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The siderophore–antibiotic conjugate LCB10-0200 (a.k.a. GT-1) has been developed to combat multidrug-resistant Gram-negative bacteria. In this study, the in vitro activity of LCB10-0200 and LCB10-0200/avibactam (AVI) has been investigated against carbapenem-resistant Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. Minimal inhibitory concentrations (MICs) of LCB10-0200, LCB10-0200/AVI, aztreonam, aztreonam/AVI, ceftazidime, ceftazidime/AVI, and meropenem were measured using the agar dilution method. Whole genome sequencing was performed using Illumina and the resistome was analyzed. LCB10-0200 displayed stronger activity than the comparator drugs in meropenem-resistant E. coli and K. pneumoniae, and the addition of AVI enhanced the LCB10-0200 activity to MIC ≤ 0.12 mg/L for 90.5% of isolates. In contrast, whereas LCB10-0200 alone showed potent activity against meropenem-resistant A. baumannii and P. aeruginosa at MIC ≤ 4 mg/L for 84.3% of isolates, the combination with AVI did not improve its activity. LCB10-0200/AVI was active against CTX-M-, SHV-, CMY-, and KPC- producing E. coli and K. pneumoniae, while LCB10-0200 alone was active against ADC-, OXA-, and VIM- producing A. baumannii and P. aeruginosa. Both LCB10-0200 and LCB10-0200/AVI displayed low activity against IMP- and NDM- producing strains. LCB10-0200 alone exhibited strong activity against selected strains. The addition of AVI significantly increased LCB10-0200 activity against carbapenem-resistant E. coli, K. pneumoniae.

Background & Aims Fucosyltransferase 2 (Fut2)-mediated intestinal α1- 2-fucosylation is important for host–microbe interactions and has been associated with several diseases, but its role in obesity and hepatic steatohepatitis is not known. The aim of this study was to investigate the role of Fut2 in a Western-style diet–induced mouse model of obesity and steatohepatitis. Methods Wild-type (WT) and Fut2-deficient littermate mice were used and features of the metabolic syndrome and steatohepatitis were assessed after 20 weeks of Western diet feeding. Results Intestinal α1-2-fucosylation was suppressed in WT mice after Western diet feeding, and supplementation of α1-2-fucosylated glycans exacerbated obesity and steatohepatitis in these mice. Fut2-deficient mice were protected from Western diet–induced features of obesity and steatohepatitis despite an increased caloric intake. These mice have increased energy expenditure and thermogenesis, as evidenced by a higher core body temperature. Protection from obesity and steatohepatitis associated with Fut2 deficiency is transmissible to WT mice via microbiota exchange; phenotypic differences between Western diet–fed WT and Fut2-deficient mice were reduced with antibiotic treatment. Fut2 deficiency attenuated diet-induced bile acid accumulation by altered relative abundance of bacterial enzyme 7-α-hydroxysteroid dehydrogenases metabolizing bile acids and by increased fecal excretion of secondary bile acids. This also was associated with increased intestinal farnesoid X receptor/fibroblast growth factor 15 signaling, which inhibits hepatic synthesis of bile acids. Dietary supplementation of α1-2-fucosylated glycans abrogates the protective effects of Fut2 deficiency. Conclusions α1-2-fucosylation is an important host-derived regulator of intestinal microbiota and plays an important role for the pathogenesis of obesity and steatohepatitis in mice., Graphical abstract

A potentially therapeutic Twort-like myophage, Esa1, with specificity toward Staphylococcus aureus was isolated from lake water. We report the complete genome sequence of ESa1, assembled using both MinION and Illumina MiSeq reads, consisting of 153,106 bp, with 30.3% GC content, 253 protein coding sequences, 4 tRNAs, and 10,437-bp direct terminal repeats.

Antibiotic-resistant Staphylococcus aureus is an opportunistic pathogen causing serious human infections worldwide. Here, we report the complete annotated genome of bacteriophage SA75, a member of the Siphoviridae family which could be an alternative to traditional antibiotics for treating Staphylococcus infections. We used a hybrid approach combining MinION and Illumina MiSeq sequencing, which yielded a 43,134-bp genome and 65 open reading frames.

Neisseria gonorrhoeae is the etiological agent of gonorrhea, the second most common notifiable disease in the United States. Here, we used a hybrid approach combining Oxford Nanopore Technologies MinION and Illumina MiSeq sequencing data to obtain closed genome sequences of nine clinical N. gonorrhoeae isolates.

In the treatment of serious bacterial infections, the rapid institution of appropriate antimicrobial chemotherapy may be lifesaving. Choosing the correct antibiotic or combination of antibiotics is becoming very important, as multidrug resistance is found in many pathogens. Using a collection of 75 well-characterized multidrug-resistant (MDR) Acinetobacter sp. isolates, we show that PCR followed by electrospray ionization mass spectrometry (PCR/ESI-MS) and base composition analysis of PCR amplification products can quickly and accurately identify quinolone resistance mediated by mutations in the quinolone resistance-determining regions of gyrA and parC , two essential housekeeping genes. Single point mutations detected by PCR/ESI-MS in parC (found in 55/75 of the isolates) and in gyrA (found in 66/75 of the isolates) correlated with susceptibility testing and sequencing. By targeting resistance determinants that are encoded by genes with highly conserved DNA sequences (e.g., gyrA and parC ), we demonstrate that PCR/ESI-MS can provide critical information for resistance determinant identification and can inform therapeutic decision making in the treatment of Acinetobacter sp. infections.

The recent emergence of multidrug resistance (MDR) in Acinetobacter baumannii has raised concern in health care settings worldwide. In order to understand the repertoire of resistance determinants and their organization and origins, we compared the genome sequences of three MDR and three drug-susceptible A. baumannii isolates. The entire MDR phenotype can be explained by the acquisition of discrete resistance determinants distributed throughout the genome. A comparison of closely related MDR and drug-susceptible isolates suggests that drug efflux may be a less significant contributor to resistance to certain classes of antibiotics than inactivation enzymes are. A resistance island with a variable composition of resistance determinants interspersed with transposons, integrons, and other mobile genetic elements is a significant but not universal contributor to the MDR phenotype. Four hundred seventy-five genes are shared among all six clinical isolates but absent from the related environmental species Acinetobacter baylyi ADP1. These genes are enriched for transcription factors and transporters and suggest physiological features of A. baumannii that are related to adaptation for growth in association with humans.

Acute necrotizing encephalopathy (ANE) is a rapidly progressive encephalopathy that can occur in otherwise healthy children after common viral infections such as influenza and parainfluenza. Most ANE is sporadic and nonrecurrent (isolated ANE). However, we identified a 7 Mb interval containing a susceptibility locus (ANE1) in a family segregating recurrent ANE as an incompletely penetrant, autosomal-dominant trait. We now report that all affected individuals and obligate carriers in this family are heterozygous for a missense mutation (c.1880C-->T, p.Thr585Met) in the gene encoding the nuclear pore protein Ran Binding Protein 2 (RANBP2). To determine whether this mutation is the susceptibility allele, we screened controls and other patients with ANE who are unrelated to the index family. Patients from 9 of 15 additional kindreds with familial or recurrent ANE had the identical mutation. It arose de novo in two families and independently in several other families. Two other patients with familial ANE had different RANBP2 missense mutations that altered conserved residues. None of the three RANBP2 missense mutations were found in 19 patients with isolated ANE or in unaffected controls. We conclude that missense mutations in RANBP2 are susceptibility alleles for familial and recurrent cases of ANE.

The use of phylogenetic analysis to predict positive selection specific to human genes is complicated by the very close evolutionary relationship with our nearest extant primate relatives, chimpanzees. To assess the power and limitations inherent in use of maximum-likelihood (ML) analysis of codon substitution patterns in such recently diverged species, a series of simulations was performed to assess the impact of several parameters of the evolutionary model on prediction of human-specific positive selection, including branch length and dN/dS ratio. Parameters were varied across a range of values observed in alignments of 175 transcription factor (TF) genes that were sequenced in 12 primate species. The ML method largely lacks the power to detect positive selection that has occurred since the most recent common ancestor between humans and chimpanzees. An alternative null model was developed on the basis of gene-specific evaluation of the empirical distribution of ML results, using simulated neutrally evolving sequences. This empirical test provides greater sensitivity to detect lineage-specific positive selection in the context of recent evolutionary divergence.

In females, most genes on the X chromosome are generally assumed to be transcriptionally silenced on the inactive X as a result of X inactivation. However, particularly in humans, an increasing number of genes are known to “escape” X inactivation and are expressed from both the active (Xa) and inactive (Xi) X chromosomes; such genes reflect different molecular and epigenetic responses to X inactivation and are candidates for phenotypes associated with X aneuploidy. To identify genes that escape X inactivation and to generate a first-generation X-inactivation profile of the X, we have evaluated the expression of 224 X-linked genes and expressed sequence tags by reverse-transcription–PCR analysis of a panel of multiple independent mouse/human somatic cell hybrids containing a normal human Xi but no Xa. The resulting survey yields an initial X-inactivation profile that is estimated to represent ≈10% of all X-linked transcripts. Of the 224 transcripts tested here, 34 (three of which are pseudoautosomal) were expressed in as many as nine Xi hybrids and thus appear to escape inactivation. The genes that escape inactivation are distributed nonrandomly along the X; 31 of 34 such transcripts map to Xp, implying that the two arms of the X are epigenetically and/or evolutionarily distinct and suggesting that genetic imbalance of Xp may be more severe clinically than imbalance of Xq. A complete X-inactivation profile will provide information relevant to clinical genetics and genetic counseling and should yield insight into the genomic and epigenetic organization of the X chromosome.