Carbapenemase-producing Enterobacteriaceae(CPE) isolates are recognized as one of the most severe threats to public health. However, the population structure and genetic characteristics of CPE isolates among bloodstre...Carbapenemase-producing Enterobacteriaceae(CPE) isolates are recognized as one of the most severe threats to public health. However, the population structure and genetic characteristics of CPE isolates among bloodstream infections(BSIs) are largely unknown. To address this knowledge gap, in this study,we included patients with clinically significant BSIs due to Enterobacterales isolates, recruited from 26 sentinel hospitals in China(2014–2015). CPE isolates were microbiologically and genomically characterized,including their susceptibility profiles, molecular typing, phylogenetic features, and genetic context analysis of carbapenemase-encoding genes. Of the 2569 BSI Enterobacterales isolates enrolled, 42(1.6%) were carbapenemase-positive. Moreover, among the 2242 investigated isolates, 1111(49.6%) extendedspectrum β-lactamase(ESBL)-producing isolates were identified in Escherichia coli(E. coli), Klebsiella pneumoniae(K. pneumoniae), Proteus mirabilis(P. mirabilis), and Klebsiella oxytoca. Whole genome sequencing analysis showed the clonal spread of K. pneumoniae carbapenemase(KPC)-2-producing K. pneumoniae sequence type(ST) 11 and New Delhi metallo-β-lactamase(NDM)-5-producing E. coli ST167 in our collection. Plasmid analysis revealed that carbapenemase-encoding genes were located on multiple plasmids. A high prevalence of biofilm-encoding type 3 fimbriae clusters and yesiniabactin-associated genes was observed in K. pneumoniae isolates. This work demonstrates the high prevalence of ESBLs and the wide dissemination of CPE among BSI isolates in China, which represent real clinical threats. Moreover, our findings first illustrate a more comprehensive genome scenario of CPE isolates among BSIs. The clonal spread of KPC-2-producing K. pneumoniae ST11 and NDM-5-producing E. coli ST167 needs to be closely monitored.展开更多
<strong>Background:</strong> Enterobacteriaceae causes many types of infections which are often treated with quinolones and fluoroquinolone (Q/FQ). The resistance mechanisms to Q/FQ are usually associated ...<strong>Background:</strong> Enterobacteriaceae causes many types of infections which are often treated with quinolones and fluoroquinolone (Q/FQ). The resistance mechanisms to Q/FQ are usually associated with mutations in the quinolone resistance determining region which alter the conformation of target amino acid residues within the protein and in the <em>qnr</em> genes. This study aimed at determining the antimicrobial resistant profile of a sample of Enterobacteriaceae from Cameroon and the genetic diversity in quinolone-resistant isolates in view of implementing a better management, treatment, control and prevention of the transmission of these resistant strains. <strong>Methods:</strong> Identification and antimicrobial susceptibility testing was done using VITEK 2. The detection of plamid-mediated quinolone resistance (PMQR) genes was carried out using the conventional PCR method. Sequencing was done using the Applied Biosystem 3500 genetic analyser. DNA fingerprint was obtained using Pulsed-Field Gel electrophoresis. <strong>Results:</strong> Among 440 Enterobacteriaceae, the most prevalent genera were: <em>Escherichia</em> 178/440 (39.5%);<em>Klebsiella</em> 148/440 (33.6%);<em>Enterobacter </em>35/440 (8%);<em>Pantoea</em> 28/440 (6.4%);<em>Proteus</em> 14/440 (3.2%) <em>Salmonella </em>13/440 (3%). Ampicillin resistance showed the highest prevalence with 371/440 (81%) and Imipenem the lowest resistance 9/440 (2.1%). The ciprofloxacin resistance rate was 161/440 (36.6%). The detected plasmid mediated quinolone resistance (PMQR) genes were: <em>qnrA</em>, 2/161 (1.2%);<em>qnrB</em>, 31/161 (19.3%);<em>qnrS</em>, 13/161 (8.1%): <em>Aac</em> (6')<em>Ib-cr</em>, 84/161 (52.2%) and <em>qepA</em>, 3/161 (1.9%). There were several mutations in the <em>parC</em> gene of <em>Klebsiella</em> leading to S80D and S80N substitutions. Two pairs of <em>Klebsiella</em> <em>peumoniae</em> strains were phenotypically and genotypically identical with 100% similarity in the dendrogramme. <strong>Conclusion:</strong> This study showed that quinolone resistance was high. The PMQR genes contributing to this resistance were diverse. This high PMQR indicates that there has been an unknown circulation of these genes in our community. To avoid the rapid dissemination of these PMQR genes continuous surveillance of antimicrobial resistance should be carried out not only in humans but also in animals to monitor the evolution of these genes.展开更多
Fluoroquinolones are critical antibiotics for treating bacterial infections,especially those caused by Escherichia coli in human or veteri-nary medicine.However,increasing resistance to these antibiotics has become a ...Fluoroquinolones are critical antibiotics for treating bacterial infections,especially those caused by Escherichia coli in human or veteri-nary medicine.However,increasing resistance to these antibiotics has become a serious public health issue,impacting clinical out-comes and treatment efficacy.Understanding the mechanisms driving fluoroquinolone resistance in E.coli and the environmental fac-tors influencing the spread of resistance is essential for developing effective strategies to combat this issue.Fluoroquinolone resistance in E.coli is driven primarily by target site mutations,the activation of efflux pumps,reduced cell permeability and the acquisition of plasmid-mediated resistance genes.These mechanisms collectively increase the ability of E.coli to survive antibiotic exposure.More-over,environmental stressors such as heavy metals play a significant role in sustaining and disseminating resistance genes.The pres-ence of plasmid-borne resistance elements further facilitates horizontal gene transfer between bacterial populations,complicating infec-tion control efforts.Given the complexity and multifactorial nature of fluoroquinolone resistance,an integrated approach is urgently needed.This includes reinforcing antibiotic use stewardship,implementing stricter environmental controls and enhancing surveillance across clinical and environmental settings.Coordinated efforts in these areas are critical to preserving the effectiveness of fluoroquinolones and safeguarding public health.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the financial support of the National Key Research and Development Program of China (2017YFC1200203 and 2016YFD0501105)the Mega-projects of Science Research of China (2018ZX10733402-004 and 2018ZX10712001-005)+2 种基金the National Natural Science Foundation of China (81741098 and 81711530049)the Zhejiang Provincial Key Research and Development Program (2015C03032)the Zhejiang Provincial Natural Science Foundation of China (LY17H190003)
文摘Carbapenemase-producing Enterobacteriaceae(CPE) isolates are recognized as one of the most severe threats to public health. However, the population structure and genetic characteristics of CPE isolates among bloodstream infections(BSIs) are largely unknown. To address this knowledge gap, in this study,we included patients with clinically significant BSIs due to Enterobacterales isolates, recruited from 26 sentinel hospitals in China(2014–2015). CPE isolates were microbiologically and genomically characterized,including their susceptibility profiles, molecular typing, phylogenetic features, and genetic context analysis of carbapenemase-encoding genes. Of the 2569 BSI Enterobacterales isolates enrolled, 42(1.6%) were carbapenemase-positive. Moreover, among the 2242 investigated isolates, 1111(49.6%) extendedspectrum β-lactamase(ESBL)-producing isolates were identified in Escherichia coli(E. coli), Klebsiella pneumoniae(K. pneumoniae), Proteus mirabilis(P. mirabilis), and Klebsiella oxytoca. Whole genome sequencing analysis showed the clonal spread of K. pneumoniae carbapenemase(KPC)-2-producing K. pneumoniae sequence type(ST) 11 and New Delhi metallo-β-lactamase(NDM)-5-producing E. coli ST167 in our collection. Plasmid analysis revealed that carbapenemase-encoding genes were located on multiple plasmids. A high prevalence of biofilm-encoding type 3 fimbriae clusters and yesiniabactin-associated genes was observed in K. pneumoniae isolates. This work demonstrates the high prevalence of ESBLs and the wide dissemination of CPE among BSI isolates in China, which represent real clinical threats. Moreover, our findings first illustrate a more comprehensive genome scenario of CPE isolates among BSIs. The clonal spread of KPC-2-producing K. pneumoniae ST11 and NDM-5-producing E. coli ST167 needs to be closely monitored.
文摘<strong>Background:</strong> Enterobacteriaceae causes many types of infections which are often treated with quinolones and fluoroquinolone (Q/FQ). The resistance mechanisms to Q/FQ are usually associated with mutations in the quinolone resistance determining region which alter the conformation of target amino acid residues within the protein and in the <em>qnr</em> genes. This study aimed at determining the antimicrobial resistant profile of a sample of Enterobacteriaceae from Cameroon and the genetic diversity in quinolone-resistant isolates in view of implementing a better management, treatment, control and prevention of the transmission of these resistant strains. <strong>Methods:</strong> Identification and antimicrobial susceptibility testing was done using VITEK 2. The detection of plamid-mediated quinolone resistance (PMQR) genes was carried out using the conventional PCR method. Sequencing was done using the Applied Biosystem 3500 genetic analyser. DNA fingerprint was obtained using Pulsed-Field Gel electrophoresis. <strong>Results:</strong> Among 440 Enterobacteriaceae, the most prevalent genera were: <em>Escherichia</em> 178/440 (39.5%);<em>Klebsiella</em> 148/440 (33.6%);<em>Enterobacter </em>35/440 (8%);<em>Pantoea</em> 28/440 (6.4%);<em>Proteus</em> 14/440 (3.2%) <em>Salmonella </em>13/440 (3%). Ampicillin resistance showed the highest prevalence with 371/440 (81%) and Imipenem the lowest resistance 9/440 (2.1%). The ciprofloxacin resistance rate was 161/440 (36.6%). The detected plasmid mediated quinolone resistance (PMQR) genes were: <em>qnrA</em>, 2/161 (1.2%);<em>qnrB</em>, 31/161 (19.3%);<em>qnrS</em>, 13/161 (8.1%): <em>Aac</em> (6')<em>Ib-cr</em>, 84/161 (52.2%) and <em>qepA</em>, 3/161 (1.9%). There were several mutations in the <em>parC</em> gene of <em>Klebsiella</em> leading to S80D and S80N substitutions. Two pairs of <em>Klebsiella</em> <em>peumoniae</em> strains were phenotypically and genotypically identical with 100% similarity in the dendrogramme. <strong>Conclusion:</strong> This study showed that quinolone resistance was high. The PMQR genes contributing to this resistance were diverse. This high PMQR indicates that there has been an unknown circulation of these genes in our community. To avoid the rapid dissemination of these PMQR genes continuous surveillance of antimicrobial resistance should be carried out not only in humans but also in animals to monitor the evolution of these genes.
基金supported by the Institution of Agricultural Research and Higher Education(IRESA),Tunisia.
文摘Fluoroquinolones are critical antibiotics for treating bacterial infections,especially those caused by Escherichia coli in human or veteri-nary medicine.However,increasing resistance to these antibiotics has become a serious public health issue,impacting clinical out-comes and treatment efficacy.Understanding the mechanisms driving fluoroquinolone resistance in E.coli and the environmental fac-tors influencing the spread of resistance is essential for developing effective strategies to combat this issue.Fluoroquinolone resistance in E.coli is driven primarily by target site mutations,the activation of efflux pumps,reduced cell permeability and the acquisition of plasmid-mediated resistance genes.These mechanisms collectively increase the ability of E.coli to survive antibiotic exposure.More-over,environmental stressors such as heavy metals play a significant role in sustaining and disseminating resistance genes.The pres-ence of plasmid-borne resistance elements further facilitates horizontal gene transfer between bacterial populations,complicating infec-tion control efforts.Given the complexity and multifactorial nature of fluoroquinolone resistance,an integrated approach is urgently needed.This includes reinforcing antibiotic use stewardship,implementing stricter environmental controls and enhancing surveillance across clinical and environmental settings.Coordinated efforts in these areas are critical to preserving the effectiveness of fluoroquinolones and safeguarding public health.
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.
