Preventive antibiotic treatment of calves: emergence of dysbiosis causing propagation of obese state-associated and mobile multidrug resistance-carrying bacteria

In agriculture, antibiotics are used for the treatment and prevention of livestock disease. Antibiotics perturb the bacterial gut composition but the extent of these changes and potential consequences for animal and human health is still debated. Six calves were housed in a controlled environment. Three animals received an injection of the antibiotic florfenicol (Nuflor), and three received no treatment. Faecal samples were collected at 0, 3 and 7 days, and bacterial communities were profiled to assess the impact of a therapy on the gut microbiota. Phylogenetic analysis (16S‐rDNA) established that at day 7, antibiotic‐treated microbiota showed a 10‐fold increase in facultative anaerobic Escherichia spp, a signature of imbalanced microbiota, dysbiosis. The antibiotic resistome showed a high background of antibiotic resistance genes, which did not significantly change in response to florfenicol. However, the maintenance of Escherichia coli plasmid‐encoded quinolone, oqxB and propagation of mcr‐2, and colistin resistance genes were observed and confirmed by Sanger sequencing. The microbiota of treated animals was enriched with energy harvesting bacteria, common to obese microbial communities. We propose that antibiotic treatment of healthy animals leads to unbalanced, disease‐ and obese‐related microbiota that promotes growth of E. coli carrying resistance genes on mobile elements, potentially increasing the risk of transmission of antibiotic resistant bacteria to humans

2,2'-Dimethyl-3,3'-(p-phenylenedimethylene)-diimidazol-1-ium dibromide

In the centrosymmetric title compound, C16H20N 42-·Br2+, the Br counter-ions form hydrogen bonds with protonated imidazole groups. Neighbouring cations are held together via weak C-H⋯Br hydrogen bonds and offset π-π interactions, resulting in the formation of a three-dimensional structure. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved.Articl

1,2,3-Trihydroxybenzene-pyrimidine (1/1)

In the title molecular co-crystal, C6H6O 3⋯H4N2, symmetry-related O-H⋯N hydrogen bonds with O⋯N distances of 2.790 (3) and 2.818 (2) Å link molecules of 1,2,3-trihydroxybenzene and pyrimidine to form 18-membered rings which, in turn, are constituents of infinite chains created by O-H⋯O hydrogen bonds between hydroxy groups in positions 1 and 2 of neighbouring 1,2,3-trihydroxybenzene molecules. The infinite chains are further stacked in stepped columns by offset π-π interactions, and are linked by C-H⋯π interactions, resulting in a herringbone pattern. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved.Articl

Structural heterogeneity of Ag I complexes with a flexible 1,2-bis[(imidazol-2-yl)thiomethyl]benzene ligand and issues regarding the phase purity of the bulk material

A series of Ag I coordination compounds with a new ligand, 1,2-bis[(imidazol-2-yl)thiomethyl]benzene, and counterions such as PF 6 -, SbF 6 -, CF 3SO 3 -, BF 4 - and NO 3 - was characterised by powder and single-crystal XRD. Powder XRD revealed the presence of a mixture of crystallographic phases that were further identified by single-crystal XRD. Despite conformational flexibility, 1,2-bis[(imidazol-2-yl)thiomethyl]benzene has a tendency to form N,N-chelated Ag I mononuclear cationic complexes with a linear N-Ag I-N unit. However, T-shaped geometry (N 2O) around the silver ion was also observed, which involved solvent molecules and/or counterions. The formation of a cationic 1D chain with the N,N′-bridging ligand was revealed with the BF 4 - counterion. Coordination compounds that possess different nuclearity were formed with the NO 3 - counterion. In the dinuclear and trinuclear complexes, the ligand showed bischelating behaviour with N-donor atoms that interact with one and S-donor atoms with another metal centre. Furthermore, the crystal structure of the trinuclear complex revealed the presence of two crystallographically independent cationic moieties in the asymmetric unit, which only differ by a single O-donor ligand (NO 3 - vs. H 2O), where both of the moieties possess three different geometries around the constituent silver ions. Argentophilic interactions are present in the majority of the reported structures. Available amine N atoms facilitate hydrogen bond formation and promote the occurrence of solvates. An XRD structural study of a series of Ag I coordination compounds with a new flexible ligand, 1,2-bis[(imidazol-2-yl)thiomethyl]benzene, and counterions such as PF 6 -, SbF 6 -, CF 3SO 3 -, BF 4 - and NO 3 - prepared in MeOH in a 1:1 metal/ligand ratio, reveals vast structural diversity and highlights the difficulties of solid-state characterisation of bulk materials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Influence of the metal-to-ligand ratio on the formation of metal organic complexes

Three copper(II) salts with a chloride, bromide or nitrate counterions in combination with the ditopic ligand 1,3-bis(imidazol-1-ylmethyl)benzene (L) were used to study the influence of the metal to ligand molar ratio on the formation of the final product. Single-crystal X-ray analysis revealed structural diversity of the products formed, ranging from discrete species to extended 1D and 2D coordination polymers. Similar types of 1D chains were formed for all counterions. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.Three copper(II) salts with a chloride, bromide or nitrate counterions in combination with the ditopic ligand 1,3-bis(imidazol-1-ylmethyl)benzene (L) were used to study the influence of the metal to ligand molar ratio on the formation of the final product. Single-crystal X-ray analysis revealed structural diversity of the products formed, ranging from discrete species to extended 1D and 2D coordination polymers. Similar types of 1D chains were formed for all counterions. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.ArticleArticl

The solvent-templating effect as the driving factor that influences the formation of crystalline materials based on the stacking of metallocycles

A series of recrystallisations of a 1 : 1 CuCl2 : L (L = 1,4-bis[(2-methylimidazol-1-yl)methyl]benzene) mixture from a variety of common solvents has been undertaken in order to investigate the effect of solvent templation on the resulting crystal forms. Single crystal X-ray diffraction analysis of eight new solvates of [CuCl2L]n reveals the solvent dependent formation of either a discrete dinuclear metallocycle or a one-dimensional coordination polymer. Conformational flexibility of both the ligand and the metal-ligand bonds results in the ability of these compounds to form a variety of structures. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.A series of recrystallisations of a 1 : 1 CuCl2 : L (L = 1,4-bis[(2-methylimidazol-1-yl)methyl]benzene) mixture from a variety of common solvents has been undertaken in order to investigate the effect of solvent templation on the resulting crystal forms. Single crystal X-ray diffraction analysis of eight new solvates of [CuCl2L]n reveals the solvent dependent formation of either a discrete dinuclear metallocycle or a one-dimensional coordination polymer. Conformational flexibility of both the ligand and the metal-ligand bonds results in the ability of these compounds to form a variety of structures. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.ArticleArticl

2,4-Bis(methoxymethyl)-1,3,5-trimethylbenzene

The title compound, C13H20O2, displays polar ordering owing to intermolecular C-H⋯O hydrogen bonds that link the molecules to form a three-dimensional network. A twofold rotation axis bisects the ring, passing through the unsubstituted C atom, the para-C atom and C of the attached methyl group. © 2006 International Union of Crystallography. All rights reserved.Articl

2,2′-(butane-1,4-diyl)dibenzimidazolium dichloride dihydrate

In the title compound, C18H24Cl2N 4O2, a quarternary adduct consisting of two water molecules and two chloride ions binds the centrosymmetric 2,2′-(butane-1, 4-diyl)dibenzimidazolium cations into two-dimensional hydrogen-bonded layers. © 2006 International Union of Crystallography All rights reserved.Articl

Catena-poly[[silver(I)-μ-1,4-bis(2-methyl-1H-imidazol-1-ylmethyl) benzene-k2N3:N3′ ] nitrate]

In the title complex, {[Ag(C16H18N 4)]NO3}n, the cationic part forms infinite chains where the AgI ions are coordinated in a slightly bent fashion by two N-donor atoms of imidazole rings of two distinct ligand molecules. The nitrate anions interact weakly with the silver cations to form infinite strands running in the c-axis direction, approximately perpendicular to the cationic chains. The resulting layers are stabilized by offset π-π interactions between benzene rings. Furthermore, a set of C - H⋯O and π-π interactions (imidazole rings) between adjacent layers results in the formation of a three-dimensional assembly. © 2006 International Union of Crystallography. All rights reserved.Articl