Methanobrevibacter smithii tonsillar phlegmon: a case report.
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ABSTRACT:
SUBMITTER: Djemai K
PROVIDER: S-EPMC8184653 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:This SuperSeries is composed of the SubSeries listed below.
2011-11-07 | GSE25537 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE25408: The pan-genome of the dominant human gut-associated archaeon, Methanobrevibacter smithii GSE25535: Expression data from an in vitro growth of Methanobrevibacter smithii PS Refer to individual Series
2011-11-07 | E-GEOD-25537 | biostudies-arrayexpress
Project description:BackgroundUrinary tract infections are known to be caused by bacteria, but the potential implications of archaea have never been studied in this context.MethodsIn two different university hospital centres we used specific laboratory methods for the detection and culture of archaeal methanogens in 383 urine specimens prospectively collected for diagnosing urinary tract infection (UTI).FindingsMethanobrevibacter smithii was detected by quantitative PCR and sequencing in 34 (9%) of the specimens collected from 34 patients. Escherichia coli, Klebsiella pneumoniae, Enterobacter sp., Enterococcus faecium and mixed cultures were detected along with M. smithii in eighteen, six, three, one and six urine samples, respectively. Interestingly, using our specific culture method for methanogens, we also isolated M. smithii in 31 (91%) of the 34 PCR positive urine samples. Genotyping the 31 isolates using multispacer sequence typing revealed three different genotypes which have been previously reported in intestinal microbiota. Antibiotic susceptibility testing found the 31 isolates to be in vitro susceptible to metronidazole (MIC: 1 mg/L) but resistant to fosfomycin, sulfamethoxazole-trimethoprim, amoxicillin-clavulanate and ofloxacin, commonly used to treat bacterial UTI. Finally, 19 (54%) of the 34 patients in whose urine samples M. smithii was detected were diagnosed with UTIs, including cystitis, pyelonephritis and prostatitis.InterpretationOur results show that M. smithii is part of the urinary microbiota of some individuals and could play a role in community-acquired UTI in association with enteric bacteria. FUND: This study was supported by IHU Méditerranée Infection, Marseille, France.
| S-EPMC6558020 | biostudies-literature
Project description:Methanobrevibacter smithii isolate genome sequencing and assembly
| PRJNA918448 | ENA
Project description:The F420-dependent NADP oxidoreductase enzyme from Methanobrevibacter smithii catalyzes the important electron transfer step during methanogenesis. Therefore, it may act as potential target for blocking the process of methane formation. Its protein sequence is available in GenBank (accession number: ABQ86254.1) however no report has been found about its 3D protein structure. In this work, we first time claim 3D model structure of F420-dependent NADP oxidoreductase enzyme from Methanobrevibacter smithii by comparative homology modeling method. Swiss model and ESyPred3d (via Modeller 6v2) software's were generated the 3D model by detecting 1JAX (A) as template along with sequence identities of 34.272% and 35.40%. Furthermore, PROCHECK with Ramachandran plot and ProSA analysis revealed that swiss model produced better model than Modeller6v2 with 98.90% of residues in favored and additional allowed regions (RM plot) as well as with ProSA Z score of -7.26. In addition, we investigated that the substrate F420 bound at the cavity of the model. Subsequently, inhibitor prediction study revealed that Lovastatin (-22.07 Kcal/mol) and Compactin (Mevastatin) (-21.91 Kcal/mol) produced more affinity for model structure of NADP oxidoreducatse as compared to F420 (-14.40 Kcal/mol). It indicates that the Lovastatin and Compactin (Mevastatin) compounds (Negative regulator) may act as potential inhibitor of F420 dependent NADP oxidoreducatse protein.
| S-EPMC3064846 | biostudies-literature
Project description:The human gut is home to trillions of microbes, thousands of bacterial phylotypes, as well as hydrogen-consuming methanogenic archaea. Studies in gnotobiotic mice indicate that Methanobrevibacter smithii, the dominant archaeon in the human gut ecosystem, affects the specificity and efficiency of bacterial digestion of dietary polysaccharides, thereby influencing host calorie harvest and adiposity. Metagenomic studies of the gut microbial communities of genetically obese mice and their lean littermates have shown that the former contain an enhanced representation of genes involved in polysaccharide degradation, possess more archaea, and exhibit a greater capacity to promote adiposity when transplanted into germ-free recipients. These findings have led to the hypothesis that M. smithii may be a therapeutic target for reducing energy harvest in obese humans. To explore this possibility, we have sequenced its 1,853,160-bp genome and compared it to other human gut-associated M. smithii strains and other Archaea. We have also examined M. smithii's transcriptome and metabolome in gnotobiotic mice that do or do not harbor Bacteroides thetaiotaomicron, a prominent saccharolytic bacterial member of our gut microbiota. Our results indicate that M. smithii is well equipped to persist in the distal intestine through (i) production of surface glycans resembling those found in the gut mucosa, (ii) regulated expression of adhesin-like proteins, (iii) consumption of a variety of fermentation products produced by saccharolytic bacteria, and (iv) effective competition for nitrogenous nutrient pools. These findings provide a framework for designing strategies to change the representation and/or properties of M. smithii in the human gut microbiota.
| S-EPMC1890564 | biostudies-literature
Project description:The Lon protease is highly evolutionarily conserved. However, little is known about Lon in the context of gut microbial communities. A gene encoding a Lon-like protease (Lon-like-Ms) was identified and characterized from Methanobrevibacter smithii, the predominant archaeon in the human gut ecosystem. Phylogenetic and sequence analyses showed that Lon-like-Ms and its homologs are newly identified members of the Lon family. A recombinant form of the enzyme was purified by affinity chromatography, and its catalytic properties were examined. Recombinant Lon-like-Ms exhibited ATPase activity and cleavage activity toward fluorogenic peptides and casein. The peptidase activity of Lon-like-Ms relied strictly on Mg(2+) (or other divalent cations) and ATP. These results highlight a new type of Lon-like protease that differs from its bacterial counterpart.
| S-EPMC4864567 | biostudies-literature
Project description:Introductionand Importance: Acute ischemic stroke is a rare event in children with leukemia, yet with long-term morbidity, substantial health, and economic cost. Central nervous system (CNS) leukemic involvement and chemotherapy-related stroke are the most common causes. Hyperleukocytosis induced stroke is very rarely reported.Case presentationA 2-year-old male child presented with hyperleukocytosis (leukocyte count was 320x109/L). Bone marrow evaluation revealed T-cell acute lymphoblastic leukemia. He was treated with dexamethasone, vincristine and daunorubicin, and on day 4 of chemotherapy, he developed abnormal movements, altered mental status, limb weakness and mutism. Magnetic resonance imaging of the brain showed multifocal infarctions involving left pons and both cerebellar hemispheres causing tonsillar herniation with restricted diffusion and mild hydrocephalus but no leptomeningeal enhancement or leukemic infiltrates. Magnetic resonance angiography did not show any arterial stenosis. He was intubated, sedated and managed conservatively with dexamethasone. Cytologic analysis of cerebrospinal fluid showed no blasts. Thrombophilia work up was negative. Five weeks later, the patient had significant improvement in overall neurologic status. He is free of leukemia. MRI showed interval resolution of previous infarcts.Clinical discussionHyperviscosity secondary to hyperleukocytosis was considered to be the most likely explanation for this patient stroke after excluding thrombophilia and leukemic infiltration. Prompt management with hydration and careful chemotherapy resulted in good outcome in our patient.ConclusionThis case demonstrate the value of early recognition and prompt management of posterior circulation ischemic stroke in children with leukemia and hyperleukocytosis at presentation.
| S-EPMC8441068 | biostudies-literature
Project description:The methanoarchaea Methanosphaera stadtmanae and Methanobrevibacter smithii are known to be part of the indigenous human gut microbiota. Although the immunomodulatory effects of bacterial gut commensals have been studied extensively in the last decade, the impact of methanoarchaea in human's health and disease was rarely examined. Consequently, we studied and report here on the effects of M. stadtmanae and M. smithii on human immune cells. Whereas exposure to M. stadtmanae leads to substantial release of proinflammatory cytokines in monocyte-derived dendritic cells (moDCs), only weak activation was detected after incubation with M. smithii. Phagocytosis of M. stadtmanae by moDCs was demonstrated by confocal microscopy as well as transmission electronic microscopy (TEM) and shown to be crucial for cellular activation by using specific inhibitors. Both strains, albeit to different extents, initiate a maturation program in moDCs as revealed by up-regulation of the cell-surface receptors CD86 and CD197 suggesting additional activation of adaptive immune responses. Furthermore, M. stadtmanae and M. smithii were capable to alter the gene expression of antimicrobial peptides in moDCs to different extents. Taken together, our findings strongly argue that the archaeal gut inhabitants M. stadtmanae and M. smithii are specifically recognized by the human innate immune system. Moreover, both strains are capable of inducing an inflammatory cytokine response to different extents arguing that they might have diverse immunomodulatory functions. In conclusion, we propose that the impact of intestinal methanoarchaea on pathological conditions involving the gut microbiota has been underestimated until now.
| S-EPMC4051749 | biostudies-literature