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Public health interventions to control the recent emergence of plasmid-mediated tigecycline resistance genes rely on a comprehensive understanding of its epidemiology and distribution over a wide range of geographical scales. Here we analysed an Escherichia coli collection isolated from pigs and chickens in China in 2018, and ascertained that the tet(X4) gene was not present at high prevalence across China, but was highly endemic in northwestern China. Genomic analysis of tet(X4)-positive E. coli demonstrated a recent and regional dissemination of tet(X4) among various clonal backgrounds and plasmids in northwestern China, whereas a parallel epidemic coincided with the independent acquisition of tet(X4) in E. coli from the remaining provinces. The high genetic similarity of tet(X4)-positive E. coli and human commensal E. coli suggests the possibility of its spreading into humans. Our study provides a systematic analysis of the current epidemiology of tet(X4) and identifies priorities for optimising timely intervention strategies., Sun et al. analyse E. coli strains from pigs and chickens in Chinese farms and slaughterhouses, and reveal that while the tet(X4) gene is not ubiquitous across China, it is highly endemic in northwestern China. Genomic analysis of these strains shows recent and independent acquisitions of plasmids in across regions.

The rapid dissemination of life-threatening multidrug-resistant bacterial pathogens calls for the development of new antibacterial agents and alternative strategies. The virulence factor secreted by bacteria plays a crucial role in the sophisticated processes during infections. Inspired by the unique capacity of many bacteria inducing clotting of plasma to initiate colonization, we propose a programmable antibiotic delivery system for precision therapy using methicillin-resistant S. aureus (MRSA) as a model. Coagulase utilized by MRSA to directly cleave fibrinogen into fibrin, is an ideal target not only for tracking bacterial status but for triggering the collapse of fibrinogen functionalized porous microspheres. Subsequently, staphylokinase, another virulence factor of MRSA, catalyzed hydrolysis of fibrin to further release the encapsulated antibiotics from microspheres. Our sequential triggered-release system exhibits high selectivity to distinguish live or dead MRSA from other pathogenic bacteria. Furthermore, such programmable microspheres clear 99% MRSA in 4 h, and show increased efficiency in a wound healing model in rats. Our study provides a programmable drug delivery system to precisely target bacterial pathogens using their intrinsic enzymatic cascades. This programmable platform with reduced selective stress of antibiotics on microbiota sheds light on the potential therapy for future clinical applications.

Colistin resistance has attracted substantial attention after colistin was considered as a last-resort drug for the treatment of infections caused by carbapenem-resistant and/or multidrug-resistant (MDR) Gram-negative bacteria in clinical settings. However, with the discovery of highly mobile colistin resistance (mcr) genes, colistin resistance has become an increasingly urgent issue worldwide. Despite many reviews, which summarized the prevalence, mechanisms, and structures of these genes in bacteria of human and animal origin, studies on the prevalence of mobile colistin resistance genes in aquaculture and their transmission between animals and humans remain scarce. Herein, we review recent reports on the prevalence of colistin resistance genes in animals, especially wildlife and aquaculture, and their possibility of transmission to humans via the food chain. This review also gives some insights into the routine surveillance, changing policy and replacement of polymyxins by polymyxin derivatives, molecular inhibitors, and traditional Chinese medicine to tackle colistin resistance.

Objectives To report a novel tigecycline resistance gene, tet(X6), and its variants in four bacterial species isolated from chickens and pigs in China. Methods WGS was conducted to identify the suspected resistance genes in the tigecycline-resistant Myroides phaeus 18QD1AZ29W. Functional cloning, homology modelling and molecular docking were performed to compare the function with other Tet(X) variants. Retrospective screening for tet(X6) was conducted for 80 isolates in our WGS data collection, and all genomic environments of tet(X6)-positive isolates were analysed. Results The tigecycline-resistant M. phaeus 18QD1AZ29W isolated from a pig farm in Shandong in 2018 was positive for tet(X2) and a novel tet(X) gene, designated tet(X6). Tet(X6) could increase the MICs of all tested tetracyclines/glycylcyclines for Escherichia coli only 2- to 4-fold, which was possibly due to a lower tetracycline binding capacity of Tet(X6) compared with that of other Tet(X) variants. Retrospective screening showed that seven other isolates (7/80, 8.8%), comprising four Proteus spp. and three Acinetobacter spp. from chickens and pigs in Shandong and Guangdong, were positive for three different variants of tet(X6). The analysis of the genomic environment revealed that two tet(X6)-positive isolates from M. phaeus and Proteus cibarius, respectively, contained ISCR2, which may play a role in tet(X6) transmission. Conclusions This study identified a novel type of tigecycline resistance gene, tet(X6), in Myroides, Acinetobacter and Proteus from chickens and swine. Tet(X6) conferred lower tetracycline/glycylcycline MICs than other Tet(X) variants, and ISCR2 may play a role in the transmission of tet(X6).

Campylobacter spp. are the leading cause of human gastroenteritis worldwide. RE-CmeABC is a newly identified resistance-enhancing multidrug efflux pump of Campylobacter spp. (C. spp.) that confers high-level resistance to fluoroquinolones, phenicols, macrolides, and tetracyclines (TETs), all of which are critical drugs in both human and veterinary medicine. In this study, we analyzed the presence and antimicrobial susceptibility of RE-cmeABC-positive Campylobacter isolates of food-animal origin from three representative regions (Shandong, Shanghai, and Guangdong) in China over three successive years, from 2014 to 2016. A total of 1088 Campylobacter isolates (931 C. coli and 157 C. jejuni) were recovered from the RE-cmeABC screening. We detected 122 (11.2%) RE-cmeABC-positive isolates of chicken origin, including 111 (70.7%) C. jejuni and 11 (1.2%) C. coli. This multidrug efflux pump is more prevalent among C. jejuni than C. coli. The level of resistance was significantly different in 111 RE-cmeABC-positive C. jejuni versus 46 RE-cmeABC-negative C. jejuni for florfenicol, clindamycin, and erythromycin (P

The increase in the incidence of antibiotic-resistant Staphylococcus aureus (S. aureus) associated infections necessitates the urgent development of novel therapeutic strategies and antibacterial drugs. Antivirulence strategy is an especially compelling alternative strategy due to its low selective pressure for the development of drug resistance in bacteria. Plants and microorganisms are not only important food and medicinal resources but also serve as sources for the discovery of natural products that target bacterial virulence factors. This review discusses the mechanisms of the major virulence factors of S. aureus, including the accessory gene regulator quorum-sensing system, bacterial biofilm formation, α-hemolysin, sortase A, and staphyloxanthin. We also provide an overview of natural products isolated from plants and microorganisms with activity against the major virulence factors of S. aureus and their adjuvant effects on existing antibiotics to overcome antibiotic-resistant S. aureus. Finally, the limitations and solutions of these antivirulence compounds are discussed, which will help in the development of novel antibacterial drugs against antibiotic-resistant S. aureus.

Recently we reported that in human coronary artery endothelial cells, activation of the P2Y2 receptor (P2Y2R) induces up-regulation of tissue factor (TF), a vital initiator of the coagulation cascade. However, others have shown that monocyte TF is more critical than endothelial TF in provoking a pro-thrombotic state. Thus, we aimed to study whether monocytes express the P2Y2R, its role in controlling TF expression, and its relevance in vivo. RT-PCR and receptor activity assays revealed that among the eight P2Y nucleotide receptors, the P2Y2 subtype was selectively and functionally expressed in human monocytic THP-1 cells and primary monocytes. Stimulation of the cells by ATP or UTP dramatically increased TF protein expression, which was abolished by AR-C118925, a selective P2Y2R antagonist, or by siRNA silencing the P2Y2R. In addition, UTP or ATP treatment induced a rapid accumulation of TF mRNA preceded with an increased TF pre-mRNA, indicating enhanced TF gene transcription. In addition, stimulation of the monocyte P2Y2R significantly activated ERK1/2, JNK, p38, and Akt, along with their downstream transcription factors including c-Jun, c-Fos, and ATF-2, whereas blocking these pathways respectively, all significantly suppressed P2Y2R-mediated TF expression. Furthermore, we found that LPS triggered ATP release and TF expression, the latter of which was suppressed by apyrase or P2Y2R blockage. Importantly, P2Y2R-null mice were more resistant than wild-type mice in response to a lethal dose of LPS, accompanied by much less TF expression in bone marrow cells. These findings demonstrate for the first time that the P2Y2R mediates TF expression in human monocytes through mechanisms involving ERK1/2, JNK, p38, and AKT, and that P2Y2R deletion protects the mice from endotoxemia-induced TF expression and death, highlighting monocyte P2Y2R may be a new drug target for the prevention and/or treatment of relevant thrombotic disease.

Objectives To provide a comprehensive assessment of the impact of carbapenem resistance on mortality among patients infected with Enterobacteriaceae and to explore the source of heterogeneity across studies. Design This systematic review was conducted following the guidelines of Cochrane Guidance and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Data sources We conducted a systematic literature search of the PubMed, Embase, Web of Science and Cochrane Library databases to identify relevant studies published between 1 January 1994 and 30 August 2020. Eligibility criteria We included primary observational studies published in English that reported the mortality outcomes for hospitalised patients with confirmed infections due to carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-susceptible Enterobacteriaceae (CSE). Studies with no comparison group or with a comparison group of patients infected with unconfirmed CSE were excluded. Data extraction and synthesis Data extraction and assessment of risk bias were conducted independently by two reviewers. The pooled relative risk and risk difference were calculated as effect measures with 95% CIs using a random effects model. The heterogeneity across studies was assessed by Q-statistic and I2 measures. Results Of 10 304 studies initially identified, 50 studies were included in the meta-analyses. The results of the meta-analyses showed that carbapenem resistance has a significant positive effect on the probability of death for patients infected with Enterobacteriaceae for any type of mortality outcome. The results of the stratified analysis and meta-regression suggested that the effect of carbapenem resistance on the risk of death varied by infection type, sample size and year of publication. Conclusions Our results suggested that patients with CRE infection still face a greater risk of death than patients with CSE infection do, and an urgent need to develop new antibiotics and appropriate treatments to reduce the risk of death. PROSPERO registration number CRD42020176808.

In this study, a fluorescence polarization immunoassay (FPIA) was developed based on the single-chain variable fragments (scFvs) for fumonisin B

Background: This study aimed to examine and screen patients for potential biomarkers for the diagnosis of unresponsive wakefulness syndrome (UWS). Methods: Patients with UWS, patients who regained consciousness (RC; patients in a minimally conscious state), and patients who had emerged from the minimally conscious state were evaluated using the Coma Recovery Scale-Revised (CRS-R). Cerebrospinal fluid (CSF) was collected from five healthy controls and 10 patients (5 UWS; 5 RC). Two-dimensional electrophoresis and proteomic analysis were used to examine and identify differentially expressed proteins in the CSF. Results: Compared with the control group, there were at least six proteins expressed at higher levels and two proteins expressed at lower levels in the CSF of the RC group than in the CSF of the UWS group. However, expression of vitamin D-binding protein (VDP) showed a further increase of 4.52-fold, that of DNA replication licensing factor mini-chromosome maintenance 4 (MCM4) showed a reduction of -20.61-fold, and that of hemoglobin subunit beta reversed to -8.34-fold in the UWS group. Another converse expression was of protein coenzyme Q-binding protein COQ10 homolog A (COQ10A), which was -4.31-fold in the RC group and 1.51-fold in the UWS group, compared to the control group. Expression of other proteins demonstrated an ascending trend in the RC group compared to the control group. Conclusions: The three differentially expressed proteins, VDP, DNA replication licensing factor MCM4, and hemoglobin subunit beta, may be involved in consciousness maintenance. This study identified potential biomarkers for UWS and will provide new insights into the pathogenesis of UWS.

Sandwich lateral flow immunoassays (LFIAs) based on paired antibodies are the most frequently used platform for food-borne pathogen detection. Although label-free strategies are used in LFIAs to avoid the utilization of paired antibodies, challenges of probe design and detection reliability still remain. Here, we report a new label-free and dual-readout LFIA (LD-LFIA) mediated by a 'Three-To-One' multi-functional nanocomposite with a unique combination of magnetic-adhesion-color-nanozyme properties. The strengths of the new designed nanocomposite are: (i) the Fe

Highly sensitive and accurate screening of ractopamine (RAC) residue in animal urine is greatly needed to ensure food security. The detection performance of immunoassay for RAC was always seriously harmed by the antibody inactivation derived from urea. Here, we first discovered one rabbit monoclonal antibody (RmAb) to RAC with a high affinity of 0.007 ng mL

Monoclonal antibodies (mAbs) are useful biological tools for research, diagnostics, and pharmaceuticals. Here, we proposed a new mAb discovery platform named the two-step cell selection method (TCSM) for mAbs production of some small molecule haptens as antibiotic, toxins, and pesticides. The first step was performed by a fluorescence-activated cell sorter to enrich the hapten-specific B cells, the second step was an image-based precise pick of single hapten-specific hybridoma cells by confocal laser scanning microscopy. In this study, we used tetramethylenedisulfotetramine (TETS) as a model analyte, which is a highly lethal neurotoxic rodenticide. The TETS-specific hybridoma cells selection was completed within 10 days by the TCSM, compared with at least 40 days in the traditional hybridoma method (THM). The half maximal inhibitory concentration (IC50) of the best mAb 1G6 for TETS in the TCSM was 1.98 ng mL-1, and that of mAb 2B6 in the THM was 11.49 ng mL-1. Antibody-TETS recognition also showed more interactions in mAb 1G6 than in mAb 2B6. Then, the mAb 1G6 was then successfully applied to develop an icELISA for TETS in biological samples with satisfactory sensitivity, accuracy and precision. The results demonstrated that the TCSM was a feasible and efficient method for mAb discovering of poisonous hapten molecules.

We previously found that the immune response to haptens is positively correlated with molecular hydrophobicity. The antibodies used in immunoassays for capsaicinoids (CPCs) in waste oil suffer from low affinity and loose recognition to structural analogues. To address this issue, four new haptens (hapten1-4), maximally exposing the hydrophobic alkane chain (noncommon moiety of CPCs), were designed and expected to produce antibodies with high affinity and accurate recognition to CPCs based upon our findings. The assumption was first evidenced by computational chemistry and animal immunization successively. Compared with four reported haptens (hapten5-8) that expose the hydrophilic vanillyl amide moiety (common structure of CPCs and other vanillin alkaloids), antisera from hapten1-4 showed an approximately 1000-fold increase in affinity and significantly improved recognition profiles for CPCs. The molecular recognition study showed that the high affinity of the antibody from new haptens mainly originated from hydrophobic forces. An indirect competitive enzyme-linked immunosorbent assay based on a monoclonal antibody from hapten1 was developed and exhibited limits of detection as low as 0.73-3.29 μg/kg for four CPCs in oils and with insignificant cross-reactivities for other eight vanillin alkaloids, which have been never achieved in previous reports.

The increasing emergence and dissemination of multidrug resistant (MDR) bacterial pathogens accelerate the desires for new antibiotics. Natural products dominate the preferred chemical scaffolds for the discovery of antibacterial agents. Here, the potential of natural flavonoids from plants against MDR bacteria, is demonstrated. Structure–activity relationship analysis shows the prenylation modulates the activity of flavonoids and obtains two compounds, α‐mangostin (AMG) and isobavachalcone (IBC). AMG and IBC not only display rapid bactericidal activity against Gram‐positive bacteria, but also restore the susceptibility of colistin against Gram‐negative pathogens. Mechanistic studies generally show such compounds bind to the phospholipids of bacterial membrane, and result in the dissipation of proton motive force and metabolic perturbations, through distinctive modes of action. The efficacy of AMG and IBC in four models associated with infection or contamination, is demonstrated. These results suggest that natural products of plants may be a promising and underappreciated reservoir to circumvent the existing antibiotic resistance., Isopentenylated flavonoids such as α‐mangostin and isobavachalcone are efficacious against multidrug‐resistant Gram‐positive and Gram‐negative pathogens with permeabilized outer membrane. Both α‐mangostin and isobavachalcone display rapid bactericidal activities through distinctive modes of action by targeting bacterial membrane phospholipids. Antibacterial agents targeting membrane exert fast time‐killing dynamics with less potential to develop resistance. Targeting membrane is an alternative strategy for antibacterial therapy.

Simple Summary The distribution of Kashgarian loach (Triplophysa yarkandensis) is limited to the Tarim River basin, which is the largest inland river in China. However, the population size of T. yarkandensis has been diminishing, and it is critically endangered in the Tarim River basin due to the gradual depletion of water resources, together with alien invasion and agricultural cultivation in Tarim River. In this study, we adopted the RAD-seq method to investigate the population genetics of T. yarkandensis, and a high degree of genetic variations and significant genetic differentiation was detected among T. yarkandensis populations in the Tarim River basin. The obtained data contribute to understanding the genetic status of T. yarkandensis, and help to provide the scientific management strategies and direct future monitoring and utilization of the genetic resource in Xinjiang region. Abstract The distribution of Triplophysa yarkandensis is restricted to Xinjiang’s Tarim River basin. We collected 119 T. yarkandensis samples from nine geographic populations in the Tarim River basin and utilized the RAD-seq method for SNP genotyping. In this study, a total of 164.81 Gb bases were generated with the Illumina platform, and 129,873 candidate SNPs were obtained with the Stacks pipeline for population genetic analyses. High levels of genetic diversity were detected among nine populations. The AMOVA results showed that the majority of genetic variations originated from among populations (FST = 0.67), and the pairwise FST values ranged from 0.4579 to 0.8736, indicating high levels of genetic differentiation among these populations. The discriminate analysis of principal components (DAPCs) and neighbor joining (NJ) tree revealed that the nine populations could be separated into two clusters (i.e., south and north populations), and modest genetic differentiation between south and north populations was observed, while the individuals from several populations were not clustered together by geographical location. The evidence of two genetic boundaries between south and north populations (except TTM) was supported by barrier analysis. The Bayesian skyline plotting indicated that T. yarkandensis populations in the Tarim River basin had not experienced genetic bottlenecks, and the effective population size remained stable. This study first clarified the genetic diversity and differentiation of T. yarkandensis populations in the Tarim River basin, and it provided valuable molecular data for conservation and management of natural populations.

With a nearly 100% mortality rate, African swine fever (ASF) has devastated the pork industry in many countries. Without a vaccine in sight, mitigation rests on rapid diagnosis and immediately depopulating infected or exposed animals. Unfortunately, current tests require centralized laboratories with well-trained personnel, take days to report the results, and thus do not meet the need for such rapid diagnosis. In response, we developed a portable, sample-to-answer device that allows for ASF detection at the point of need in

Since the first report of the plasmid-mediated, colistin-resistant gene, mcr-1, nine mcr genes and their subvariants have been identified. The spreading scope of mcr-1~10 varies greatly, suggesting that mcr-1~10 may have different evolutionary advantages. Depending on MCR family phylogeny, mcr-6 is highly similar to mcr-1 and -2, and mcr-7~10 are highly similar to mcr-3 and -4. We compared the expression effects of MCR-1~5 on bacteria of common physiological background. The MCR-1-expressing strain showed better growth than did MCR-2~5-expressing strains in the presence of colistin. LIVE/DEAD staining analysis revealed that MCR-3~5 expression exerted more severe fitness burdens on bacteria than did MCR-1 and -2. Bacteria expressing MCRs except MCR-2 showed enhanced virulence with increased epithelial penetration ability determined by trans-well model (p &lt, 0.05). Enhanced virulence was also observed in the Galleria mellonella model, which may have resulted from bacterial membrane damage and different levels of lipopolysaccharide (LPS) release due to MCR expression. Collectively, MCR-1-expressing strain showed the best survival advantage of MCR-1~5-expressing strains, which may partly explain the worldwide distribution of mcr-1. Our results suggested that MCR expression may cause increased bacterial virulence, which is alarming, and further attention will be needed to focus on the control of infectious diseases caused by mcr-carrying pathogens.

Mobile colistin resistance enzyme MCR‐3 is a phosphoethanolamine transferase modifying lipid A in Gram‐negative bacteria. MCR‐3 generally mediates low‐level (≤8 mg L−1) colistin resistance among Enterobacteriaceae, but occasionally confers high‐level (>128 mg L−1) resistance in aeromonads. Herein, it is determined that MCR‐3, together with another lipid A modification mediated by the arnBCADTEF operon, may be responsible for high‐level colistin resistance in aeromonads. Lipid A is the critical site of pathogens for Toll‐like receptor 4 recognizing. However, it is unknown whether or how MCR‐3‐mediated lipid A modification affects the host immune response. Compared with the wild‐type strains, increased mortality is observed in mice intraperitoneally‐infected with mcr‐3‐positive Aeromonas salmonicida and Escherichia coli strains, along with sepsis symptoms. Further, mcr‐3‐positive strains show decreased clearance rates than wild‐type strains, leading to bacterial accumulation in organs. The increased mortality is tightly associated with the increased tissue hypoxia, injury, and post‐inflammation. MCR‐3 expression also impairs phagocytosis efficiency both in vivo and in vitro, contributing to the increased persistence of mcr‐3‐positive bacteria in tissues compared with parental strains. This study, for the first time, reveals a dual function of MCR‐3 in bacterial resistance and pathogenicity, which calls for caution in treating the infections caused by mcr‐positive pathogens., The synergistic lipid A modifications by mobile colistin resistance gene (mcr‐3) and arnBCADTEF operon are responsible for high‐level colistin resistance in Aeromonas salmonicida. Both Escherichia coli and A. salmonicida strains harboring mcr‐3 suffer less phagocytosis and present enhanced pathogenicity. The dual threat, increased colistin resistance and pathogenicity, of infections caused by MCR‐producing pathogens needs considerable attention in the clinical settings.

Seven mobile oxazolidinone resistance genes, including cfr, cfr(B), cfr(C), cfr(D), cfr(E), optrA, and poxtA, have been identified to date. The cfr genes code for 23S rRNA methylases, which confer a multiresistance phenotype that includes resistance to phenicols, lincosamides, oxazolidinones, pleuromutilins, and streptogramin A compounds. The optrA and poxtA genes code for ABC-F proteins that protect the bacterial ribosomes from the inhibitory effects of oxazolidinones. The optrA gene confers resistance to oxazolidinones and phenicols, while the poxtA gene confers elevated MICs or resistance to oxazolidinones, phenicols, and tetracycline. These oxazolidinone resistance genes are most frequently found on plasmids, but they are also located on transposons, integrative and conjugative elements (ICEs), genomic islands, and prophages. In these mobile genetic elements (MGEs), insertion sequences (IS) most often flanked the cfr, optrA, and poxtA genes and were able to generate translocatable units (TUs) that comprise the oxazolidinone resistance genes and occasionally also other genes. MGEs and TUs play an important role in the dissemination of oxazolidinone resistance genes across strain, species, and genus boundaries. Most frequently, these MGEs also harbor genes that mediate resistance not only to antimicrobial agents of other classes, but also to metals and biocides. Direct selection pressure by the use of antimicrobial agents to which the oxazolidinone resistance genes confer resistance, but also indirect selection pressure by the use of antimicrobial agents, metals, or biocides (the respective resistance genes against which are colocated on cfr-, optrA-, or poxtA-carrying MGEs) may play a role in the coselection and persistence of oxazolidinone resistance genes.

The acquisition of resistance to one antibiotic sometimes leads to collateral sensitivity to a second antibiotic. Here, we show that vancomycin resistance in Enterococcus faecium is associated with a remarkable increase in susceptibility to pleuromutilin antibiotics (such as lefamulin), which target the bacterial ribosome. The trade-off between vancomycin and pleuromutilins is mediated by epistasis between the van gene cluster and msrC, encoding an ABC-F protein that protects bacterial ribosomes from antibiotic targeting. In mouse models of vancomycin-resistant E. faecium colonization and septicemia, pleuromutilin treatment reduces colonization and improves survival more effectively than standard therapy (linezolid). Our findings suggest that pleuromutilins may be useful for the treatment of vancomycin-resistant E. faecium infections.

Antimicrobial agents have been used in meat production for decades and its consumption is considered an key driver for the emergence and dissemination of antimicrobial resistance (AMR). However, large-scale studies on AMR changes in animal isolates since the introduction of antimicrobial usage remain scarce. We applied whole genome sequencing analysis to 982 animal-derived Escherichia coli collected in China from 1970s to 2019 and found increasing trends for the presence of numerous antimicrobial resistance genes (ARGs), including those conferring resistance to critically important agents for veterinary (florfenicol and norfloxacin) and human medicine (colistin, cephalosporins, and meropenem). Extensive diversity and increasing complexity of ARGs and their associated mobile genetic elements (MGEs) such as plasmids were also observed. The plasmids, IncC, IncHI2, IncK, IncI, IncX and IncF played a key role as highly effective vehicles for disseminating ARGs. Correlation analysis also revealed an association between antimicrobial production and emergence of ARGs at a spatial and temporal level. Prohibiting or strictly curtailing antimicrobial use in animals will potentially negate the current trends of AMR as the bacterial genome is highly changeable and using different drugs of the same class, or even unrelated classes, may co-select for MGEs carrying a plethora of co-existing ARGs. Therefore, limiting or ceasing antimicrobial use in animals to control AMR requires careful consideration.

Metal-organic frameworks (MOFs) has excellent adsorption performance, herein, three kinds of common MOFs were used for the adsorption of sulfamethazine (SM2) in milk, then enzyme-linked immunosorbent assay (MOF-ELISA) was established. Firstly, NH2-UiO-66, NH2-MIL-101, and ZIF-8 were successfully prepared and their adsorption characteristics for SM2 were investigated. The kinetic models of the three MOFs were more in line with the pseudo-second-order adsorption kinetics, and the saturated adsorption capacity of NH2-UiO-66, NH2-MIL-101, and ZIF-8 for SM2 at 298K were 139.64, 29.98, and 36.5 mg/g, respectively. Using three different MOFs as adsorbents, the pretreatment of milk samples could be completed within 1 h, the half inhibitory concentrations (IC50) of MOF-ELISA were 1.26, 1.86 and 2.74 ng/mL, the limit of detections (LOD) was 0.05, 0.12, and 0.19 ng/mL and the recovery rate were from 82.30% to 105.62% with the intra-day coefficient of variations (CVs) below 5.81% and inter-day CVs below 7.21%. Detection results showed good correlations with LC-MS/MS (R2>0.99), indicated that MOFs could effectively eliminate the interference of sample matrix, and has the potential to become a general pretreatment method for the detection of various matrices residues in food safety monitoring.

Bacteria infected cells acting as “Trojan horses” not only protect bacteria from antibiotic therapies and immune clearance, but also increase the dissemination of pathogens from the initial sites of infection. Antibiotics are hard and insufficient to treat such hidden internalized bacteria, especially multidrug‐resistant (MDR) bacteria. Herein, aggregation‐induced emission luminogens (AIEgens) such as N,N‐diphenyl‐4‐(7‐(pyridin‐4‐yl) benzo [c] [1,2,5] thiadiazol‐4‐yl) aniline functionalized with 1‐bromoethane (TBP‐1) and (3‐bromopropyl) trimethylammonium bromide (TBP‐2) (TBPs) show potent broad‐spectrum bactericidal activity against both extracellular and internalized Gram‐positive pathogens. TBPs trigger reactive oxygen species (ROS)‐mediated membrane damage to kill bacteria, regardless of light irradiation. TBPs effectively kill bacteria without the development of resistance. Additionally, such AIEgens activate mitochondria dependent autophagy to eliminate internalized bacteria in host cells. Compared to the routinely used vancomycin in clinic, TBPs demonstrate comparable efficacy against methicillin‐resistant Staphylococcus aureus (MRSA) in vivo. The studies suggest that AIEgens are promising new agents for the treatment of MDR bacteria associated infections., Aggregation‐induced emission luminogens (AIEgens) offer great potentials to track and dissect their modes of action in bacteria and pharmacokinetics processes in hosts. AIEgens serve as a novel class of antibiotics by triggering reactive oxygen species (ROS)‐mediated membrane damage and by activating mitochondria dependent autophagy to kill bacteria, which are promising adjuvants to boost mammalian cells for bacterial clearance and treatment of MRSA associated peritonitis.

Aim: There is an ongoing debate as to what extent antimicrobial resistance (AMR) can be transmitted from dietary to humans via the consumption of food products. We investigated this association between dietary and global spreading carbapenem-resistant gene blaNDM Methods: We did a cross-sectional study to assess the risk factors for carrier of blaNDM in health community. Healthy adults were recruited from the residents attending Community Healthcare Service in Shenzhen City (Guangdong Province, China), through 1February 2018 to 31December 2019, and 718 pre-participants were included in this study. Questionnaire were obtained and the qualitative food frequency questionnaire (Q-FFQ) were used to assess dietary intake. qPCR was applied to confirm the carrier of blaNDM in participants’fecal samples. Multivariable logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (95% CI) of each outcome according to each dietary factor before and after prosperity score matching (PSM). Results: we showed that a high intake of coarse grain (OR 1.003, 95% CI 1.001–1.005, p &lt, 0.01) and root and tuber crops (OR 1.003, 95% CI 1.001–1.004, p &lt, 0.05) were independent risk factor for blaNDM carrier in health communities, suggesting a possible transfer of AMRbetweendietary andhumans. Surprisingly, we also showed an association between a higher intake of poultry as a protective, which may be explained by the beneficial effects on the gut microbiota. Conclusion: Dietary factors such as intake of coarse grain, root and tuber crops and poultry were associated with blaNDM carrier in health communities. The influence of dietary factorson blaNDM carrier in the present study provides insights for the tangible dietary advice with guidelines to the routine of people with the risk of blaNDM carrier. This demonstrates the role of dietary intake in the prevention of blaNDM carrier, since prevention is the best way to control modifiable risk factors. A lower carrier rate of blaNDM is helpful to reduce the possibility of transmission and pathogenicity. Further studies on food, microbiota and antimicrobial resistance are necessary to confirm this possible association and unravel underlying mechanisms.

The rapid emergence and dissemination of multidrug-resistant (MDR) bacterial pathogens pose a serious threat to global healthcare. One particular concern is the carbapenem-resistant Enterobacteriaceae (CRE), a group of Gram-negative bacteria that have evolved resistance to all or nearly all available antibiotics. Coupled with the fact of barren antibiotic development pipeline nowadays, a critical approach is to revitalize existing antibiotics using antibiotic adjuvants. We found a short linear antibacterial peptide (SLAP)-S25 carrying four non-natural amino acids of 2,4-diaminobutanoic acid (Dab), which solely showed weak antibacterial activity but boosted the efficacy of antibiotics covering all major classes, including cefepime, colistin, ofloxacin, rifampicin, tetracycline and vancomycin, against MDR Gram-negative pathogens. Mechanistic studies showed that SLAP-S25 triggers membrane damage by binding to both lipopolysaccharide (LPS) in the outer membrane and phosphatidylglycerol (PG) in bacterial cytoplasmic membrane, to potentiate antibiotic efficacy through collaborative strategies. Lastly, SLAP-S25 effectively enhanced the activity of colistin against MDR Escherichia coli-associated infections in three animal models. Our findings provide a potential therapeutic option using existing antibiotics in combination with broad-spectrum antibiotic adjuvants, to address the prevalent infections caused by MDR Gram-negative pathogens worldwide.

Diphacinone (DPN) is an extensively used anticoagulant rodenticide that is also considered a hazardous chemical, which poses a threat to nontarget species. DPN poisoning cases in humans or other species frequently occur, while rapid and sensitive detection methods are rarely reported. Thus, it is meaningful to develop an immunoassay for DPN detection with high sensitivity and specificity. In this study, a hapten was synthesized and then conjugated with carrier proteins to prepare the immunogens with different conjugation ratios for the preparation of antibody. After evaluation of the antisera using an indirect competitive enzyme-linked immunosorbent assay (icELISA) and statistical analysis, we found that the immunogen prepared using the N,N-dicyclohexylcarbodiimide (DCC) method with a conjugation ratio of 28.5 could elicit mice to generate antibodies with high performance. Using hybridoma technology, we obtained the specific monoclonal antibody (mAb) 4G5 with a half maximal inhibitory concentration (IC50) of 0.82 ng/mL in buffer solution. We initially explored the recognition mechanism of DPN/CLDPN and mAb from both conformational and electronic aspects. Then, mAb 4G5 was applied to develop icELISA for biological samples. The limits of detection (LODs) of icELISA were 0.28 μg/L, 0.32 μg/L, and 0.55 μg/kg for swine plasma, urine, and liver samples, respectively, and the recoveries ranged from 72.3 to 103.3% with a coefficient of variation (CV) of less than 12.3% in spiked samples. In summary, we developed a sensitive, specific, and accurate icELISA for the detection of DPN in biological samples, which showed potential in food safety analysis and clinical diagnosis.

The emergence and rapid spread of methicillin-resistant Staphylococcus aureus (MRSA) critically requires alternative therapeutic options. New antibacterial drugs and strategies are urgently needed to combat MRSA-associated infections. Here, we investigated the antibacterial activity of flavones from Morus alba and the potential mode of action against MRSA. Kuwanon G, kuwanon H, mulberrin, and morusin displayed high efficiency in killing diverse MRSA isolates. On the basis of structure-activity analysis, the cyclohexene-phenyl ketones and isopentenyl groups were critical to increase the membrane permeability and to dissipate the proton motive force. Meanwhile, mechanistic studies further showed that kuwanon G displayed rapid bactericidal activity in vitrowith difficulty in developing drug resistance. Kuwanon G targeted phosphatidylglycerol and cardiolipin in the cytoplasmic membrane through the formation of hydrogen bonds and electrostatic interactions. Additionally, kuwanon G promoted wound healing in a mouse model of MRSA skin infection. In summary, these results indicate that flavones are promising lead compounds to treat MRSA-associated infections through disrupting the proton motive force and membrane permeability.

Tigecycline is a last-resort antibiotic that is used to treat severe infections caused by extensively drug-resistant bacteria. tet(X) has been shown to encode a flavin-dependent monooxygenase that modifies tigecycline1,2. Here, we report two unique mobile tigecycline-resistance genes, tet(X3) and tet(X4), in numerous Enterobacteriaceae and Acinetobacter that were isolated from animals, meat for consumption and humans. Tet(X3) and Tet(X4) inactivate all tetracyclines, including tigecycline and the newly FDA-approved eravacycline and omadacycline. Both tet(X3) and tet(X4) increase (by 64-128-fold) the tigecycline minimal inhibitory concentration values for Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii. In addition, both Tet(X3) (A. baumannii) and Tet(X4) (E. coli) significantly compromise tigecycline in in vivo infection models. Both tet(X3) and tet(X4) are adjacent to insertion sequence ISVsa3 on their respective conjugative plasmids and confer a mild fitness cost (relative fitness of >0.704). Database mining and retrospective screening analyses confirm that tet(X3) and tet(X4) are globally present in clinical bacteria-even in the same bacteria as blaNDM-1, resulting in resistance to both tigecycline and carbapenems. Our findings suggest that both the surveillance of tet(X) variants in clinical and animal sectors and the use of tetracyclines in food production require urgent global attention.

Fluorescence polarization (FP) assays play an important role in the detection of chemical contaminants in food and environmental due to a number of key advantages since last century. In recent decades, FP assays have achieved great progress thanks to developments in materials science and labelling techniques. This comprehensive review provides the state of art in methods design, recognition elements, fluorophores, multi-targeted analysis, practical applications with real samples, and the challenges of deploying FP assays for the detection of chemical contaminants. These new information and insightful commentary of the review will be critically important to the development and innovation of next-generation FP assays.

A multiplex immunochromatographic assay (ICA) based on dual-color fluorescent microspheres (FMs) as a sensitive label was developed for the first time. Two typical algae toxins, microcystin-LR (MC-LR) and okadaic acid (OA), were chosen as proof-of concept targets to evaluate the feasibility of this ICA format. Commercial red- and green-colored FMs were selected to couple with monoclonal antibodies as fluorescent probes. The use of dual-wavelength FMs as labels guaranteed a lower consumption of material strips, lower sample volume, and shorter reaction time without increasing the length of ICA strips. Under optimal conditions, the multiplex FM-ICA could be completed in 20 min and reached limits of detection for the simultaneous determination of MC-LR and OA in fish samples, which were 0.074 and 2.42 μg/kg, respectively. The developed technique was validated using artificially spiked and naturally contaminated fish samples. Ultra-high-performance liquid chromatography-tandem mass spectrometry was used as confirmatory technique. In summary, this portable ICAs detection mode based on dual-wavelength FMs provided a reliable and sensitive on-site detection of multiple contaminants in food samples, which opens a new field for application of FMs in food safety.

Diazepam (DZP) is often found in source water and drinking water at dozens of nanograms per liter levels. The transformation of DZP in water chlorination disinfection process has aroused new concern because the toxic disinfection byproducts (DBPs) might be produced. However, the DBPs of DZP have not been fully identified, and their occurrence levels in drinking water have not been reported. In our chlorination experiment, five emerging DBPs of diazepam: (5-chloro-2-(methylamino) phenyl) (phenyl)methanone (BP-246), 6-chloro-1-methyl-4-phenylquinazolin-2(1H)-one (BP-271), N-(2-benzoyl-4,6-dichlorophenyl)formamide (BP-294), methyl-(2-benzoyl-4-chlorophenyl) (methyl)carbamate (BP-304 (1)) and 6-chloro-4-methoxy-1-methyl-4-phenyl-1,4-dihydro2H -benzo[d][1,3]oxazin-2-one (BP-304 (2)), were tentatively identified by high-resolution mass spectrometry and further characterized by nuclear magnetic resonance spectroscopy. We developed a trace analytical method for the analysis of these five DBPs in drinking water based on solid-phase extraction (SPE) followed liquid chromatography coupled with electrospray ionization tandem mass spectrometric detection. Ultrahigh sensitivities were achieved with limits of detection as low as 7 pg per liter. The recoveries at different spiking levels were all higher than 80% except for that of BP-246. Four of the DBPs and DZP were detected in real drinking water samples at concentrations ranging from several to dozens of nanograms per liter with relatively high detection frequencies. This is the first report on the existence of DZP-DBPs in drinking water. The method and results will be useful for further studies on the occurrence, toxicity, human exposure and control measures of these DBPs.

Antibody-based sensors are the most widely used for screening antibiotic residues in food samples. However, these sensors always suffer from cross-reacting antibiotics which are able to bind the employed antibodies in a manner similar to the target, thus resulting in inaccurate quantification. In this study, we developed a highly specific and sensitive chemiluminescence aptasensor for sulfamethazine (SMZ) by employing the supernormal selectivity of a new selected aptamer. Four SMZ-specific aptamers (Kd ranging from 79 to 274 nM) were selected in vitro by MB-SELEX with an intentional counter selection to avoid the recognition other sulfonamides, which is impossible to achieve in the corresponding procedure of antibody production. The binding mechanism of aptamers for SMZ was further analyzed and clarified with molecular simulation and docking. Under optimum conditions, the chemiluminescence aptasensor based on the highest affinity aptamer named SA07 provided a limit of detection of 0.92 ng/mL with negligible cross-reactivity with the 27 tested sulfonamides. The developed aptasensor was applied to milk samples, and achieved good accuracy and precision. These results demonstrated that the integration of an aptamer and chemiluminescence in a sensor platform is a promising method for the sensitive, specific, rapid and accurate detection of antibiotic residues of interest in food samples.

Covering: 2000 to 2018, particularly from 2010 to early 2018 The increase in the incidence of antibiotic resistant infections is threatening to overwhelm healthcare practices worldwide. Most antibiotics in clinical use are becoming ineffective, so therefore it is imperative to develop new antibiotics and novel therapeutic strategies. Traditionally, the chemical and mechanistic diversity of nonribosomal antibacterial peptides (NRAPs) as lead compounds have meant that their structures are ideal for antibiotic discovery. Here, we summarize the state of our current knowledge about the mechanisms of antibiotic resistance, which can be used to guide the development of new antibiotics. Furthermore, we provide an overview of NRAPs for treating multi-drug resistant bacteria, including innovative approaches for screening NRAPs from new sources and the underlying mechanisms of antibacterial activity. Finally, we discuss the design of NRAP scaffolds for precise medicine and combinatorial NRAP therapies with existing antibiotics to overcome resistance, which will help to control infections in the post-antibiotic era.

Recently, several studies showed that microcystin-LR (MCLR) can accumulate and induce toxicity in kidney. However, the exact mechanism is unknown. The aim of this study was to explore the mechanism of MCLR-induced nephrotoxicity. To this end, adult zebrafish were exposed to MCLR (0, 1, 5 and 25 μg/L) for 60 days. Exposure to MCLR caused histopathological lesions, which were characterized by renal tubules filled with eosinophilic casts, abnormal renal tubules, intertubular space decrease, and blood infiltration in renal cells. RNA-Seq analysis indicated that exposure to MCLR significantly interfered with renal gene expressions, and these genes were enriched in various pathways, such as oxidative phosphorylation, cell cycle, and protein processing in endoplasmic reticulum, which were related to apoptosis. Furthermore, terminal deoxynucleotide transferase-mediated deoxy-UTP nick end labelling (TUNEL) assay showed that MCLR exposure induced renal cell apoptosis. In addition, negative changes of the reactive oxygen species (ROS) level as well as apoptotic-related gene, protein expressions and enzyme activities suggested that MCLR could induce production of ROS, subsequently triggering apoptosis via p53-bcl-2 and caspase-dependent pathway in the kidney of zebrafish. Therefore, it can be concluded that apoptosis is a primary case of MCLR-induced nephrotoxicity.

Colistin therapy can cause pulmonary toxicity, however, our understanding of the underlying molecular mechanism remains incomplete. This study aimed to investigate the molecular mechanism of colistin-induced pulmonary toxicity in vitro and in vivo. Our results showed that intraperitoneal colistin treatment significantly increased the expression of TGF-β and NOX4 protein and mRNA, then triggers oxidative stress, mitochondrial dysfunction, and apoptosis in the lung tissue of mice and A549 cells. Moreover, colistin treatment significantly increased levels of mitochondrial ROS (mtROS) and autophagy flux in A549 cells. Inhibition of NOX4 protected A549 cells against colistin-induced mtROS and apoptosis. Colistin treatment also down-regulated the expression of p-Akt and p-mTOR proteins (all P 0.05 or 0.01) in lung tissues of mice or A549 cells. Inhibition of autophagy or Akt pathways by chloroquine (CQ), 3-Methyladenine (3-MA) or LY294002 promoted colistin-induced mitochondrial damage, and caspase-dependent cellular apoptosis. Whereas, activation of autophagy by rapamycin pretreatment of A549 cells partly abolished colistin-induced cytotoxicity, mitochondrial dysfunction, and apoptosis. This is first study to show that colistin-induced pulmonary toxicity involves the activation of TGF-β/NOX4/mtROS pathway and the inhibition of Akt/mTOR pathway in lung tissues of mice and highlights the key protective role of autophagy activation.

The two sensitive fluorescence quantitative immunochromatographic assays (FQICAs), background fluorescence quenching immunochromatographic assay (bFQICA) and time-resolved fluorescent immunochromatographic assay (TRFICA), play an important role increasingly in rapid detection technology for food safety. Amantadine (AMD), used extensively in virus infections in livestock and poultry, has been prohibited due to hazard concerns over public human health. Therefore, AMD was used as a model molecule in the FQICAs establishment and comparison based on the same bioreagents. The outstanding performance in technical parameters of the two FQICAs indicated that they could provide rapid, precise, reliable technical support for large-scale on-site screening for AMD detection. What's more, the systematic and comprehensive comparison of the two FQICAs would give useful suggestions for scientists and users in monitoring the harmful compounds.

The accumulation of diminutive plastic waste in the environment, including microplastics and nanoplastics, has threatened the health of multiple species. Nanoplastics can adsorb the pollutants from the immediate environment, and may be used as carriers for pollutants to enter organisms and bring serious ecological risk. To evaluate the toxic effects of microcystin-LR (MCLR) on the liver of adult zebrafish (Danio rerio) in the presence of 70 nm polystyrene nanoplastics (PSNPs), zebrafish were exposed to MCLR alone (0, 0.9, 4.5 and 22.5 μg/L) and a mixture of MCLR + PSNPs (100 μg/L) for three months. The results indicated that groups with combined exposure to MCLR and PSNPs further enhanced the accumulation of MCLR in the liver when compared to groups only exposed to MCLR. Cellular swelling, fat vacuolation, and cytoarchitectonic damage were observed in zebrafish livers after exposure to MCLR, and the presence of PSNPs exacerbated these adverse effects. The results of biochemical tests showed the combined effect of MCLR + PSNPs enhanced MCLR-induced hepatotoxicity, which could be attributed to the altered levels of reactive oxygen species, malondialdehyde and glutathione, and activities of catalase. The expression of genes related to antioxidant responses (p38a, p38b, ERK2, ERK3, Nrf2, HO-1, cat1, sod1, gax, JINK1, and gstr1) was further performed to study the mechanisms of MCLR combined with PSNPs aggravated oxidative stress of zebrafish. The results showed that PSNPs could improve the bioavailability of MCLR in the zebrafish liver by acting as a carrier and accelerate MCLR-induced oxidative stress by regulating the levels of corresponding enzymes and genes.

Objectives Since the identification of VIM-1, point substitutions resulting in variants with differing hydrolytic activities have occurred, driving the evolution of the VIM enzymes. We previously detected a novel variant, VIM-48, containing 11 successive amino acid (aa) alterations in the C-terminal region compared with VIM-2. Single aa substitutions significantly change enzyme properties, but the effects of successive aa alterations have not previously been studied. Herein, we aimed to investigate the sequence and biochemical characteristics of VIM-48, including the role of the 11 successive aa substitutions. Methods VIM-48, VIM-2 and a truncated VIM-D(Δ) mutant missing 11 aa at the C-terminus relative to VIM-48 were characterized by antimicrobial susceptibility testing, protein expression and purification, determination of kinetic parameters, and homology modelling. Protein secondary structure and thermal stability measurements were also performed using circular dichroism spectral analysis. Results Compared with blaVIM-2, blaVIM-48 conferred higher resistance to carbapenems. VIM expression in Pseudomonas putida resulted in higher MICs than in E. coli. VIM-48 demonstrated increased hydrolytic activity against carbapenems relative to VIM-2, while VIM-D(Δ) had significantly decreased catalytic efficiency compared with VIM-2 and VIM-48 as a result of aa deletion. In addition, secondary structure analysis revealed that VIM-48 had the greatest proportion of α-helices among the tested enzymes, corresponding to increased thermostability, while VIM-D(Δ) had the lowest proportion of α-helices and decreased thermostability. Conclusions VIM-48 has increased enzymatic activity and thermostability and increases host β-lactam resistance. Observed changes in the secondary structure of VIM-48 resulted from successive aa alterations. Therefore, VIM evolution likely occurs via both single and successive aa substitutions.

This study synthesized a new alternariol (AOH) hapten. The AOH had an alkylation reaction with ethyl 4-bromobutyrate, followed by hydrolysis and purification, and then conjugated with keyhole limpet hemocyanin to immunize mice and successfully produced two kinds of monoclonal antibodies (mAbs), namely the antibodies which can recognize both AOH and alternariol monomethyl ether (AME) and the ones that can specifically recognize AOH. Wherein, mAb 13D8 can uniformly recognize AOH and AME with the 50% inhibition concentration (IC50) values of 9.4 ng/mL and 9.7 ng/mL, respectively. An indirect competitive ELISA (icELISA) was established by mAb 13D8 to simultaneously detect AOH and AME, with the limit of detection (LOD) being 0.7 ng/mL and 1.0 ng/mL, respectively. The average recoveries in spiked wheat sample were 84.5–107.6% with the coefficient of variation (CV) lower than 10%. The established icELISA method was used to detect 13 real samples with the same results as HPLC-MS/MS, indicating that the method is suitable for simultaneous detection of AOH and AME in wheat.

The use of organic solvents to extract chemical contaminants for an immunoassay is mostly inevitable. On this occasion, the intolerance of natural antibodies against organic solvent is detrimental to the performance of immunoassays in terms of sensitivity, assay time, accuracy, and precision. Few studies have focused on improving the low tolerance of natural antibodies to organic solvents for analytical purposes. In this study, we engineered the monoclonal antibody (mAb) 4D11 to sulfonamides through CDR grafting by using one proven highly stable humanized antibody (hAb) 4D5 for the first time. The engineered antibody hAb 4D11 showed significantly improved tolerance abilities to acetonitrile (2% to 20%) and methanol (10% to 20%), and retained the highly affinity and class-specificity to sulfonamides. This study provided a general strategy to improve antibody tolerance to organic solvents and was greatly beneficial to the robust development of immunoassays.

Presently, toxicological assessment of multiple veterinary antimicrobials has not been performed on mammals. In this study, we assessed the short-term toxicity of enrofloxacin (E) combined with colistin (C) and quinocetone (Q). Young male rats were orally dosed drug mixtures and single drugs in 14 consecutive days, each at the dose of 20, 80, and 400 mg/(kg·BW) for environmental toxicologic study. The results showed that at the high dose treatment, the combination of E + C+Q significantly decreased body intake, lymphocytes count on rats; significantly increased the values of Alanine aminotransferase (ALT), Glutamic oxaloacetic transaminase (AST) and, cholinesterase (CHE); it also got the severest histopathological changes, where sinusoidal congestion and a large number of black particles in sinusoids were observed. This means E + C+Q in the high dose groups was able to cause significant damage to the liver. Other combinations or doses did not induce significant liver damage. Transcriptome analysis was then performed on rats in high dose group for further research. For E + C and E + Q, an amount of 375 and 480 differently expressed genes were filtered out, revealing their possible underlying effect on genomes. For E + C+Q, a weighted gene co-expression network analysis was performed and 96 hub genes were identified to reveal the specific effect induced by this combination. This study indicates that joint toxicity should be taken into consideration when involving the risk assessment of these antimicrobials.

The occurrence of 187 pharmaceuticals and personal care products (PPCPs) was investigated in bottled water samples (35 and 33 from Chinese and foreign brands, respectively). Forty-four compounds belonging to 14 PPCP categories were detected in 56 of the 68 bottled water samples. Further, more than 35% of water samples contained at least three PPCPs, and in one particular sample, 11 different PPCPs were detected. Macrolides constituted the most prevalent PPCP category, and salbutamol, erythromycin, and azithromycin showed the highest detection frequency (17.6%). The thermal stabilities of the 187 PPCPs were determined, and the results obtained showed that only 35 out of the 187 compounds were degraded by more than 50% after boiling for 5 min. Even though the risk quotients (RQs) of detected PPCPs showed low risk levels, the RQs of 13 compounds with RQs ≥ 0.0001 were 2–4 fold higher in infants than in other life stages. Moreover, further studies are necessary to evaluate the toxicity of PPCP mixtures, the effects of PPCPs on human intestinal microbiota, and their risk of induction of drug-resistant bacteria and drug-resistant genes.

What is already known about this topic? Salmonella causes acute and chronic diseases in food animals, and infected food animals are one of the most important source of human infection. What does this report contribute? The prevalence of Salmonella was 10.5% in chicken samples, 24.4% in pig, 23.3% in duck, and 29.4% in milk. Salmonella isolates were highly resistant to ampicillin (59.60%). What are the implications for public health practices? Data on Salmonella infections among food animals in China could help identify sources and factors related to the spread of Salmonella in food animals and food production chains.

The emergence and worldwide dissemination of plasmid-mediated colistin resistance gene mcr-1 has attracted global attention. The MCR-1 enzyme mediated colistin resistance by catalyzing phosphoethanolamine (PEA) transfer onto bacterial lipid A. However, the interaction partners of MCR-1 located in membrane protein in E. coli are unknown. Co-immunoprecipitation (Co-IP) and Mass Spectrometry were performed to define the interacting proteins of MCR-1. A total of three different anti-MCR-1 monoclonal antibody (mAbs) were prepared and 3G4 mAb was selected as the bait protein by compared their suitability for Co-IP. We identified 53, 13, and 14 interacting proteins in E. coli BL21 (DE3) (pET28a-mcr-1), E. coli BL21 (DE3) (pET28a-mcr-1-200), and E. coli DH5α (pUC19-mcr-1), respectively. Six proteins, including the stress response proteins DnaK (chaperone protein) and SspB (stringent starvation protein B), the transcriptional regulation protein H-NS, and ribosomal proteins (RpsE, RpsJ, and RpsP) were identified in all these three strains. These MCR-1-interacting proteins were mainly involved in ribosome and RNA degradation, suggesting that MCR-1 influences the protein biosynthesis through the interaction with ribosomal protein. Multidrug efflux pump AcrA and TolC were important interacting membrane proteins of MCR-1 referred to drug efflux during the PEA modification of the bacterial cell membrane. Overall, we firstly identified the functional interactome profile of MCR-1 in E. coli and discovered that two-component AcrA-TolC multidrug efflux pump was involved in mcr-1-mediated colistin resistance.