Read by QxMD icon Read


Daniel C Bailey, Eric J Drake, Thomas D Grant, Andrew M Gulick
Iron is a vital mineral nutrient required by virtually all life forms to prosper; pathogenic bacteria are no exception. Despite the abundance of iron within the human host, highly regulated iron physiology can result in exceedingly low levels of iron bioavailable to prospective invading bacteria. To combat this scarcity of iron, many pathogenic bacteria have acquired specific and efficient iron acquisition systems, which allow them to thrive in iron-deficient host environments. One of the more prominent bacterial iron acquisition systems involves the synthesis, secretion, and reuptake of small-molecule iron chelators known as siderophores...
June 28, 2016: Biochemistry
Yunfang Sun, Hua Wu, Dingxia Shen
OBJECTIVE: Hypervirulent Klebsiella pneumoniae (hvKP) has been characterized as the major pathogen associated with the development of liver abscesses. Although the prevalence of K. pneumoniae in liver abscesses in Chinese patients is on the rise, methods for the early laboratory identification and recognition of hvKP are lacking, and hvKP detection and surveillance are thus limited. METHODS: A retrospective study was conducted in 240 patients with cultures that were positive for K...
2016: Journal of Molecular Microbiology and Biotechnology
Rong Zhang, Dachuan Lin, Edward Wai-Chi Chan, Danxia Gu, Gong-Xiang Chen, Sheng Chen
We report the emergence of five carbapenem-resistant K1 hypervirulent Klebsiella pneumoniae (hvKP) strains which caused fatal infections in hospital patients in Zhejiang Province, China, upon entry through surgical wounds. Genotyping results revealed the existence of three genetically related strains which exhibited a new sequence type, ST1797, and revealed that all strains harbored the magA and wcaG virulence genes and a plasmid-borne bla(KPC-2) gene. These findings indicate that K1 hvKP is simultaneously hypervirulent, multidrug resistant, and transmissible...
January 2016: Antimicrobial Agents and Chemotherapy
Yawei Zhang, Ji Zeng, Wenen Liu, Feng Zhao, Zhidong Hu, Chunjiang Zhao, Qi Wang, Xiaojuan Wang, Hongbin Chen, Henan Li, Feifei Zhang, Shuguang Li, Bin Cao, Hui Wang
OBJECTIVES: Hypervirulent Klebsiella pneumoniae (hvKP) infections occur worldwide, but carbapenem-resistant hvKP strain has rarely been observed. METHODS: A retrospective study was conducted in 28 cases of carbapenem-resistant K. pneumoniae (CRKP) infections from 9 cities in China. Clinical data were collected from medical records. All the isolates were characterized by antimicrobial susceptibility testing, string test, multilocus sequence typing, and capsular genotyping...
November 2015: Journal of Infection
Yibo Zhang, Jingyong Sun, Chenrong Mi, Wenhui Li, Shengyuan Zhao, Qun Wang, Dake Shi, Luo Liu, Bingyu Ding, Yung-Fu Chang, Hongxiong Guo, XiaoKui Guo, Qingtian Li, Yongzhang Zhu
Here, we present the first report of one suspected dead case and two confirmed rapid-onset fatal infections caused by a newly emerging hypervirulent Klebsiella pneumoniae ST86 strain of serotype K2. The three cases occurred in a surgery ward during 2013 in Shanghai, China. A combination of multilocus sequence typing, pulsed-field gel electrophoresis, phenotypic and PCR tests for detecting virulence factors (VFs) was used to identify the isolates as K2 ST86 strains with common VFs, including Aerobactin and rmpA...
2015: Frontiers in Microbiology
Carsten Struve, Chandler C Roe, Marc Stegger, Steen G Stahlhut, Dennis S Hansen, David M Engelthaler, Paal S Andersen, Elizabeth M Driebe, Paul Keim, Karen A Krogfelt
UNLABELLED: Highly invasive, community-acquired Klebsiella pneumoniae infections have recently emerged, resulting in pyogenic liver abscesses. These infections are caused by hypervirulent K. pneumoniae (hvKP) isolates primarily of capsule serotype K1 or K2. Hypervirulent K1 isolates belong to clonal complex 23 (CC23), indicating that this clonal lineage has a specific genetic background conferring hypervirulence. Here, we apply whole-genome sequencing to a collection of K. pneumoniae isolates to characterize the phylogenetic background of hvKP isolates with an emphasis on CC23...
2015: MBio
Bei Yao, Xiumei Xiao, Fei Wang, Lei Zhou, Xiaowei Zhang, Jie Zhang
OBJECTIVES: To provide the clinical and molecular characteristics of carbapenem-resistant hypervirulent (hypermucoviscous) Klebsiella pneumoniae (cr-hvKP) in a tertiary hospital in Beijing, China. METHODS: The clinical characteristics of four patients with cr-hvKP isolates and 29 patients with carbapenem-resistant classic K. pneumoniae (cr-cKP) infections were analyzed retrospectively. The molecular characteristics of cr-hvKP and cr-cKP isolates were compared. RESULTS: The KPC-2 gene was detected in all cr-hvKPs except for cr-hvKP6...
August 2015: International Journal of Infectious Diseases: IJID
Thomas A Russo, Ruth Olson, Ulrike MacDonald, Janet Beanan, Bruce A Davidson
The siderophore aerobactin is the dominant siderophore produced by hypervirulent Klebsiella pneumoniae (hvKP) and was previously shown to be a major virulence factor in systemic infection. However, strains of hvKP commonly produce the additional siderophores yersiniabactin, salmochelin, and enterobactin. The roles of these siderophores in hvKP infection have not been optimally defined. To that end, site-specific gene disruptions were created in hvKP1 (wild type), resulting in the generation of hvKP1ΔiucA (aerobactin deficient), hvKP1ΔiroB (salmochelin deficient), hvKP1ΔentB (enterobactin and salmochelin deficient), hvKP1Δirp2 (yersiniabactin deficient), and hvKP1ΔentBΔirp2 (enterobactin, salmochelin, and yersiniabactin deficient)...
August 2015: Infection and Immunity
Ting-ting Qu, Jian-cang Zhou, Yan Jiang, Ke-ren Shi, Bin Li, Ping Shen, Ze-qing Wei, Yun-song Yu
BACKGROUND: Klebsiella pneumoniae has been the dominant pathogen for liver abscesses in several Asian countries. Although the prevalence of K. pneumoniae liver abscess (KLA) in mainland China is increasing recently, the clinical and microbiological characteristics of KLA in China have not been elucidated. METHODS: Clinical and microbiology characteristics of 45 consecutive patients with KLA from a tertiary teaching hospital in China between June 2008 and June 2012 were retrospectively evaluated...
2015: BMC Infectious Diseases
Suzanne Bialek-Davenet, Alexis Criscuolo, Florent Ailloud, Virginie Passet, Marie-Hélène Nicolas-Chanoine, Dominique Decré, Sylvain Brisse
Hypervirulent Klebsiella pneumoniae isolates of capsular serotype K2 (hvKP-K2) that cause community-acquired invasive infections represent several unrelated clones, which all belong to phylogenetic group KpI. These clones can be recognized using multilocus sequence typing and genomic analyses, but no rapid method currently exists to differentiate them. In this work, a multiplex PCR assay was developed to identify three hvKP-K2 groups: (i) sequence type (ST)86; (ii) ST380 and ST679 (i.e. clonal group 380); and (iii) ST65 and ST375...
December 2014: Journal of Medical Microbiology
Ying Mei Liu, Bin Bin Li, Yu Yu Zhang, Wu Zhang, Hong Shen, Hui Li, Bin Cao
Recently, the newly emerged hypervirulent Klebsiella pneumoniae strain (hvKP) has caused great concern globally, but the clinical features and molecular characteristics of bacteremia caused by hvKP are rarely reported in mainland China. Seventy patients with K. pneumoniae bacteremia were investigated to study the clinical features of hvKP infection from 2008 till 2012 in Beijing Chao-Yang Hospital. The molecular characteristics of the hvKP strains were also studied using PCR, multilocus sequence typing, and pulsed-field gel electrophoresis (PFGE) methods...
September 2014: Antimicrobial Agents and Chemotherapy
Thomas A Russo, Ruth Olson, Ulrike Macdonald, Daniel Metzger, Lauren M Maltese, Eric J Drake, Andrew M Gulick
Hypervirulent (hypermucoviscous) Klebsiella pneumoniae (hvKP) strains are an emerging variant of "classical" K. pneumoniae (cKP) that cause organ and life-threatening infection in healthy individuals. An understanding of hvKP-specific virulence mechanisms that enabled evolution from cKP is limited. Observations by our group and previously published molecular epidemiologic data led us to hypothesize that hvKP strains produced more siderophores than cKP strains and that this trait enhanced hvKP virulence. Quantitative analysis of 12 hvKP strains in iron-poor minimal medium or human ascites fluid showed a significant and distinguishing 6- to 10-fold increase in siderophore production compared to that for 14 cKP strains...
June 2014: Infection and Immunity
Wei Li, Guizhen Sun, Yanhua Yu, Ning Li, Ming Chen, Ronghua Jin, Yanmei Jiao, Hao Wu
BACKGROUND: New hypervirulent variants of Klebsiella pneumoniae (hvKP) are emerging globally, most of which exhibit antimicrobial susceptibility. METHODS: A retrospective study was conducted in 88 patients with cultures positive for K. pneumoniae hospitalized in the Beijing You'an Hospital from April 2010 to June 2012. The clinical and molecular data of the hvKP isolates (defined as string test positive) were compared with those of the classic K. pneumoniae (cKP) isolates...
January 2014: Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
Qingli Kong, Janet M Beanan, Ruth Olson, Ulrike Macdonald, Alyssa S Shon, Daniel J Metzger, Alexander O Pomakov, Thomas A Russo
A new hypervirulent (hypermucoviscous) clinical variant of Klebsiella pneumoniae (hvKP) has emerged over the last decade. Our goal is to identify new mechanisms, which increase the virulence hvKP. It has been shown that hvKP strains produce more biofilm than "classical" stains of K. pneumoniae, therefore we hypothesized that biofilm formation may contribute to the pathogenesis of systemic infection. To test this hypothesis, transposon mutants of the model pathogen hvKP1 were generated and screened for decreased production of biofilm...
May 1, 2012: Virulence
Thomas A Russo, Alyssa S Shon, Janet M Beanan, Ruth Olson, Ulrike MacDonald, Alexander O Pomakov, Mark P Visitacion
BACKGROUND: A new hypervirulent (hypermucoviscous) clinical variant of Klebsiella pneumoniae (hvKP) has emerged over the last decade. Our goal is to identify new mechanisms, which increase the virulence hvKP compared to "classic" K. pneumoniae (cKP). METHODOLOGY/PRINCIPAL FINDINGS: Various growth assays were performed in human ascites, human serum, and laboratory medium with the hvKP strain hvKP1 (wt), randomly chosen blood isolates of cKP strains (cKP1-4), and mutant constructs deficient in the secretion of selected compounds...
2011: PloS One
D K Pomakova, C-B Hsiao, J M Beanan, R Olson, U MacDonald, Y Keynan, T A Russo
The purpose of this study was to increase awareness, gain insight into acquisition, and assess the virulence of the hypervirulent (hypermucoviscous) clinical variant (hvKP) that is entrenched in the Pacific Rim but emerging in Western countries. A case of community-acquired liver abscess with metastatic spread to the spleen is described. Comparative in vitro and in vivo virulence studies on this isolate (hvKP1) and four randomly chosen blood isolates of "classic" K. pneumonia strains (cKP1-4) were performed...
June 2012: European Journal of Clinical Microbiology & Infectious Diseases
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"