Draft genome sequence analysis of a mcr-1-producing Klebsiella pneumoniae ST661 isolated from a mink in China.

OBJECTIVES: Klebsiella pneumoniae is a major opportunistic pathogen that is a member of the Enterobacteriaceae. Klebsiella pneumoniae causes pneumonia in mink and has become the primary infectious disease that limits mink farming. In this study, we report the draft genome sequence of a multidrug-resistant (MDR) strain of K. pneumoniae that harbours the mcr-1 gene isolated from a mink in China. METHODS: The agar microdilution method was used to determine the minimum inhibitory concentration of the strain. The entire genomic DNA was sequenced using an Illumina MiSeq platform. A multilocus sequence type (MLST) and a core genome SNP phylogenetic tree analysis with a heatmap of the resistance genes and virulence genes were performed. RESULTS: The size of the genome was 5451.826 kb, and it included one chromosome and one plasmid. The draft genome of K. pneumoniae indicated that the isolate was a member of MLST 661. Four types of virulence genes were detected. The results of antimicrobial susceptibility testing showed multiple drug resistance, and 17 resistance genes were identified. CONCLUSION: The genome sequence reported in this study will help to reveal the key role of antibiotic resistance and pathogenic mechanisms. It will provide useful information for the role of mobile genetic elements in the adaptive translocation and spread of antimicrobial resistance.

Identification of a novel enterovirus E isolates HY12 from cattle with severe respiratory and enteric diseases.

In this study, a virus strain designated as HY12 was isolated from cattle with a disease of high morbidity and mortality in Jilin province. Biological and physiochemical properties showed that HY12 isolates is cytopathic with an extremely high infectivity. HY12 is resistant to treatment of organic solvent and acid, and unstable at 60°C for 1 h. Electron microscopy observation revealed the virus is an approximately 22-28 nm in diameter. The complete genome sequence of HY12 consists of 7416 nucleotides, with a typical picornavirus genome organization including a 5'-untranslated region (UTR), a large single ORF encoding a polyprotein of 2176 amino acids, and a 3'-UTR. Phylogenetic analysis clustered HY12 isolates to a new serotype/genotype within the clade of enterovirus E (formerly BEV-A). Alignment analysis revealed a unique insertion of 2 amino acid residues (NF) at the C-terminal of VP1 protein between aa 825 and 826, and several rare mutations in VP1 and VP4 of HY12 isolates in relation to known bovine enterovirus (BEV) strains. This is the first report of an enterovirus E in China, which is potentially associated with an outbreak in cattle with severe respiratory and enteric diseases.

Protective effect of taraxasterol on acute lung injury induced by lipopolysaccharide in mice.

Taraxasterol, a pentacyclic-triterpene isolated from Taraxacum officinale, has been reported to have potent anti-inflammatory properties. However, the effect of taraxasterol on lipopolysaccharide (LPS)-induced mice acute lung injury has not been investigated. The aims of this study were to investigate whether taraxasterol could ameliorate the inflammation response in LPS-induced acute lung injury and to clarify the possible mechanism. Male BALB/c mice were pretreated with taraxasterol 1h before intranasal instillation of LPS. 7h after LPS administration, the myeloperoxidase (MPO) in lung tissues, lung wet/dry ratio and inflammatory cells in the bronchoalveolar lavage fluid (BALF) were detected. The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß) in the BALF were measured by ELISA. The extent of phosphorylation of IκB-α, p65 NF-κB, p46-p54 JNK, p42-p44 ERK, and p38 were determined by western blotting. The results showed that taraxasterol attenuated the infiltration of inflammatory cells, the activity of myeloperoxidase (MPO), lung wet/dry ratio, and the expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß) in a dose-dependent manner. Additionally, western blotting results showed that taraxasterol inhibited the phosphorylation of IκB-α, p65 NF-κB, p46-p54 JNK, p42-p44 ERK, and p38 caused by LPS. Our data suggest that anti-inflammatory effects of taraxasterol against the LPS-induced ALI may be due to its ability of inhibition of the NF-κB and MAPK signaling pathways.