Yan Jiang

Bio: Yan Jiang is an academic researcher from Zhejiang University. The author has contributed to research in topics: Klebsiella pneumoniae & Medicine. The author has an hindex of 21, co-authored 66 publications receiving 1804 citations. Previous affiliations of Yan Jiang include Sir Run Run Shaw Hospital.

Emergence of NDM-1-producing Acinetobacter baumannii in China

Abstract: Results: Four A. baumannii isolates with blaNDM-1 were identified in four different provinces in China: no positive isolates were detected among E. coli, K. pneumoniae and P. aeruginosa. These blaNDM-1-positive A. baumannii were resistant to all carbapenems and cephalosporins, and three remained susceptible to fluoroquinolones, aminoglycosides and colistin. The four NDM-1-producing A. baumannii were clonally diverse and carried blaNDM-1 on different plasmids. Plasmids carrying blaNDM-1 were successfully transferred from three of the four isolates to E. coli recipients, although the transconjugants and transformants were prone to lose the transferred plasmids after passage in the absence of ampicillin selection. Conclusions: We describe the emergence of A. baumannii producing NDM-1 in China. Systemic surveillance network should be established for monitoring these resistant bacteria.

Plasmid-mediated quinolone resistance determinants qnr and aac(6′)-Ib-cr in extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in China

Abstract: Results: Twenty-nine (8.0%) of 362 isolates were positive for qnr genes, and the qnrA-, qnrB- and qnrS-type genes were detected alone or in combination in 13 (3.6%), 8 (2.2%) and 9 (2.5%), respectively. Sixty-two (17.1%) isolates were positive for aac(6 0 )-Ib, of which 36 (9.9% of all) had the -cr variant. Conjugation and Southern hybridization revealed that qnrA, aac(6 0 )-Ib-cr and ESBL-encoding genes were always located on the same plasmids. Conclusions: qnr and aac(6 0 )-Ib-cr genes were detected in 8.0% and 9.9% of ESBL-producing E. coli and K. pneumoniae, respectively. The plasmids carrying the qnr gene could be transferred by conjugation together with ESBL-encoding genes and aac(6 0 )-Ib-cr.

Prevalence of mcr-1 in Escherichia coli and Klebsiella pneumoniae recovered from bloodstream infections in China: a multicentre longitudinal study

Abstract: Summary Background Polymyxin antibiotics are used as last-resort therapies to treat infections caused by multidrug-resistant Gram-negative bacteria. The plasmid-mediated colistin resistance determinant MCR-1 has been identified in Enterobacteriaceae in China. We did this study to investigate the prevalence of the mcr-1 gene in clinical isolates from patients with bloodstream infections in China. Methods Clinical isolates of Escherichia coli and Klebsiella pneumoniae were collected from patients with bloodstream infections at 28 hospitals in China, then screened for colistin resistance by broth microdilution and for the presence of the mcr-1 gene by PCR amplification. We subjected mcr -1-positive isolates to genotyping, susceptibility testing, and clinical data analysis. We established the genetic location of mcr-1 with Southern blot hybridisation, and we analysed plasmids containing mcr-1 with filter mating, electroporation, and DNA sequencing. Findings 2066 isolates, consisting of 1495 E coli isolates and 571 K pneumoniae isolates were collected. Of the 1495 E coli isolates, 20 (1%) were mcr-1 -positive, whereas we detected only one ( mcr -1-positive isolate among the 571 K pneumoniae isolates. All mcr -1-positive E coli and K pneumoniae isolates were resistant to colistin, with minimum inhibitory concentrations values in the range of 4–32 mg/L, except for one E coli isolate that had a minimum inhibitory concentration less than or equal to 0·06 mg/L. All 21 mcr -1-positive isolates were susceptible to tigecycline and 20 isolates (95%) were susceptible to the carbapenem and β-lactamase inhibitor combination piperacillin and tazobactam. One mcr -1-positive E coli isolate also produced NDM-5, which confers resistance to beta-lactam antibiotics. The 21 mcr -1-positive isolates were clonally diverse and carried mcr-1 on two types of plasmids, a 33 kb IncX4 plasmid and a 61 kb Inc12 plasmid. The 30 day mortality of the patients with bloodstream infections caused by mcr -1-positive isolates was zero. Interpretation mcr -1-positive isolates from bloodstream infections were rare, sporadic, and remained susceptible to many antimicrobial agents. E coli , rather than K pneumoniae , was the main host of the mcr-1 gene. Further studies are needed to clarify the clinical impact of this novel resistance gene. Funding National Natural Science Foundation of China.

Novel Genetic Environment of the Carbapenem-Hydrolyzing β-Lactamase KPC-2 among Enterobacteriaceae in China

Abstract: Thirty-nine blaKPC-producing isolates of the family Enterobacteriaceae with carbapenem resistance or reduced carbapenem susceptibility were obtained from inpatients from eight hospitals in six cities of three provinces in eastern China. The pulsed-field gel electrophoresis analysis of all 36 Klebsiella pneumoniae isolates revealed six major patterns. The resistant plasmids of most isolates were successfully transferred by conjugation and evaluated experimentally to be 40 to 180 kb in size. A 20.2-kb blaKPC-surrounding nucleotide sequence from plasmid pKP048 has been obtained and contains an integration structure of a Tn3-based transposon and partial Tn4401 segment, with the gene order Tn3-transposase, Tn3-resolvase, ISKpn8, the blaKPC-2 gene, and the ISKpn6-like element. The chimera of several transposon-associated elements indicated a novel genetic environment of the K. pneumoniae carbapenemase β-lactamase gene in isolates from China.

Complete Nucleotide Sequence of Klebsiella pneumoniae Multidrug Resistance Plasmid pKP048, Carrying blaKPC-2, blaDHA-1, qnrB4, and armA

Abstract: The Klebsiella pneumoniae multidrug resistance plasmid pKP048 was completely sequenced. This plasmid carries several important resistance determinants, such as bla(KPC-2), bla(DHA-1), qnrB4, and armA, which confer resistance to carbapenems, cephalosporins, fluoroquinolones, and aminoglycosides, respectively. Analysis of the finished 151,188-bp sequence data revealed 163 putative genes, 108 of which were assigned functions such as replication, stable inheritance, antibiotic resistance, a mobile element, conjugal transfer, and a restriction-modification system, showing the strong phylogenetic mosaicism and plasticity of the plasmid.

Department of health & human services

Abstract: Vision for Transformation Strengths: The SHSIP describes a holistic transformation plan and ensures connections between various plan components. The State’s Plan seeks to reward health care providers for better care, smarter spending, and healthier people through higher quality, instead of quantity of services by utilizing valuebased purchasing across public and private payers. The SHSIP provides a well-detailed description of the proposed value-based models of care through the Patient-Centered Medical Home (PCMH) model, resulting in the statewide implementation of Accountable Health Communities (AHCs). The SHSIP outlines a long-term vision of building and expanding the PCMH model into a Community Centered Health Homes (CCHHs) model, which will focus on prevention and collaboration with other communitybased organizations. Another strength identified is the amount of existing PCMHs operating within the State. The SHSIP provides a course of action to assist non-PCMH practices to become nationally certified, as well as, goals for a single, statewide PCMH model to be used by all providers and payers within the state. The implementation of the AHCs will be key in addressing social determinants of health within various communities and seems to align well with the PCMH goals. This focus on population and community health will enable the State to make a broader impact and support the long-term goal of moving towards a CCHH model. The focus on the improvement of clinical, behavioral, and oral health care within the urban, rural, and frontier communities is well aligned and consistent with the SIM goals and the overall Triple Aim initiative. Figure 18: Driver Diagram clearly shows how the State plans to achieve the Triple Aim by 2020.

Clinical epidemiology of the global expansion of Klebsiella pneumoniae carbapenemases

Abstract: Klebsiella pneumoniae carbapenemases (KPCs) were originally identified in the USA in 1996. Since then, these versatile β-lactamases have spread internationally among Gram-negative bacteria, especially K pneumoniae, although their precise epidemiology is diverse across countries and regions. The mortality described among patients infected with organisms positive for KPC is high, perhaps as a result of the limited antibiotic options remaining (often colistin, tigecycline, or aminoglycosides). Triple drug combinations using colistin, tigecycline, and imipenem have recently been associated with improved survival among patients with bacteraemia. In this Review, we summarise the epidemiology of KPCs across continents, and discuss issues around detection, present antibiotic options and those in development, treatment outcome and mortality, and infection control. In view of the limitations of present treatments and the paucity of new drugs in the pipeline, infection control must be our primary defence for now.

The Challenge of Efflux-Mediated Antibiotic Resistance in Gram-Negative Bacteria

Abstract: The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.

The role of the natural environment in the emergence of antibiotic resistance in Gram-negative bacteria

Abstract: During the past 10 years, multidrug-resistant Gram-negative Enterobacteriaceae have become a substantial challenge to infection control. It has been suggested by clinicians that the effectiveness of antibiotics is in such rapid decline that, depending on the pathogen concerned, their future utility can be measured in decades or even years. Unless the rise in antibiotic resistance can be reversed, we can expect to see a substantial rise in incurable infection and fatality in both developed and developing regions. Antibiotic resistance develops through complex interactions, with resistance arising by de-novo mutation under clinical antibiotic selection or frequently by acquisition of mobile genes that have evolved over time in bacteria in the environment. The reservoir of resistance genes in the environment is due to a mix of naturally occurring resistance and those present in animal and human waste and the selective effects of pollutants, which can co-select for mobile genetic elements carrying multiple resistant genes. Less attention has been given to how anthropogenic activity might be causing evolution of antibiotic resistance in the environment. Although the economics of the pharmaceutical industry continue to restrict investment in novel biomedical responses, action must be taken to avoid the conjunction of factors that promote evolution and spread of antibiotic resistance.