Objective To trace the source of human H7N9 cases in Huai＇an and elucidate the genetic characterization of Huai＇an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillanc...Objective To trace the source of human H7N9 cases in Huai＇an and elucidate the genetic characterization of Huai＇an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai＇an.Clinical specimens,cloacal swabs,and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction（RT-PCR） for H7N9 virus.The positive samples were subjected to further RT-PCR and genome sequencing.The phylodynamic patterns of H7N9 virus within and separated from Huai＇an and evolutionary dynamics of the virus were analyzed.Results Six patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever（〉38.0 °C） and headaches.Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure.Phylogenetic analysis revealed that all novel H7N9 viruses,including Huai＇an strains,could be classified into two distinct clades,A and B.Additionally,the diversified H7N9 virus circulated in live poultry markets in Huai＇an.Interestingly,the common ancestors of the Huai＇an H7N9 virus existed in January 2012.The mean nucleotide substitution rates for each gene segment of the H7N9 virus were（3.09-7.26）×10-3 substitutions/site per year（95% HPD：1.72×10-3 to 1.16×10-2）.Conclusion Overall,the source of exposure of human H7N9 cases in Huai＇an was live poultry market,and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai＇an.展开更多
Salmonella Corvallis ST1541 has recently emerged as a globally disseminated pathogenic strain that often causes severe food-borne infections.Unlike most pandemic serotypes of Salmonella,the ST1541 strains harbored Col...Salmonella Corvallis ST1541 has recently emerged as a globally disseminated pathogenic strain that often causes severe food-borne infections.Unlike most pandemic serotypes of Salmonella,the ST1541 strains harbored ColRNA1 plasmids that contain qnr-like determinants known to be responsible for the increasing incidence of ciprofloxacin-resistant food-borne Salmonella infections.In this study,we conducted a genomic analysis of a global collection of 388 S.Corvallis ST1541 strains collected within a twenty-year period.We investigated the genetic characteristics of plasmid-mediated quinolone resistance(PMQR)plasmids harbored by these S.Corvallis strains,established a mini-mum spanning tree(MST)to determine the temporal and spatial distribution of the top 10 MST clusters,inferred a time-phylogenies for the major sub-lineages and traced the routes of international dissemination of this serotype strains.Bayesian algorithm predicted that UK might be the origin of S.Corvallis strains currently prevalent in various countries.This idea is supported by the observation of the emergence of intercontinental-disseminated clonal strains and extensive transmission of the extensive-drug resistance(XDR)-encoding plasmid pSA663.This study there-fore provides valuable insight into the evolution of globally transmitted S.Corvallis strains and suggests a need to strengthen cooperation between different countries to control the dissemination of these drug-resistant bacteria.展开更多
基金supported by grants HAYf201516 from Huai’an Preventive Medicine Associationgrant HAS2015019-3 from Huai’an Scientific Technological Special Project
文摘Objective To trace the source of human H7N9 cases in Huai＇an and elucidate the genetic characterization of Huai＇an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai＇an.Clinical specimens,cloacal swabs,and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction（RT-PCR） for H7N9 virus.The positive samples were subjected to further RT-PCR and genome sequencing.The phylodynamic patterns of H7N9 virus within and separated from Huai＇an and evolutionary dynamics of the virus were analyzed.Results Six patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever（〉38.0 °C） and headaches.Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure.Phylogenetic analysis revealed that all novel H7N9 viruses,including Huai＇an strains,could be classified into two distinct clades,A and B.Additionally,the diversified H7N9 virus circulated in live poultry markets in Huai＇an.Interestingly,the common ancestors of the Huai＇an H7N9 virus existed in January 2012.The mean nucleotide substitution rates for each gene segment of the H7N9 virus were（3.09-7.26）×10-3 substitutions/site per year（95% HPD：1.72×10-3 to 1.16×10-2）.Conclusion Overall,the source of exposure of human H7N9 cases in Huai＇an was live poultry market,and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai＇an.
基金supported by the Key Research and Development Program of Guangdong Province(Grant number,2022B1111040002)the Collaborative Research Fund from Research Grant Council of the Government of Hong Kong SAR(Grant numbers,C7147-20G,C7003-20G).
文摘Salmonella Corvallis ST1541 has recently emerged as a globally disseminated pathogenic strain that often causes severe food-borne infections.Unlike most pandemic serotypes of Salmonella,the ST1541 strains harbored ColRNA1 plasmids that contain qnr-like determinants known to be responsible for the increasing incidence of ciprofloxacin-resistant food-borne Salmonella infections.In this study,we conducted a genomic analysis of a global collection of 388 S.Corvallis ST1541 strains collected within a twenty-year period.We investigated the genetic characteristics of plasmid-mediated quinolone resistance(PMQR)plasmids harbored by these S.Corvallis strains,established a mini-mum spanning tree(MST)to determine the temporal and spatial distribution of the top 10 MST clusters,inferred a time-phylogenies for the major sub-lineages and traced the routes of international dissemination of this serotype strains.Bayesian algorithm predicted that UK might be the origin of S.Corvallis strains currently prevalent in various countries.This idea is supported by the observation of the emergence of intercontinental-disseminated clonal strains and extensive transmission of the extensive-drug resistance(XDR)-encoding plasmid pSA663.This study there-fore provides valuable insight into the evolution of globally transmitted S.Corvallis strains and suggests a need to strengthen cooperation between different countries to control the dissemination of these drug-resistant bacteria.
