Hypervirulent Klebsiella pneumoniae (hvKP) typically causes severe invasive infections affecting multiple sites in healthy individuals. In the past, hvKP was characterized by a hypermucoviscosity phenotype, susceptibility to antimicrobial agents, and its tendency to cause invasive infections in healthy individuals within the community. However, there has been an alarming increase in reports of multidrug-resistant hvKP, particularly carbapenem-resistant strains, causing nosocomial infections in critically ill or immunocompromised patients. This presents a significant challenge for clinical treatment. Early identification of hvKP is crucial for timely infection control. Notably, identifying hvKP has become confusing due to its prevalence in nosocomial settings and the limited predictive specificity of the hypermucoviscosity phenotype. Novel virulence predictors for hvKP have been discovered through animal models or machine learning algorithms, while standardization of identification criteria is still necessary. Timely source control and antibiotic therapy have been widely employed for the treatment of hvKP infections. Additionally, phage therapy is a promising alternative approach due to escalating antibiotic resistance. In summary, this narrative review highlights the latest research progress in the development, virulence factors, identification, epidemiology of hvKP, and treatment options available for hvKP infection.

Objectives Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major nosocomial infectious pathogen with rapidly increasing prevalence. The genomic epidemiological characteristics of CRKP nationwide, especially the evolving trends within the predominant clones, should be evaluated clearly.Methods We collected 3415 K. pneumoniae strains from 28 hospitals across China. Antimicrobial susceptibility testing and WGS were performed. Subsequent genomic analyses, including sequence typing, K-locus (KL) identification, antimicrobial resistance gene screening, and virulence score assessment were performed. The phylogenetic relationship of clonal group 11 was determined based on core-genome analysis, and the presence of the pLVPK-like virulence plasmid in ST11 isolates was confirmed using plasmid core-gene analysis. Additionally, the trends of the ST11 lineage with different KL types on a global scale were investigated using Beast2.Results Of the K. pneumoniae strains, 708 were identified as CRKP isolates (20.7%), of which 97.7% were MDR. ST11 was the predominant clone, and KPC-2 was the prevalent carbapenemase in China, although the prevalence of specific clones and carbapenemases varied by geographic region. Among ST11 isolates, KL47 and KL64 were the predominant KL types, and KL64 gradually replaced KL47, with a higher percentage of KL64 isolates harbouring the pLVPK-like plasmid. Global genome data showed a significant increase in the effective population size of KL64 over the last 5 years.Conclusions The prevalence of CRKP was very high in certain regions in China. The increasing convergence of virulence and resistance, particularly in ST11-KL64 isolates, should be given more attention and further investigation.

Siderophore is a group of low molecular weight compounds with high affinity for ferric iron, which could facilitate bacterial iron consumption. Similarly, hemin/heme scavenged by the hemin uptake system HmuRSTUV usually act as another critical iron source for K. pneumoniae .

针对当前我国受到贸易战影响导致芯片断供,而国内嵌入式系统等课程以国外处理器为核心的教学现状,提出"国产化处理器进入高校课堂,加强实践能力,培养爱国情怀"的教学思想,以国产化昇腾处理器为核心,探讨如何建立以国产处理器案例教学为主的教学内容体系和实验教学方法,通过展示学生在嵌入式系统课程中的实验作品,说明该教学模式在实际教学有较好的效果,值得进一步推广.

前视声呐(Forward-Looking Sonar,FLS)使用换能器基阵收发声波,通过回波探测水下物体.在浅海环境,由于水下介质的反射、散射与不均匀波动,前视声呐图像极易引入散斑噪声.本文针对前视声呐图像散斑噪声,结合SRResNet与非对称金字塔非局部块,提出了ANLResNet网络用于前视声呐图像去噪,并针对前视声呐图像特性,使用FieldII构建模拟前视声呐图像数据集,对网络进行训练.实验结果表明,本文提出的ANLResNet网络能有效的去除前视声呐图像中的散斑噪声,获得良好的视觉效果.并通过峰值信噪比(Peak Signal to Noise Ratio,PSNR)、等效视数(Equivalent Number of Looks,ENL)、散斑抑制指数(Speckle Suppression Index,SSI)3个图像质量评价指标评价降噪效果.在模拟前视声呐图像去噪上,本文算法相比于传统算法、改进BM3D算法和Autoencoder网络,平均PSNR至少提高了8.12％.在真实前视声呐图像去噪上,本文算法相比于传统算法、改进BM3D算法和SRResNet等效视数至少提高了16.77％,散斑抑制指数至少降低了2.84％.相比于Autoencoder网络等效视数提高了4.30％.本文方法主要用于前视声呐图像去噪,对于其他声学图像的降噪,散斑噪声的抑制上也有一定的应用价值.

针对前视声呐线阵波束形成各向同性较差及半圆阵有效孔径受限的问题,提出了一种优化的圆弧接收阵列结构设计方法.根据不同的成像开角,设计圆弧接收阵圆心角使全部阵元参与所有来波方向的波束形成.建立圆弧接收阵的远近场聚焦模型,并推导圆弧接收阵的指向性函数,根据边界波束栅瓣阈值条件计算具有最佳波束性能的圆弧接收阵半径.对圆弧阵、线阵及半圆阵在不同扇区开角下的波束性能及扫查开角120°、纵深100 m的仿真图像对比表明,在成像开角为90°到130°时,圆弧接收阵主瓣性能提升了8％,边界波束栅瓣级优化了4％,交叉向分辨深度相对线阵与半圆阵分别增加了20 m和45 m,同时参数存储量仅为线阵的2.7％.该阵列兼具有效孔径大、波束各向同性的优点,能有效提高前视声呐系统探测性能,并降低算法实现难度.

脊柱念珠菌感染在临床上较少见，由于其临床表现、实验室检查、影像学检查表现缺乏特异性，诊断较困难，尽早进行活检获取组织进行培养是诊断的金标准。脊柱念珠菌感染的抗真菌疗程较长，部分患者需联合手术治疗。本文回顾性分析2019年1月至2021年8月浙江大学医学院附属邵逸夫医院确诊的4例脊柱念珠菌感染患者的病例资料，并结合文献进行讨论分析。

Objective:To investigate the resistance and transmission mechanism of carbapenem-resistant Enterobacterales (CRE), so as to provide the scientific evidence for the treatment and prevention of CRE infection.Methods:Seventy-six isolates of CRE isolated from Shaoxing Second Hospital between May 2016 and August 2018 were included. The isolates were re-identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The minimum inhibitory concentrations (MICs) of colistin, tigecycline, ceftazidime-avibactam, fosfomycin and other antibacterial drugs were determined using broth microdilution or agar dilution methods. PCR and sequencing analysis were performed to detect carbapenemase encoding genes ( blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48). Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to analyze homology of strains. S1-PFGE combined with Southern blot hybridization were used to locate the carbapenamase genes. Filter mating test were performed to determine the horizontal transfer ability of plasmids harboring carbapenamase genes. Results:Among the 76 isolates of CRE, 51 isolates were Klebsiella pneumoniae; 10 isolates were Escherichia coli; 15 isolates were other Enterobacterales. The 76 CREs were mainly isolated from urine, sputum and blood samples. The distribution rate of ICU was the highest (55.26%). The 76 CREs showed low resistance rates (0%, 1.33%, 18.42%) to colistin, tigecycline and ceftazidime-avibactam. The resistance rates to amikacin and fosfomycin were <45%, and the resistance rates to other drugs were >97%. The detection rate of KPC-2 carbapenemase was the highest (85.33%). The ST11 CRKP producing KPC-2 carbapenemase accounted for the highest proportion (62.75%), mainly distributed in the ICU (62.50%). Southern blot hybridization showed that blaKPC-2 was mainly located on a plasmid about 90 kb (39/63). Filter mating test showed that blaKPC, blaNDM and blaIMP could be transferred horizontally to recipient bacteria through plasmids. Conclusions:The 76 CRE isolates were only susceptible to a few antibacterial drugs, such as colistin, tigecycline and ceftazidime-avibactam. The production of KPC-2 carbapenemase was the main reason for the resistance of Enterobacterales to carbapenems. KPC-2 carbapenemase-producing ST11 Klebsiella pneumoniae was the main epidemic clone of carbapenem-resistant Klebsiella pneumoniae (CRKP). The 90 kb size plasmid was the main plasmid encoding blaKPC-2 gene. Carbapenemase genes can be transferred horizontally through plasmids. The hospital should strengthen prevention of nosocomial infections to control the clonal prevalence of CRE.

Klebsiella pneumoniae strains carrying OXA-48-like carbapenemases are increasingly prevalent across the globe. There is thus an urgent need to better understand the mechanisms that underpin the dissemination of bla OXA-48-like carbapenemases. To this end, four ertapenem-resistant K. pneumoniae isolates producing OXA-48-like carbapenemases were isolated from two patients. Genome sequencing revealed that one sequence type (ST) 17 isolate carried bla OXA-181, whilst three isolates from a single patient, two ST76 and one ST15, carried bla OXA-232. The 50514 bp bla OXA-181-harbouring plasmid, pOXA-181_YML0508, was X3-type with a conjugation frequency to Escherichia coli of 1.94×10−4 transconjugants per donor. The bla OXA-232 gene was located on a 6141 bp ColKP3-type plasmid, pOXA-232_WSD, that was identical in the ST76 and ST15 K. pneumoniae isolates. This plasmid could be transferred from K. pneumoniae to E. coli at low frequency, 8.13×10−6 transconjugants per donor. Comparative analysis revealed that the X3 plasmid acquired the bla OXA-48-like gene via IS3000-mediated co-integration of the ColKP3-type plasmid. Our study highlights how plasmid integration and rearrangements can contribute to the spread of bla OXA-48-like genes, which provides important clues for clinical prevention of the dissemination of K. pneumoniae strains carrying bla OXA-48-like carbapenemases.

Rapid and accurate pathogen identification is necessary for appropriate treatment of pneumonia. Here, we describe the use of shotgunmetagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage for pathogen identification in pneumonia in a large-scale multicenter prospective study with 159 patients enrolled. The results of mNGS were compared with standard methods including culture, staining, and targeted PCR, and the clinical impact of mNGS was evaluated. A positive impact was defined by a definitive diagnosismade using the mNGS results, or change ofmanagement because of themNGS results, leading to a favorable clinical outcome. Overall, mNGS identified more organisms than standard methods (117 versus 72), detected 17 pathogens that consistently were missed in all cases by standard methods, and had an overall positive clinical impact in 40.3% (64 of 159) of cases. mNGS was especially useful in identification of fastidious and atypical organisms causing pneumonia, contributing to detection of definitive pathogens in 45 (28.3%) cases in which standard results were either negative or insufficient. mNGS also helped reassure antibiotic de-escalation in 19 (11.9%) cases. Overall, mNGS led to a change of treatment in 59 (37.1%) cases, including antibiotic de-escalation in 40 (25.2%) cases. This study showed the significant value of mNGS of bronchoalveolar lavage for improving the diagnosis of pneumonia and contributing to better patient care.

We read the recent published review by Han and colleagues in this journal with great interest, which described the epidemiology, clinical features and treatment of Corona Virus Disease 2019 (COVID-19) and mentioned that people who were asymptomatic or in incubation period can be the sources of infection.1Han Q. Lin Q. Jin S. You L. Coronavirus 2019-nCoV: A brief perspective from the front line.J Infect. 2020; https://doi.org/10.1016/j.jinf.2020.02.010Abstract Full Text Full Text PDF Scopus (201) Google Scholar An ongoing epidemic caused by a new coronavirus, which was formally named as SARS-Cov-2 by Coronavirus research group (CSG) of the International Committee, started in late 2019 in Wuhan, Hubei province, China and had become a worldwide public health concern.2Zhu N. Zhang D. Wang W. Li X. Yang B. Song J. et al.A Novel Coronavirus from Patients with Pneumonia in China, 2019.Engl J Med. 2020; https://doi.org/10.1056/NEJMoa2001017Crossref Scopus (18375) Google Scholar A total of 81300 cases were confirmed in China so far (March 20, 2020) and increasingly more cases were confirmed abroad, especially in Europe. On Jan 30, 2020, the WHO Emergency Committee declared the outbreak as a global health emergency. Furthermore, it still remains unclear about the origin, transmission mode and incubation period of the SARS-Cov-2. Previous research has demonstrated the person-to-person transmission of the novel Coronavirus.3Chan J.F.-W. Yuan S. Kok K.-H. To K.K.-W. Chu H. Yang J. et al.A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster.Lancet. 2020; 395: 514-523https://doi.org/10.1016/S0140-6736(20)30154-9Abstract Full Text Full Text PDF PubMed Scopus (6150) Google Scholar Here, we report the clinical features of a cluster of seven patients suffered from pneumonia associated with the SARS-Cov-2 in Lishui City of Zhejiang Province, China. Epidemiological, demographic, clinical, laboratory, radiological and treatment data were collected through detailed interviews with each patient and electronic medical records. Laboratory confirmation of the virus was performed using RT-PCR by Lishui Center for Disease Control and Prevention (CDC). Case definitions of confirmed COVID-19 are in accordance with the interim guidance from a rapid advice guideline.4Jin Y.H. Cai L. Cheng Z.S. Cheng H. Deng T. Fan Y.P. et al.A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-nCoV) infected pneumonia (standard version).Mil Med Res. 2020; 7: 4https://doi.org/10.1186/s40779-020-0233-6Crossref PubMed Scopus (1533) Google Scholar The first enrolled patient (Patient A) returned to Lishui from Wenzhou on Jan 18, 2020 and participated a house-warming banquet. Two days later, he suffered with fever, chill, cough and generalized weakness, and was hospitalized on Jan 23, later diagnosed as COVID-19 on Jan 25. Patient B, father of patient A, presented with cough and fever on Jan 21 and was diagnosed on Jan 27. On the same day, patient C was diagnosed as COVID-19 with primary symptoms of cough and sputum. Tracking the medical history of patient C, he began to cough on Jan 16 (two days before the banquet) when he was still in Yongkang, a city adjacent to Lishui. Patient D developed a bad cough on Jan 22 and patient E presented with similar symptom on Jan 26. They were diagnosed on Feb 1 and Feb 2, respectively. Patient F was hospitalized on Jan 30 with fever, chill, cough and generalized weakness and diagnosed as COVID-19 on Feb 1. All the above six patients attended the same house-warming banquet. Oddly enough, patient G, who did not attend the same party, had fever on Feb 1 and was soon diagnosed on Feb 2. Tracing the history of epidemiology, she had dinner with patient C on Jan 24. It is worth noting that the cluster of seven patients did not go to Wuhan or Hubei province in the preceding 14 days, and they denied any exposure with wild animals, confirmed COVID-19 patients or febrile patients (Fig. 1). Two possible scenarios of transmission exist. The first and most likely scenario is that patient A acquired the infection from an asymptomatic patient in Wenzhou (a city with most cases in Zhejiang province) before Jan 18, 2020. This period overlapped with the time period during the announcement of the first case of COVID-19 in Wenzhou (symptom onset on Jan 4, diagnosed on Jan 21) according to the Zhejiang Provincial Health Committee (http://www.zjwjw.gov.cn/col/col1659205/index.html). The other five patients (B∼F) attended the same house-warming banquet and had lunch together in a crowded, noisy hotel restaurant with patient A. Even more, patient B and C had taken the same car with patient A from Lishui back to Qingyuan. As a result, all the five patients were in close contact with patient A, who most likely had been infected before. Then patient G was infected because she was exposed to patient C. The second scenario is that patient C acquired the infection in Yongkang, because he had begun coughing two days before the banquet. As described in the first scenario, other patients were all in close contact with him and got infected. Though the median incubation varies from 3∼6.4 days according to the previous studies,5Guan W.J. Ni Z.Y. Hu Y. Liang W.H. Ou C.Q. He J.X. et al.Clinical Characteristics of Coronavirus Disease 2019 in China.Engl J Med. 2020; https://doi.org/10.1056/NEJMoa2002032Crossref Scopus (20094) Google Scholar,6Xu X.W. Wu X.X. Jiang X.G. Xu K.J. Ying L.J. Ma C.L. et al.Clinical findings in a group of patients infected with the 2019 novel coronavirus (SARS-Cov-2) outside of Wuhan, China: retrospective case series.BMJ. 2020; 368: m606https://doi.org/10.1136/bmj.m606Crossref PubMed Scopus (1437) Google Scholar it is sometimes difficult to calculate the incubation period accurately such as patient A and patient C. Regardless of how the virus transmitted among the seven patients, it further indicated that the SARS-Cov-2 infection could cause clustering onset.7Chen N. Zhou M. Dong X. Qu J. Gong F. Han Y. et al.Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study.Lancet. 2020; 395: 507-513https://doi.org/10.1016/S0140-6736(20)30211-7Abstract Full Text Full Text PDF PubMed Scopus (14212) Google Scholar Quarantine and keeping social distance paly pivotal roles in the prevention of local outbreak of COVID-19.8Wilder-Smith A. Freedman D.O. Isolation, quarantine, social distancing and community containment: pivotal role for old-style public health measures in the novel coronavirus (2019-nCoV) outbreak.J Travel Med. 2020; https://doi.org/10.1093/jtm/taaa020Crossref Scopus (1441) Google Scholar The exact transmission mode still needs to be further studied. The seven patients were aged 23–72 years old. Except patient G, the remaining 6 patients were all males. All patients had no chronic disease except patient C, who had mania years ago. On admission, cough (7/7), generalised weakness (7/7), sore throat (7/7), fever (4/7) and insomnia (4/7) were the main symptoms. The range of incubation period from exposure to symptoms was 3∼11 days (Table 1).Table 1Summary of clinical features of the cluster patients infected with SARS-Cov-2 (on admission).IndexPatient APatient BPatient CPatient DPatient EPatient FPatient GAge(Year)45725136512347SexMaleMaleMaleMaleMaleMaleFemaleOccupationBusiness manFarmerFarmerFarmerFarmerCivil servantFarmerSmokeYYNYYYNAlcohol drinking habitYYNYYYNChronic medical illnessNNManiaNNNNInterval between Admission to hospital and Symptom onset (days)34Uncertain7410.5Incubation period (days)Uncertain3Uncertain48118Presenting symptoms and signFeverYYNNNYYChillYYNNNNNCoughYYYYYYYNasal congestionYNNNYNYRhinorrhoeaYNNNYNYSneezingYNNNYNYDyspneaYNNNNNNSore throatYYYYYYYChest painNNNNNNNGeneralized weaknessYYYYYYYDiarrhoeaYNYYNNNNausea and(or) VomitingYNYNNNNHeadacheNNNNNNYInsomniaYYYNNNYBody temperature (°C)393836.336.83738.437.5Oximetry saturation (%)98959899999998N: no; Y: yes. Open table in a new tab N: no; Y: yes. Regarding the inflammatory indicators, leucocytes, neutrophils, lymphocytes and procalcitonin (PCT) of all the patients were normal and C-reactive protein (CRP) were slightly increased in three patients on admission. Liver function was mildly abnormal in one patient and no patient developed renal dysfunction. Abnormalities in chest CT images were detected among all patients, among which 5 patients showed bilateral pneumonia while only 2 patients showed unilateral pneumonia. All patients showed multiple mottling and ground­glass opacities. Compared with COVID-19 patients initially found in Wuhan, all patients in this study had mild to moderate symptoms. No complications such as acute respiratory distress syndrome, renal dysfunction, myocardial injury and secondary bacterial infection occurred. Symptoms and abnormalities in chest CT scan of all the 7 patients disappeared or significantly improved after antiviral and supportive treatments. In conclusion, this study further indicates that the SARS-Cov-2 infection can cause clustering onset, person-to-person transmission and intercity spread, and it is more likely to happen in crowded places. We urgently need to pay attention to the scale of transmission from asymptomatic or mildly symptomatic patients during the early phase of infection. The study has been approved by the research ethics committee of Lishui Peoples' Hospital (LLW-FO-403). Written informed consent has been waived in light of the urgent need to collect clinical data. None We thank the Lishui CDC for the SARS-Cov-2 nucleic acid tests. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

A method for designing sparse large planar arrays in whole field with a minimum number of elements is proposed in this Letter. The method is developed by compressed sensing algorithms and a new composite beam pattern covering both far- and near-field information. The experimental results demonstrate that the sparse planar array achieves a 95.3% element thinning compared to the fully sampled planar array and the side lobe peaks in near-field conditions are at least 3.4 dB lower than those in previous studies.

Three-dimensional fluorescence spectroscopy has been widely used for the analysis of water contaminants. However, the problems of weak signals and overlapping fluorescence peaks remain unresolved. In this work, we studied the impact of absorption on the spectral shape of fluorescence and found that it is a major cause of overlapping peaks and weak signals. An approach is proposed to purify fluorescent signals and enhance fluorescence signatures based on the theory of fluorescence quantum yield. Using this theory, the problems of noise amplification and singularity points were identified, and an optimization algorithm was proposed related to Wiener filtering. For practical application to multiple compounds, three overlapping cases were discussed theoretically. The effectiveness of this procedure in subsequent parallel factor analysis was assessed and compared with original data by conducting experiments with six typical compounds and real water samples. The results indicate that overlapping along the excitation wavelength axis can be reduced despite the existence of multiple compounds, and the sensitivity of weak fluorescent signals can be significantly improved. The proposed method can enhance fluorescence signatures for the separation and analysis of fluorescent components in water contaminants.

Infectious disease is still one of the leading causes of death nowadays .More than half of pathogens causing infections are still unclear through conventional microbiological diagnostics in clinical laboratory.Recently, the metagenomic sequencing is being applied in the pathogenic diagnosis with full coverage, high efficiency and few bias.Though metagenomic sequencing has shown good performance in pathogenic diagnosis for respiratory tract infection , central nervous system infection and bloodstream infection, it still cannot replace the conventional microbiological tests ; however, this state-of-the-art tool should be considered as an effective supplement to pathogen diagnosis .This article reviews the current application of metagenomic sequencing in clinical scenarios and related pitfalls , with the aim of promoting better utilization of the tool.

OBJECTIVE:Here, we report a case of severe infection caused by Escherichia coli that harbored mcr-1, bla NDM-5, and acquired resistance to tigecycline during tigecycline salvage therapy.METHODS:Antimicrobial susceptibility testing, Southern blot hybridization, and complete genome sequence of the strains were carried out. The genetic characteristics of the mcr-1 and bla NDM-5 plasmids were analyzed. The whole genome sequencing of mcr-1-containing plasmid was completed. Finally, putative single nucleotide polymorphisms and deletion mutations in the tigecycline-resistant strain were predicted.RESULTS:Three E. coli isolates were obtained from ascites, pleural effusion, and stool of a patient; they were resistant to almost all the tested antibiotics. The first two strains separated from ascites (E-FQ) and hydrothorax (E-XS) were susceptible to amikacin and tigecycline; however, the third strain from stool (E-DB) was resistant to tigecycline after nearly 3 weeks' treatment with tigecycline. All three isolates possessed both mcr-1 and bla NDM-5. The bla NDM-5 gene was found on the IncX3 plasmid, whereas the mcr-1, fosA3 and blaCTX-M-14 were located on the IncHI2 plasmid. Mutations in acrB and lon were the reason for the resistance to tigecycline.CONCLUSION:This is the first report of a colistin-, carbapenem-, and tigecycline-resistant E. coli in China. Tigecycline resistance acquired during tigecycline therapy is of great concern for us because tigecycline is a drug of last resort to treat carbapenem-resistant Gram-negative bacterial infections. Furthermore, the transmission of such extensively drug-resistant isolates may pose a great threat to public health.

At present the general scatter handling methods are unsatisfactory when scatter and fluorescence seriously overlap in excitation emission matrix. In this study, an adaptive method for scatter handling of fluorescence data is proposed. Firstly, the Raman scatter was corrected by subtracting the baseline of deionized water which was collected in each experiment to adapt to the intensity fluctuations. Then, the degrees of spectral overlap between Rayleigh scatter and fluorescence were classified into three categories based on the distance between the spectral peaks. The corresponding algorithms, including setting to zero, fitting on single or both sides, were implemented after the evaluation of the degree of overlap for individual emission spectra. The proposed method minimized the number of fitting and interpolation processes, which reduced complexity, saved time, avoided overfitting, and most importantly assured the authenticity of data. Furthermore, the effectiveness of this procedure on the subsequent PARAFAC analysis was assessed and compared to Delaunay interpolation by conducting experiments with four typical organic chemicals and real water samples. Using this method, we conducted long-term monitoring of tap water and river water near a dyeing and printing plant. This method can be used for improving adaptability and accuracy in the scatter handling of fluorescence data.

The inactivated mgrB gene and the mcr-1 gene are important mechanisms of colistin resistance in Klebsiella pneumoniae and they are threats to the clinical use of colistin. In this study, mcr-1 gene was cloned into K. pneumoniae strains (XH209 and KP10) and their derived strains (XH209M and KP10M), which showed high-level resistance to colistin. The acquisition of the mcr-1 gene led to colistin resistance in XH209 and KP10, but the addition of mcr-1 gene did not cause change of colistin minimum inhibitory concentrations in the XH209M and KP10M. In addition, the impact of mcr-1 gene on growth rate showed strain specific in K. pneumoniae. In conclusion, the mcr-1 gene does not cause the same level of colistin resistance as the inactivated mgrB gene in K. pneumoniae. The mcr-1 gene has no effect on colisitin resistance when it coexists with inactivated mgrB gene in K. pneumoniae.

Fluorescence spectroscopy and absorption spectroscopy are common physical methods used for water quality monitoring and analysis. However, in terms of sensitivity and selectivity, the absorption spectroscopy is still inferior; limited categories of organic contaminants can emit fluorescence, which constrains the analytical range. Here in, a novel feature extraction method is proposed in conjoint analysis of fluorescence and absorption spectroscopy to predict the category of water contaminants. The three-dimensional fluorescence spectra and absorption spectra of eight typical substances were studied. We extracted the outline of every three-dimensional fluorescence spectrum along the emission wavelengths axis, and then transformed it into a wavenumber spectrum. The symmetry axis and Stokes shift between fluorescence emission peak and absorption peak in their wavenumber spectra were set as two features. Theoretically, they depend only on the molecular structures of different substances. Moreover, four integral parameters in different absorption spectral ranges corresponding to functional groups were introduced to expand the analytical coverage of diverse contaminants including some non-fluorescent substances. Furthermore, we conducted long-term monitoring of river water near a dyeing and printing plant to demonstrate the prediction potential of this method. As an early warning system, the rapid prediction results can provide guidance for more targeted and detailed analysis and treatment.

Objectives Community-onset bloodstream infections (COBSIs) caused by ESBL-producing Escherichia coli (ESBL-EC) and ESBL-producing Klebsiella pneumoniae (ESBL-KP) are increasing globally. This study aimed to investigate the epidemiology and risk factors of ESBL-EC and ESBL-KP in COBSIs in China. Methods A prospective, multicentre study was performed in 28 tertiary hospitals from September 2013 to November 2014. All isolates and ESBLs were microbiologically characterized. A statistical analysis of risk factors was performed using binary logistic regression. The trial was registered with ClinicalTrials.gov (NCT01961206). Results A total of 919 consecutive episodes of COBSIs were reported and 640 E. coli and 279 K. pneumoniae isolates (non-duplicate) were collected. According to the criteria, 662 (72.0%) cases were classified as having community-acquired bloodstream infections, while the remaining 257 (28.0%) were classified as having healthcare-associated bloodstream infections. The proportions of ESBL producers were 55.5% (355/640) among E. coli isolates and 16.5% (46/279) among K. pneumoniae isolates, respectively. Healthcare-associated infections, obstructive urinary tract disease, previous surgical history and use of a cephalosporin antibiotic within 3 months were independent predictors of COBSIs caused by ESBL-EC. Heart failure was the only independent risk factor for COBSIs due to ESBL-KP. Age was not independently associated with infections caused by ESBL producers. CTX-M-14 was the most common ESBL genotype and was widespread throughout the country. Conclusions ESBL producers are highly prevalent in COBSIs in China, especially among cases caused by E. coli. For these resistant pathogens, clinicians should consider adequate empirical therapy, and different risk factors for prediction should be used in this country.