The mcr-1 gene was detected in 5.11% (58/1136) of Escherichia coli isolates of chicken origin from 13 provinces in China. A novel mcr-1 variant, named mcr-1.3, encoding an Ile-to-Val functional variant of MCR-1 was identified in a sequence type 155 (ST155) strain. An mcr-1.3-containing IncI2 plasmid, pHeN867 (60,757 bp), was identified. The transfer of pHeN867 led to a 32-fold increase in the MIC of colistin in the recipient, exhibiting an effect on colistin resistance that was similar to that of mcr-1. KEYWORDS E. coli, colistin resistance, mcr-1.3, plasmid P olymyxins (polymyxin B and colistin) are a last-resort treatment for infections caused by multidrug-resistant (MDR) Gram-negative bacteria (1). In veterinary use, colistin is administered with food in pig and poultry farming to prevent infections caused by pathogens (2). The mcr-1 gene, which confers plasmid-mediated colistin resistance to Enterobacteriaceae, was identified in an IncI2 plasmid from Escherichia coli and Klebsiella pneumoniae in China in 2016 (3). The mcr-1 gene found in E. coli (4), K. pneumoniae (5), and Salmonella spp. (6) has been proven to disseminate ubiquitously. The transmission of mcr-1-mediated colistin resistance between animals and human has been a threat to human health. It has also been demonstrated that the mcr-1 gene can coexist with bla CTX-M (5), bla NDM (7), and other resistance genes (4), which threatens a return of untreatable infections worldwide. Previous reports described the unique mcr-1 gene sequence compared with that of the originally published sequence (3), which indicates that mcr-1 is relatively conserved. Recently, a point mutation of A¡T at position 8 in mcr-1 was identified in K. pneumoniae (8). To investigate the epidemiology of mcr-1 and its variant, E. coli isolates collected from chickens nationwide in China were assessed.In total, 1,136 nonduplicate E. coli isolates were collected between 2010 and 2015 from sick chickens in 20 provinces and municipalities in China. All of these isolates were preliminarily screened on Mueller-Hinton agar medium with 2 g/ml colistin. Because the cooccurrence of mcr-1 with bla CTX-M may accelerate the transmission of resistance to colistin and cephalosporins, the mcr-1 (3) and bla CTX-M (9) genes were detected by PCR amplification of the isolates with resistance to colistin. The corresponding primers used to amplify the whole mcr-1 gene and parts of the ISApl1 element are listed in Table S1 in the supplemental material. For all of the positive PCR products of mcr-1, Sanger sequencing was performed (Tsingke Biological Technology, Chengdu, China) by using a DNA analyzer (Applied Biosystems, Life Technologies, Carlsbad, CA). We found a total of 58 (5.11%) mcr-1-positive isolates, including one isolate harboring the mcr-1 gene with mutations not found in the originally published gene sequence (3). MICs of colistin

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A high-fat diet-induced C57BL/6N mouse model of non-alcoholic fatty liver disease (NAFLD) was established. The effect and mechanism of Raw Bowl Tea polyphenols (RBTP) on preventing NAFLD via regulating intestinal function were observed. The serum, liver, epididymis, small intestine tissues, and feces of mice were examined by biochemical and molecular biological methods, and the composition of RBTP was analyzed by HPLC assay. The results showed that RBTP could effectively reduce the body weight, liver weight, and liver index of NAFLD mice. The serum effects of RBTP were: (1) decreases in alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), D-lactate (D-LA), diamine oxidase (DAO), lipopolysaccharide (LPS), and an increase of high density lipoprotein cholesterol (HDL-C) levels; (2) a decrease of inflammatory cytokines such as interleukin 1 beta (IL-1β), interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α), and interferon gamma (INF-γ); (3) a decrease the reactive oxygen species (ROS) level in liver tissue; and (4) alleviation of pathological injuries of liver, epididymis, and small intestinal tissues caused by NAFLD and protection of body tissues. qPCR and Western blot results showed that RBTP could up-regulate the mRNA and protein expressions of LPL, PPAR-α, CYP7A1, and CPT1, and down-regulate PPAR-γ and C/EBP-α in the liver of NAFLD mice. In addition, RBTP up-regulated the expression of occludin and ZO-1, and down-regulated the expression of CD36 and TNF-α in the small intestines of NAFLD mice. Studies on mice feces showed that RBTP reduced the level of Firmicutes and increased the minimum levels of Bacteroides and Akkermansia, as well as reduced the proportion of Firmicutes/Bacteroides in the feces of NAFLD mice, which play a role in regulating intestinal microecology. Component analysis showed that RBTP contained seven polyphenolic compounds: Gallic acid, (-)-epigallocatechin, catechin, L-epicatechin, (-)-epigallocatechin gallate, (-)-gallocatechin gallate, and (-)-epicatechin gallate (ECG), and high levels of caffeine, (-)-epigallocatechin (EGC), and ECG. RBTP improved the intestinal environment of NAFLD mice with the contained active ingredients, thus playing a role in preventing NAFLD. The effect was positively correlated with the dose of 100 mg/kg, which was even better than that of the clinical drug bezafibrate.

SXT/R391 integrative and conjugative elements (ICEs) were detected in 8 out of 125 Proteus mirabilis isolates from food-producing animals in China. Whole-genome sequencing revealed that seven ICEs were identical to ICEPmiJpn1, carrying the cephalosporinase gene bla CMY-2 . Another one, designated ICEPmiChn1, carried five resistance genes. All eight ICEs could be transferred to Escherichia coli via conjugation. The results highlight the idea that animal farms are important reservoir of the SXT/ R391 ICE-containing P. mirabilis.

Sixteen different sequence types (STs) of Escherichia coli isolates from a commercial swine farm in China were confirmed to coharbor the carbapenem resistance gene bla and the colistin resistance gene mcr-1. Whole-genome sequencing revealed that bla NDM-5 and mcr-1 were located on a 46-kb IncX3 plasmid and a 32-kb IncX4 plasmid, respectively. The two plasmids can transfer together with a low fitness cost, which might explain the presence of various STs of E. coli coharboring bla NDM-5 and mcr-1.KEYWORDS Escherichia coli, carbapenems, bla NDM-5 , colistin, mcr-1, fitness cost C arbapenemase-producing Enterobacteriaceae has become a major public health threat around the world (1). The recently identified carbapenemase New Delhi metallo-␤-lactamase confers resistance to all ␤-lactam antimicrobials except monobactam (2). The NDM-5-encoding gene bla NDM-5 was first identified in an Escherichia coli strain recovered from a patient in the United Kingdom in 2011 (3). Since then, bla was identified in many countries, such as Algeria (4-6), the United States (7), Australia (8), China (9-12), Denmark (13), Japan (14), India (15), and the United Kingdom (3). The widespread occurrence of NDM-5 in recent years should arouse our attention. Colistin is a critically important medication for humans in the treatment of carbapenemaseproducing Enterobacteriaceae, and it has been widely used in veterinary medicine in China (16,17). The first plasmid-mediated colistin resistance gene, mcr-1, was reported in E. coli in 2015 (18). In a short period, colistin-resistant E. coli carrying the mcr-1 gene were reported worldwide (19,20). Recently, mcr-1 was reported to coexist with bla NDM (21-23) and bla CTX-M (24), which brought great challenges for the treatment of bacterial infection. In the present study, we are the first to report the presence of isolates of various sequence types of E. coli coharboring bla NDM-5 and mcr-1 genes from a commercial pig farm in China.A total of 105 anal swabs samples from swine were collected from a commercial pig farm on 1 October 2015 in Sichuan province. E. coli strains were selected by eosinmethylene blue agar, and only 1 isolate was picked up from each sample. All 105 isolates were identified by BD Phoenix 100 diagnostic systems (Sparks, MD). Sixty-four strains were nonsusceptible to imipenem and polymyxin B, identified by the agar dilution method according to Clinical and Laboratory Standards Institute guidelines (25). Isolates were divided into 16 different clones by pulsed-field gel electrophoresis after XbaI digestion according to the standard PulseNet conditions (26) (Fig. 1). Phy-