the gut microbiota in response to an energy-rich Western diet and the potential leak of bacteria and/or bacterial products from the intestine to the liver is perceived as a potential risk factor for the development of non-alcoholic fatty liver disease (NAFLD). We investigated the microbiome in liver biopsies from healthy lean and obese individuals and compared it with their blood microbiome.MethodsWe examined liver biopsies from 15 healthy lean and 14 obese individuals (BMI of 18.5–25 and 30–40 kg/m2, respectively). Bacterial 16S ribosomal DNA (rDNA) was analysed by quantitative polymerase chain reaction (qPCR) and 16S metagenomic sequencing targeting the hypervariable V3–V4 region. Metagenomic analysis was performed using the linear discriminant analysis effect size (LEfSe) algorithm. Data are medians with IQRs in brackets.ResultsHistology revealed hepatic steatosis in 13 obese individuals and in 2 lean individuals. A robust signal from qPCR revealed significantly higher amounts of bacterial rDNA copies in liver samples from obese individuals compared with those from lean individuals (148 [118–167] vs. 77 [62–122] 16S copies/ng DNA, p <0.001). Liver biopsies from the obese group were characterised by lower alpha diversity at the phylum level (Shannon index 0.60 [0.55–0.76] vs. 0.73 [0.62–0.90], p = 0.025), and metagenomic profiling revealed a significantly higher proportion of Proteobacteria in this group (81.0% [73.0–82.4%] vs. 74.3% [68.4–78.4%], p = 0.014).ConclusionsWe provide evidence for the presence of bacterial rDNA in the healthy human liver. Based on differences in the hepatic microbiome between obese individuals and healthy lean individuals, we suggest that changes in the liver microbiome could constitute an additional risk factor for the development of NAFLD.Lay summaryNon-alcoholic fatty liver disease (NAFLD) has become the most common liver disease globally, and new evidence suggests that obesity is associated with a disturbed gut bacterial composition, which may influence the development of NAFLD. We examined the composition of bacterial DNA in liver biopsies from healthy lean and obese individuals and found a different composition of bacterial DNA in liver biopsies from the obese group. We propose that the increased bacterial DNA load in the livers of obese individuals could constitute an early risk factor for the progression of NAFLD.Clinical trial numberNCT02337660

Impact of Poly I:C induced maternal immune activation on offspring's gut microbiome diversity – Implications for schizophrenia

BackgroundImmunopathological concepts have been intensively discussed for schizophrenia. The polyriboinosinic–polyribocytidylic (PolyI:C) mouse model has been well validated to invasively study this disease. The intestinal microbiome exhibits broad immunological and neuronal activities. The relevance of microbiome alterations in the PolyI:C model to human schizophrenia should be explored.MethodsFeces of offspring from mice mothers, who were administered to PolyI:C or NaCl (controls) at ED 9, were collected at PND 30 and 180 (PolyI:C and control mice (N = 32 each; half males and females). This was analyzed for bacterial 16S ribosomal DNA (rDNA) using a gut microbiome polymerase chain reaction (PCR) microarray tool.ResultsDifferences were found in species richness of microbiome between animals of different ages (PND 30 and 180), but also between offspring from PolyI:C vs. NaCl treated mothers. In female mice at PND 30, the abundance of Prevotellaceae and Porphyromonadaceae was lower and that of Lactobacillales was higher, whereas in male mice at the same time point the abundance of four families of the Firmicutes phylum (Clostridia vadinBB60 group, Clostridiales Family XIII, Ruminococcaceae and Erysipelotrichaceae) was increased relative to the control group.LimitationsNo further analyses of cell types or cytokines involved in autoimmune gut and brain processes.ConclusionsThese finding seem to be similar to microbiome disturbances in patients with schizophrenia. The differential bacterial findings at day 30 (i.e., similar to the prodromal phase in patients with schizophrenia) correspond to the tremendous activation of the immune system with a strong increase in microglial cells which might be responsible for neuroplasticity reduction in cortical areas in patients with schizophrenia.

Salivary dysbiosis in Sj\xf6gren\u2019s syndrome and a commensal-mediated immunomodulatory effect of salivary gland epithelial cells

Salivary gland epithelial cells (SGECs) have been implicated in the pathogenesis of Sjögren’s syndrome due to aberrant antigen-presentation function. This study examined the hypothesis that oral dysbiosis modulates the antigen-presentation function of SGECs, which regulates CD4 T cell proliferation in primary Sjögren’s syndrome (pSS). Saliva samples from 8 pSS patients and 16 healthy subjects were analyzed for bacterial 16S ribosomal DNA. As a result, 39 differentially abundant taxa were identified. Among them, the phylum Proteobacteria comprised 21 taxa, and this phylum was mostly enriched in the healthy controls. The proteobacterium Haemophilus parainfluenzae was enriched in the healthy controls, with the greatest effect size at the species level. Treatment of A253 cells in vitro with H. parainfluenzae upregulated PD-L1 expression, and H. parainfluenzae-pretreated A253 cells suppressed CD4 T cell proliferation. The suppression was partially reversed by PD-L1 blockade. Among low-grade xerostomia patients, salivary abundance of H. parainfluenzae decreased in pSS patients compared to that in non-pSS sicca patients. Our findings suggest that H. parainfluenzae may be an immunomodulatory commensal bacterium in pSS.

16S rDNA metabarcoding of the bacterial community associated with workers of Pheidole rugaticeps Emery (Hymenoptera: Formicidae)

Insect microbiota are receiving increasing attention from researchers, particularly with the continued advances in next generation sequencing (NGS) techniques. However, there is a paucity of data on the microbiota of ants that scavenge around human settlements. In this study, we characterized the bacterial communities of Pheidole rugaticeps Emery that were collected scavenging on other household insects using Illumina MiSeq high-throughput sequencing of the bacterial 16S ribosomal DNA gene. P. rugaticeps DNA was extracted from the insect samples using a HiYield™ Genomic DNA isolation kit according to the manufacturer’s protocols and amplified using polymerase chain reaction (PCR). The PCR products were sequenced with the Illumina MiSeq platform according to the standard protocols to amplify the V3–V4 of the 16S rDNA gene. The results for the 16S rDNA genes were analysed using QIIME 2 Core − 2020.6, and a 16S rDNA metabarcoding dataset was presented. A total of 46,651 reads were obtained from three genomic samples. A total of 368 amplicon sequence variants (ASV) comprising 165 genera were revealed and classified into 17 phyla. Proteobacteria (57.47%) and Firmicutes (33.14%) were the most abundant taxa, while Acinetobacter (37.10%) was the most abundant genus in all three sampling groups. Pathogenic bacteria species, such as Acinetobacter baumannii (15%) and Pseudomonas aeruginosa (2.92%), were identified from P. rugaticeps samples collected from a hospital environment. However, this study recommends more studies on the microbiota of Pheidole ants with different feeding habits and habitats to establish their core microbiome.

Rifaximin Improves Visceral Hyperalgesia via TRPV1 by Modulating Intestinal Flora in the Water Avoidance Stressed Rat.

Background Rifaximin is effective in relieving pain symptoms with IBS patients, although the mechanisms were not clear. The aims of the research were to investigate whether the visceral hyperalgesia was alleviated by rifaximin via TRPV1 channel in rats. Methods Rats were subjected to water avoidance stress (WAS) and were pretreated with rifaximin by oral gavage. The visceromotor response to colorectal distension was measured. The changes of TRPV1 in peripheral and central neurons of rats were detected by immunofluorescence, western blot method, and RT-PCR. Bacterial 16S ribosomal DNA in ileal contents was assessed using the Illumina MiSeq platform. The effect of intestinal flora on TRPV1 channel was observed by fecal microbiota transplantation (FMT) methods. Results Rifaximin could relieve the visceral hyperalgesia and reduce the TRPV1 expression of neurons and ileum mucosa in rats induced by WAS. The reduced relative abundance of intestinal flora induced by WAS could be partly prevented by rifaximin. The electromyographical activities and immunoreactivity of TRPV1 in rats could be changed after FMT. Conclusions Rifaximin could improve visceral hyperalgesia via TRPV1 channels of peripheral and central neurons by modulating intestinal flora in rats.

Feasibility of microbial sample collection on the skin from people in Yaoundé, Cameroon

Characterization of microbial communities in the skin in healthy individuals and diseased patients holds valuable information for understanding pathogenesis of skin diseases and as a source for developing novel therapies. Notably, resources regarding skin microbiome are limited in developing countries where skin disorders from infectious diseases are extremely common. A simple method for sample collection and processing for skin microbiome studies in such countries is crucial. The aim of this study is to confirm the feasibility of collecting skin microbiota from individuals in Yaoundé, a capital city of Cameroon, and subsequent extraction of bacterial DNA in a resource limited setting. Skin swabs from several individuals in Yaoundé were successfully obtained, and sufficient amount of bacterial 16S ribosomal RNA-coding DNA was collected, which was confirmed by quantitative PCR. The median copy number of 16S ribosomal RNA gene varied across participants and collection sites, with significantly more copies in samples collected from the forehead compared to the left and right forearm, or back. This study demonstrated that collecting surface skin microbes using our swabbing method is feasible in a developing country. We further showed that even with limited resources, we could collect sufficient amount of skin microbiota from the inhabitants in Yaoundé where no studies of skin microbiome were reported, which can be passed to further metagenomic analysis such as next generation sequencing.

Maturation of the Oral Microbiome in Caries-Free Toddlers: A Longitudinal Study

Understanding the development of the oral microbiota in healthy children is of great importance to oral and general health. However, limited data exist on a healthy maturation of the oral microbial ecosystem in children. Moreover, the data are biased by mislabeling “caries-free” populations. Therefore, we aimed to characterize the healthy salivary and dental plaque microbiome in young children. Caries-free (ICDAS [International Caries Detection and Assessment System] score 0) children (n = 119) and their primary caregivers were followed from 1 until 4 y of child age. Salivary and dental plaque samples were collected from the children at 3 time points (T1, ~1 y old; T2, ~2.5 y old; and T3, ~4 y old). Only saliva samples were collected from the caregivers. Bacterial V4 16S ribosomal DNA amplicons were sequenced using Illumina MiSeq. The reads were denoised and mapped to the zero-radius operational taxonomic units (zOTUs). Taxonomy was assigned using HOMD. The microbial profiles of children showed significant differences (P = 0.0001) over time. Various taxa increased, including Fusobacterium, Actinomyces, and Corynebacterium, while others showed significant decreases (e.g., Alloprevotella and Capnocytophaga) in their relative abundances over time. Microbial diversity and child-caregiver similarity increased most between 1 and 2.5 y of age while still not reaching the complexity of the caregivers at 4 y of age. The microbiome at 1 y of age differed the most from those at later time points. A single zOTU (Streptococcus) was present in all samples (n = 925) of the study. A large variation in the proportion of shared zOTUs was observed within an individual child over time (2% to 42% of zOTUs in saliva; 2.5% to 38% in dental plaque). These findings indicate that the oral ecosystem of caries-free toddlers is highly heterogeneous and dynamic with substantial changes in microbial composition over time and only few taxa persisting across the 3 y of the study. The salivary microbiome of 4-y-old children is still distinct from that of their caregivers.

Pilot Study of Telmisartan (Micardis) for Prevention of Acute Graft Vs. Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation: Interim Analysis

Telmisartan (TMS) is an angiotensin receptor blocker with anti-inflammatory properties and little or no clinical immunosuppressive effect. We undertook an unblinded, single arm, pilot study of TMS (160 mg/d p.o.) for prevention of acute graft vs. host disease (aGvHD) in recipients of HLA matched allogeneic hematopoietic stem cell transplants (HSCTs). Primary endpoints of Grade II or &gt;Grade III aGvHD (1994 Consensus Conference on Acute GVHD Grading) were compared with 178 similar HSCT historical controls over the preceding 3 yrs at our institution: 26% &gt;Grade III, 74% Grade II. Safety endpoints included engraftment, relapse/progression by day (d) 180, non-relapse mortality by d 180, and serious drug-related adverse reactions. Experimental data were collected on blood endotoxin levels and stool microbiome composition. The study was powered to detect 20% or 50% reduced rates of, respectively, Grade II or &gt;Grade III. We report results from a planned interim analysis triggered when the first 22 evaluable patients (pts) reached d 100. Of 27 evaluable pts, 24 were beyond d 180 by completion of this interim analysis. The study was designed to treat pts for two days prior to, and day of HSCT, and for an additional 98 days post-transplant, but pts were considered evaluable if they completed &gt;14 days of post- transplant TMS, including pre-determined dose reductions. One enrollee received TMS for 13 days post-HSCT and was excluded from analysis. Five pts received 14-24 days of drug (4 by choice, 1 died of sepsis). More than half the evaluable patients (17/27) completed &gt;94 days of post-HSCT therapy, including 6 who experienced an episode of hypotension. Almost half (13/27) received &gt;80% of the full 101 day dose (16,160 mg), including 5 who experienced hypotension. Of the 6 enrollees receiving &lt;24 days of drug, two had documented hypotension. No other serious drug-attributed adverse reactions were reported. Reasons cited for pts choosing to discontinue TMS were inconvenience of taking pills, and home stool sampling. Safety Endpoints: All pts engrafted promptly (ANC &gt;500/uL, platelet &gt;20,000/uL). Peripheral donor CD3+ T cell median and range of chimerism on days 28 and 84 were 99.5% (37-100) and 100.0% (36-100); bone marrow donor CD34+ cell chimerism was 97.0% (62-100). There was a single NRM during the 180 d study, and no graft rejection or increase in relapse or progression. Four relapses occurred within 180 days, and 2 more after d 180, resulting in two relapse deaths (d 370, and d 600). Primary Endpoints:A single individual developed hyperacute Grade III skin GvHD on day 7 p-HSCT. Another 12 of 27 patients developed Grade 2 aGvHD, one after the conventional 100 d window (d 141). Compared with historical controls, the incidence of aGvHD was significantly reduced for Grade II (p &lt; 0.005) and Grade &gt;III (p = 0.01), using the two-tailed Z-test of proportions. Experimental Endpoints: Acute GvHD is associated with increased gut permeability, bacterial translocation, and loss of gut microbiome diversity. Endotoxemia, an indicator of intestinal integrity, as measured by the endotoxin activity assay (EAA, Spectral Medical) reached septic levels in 40% of patients during pre-transplant conditioning (d -3 - d 0), and subsequently returned to, or maintained, non-septic levels from week 5 onward in 90% of patients, with an overall downward group trend of EAA scores during 180 days of follow up. Genotyping and analysis of bacterial V4 16S ribosomal DNA from weekly stool samples of the first 10 evaluable patients revealed no decrease in OTU richness or Shannon diversity at any time point pre- vs. post- treatment. Among the 5 most abundant phyla, Bacteroidetes was significantly less abundant post-treatment compared to pre-treatment. Among the 8 most abundant families, Bacteroidaceae significantly decreased post- vs. pre- treatment. While historic microbiome controls from our institution are not available, our finding of increased Bacteroidetes is in contrast to reported decreased Bacteroidetes in allogeneic HSCTs not receiving TMS, but may resemble changes after autologous HSCT. This trial, funded by the Gateway Foundation, is ongoing. Preliminary results indicate TMS is well tolerated, with a beneficial impact on aGvHD and no increased relapse or NRM, with excellent engraftment, and preservation of anti-tumor effect, intestinal barrier integrity, and gut microbial diversity. Disclosures Iyengar: Hackensack University Medical Center: Patents &amp; Royalties: Telmisartan use patent.. Rowley:Allergan: Equity Ownership; Fate Therapeutics: Consultancy. Schwartz:Hackensack University Medical Center: Patents &amp; Royalties: Telmisartan use patent. OffLabel Disclosure: Telmisartan. Indicated for treatment of hypertension.

Next-generation DNA sequencing shows a microbiota shift after an incursion of &lt;i&gt;Pseudomonas syringae &lt;/i&gt;pv. &lt;i&gt;actinidiae &lt;/i&gt;(Psa) on a single kiwifruit orchard

A virulent strain of Pseudomonas syringae pv. actinidiae (Psa) is a major pathogen for New Zealand’s $3B kiwifruit (Actinidia spp.) industry, and was first identified from a Te Puke orchard on 5 November 2010. Psa was first found on the Kerikeri research orchard (KRO) of Plant &amp; Food Research on 19 September 2014. The samples for this study were collected from the same orchard on 7 December 2012 and 25 November 2014, i.e. before and after the Psa incursion. Polymerase chain reaction (PCR) was conducted on total genomic DNA from four leaf discs of 15 individual vines sampled from two kiwifruit cv. ‘Hort16A’ orchard blocks at KRO, using modified PCR primers complementary to bacterial 16S ribosomal DNA and the fungal inter-transcribed spacer (ITS) region. The microbiota present before and after the Psa incursion were investigated by Illumina MiSeq™ next-generation sequencing to produce 2 × 300 bp pair end reads, followed by metabarcoding analysis using QIIME2 software. Populations of fungi from the Basidiomycete orders Filobasidiales, Sporidiobolales, Tremellales and Leucosporidiales, and genera of bacteria with known biological control activity, such as Erwinia, Pantoea, Methylobacterium, Sphingomonas and Paenibacillus, increased in the presence of Psa.

Heart failure developed after myocardial infarction does not affect gut microbiota composition in the rat.

There is a body of evidence that supports the notion that gut dysbiosis plays a role in the pathogenesis of cardiovascular diseases. Decreased cardiac function can reduce intestinal perfusion, resulting in morphological alterations, which may contribute to changes in the gut microbiota composition in patients with heart failure (HF). In this regard, a germane question is whether changes in gut microbiota composition are a cause or consequence of the cardiovascular disturbance. We tested the hypothesis that the development of HF, after myocardial infarction, would cause gut dysbiosis. Fecal samples were collected before and 6 wk after myocardial infarction or sham surgery. Gut microbiota were characterized by sequencing the bacterial 16S ribosomal DNA. The composition of bacterial communities in the fecal samples was evaluated by calculating three major ecological parameters: 1) the Chao 1 richness, 2) the Pielou evenness, and 3) the Shannon index. None of these indices was changed in either sham or HF rats. The Firmicutes/Bacteroidetes ratio was not altered in HF rats. The number of species in each phylum was also not different between sham and HF rats. β-Diversity analysis showed that the composition of gut microbiota was not changed with the development of HF. Bacterial genera were grouped according to their major metabolic end-products (acetate, butyrate, and lactate), but no differences were observed in HF rats. Therefore, we conclude that HF induced by myocardial infarction does not affect gut microbiota composition, at least in rats, indicating that the dysbiosis observed in patients with HF may precede cardiovascular disturbance.NEW & NOTEWORTHY Our study demonstrated that, following myocardial infarction in rats, heart failure (HF) development did not affect the intestinal microbiota despite distinct differences reported in the gut microbiota of humans with HF. Our finding is consistent with the notion that dysbiosis observed in patients with HF may precede cardiovascular dysfunction and therefore offers potential for early diagnosis and treatment.

Biomarkers of Macrophage Activation and Immune Danger Signals Predict Clinical Outcomes in Alcoholic Hepatitis.

Although mortality due to acute alcoholic hepatitis (AH) correlates with Model for End-Stage Liver Disease (MELD) scores, biomarkers are critically needed to manage this disease. Increases in inflammatory markers and macrophage activation are associated with acute AH and could be potential biomarkers of clinical events and/or mortality. We enrolled 89 clinically diagnosed AH patients in four US academic medical centers. Plasma from AH patients had a significant increase in gut microbial translocation indicators (endotoxin, bacterial 16S ribosomal DNA) and host response indicators (soluble cluster of differentiation 14 [sCD14] and lipopolysaccharide binding protein [LBP]) compared to controls. Patient MELD score and Glasgow Alcoholic Hepatitis score (GAHS) correlated with endotoxin levels. AH patients also had a significant increase in high mobility group protein 1 (HMGB1), a sterile danger signal molecule, and osteopontin (OPN), a multifunctional phosphoprotein involved in neutrophil activation, compared to controls. Increased levels of OPN positively correlated with increasing MELD score, GAHS, and LBP levels. Consistent with these results, AH patients had significantly increased circulating levels of macrophage activation (sCD163 and sCD206) markers compared to healthy controls, and sCD163 and sCD206 significantly and positively correlated with OPN, HMGB1, and LBP levels as well as with MELD score and GAHS. These findings indicate a connection between microbial translocation, immune cell activation, and AH severity. Plasma sCD14, OPN, sCD163, and sCD206 levels were significantly higher in nonsurvivors than survivors. In multivariate regression models, we identified sCD14, sCD163, and OPN as independent predictors of 90-day mortality, infection, and organ failure development, respectively. Conclusion: Our study suggests that sCD14, LBP, OPN, sCD163, and sCD206 are biomarkers to indicate severity and predict clinical outcomes in AH.