Mobiluncus curtisii Bacteremia: Case Study and Literature Review

Background: There are few reports of bacteremia caused by Mobiluncus curtisii in the literature. We present a review of the literature in addition to a case study. Method: We describe the case of an 82-year-old patient who underwent gastrointestinal surgery and subsequently presented with dehydration, nausea, and hyperkalemia secondary to diarrhea. Further clinical work included blood cultures, and the patient was started empirically on piperacillin/tazobactam. Results: After five days, the blood culture bottle showed growth of a gram-variable, curved rod-shaped organism. After culture under anaerobic conditions on sheep blood agar, the organism was identified as Mobiluncus curtisii by MALDI-TOF mass spectrometry and enzymatic technology. A review of the literature reveals five additional cases of Mobiluncus curtisii bacteremia. Conclusions: This is the sixth case in the literature describing Mobiluncus species bacteremia. This organism is rarely identified in blood culture and is most often thought of in the context of bacterial vaginosis. However, the reported cases of bacteremia show gastrointestinal symptoms and presumed gastrointestinal source of infection. The pathogenesis of infection of this organism requires further investigation.

Roseburia intestinalis: A Beneficial Gut Organism From the Discoveries in Genus and Species

Roseburia intestinalis is an anaerobic, Gram-positive, slightly curved rod-shaped flagellated bacterium that produces butyrate in the colon. R. intestinalis has been shown to prevent intestinal inflammation and maintain energy homeostasis by producing metabolites. Evidence shows that this bacterium contributes to various diseases, such as inflammatory bowel disease, type 2 diabetes mellitus, antiphospholipid syndrome, and atherosclerosis. This review reveals the potential therapeutic role of R. intestinalis in human diseases. Patients with inflammatory bowel disease exhibit significant changes in R. intestinalis abundance, and they may benefit a lot from modulations targeting R. intestinalis. The data reviewed here demonstrate that R. intestinalis plays its role in regulating barrier homeostasis, immune cells, and cytokine release through its metabolite butyrate, flagellin and other. Recent advancements in the application of primary culture technology, culture omics, single-cell sequencing, and metabonomics technology have improved research on Roseburia and revealed the benefits of this bacterium in human health and disease treatment.

Helicobacter cyclurae sp. Nov., Isolated From Endangered Blue Iguanas (Cyclura lewisi)

Blue iguanas (Cyclura lewisi) are endangered reptiles found only on Grand Cayman. Previously, DNA for a novel Helicobacter species GCBI1 was detected in sick and dead iguanas. In the current study, fecal and cloacal swab samples were obtained from 25 iguanas. Through molecular and microbiological techniques, a novel Helicobacter species was cultured from feces and characterized, for whom we propose the name Helicobacter cyclurae. This novel helicobacter had a prevalence of 56% by PCR and 20% by culture in samples analyzed. The type strain MIT 16-1353 was catalase, oxidase, and gamma-glutamyl transpeptidase positive. By electron microscopy, H. cyclurae has a curved rod morphology and a single sheathed polar flagellum. Phylogenetic analysis using 16S rRNA, gyrB, and hsp60 indicated that these strains were most closely related to Helicobacter sp. 12502256-12 previously isolated from lizards. H. cyclurae has a 1.91-Mb genome with a GC content of 33.37%. There were 1,969 genes with four notable virulence genes: high temperature requirement-A protein-secreted serine protease, gamma-glutamyl transpeptidase, fibronectin/fibrinogen binding protein, and neutrophil-activating protein. Whole-genome phylogeny, average nucleotide identity, and digital DNA–DNA hybridization analysis confirmed that H. cyclurae is a novel species, and the first helicobacter cultured and characterized from blue iguanas.

Arenibacter amylolyticus sp. nov., an amylase-producing bacterium of the family Flavobacteriaceae isolated from marine water in India

A novel Gram-stain-negative, curved rod-shaped, 0.5–0.7 µm wide and 3.0–10.0 µm long, non-motile bacterium, designated strain AK53T, was isolated from a 5 m depth water sample collected from the Bay of Bengal, Visakhapatnam, India. Colonies on marine agar were circular, small, dark orange, shiny, smooth, translucent, flat, with an entire margin. The major fatty acids included iso-C15 : 0, iso-C15 : 0 3OH, anteiso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3OH and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c and/or iso-C15 : 0-2OH). Polar lipids included phosphatidylethanolamine and five unidentified lipids. The DNA G+C content of the strain AK53T was found to be 40.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain AK53T was closely related to Arenibacter latericius KMM 426T and Arenibacter certesii KMM3941T (pair-wise sequence similarity of 99.17 and 98.89 %, respectively), forming a distinct branch within the genus Arenibacter and clustering with A. latericius . Strain AK53T shared average nucleotide identity (ANIb, based on blast) of 78.07 and 77.44 % with A. latericius JCM 13508T and A. certesii JCM 13507T, respectively. Based on the observed phenotypic, chemotaxonomic characteristics and phylogenetic analysis, strain AK53T is described in this study as representing a novel species in the genus Arenibacter , for which the name Arenibacter amylolyticus sp. nov. is proposed. The type strain of Arenibacter amylolyticus is AK53T (=MTCC 12004T= JCM 19206T=KCTC 62553T).

Maribellus comscasis sp. nov., isolated from the deep-sea cold seep

ABSTRACTA facultatively anaerobic, Gram-stain-negative, non-motile, curved rod-shaped bacterium, designated WC007T, was isolated from the deep-sea cold seep, P. R. China. Strain WC007T was found to grow at temperatures from 28 to 37 °C (optimum, 30 °C), at pH values between pH 6.0 and 8.0 (optimum, pH 7.0) and in 0-5.0% (w/v) NaCl (optimum, 1.0%). The major fatty acids (>10.0%) were iso-C15:0, C16:0, summed feature 3 and summed feature 8. The major isoprenoid quinone was MK-7. Predominant polar lipids were phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid and one unidentified lipid. The G+C content of the genomic DNA was 38.38%. The average nucleotide identity (ANIb and ANIm), amino acid identity (AAI), the tetranucleotide signatures (Tetra) and in silico DNA-DNA hybridization (isDDH) similarities between the genome sequences of isolate WC007T and Maribellus luteus XSD2T were 70.11%, 84.94%, 71.0%, 0.92022 and 20.40%, respectively, indicating that strain WC007T was distinguished from M. luteus. Phylogenetic analysis based on 16S rRNA gene sequences placed strain WC007T within the genus Maribellus and showed the highest similarity to strain XSD2T (95.70%). In combination of the results of phylogenetic analysis and phenotypic and chemotaxonomic data, strain WC007T was considered to represent a novel species of the genus Maribellus, for which the name Maribellus comscasis sp. nov. is proposed. The type strain is WC007T (=KCTC 25169T = MCCC 1K04777T). The available of the genome sequence of strain WC007T would be helpful in understanding the degradation mechanism of difficult-to-degrade polysaccharides.

Rate of deformation in the cross section of a spatially curved rod with various assumptions

The article considers incremental relations connecting the changes in the kinematic parameters of the rod cross section with the deformation rate. These relations allow assessing the deformation rate on the elemental areas of a spatially curved rod, as well as considering the distortion of cross-section in its plane due to shear and torsion. Assessment of such relations between deformation rates and the rates of kinematic parameters allows developing the method of nonlinear calculation of rod systems based on integral expressions. Subsequently, these relations will be used for assessing the tangential stiffness of the rod element cross-section subjected to elastic-plastic calculation.

Manometric Tubular Springs Oscillatory Processes Modeling with Consideration of its Viscoelastic Properties

This article is dedicated to the operation and management of systems of machine-building and aviation enterprises, systems of production, transport, storage of oil and gas, issues of control of technological processes are of great importance. Control of technological processes is carried out by monitoring the pressure and other parameters. These measuring instruments must have high reliability and the necessary accuracy. In this connection, there is a sharp increase in interest in determining the dynamic parameters of the elements of measuring devices. The main elements of such devices are monomeric tubular springs (Bourdon tubes). The paper considers the natural and forced steady-state oscillations of a thin curved rod interacting with a liquid. Based on the principle of possible displacements, a resolving system of partial differential equations and the corresponding boundary conditions are obtained. The problem is solved numerically by the Godunov orthogonal run method, and the Muller method and the Eigen frequencies found are compared with the experimental results. As a result, for a given axial perturbation, it was possible to select such an effect, in the orthogonal direction, that the amplitude of the longitudinal vibrations of the rod at the first resonance decreased by 20 times. The described vibration damping effect is due to the interrelation of transverse and longitudinal vibrations and is fundamentally impossible in the case of a straight rod.

RNA-mediated control of cell shape modulates antibiotic resistance in Vibrio cholerae

Vibrio cholerae, the cause of cholera disease, exhibits a characteristic curved rod morphology, which promotes infectivity and motility in dense hydrogels. Periplasmic protein CrvA determines cell curvature in V. cholerae, yet the regulatory factors controlling CrvA are unknown. Here, we discover the VadR small RNA (sRNA) as a post-transcriptional inhibitor of the crvA mRNA. Mutation of vadR increases cell curvature, whereas overexpression has the inverse effect. We show that vadR transcription is activated by the VxrAB two-component system and triggered by cell-wall-targeting antibiotics. V. cholerae cells failing to repress crvA by VadR display decreased survival upon challenge with penicillin G indicating that cell shape maintenance by the sRNA is critical for antibiotic resistance. VadR also blocks the expression of various key biofilm genes and thereby inhibits biofilm formation in V. cholerae. Thus, VadR is an important regulator for synchronizing peptidoglycan integrity, cell shape, and biofilm formation in V. cholerae.