‘Unforeseen Developments’ Before and After US – Safeguard Measure on PV Products : High Standard or New Standard?

This paper offers a comprehensive study of the jurisprudence on the ‘as a result of unforeseen developments’ test under the WTO’s safeguards (SG) rules. It contributes to the existing scholarship by making three fresh arguments. First, the Appellate Body’s decision to ‘revive’ this test as a prerequisite for the application of SG measures is not necessarily incompatible with the drafting record of the SG Agreement, even though this agreement does not make explicit reference to the test. Second, the test is not excessively difficult to satisfy under the standard of review established by case law, even though governments failed to pass it in almost all SG disputes to date. Third, in sharp contrast, the recent US–Safeguard Measure on PV Products decision took a strikingly more deferential approach which fell far short of the established standard of review, leading to the first and only decision in which the test was found to be satisfied. This decision has arguably created a new standard which could lead to abuse of SG measures and damage to the dispute settlement system and hence should be avoided in future disputes

Subsidizing Technology Competition: China’s Evolving Practices and International Trade Regulation

This article contributes to the growing debate about industrial policies and subsidies, the adequacy of the rules of the World Trade Organization (WTO), and future international negotiations of industrial subsidies, using China’s practices in the high-tech sector as an illustration. Through a review of China’s industrial policies in the high-tech sector including the 14th Five-Year Plan (2021-2025), we show China’s entrenched commitments and ambitions towards indigenous innovation, technology independence, and global leadership in key and emerging technologies especially in strategic sectors. However, we challenge the mainstream view that the existing WTO rules are inadequate to deal with Chinese subsidies. Based on a detailed analysis of the general subsidy rules and the relevant China-specific rules, we argue that the current rules create no hurdle to tackling the major types of technology subsidies in China. Any perceived deficiencies are not China-specific and can only be addressed by WTO Members via negotiations. If such negotiations are desirable, then governments should seek to leverage the impacts of the pandemic and the global (ab)use of subsidies to generate the political will needed. Drawing on existing proposals for the reform of WTO subsidy rules, we develop some general principles and approaches to facilitate future negotiations emphasizing the need to focus on targeting trade-distortive subsidies rather than China, to balance between strengthening subsidy rules and preserving policy space, to follow economic guidance and data while accommodating political considerations, and most innovatively, to shift from the ‘one-size-fits-all’ approach to a country-specific approach through a scheduling method whereby an Industrial Subsidy Schedule is created to record policy objectives, subsidy commitments, and exceptions of each nation

Global burden of colistin-resistant bacteria : mobilized colistin resistance genes study (1980-2018)

Colistin is considered to be an antimicrobial of last-resort for the treatment of multidrug-resistant Gram-negative bacterial infections. The recent global dissemination of mobilized colistin resistance (mcr) genes is an urgent public health threat. An accurate estimate of the global prevalence of mcr genes, their reservoirs and the potential pathways for human transmission are required to implement control and prevention strategies, yet such data are lacking. Publications from four English (PubMed, Scopus, the Cochrane Database of Systematic Reviews and Web of Science) and two Chinese (CNKI and WANFANG) databases published between 18 November 2015 and 30 December 2018 were identified. In this systematic review and meta-analysis, the prevalence of mcr genes in bacteria isolated from humans, animals, the environment and food products were investigated. A total of 974 publications were identified. 202 observational studies were included in the systematic review and 71 in the meta-analysis. mcr genes were reported from 47 countries across six continents and the overall average prevalence was 4.7% (0.1-9.3%). China reported the highest number of mcr-positive strains. Pathogenic Escherichia coli (54%), isolated from animals (52%) and harboring an IncI2 plasmid (34%) were the bacteria with highest prevalence of mcr genes. The estimated prevalence of mcr-1 pathogenic E. coli was higher in food-animals than in humans and food products, which suggests a role for foodborne transmission. This study provides a comprehensive assessment of prevalence of the mcr gene by source, organism, genotype and type of plasmid

Antibiotic Resistance in Salmonella Typhimurium Isolates Recovered From the Food Chain Through National Antimicrobial Resistance Monitoring System Between 1996 and 2016

Salmonella is a major foodborne pathogen which causes widespread contamination and infection worldwide. Salmonella Typhimurium is one of the leading serovars responsible for human and animal salmonellosis, globally. The increasing rate of antibiotic resistance in Salmonella Typhimurium poses a significant global concern, and an improved understanding of the distribution of antibiotic resistance patterns in Salmonella Typhimurium is essential for choosing the suitable antibiotic for the treatment of infections. To evaluate the roles of animal and human in antibiotic resistance dissemination, this study aims to categorize 11,447 S. Typhimurium strains obtained across the food-chain, including food animals, retail meats and humans for 21 years in the United States by analyzing minimum inhibitory concentrations (MICs) values for 27 antibiotics. Random Forest Algorithm and Hierarchical Clustering statistics were used to group the strains according to their minimum inhibitory concentration values. Classification and Regression Tree analysis was used to identify the best classifier for human- and animal-populations’ isolates. We found the persistent population or multi-drug resistant strains of S. Typhimurium across the four time periods (1996∼2000, 2001∼2005, 2006∼2010, 2011∼2016). Importantly, we also detected that there was more diversity in the MIC patterns among S. Typhimurium strains isolated between 2011 and 2016, which suggests significant emergence of diversified multi-drug resistant strains. The most frequently observed (43%) antibiotic resistance patterns found in S. Typhimurium were tetra-resistant pattern ASSuT (ampicillin, streptomycin, sulfonamides, and tetracycline) and the penta-resistant pattern ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline). Animals (mainly swine and bovine) are the major source for these two frequently found antibiotic resistance patterns. The occurrence of antibiotic resistant strains from humans and chicken is alarming. Strains were mostly susceptible to fluoroquinolones. Together, this study helped in understanding the expansion of dynamics of antibiotic resistance of S. Typhimurium and recommended fluoroquinolones as a possible treatment options against S. Typhimurium infection

Functional exchangeability of the nuclear localization signal (NLS) of capsid protein between PCV1 and PCV2 in vitro: Implications for the role of NLS in viral replication

<p>Abstract</p> <p>Background</p> <p>Porcine circovirus type 2 (PCV2) is believed to be the primary causative agent of postweaning multisystemic wasting syndrome (PMWS). It is supposed that capsid protein of PCV may contribute to replication control via interaction between Cap and Rep in the nucleoplasm. In this study, we described the construction and in vitro characterization of NLS-exchanged PCV DNA clones based on a PMWS-associated PCV2b isolate from China to determine the role of ORF2 NLS in PCV replication.</p> <p>Results</p> <p>The PCV1, PCV2, PCV2-NLS1 and PCV1-NLS2 DNA clone were generated by ligating a copy of respective genome in tandem with a partial duplication. The PCV2-NLS1 and PCV1-NLS2 DNA clone contained a chimeric genome in which the ORF2 NLS was exchanged. The four DNA clones were all confirmed to be infectious in vitro when transfected into PK-15 cells, as PCV capsid protein were expressed in approximately 10-20% of the transfected cells. The in vitro growth characteristics of the DNA clones were then determined and compared. All the recovered progeny viruses gave rise to increasing infectious titers during passages and were genetically stable by genomic sequencing. The chimeric PCV1-NLS2 and PCV2-NLS1 viruses had the final titers of about 10^4.2and 10^3.8TCID₅₀/ml, which were significantly lower than that of PCV1 and PCV2 (10^5.6and 10^5.0TCID₅₀/ml, respectively). When the ORF2 NLS exchanged, the mutant PCV2 (PCV2-NLS1) still replicated less efficiently and showed lower infectious titer than did PCV1 mutant (PCV1-NLS2), which was consistent with the distinction between wild type PCV1 and PCV2.</p> <p>Conclusions</p> <p>Recovery of the chimeiric PCV1-NLS2 and PCV2-NLS1 progeny viruses indicate that the nuclear localization signal sequence of capsid protein are functionally exchangeable between PCV1 and PCV2 with respect to the role of nuclear importing and propagation. The findings also reveal that ORF2 NLS play an accessory role in the replication of PCV. However, we found that ORF2 NLS was not responsible for the distinction of in vitro growth characteristic between PCV1 and PCV2. Further studies are required to determine the in vivo viral replication and pathogenicity of the NLS chimeric DNA clones.</p

Antigenic analysis of classical swine fever virus E2 glycoprotein using pig antibodies identifies residues contributing to antigenic variation of the vaccine C-strain and group 2 strains circulating in China

BACKGROUND: Glycoprotein E2, the immunodominant protein of classical swine fever virus (CSFV), can induce neutralizing antibodies and confer protective immunity in pigs. Our previous phylogenetic analysis showed that subgroup 2.1 viruses branched away from subgroup 1.1, the vaccine C-strain lineage, and became dominant in China. The E2 glycoproteins of CSFV C-strain and recent subgroup 2.1 field isolates are genetically different. However, it has not been clearly demonstrated how this diversity affects antigenicity of the protein. RESULTS: Antigenic variation of glycoprotein E2 was observed not only between CSFV vaccine C-strain and subgroup 2.1 strains, but also among strains of the same subgroup 2.1 as determined by ELISA-based binding assay using pig antisera to the C-strain and a representative subgroup 2.1 strain QZ-07 currently circulating in China. Antigenic incompatibility of E2 proteins markedly reduced neutralization efficiency against heterologous strains. Single amino acid substitutions of D705N, L709P, G713E, N723S, and S779A on C-strain recombinant E2 (rE2) proteins significantly increased heterologous binding to anti-QZ-07 serum, suggesting that these residues may be responsible for the antigenic variation between the C-strain and subgroup 2.1 strains. Notably, a G713E substitution caused the most dramatic enhancement of binding of the variant C-strain rE2 protein to anti-QZ-07 serum. Multiple sequence alignment revealed that the glutamic acid residue at this position is conserved within group 2 strains, while the glycine residue is invariant among the vaccine strains, highlighting the role of the residue at this position as a major determinant of antigenic variation of E2. A variant Simpson's index analysis showed that both codons and amino acids of the residues contributing to antigenic variation have undergone similar diversification. CONCLUSIONS: These results demonstrate that CSFV vaccine C-strain and group 2 strains circulating in China differ in the antigenicity of their E2 glycoproteins. Systematic site-directed mutagenesis of the antigenic units has revealed residues that limit cross-reactivity. Our findings may be useful for the development of serological differential assays and improvement of immunogenicity of novel classical swine fever vaccines

Internalin profiling and multilocus sequence typing suggest four Listeria innocua subgroups with different evolutionary distances from Listeria monocytogenes

<p>Abstract</p> <p>Background</p> <p>Ecological, biochemical and genetic resemblance as well as clear differences of virulence between <it>L. monocytogenes </it>and <it>L. innocua </it>make this bacterial clade attractive as a model to examine evolution of pathogenicity. This study was attempted to examine the population structure of <it>L. innocua </it>and the microevolution in the <it>L. innocua</it>-<it>L. monocytogenes </it>clade via profiling of 37 internalin genes and multilocus sequence typing based on the sequences of 9 unlinked genes <it>gyrB</it>, <it>sigB</it>, <it>dapE</it>, <it>hisJ</it>, <it>ribC</it>, <it>purM</it>, <it>gap</it>, <it>tuf </it>and <it>betL</it>.</p> <p>Results</p> <p><it>L. innocua </it>was genetically monophyletic compared to <it>L. monocytogenes</it>, and comprised four subgroups. Subgroups A and B correlated with internalin types 1 and 3 (except the strain 0063 belonging to subgroup C) and internalin types 2 and 4 respectively. The majority of <it>L. innocua </it>strains belonged to these two subgroups. Subgroup A harbored a whole set of <it>L. monocytogenes</it>-<it>L. innocua </it>common and <it>L. innocua</it>-specific internalin genes, and displayed higher recombination rates than those of subgroup B, including the relative frequency of occurrence of recombination versus mutation (ρ/θ) and the relative effect of recombination versus point mutation (r/m). Subgroup A also exhibited a significantly smaller exterior/interior branch length ratio than expected under the coalescent model, suggesting a recent expansion of its population size. The phylogram based on the analysis with correction for recombination revealed that the time to the most recent common ancestor (TMRCA) of <it>L. innocua </it>subgroups A and B were similar. Additionally, subgroup D, which correlated with internalin type 5, branched off from the other three subgroups. All <it>L. innocua </it>strains lacked seventeen virulence genes found in <it>L. monocytogenes </it>(except for the subgroup D strain L43 harboring <it>inlJ </it>and two subgroup B strains bearing <it>bsh</it>) and were nonpathogenic to mice.</p> <p>Conclusions</p> <p><it>L. innocua </it>represents a young species descending from <it>L. monocytogenes </it>and comprises four subgroups: two major subgroups A and B, and one atypical subgroup D serving as a link between <it>L. monocytogenes </it>and <it>L. innocua </it>in the evolutionary chain. Although subgroups A and B appeared at approximately the same time, subgroup A seems to have experienced a recent expansion of the population size with higher recombination frequency and effect than those of subgroup B, and might represent the possible evolutionary direction towards adaptation to enviroments. The evolutionary history in the <it>L. monocytogenes</it>-<it>L. innocua </it>clade represents a rare example of evolution towards reduced virulence of pathogens.</p

B cells Using Calcium Signaling for Specific and Rapid Detection of Escherichia coli O-157:H-7

A rapid and sensitive detection technology is highly desirable for specific detection of E. coli O-157:H-7, one of the leading bacterial pathogens causing foodborne illness. In this study, we reported the rapid detection of E. coli O-157: H-7 by using calcium signaling of the B cell upon cellular membrane anchors anti-E. coli O-157: H-7 IgM. The binding of E. coli O-157:H-7 to the IgM on B cell surface activates the B cell receptor (BCR)-induced Ca2+ signaling pathway and results in the release of Ca2+ within seconds. The elevated intracellular Ca2+ triggers Fura-2, a fluorescent Ca2+ indicator, for reporting the presence of pathogens. The Fura-2 is transferred to B cells before detection. The study demonstrated that the developed B cell based biosensor was able to specifically detect E. coli O-157:H-7 at the low concentration within 10 min in pure culture samples. Finally, the B cell based biosensor was used for the detection of E. coli O-157:H-7 in ground beef samples. With its short detection time and high sensitivity at the low concentration of the target bacteria, this B cell biosensor shows promise in future application of the high throughput and rapid food detection, biosafety and environmental monitoring

BolA-like protein (IbaG) promotes biofilm formation and pathogenicity of Vibrio parahaemolyticus

Vibrio parahaemolyticus is a gram-negative halophilic bacterium widespread in temperate and tropical coastal waters; it is considered to be the most frequent cause of Vibrio-associated gastroenteritis in many countries. BolA-like proteins, which reportedly affect various growth and metabolic processes including flagellar synthesis in bacteria, are widely conserved from prokaryotes to eukaryotes. However, the effects exerted by BolA-like proteins on V. parahaemolyticus remain unclear, and thus require further investigation. In this study, our purpose was to investigate the role played by BolA-like protein (IbaG) in the pathogenicity of V. parahaemolyticus. We used homologous recombination to obtain the deletion strain ΔibaG and investigated the biological role of BolA family protein IbaG in V. parahaemolyticus. Our results showed that IbaG is a bacterial transcription factor that negatively modulates swimming capacity. Furthermore, overexpressing IbaG enhanced the capabilities of V. parahaemolyticus for swarming and biofilm formation. In addition, inactivation of ibaG in V. parahaemolyticus SH112 impaired its capacity for colonizing the heart, liver, spleen, and kidneys, and reduced visceral tissue damage, thereby leading to diminished virulence, compared with the wild-type strain. Finally, RNA-sequencing revealed 53 upregulated and 71 downregulated genes in the deletion strain ΔibaG. KEGG enrichment analysis showed that the two-component system, quorum sensing, bacterial secretion system, and numerous amino acid metabolism pathways had been altered due to the inactivation of ibaG. The results of this study indicated that IbaG exerts a considerable effect on gene regulation, motility, biofilm formation, and pathogenicity of V. parahaemolyticus. To the best of our knowledge, this is the first systematic study on the role played by IbaG in V. parahaemolyticus infections. Thus, our findings may lead to a better understanding of the metabolic processes involved in bacterial infections and provide a basis for the prevention and control of such infections