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Jeffrey Bulger, Ulrike MacDonald, Ruth Olson, Janet Beanan, Thomas A Russo
Hypervirulent Klebsiella pneumoniae (hvKP) is an emerging pathotype that is capable of causing tissue-invasive, organ and life threatening infections in healthy individuals from the community. Knowledge on the virulence factors specific to hvKP is limited. In this report we describe a new factor (PEG344) that increases the virulence of the hvKP strain hvKP1. peg344 is present on the hvKP1 virulence plasmid, is broadly prevalent among hvKP strains, and has increased RNA abundance when grown in human ascites...
July 17, 2017: Infection and Immunity
Lifeng Wang, Dingxia Shen, Hua Wu, Yanning Ma
Hypervirulent Klebsiella pneumoniae (HvKP) is hypermucoviscous organism, carrying genes of rmpA and aerobactin, causing serious community-acquired infection and metastatically spread in young healthy hosts. Neutrophils play an important role during innate immune response against bacterial infection by phagocytosis and neutrophil extracellular traps (NETs). Whether neutrophils can effectively defend against HvKP remains unclear. In this study, we observed that the HvKP was significantly more resistant to neutrophil-mediated phagocytosis and intracellular killing than classic Klebsiella pneumoniae (cKP) isolates...
2017: PloS One
Hua Wu, Dongdong Li, Haijian Zhou, Yunfang Sun, Ling Guo, Dingxia Shen
OBJECTIVES: To investigate bacteremia and other body site infection caused by hypervirulent Klebsiella pneumoniae (hvKP), a recently recognized pathogen of invasive infection, and classic Klebsiella pneumoniae (cKP), a very common organism associated with many kinds of nosocomial infection. METHODS: Clinical information obtained from patients with both bacteremia and other body site infections caused by hvKP and/or cKP was retrospectively reviewed. Homo-hvKP (or homo-cKP) was defined as homologous hvKP (or cKP) strains from different body sites in each individual patient according to string test, virulence gene amplification and PFGE pattern...
March 2017: Microbial Pathogenesis
Meiping Ye, Jianfei Tu, Jianping Jiang, Yingmin Bi, Weibo You, Yanliang Zhang, Jianmin Ren, Taohui Zhu, Zhuo Cao, Zuochun Yu, Chuxiao Shao, Zhen Shen, Baixing Ding, Jinyi Yuan, Xu Zhao, Qinglan Guo, Xiaogang Xu, Jinwei Huang, Minggui Wang
Hypervirulent variants of Klebsiella pneumoniae (hvKp) that cause invasive community-acquired pyogenic liver abscess (PLA) have emerged globally. Little is known about the virulence determinants associated with hvKp, except for the virulence genes rmpA/A2 and siderophores (iroBCD/iucABCD) carried by the pK2044-like large virulence plasmid. Here, we collected most recent clinical isolates of hvKp from PLA samples in China, and performed clinical, molecular, and genomic sequencing analyses. We found that 90.9% (40/44) of the pathogens causing PLA were K...
2016: Frontiers in Cellular and Infection Microbiology
Bénédicte Melot, Sylvain Brisse, Sébastien Breurec, Virginie Passet, Edith Malpote, Isabelle Lamaury, Guillaume Thiery, Bruno Hoen
BACKGROUND: Community-acquired bacterial meningitis due to Klebsiella pneumoniae has mainly been described in Southeast Asia and has a poor prognosis. Severe invasive infections caused by K. pneumoniae, including meningitis, are often due to hypervirulent strains (hvKP), which are characterized by capsular serotypes K1 and K2, a gene responsible for hypermucoviscosity, and the cluster for synthesis of the siderophore aerobactin. CASE PRESENTATION: A 55 year old man with a history of essential hypertension, benign prostate hyperplasia, hyperlipidemia, obstructive sleep apnea, and chronic alcoholism was admitted for meningitis due to Klebsiella pneumoniae with a wild-type susceptibility profile...
December 7, 2016: BMC Infectious Diseases
Jing Zhang, Kai Zhou, Beiwen Zheng, Lina Zhao, Ping Shen, Jinru Ji, Zeqing Wei, Lanjuan Li, Jianying Zhou, Yonghong Xiao
The aim of this work was to investigate the epidemiological and genetic characteristics of ESBL-producing Klebsiella pneumoniae (ESBL-Kp) causing community-onset infections. K. pneumoniae isolates were collected from 31 Chinese secondary hospitals between August 2010 and 2011. Genes encoding ESBL and AmpC beta-lactamases were detected by PCR. The isolates were assigned to sequence types (STs) using multi-locus sequence typing (MLST). Eleven ESBL-Kp strains were selected for whole-genome sequencing (WGS) for investigating the genetic environment and plasmids encoding ESBL genes...
2016: Frontiers in Microbiology
Hiroki Namikawa, Koichi Yamada, Hiroki Fujimoto, Ken-Ichi Oinuma, Yoshihiro Tochino, Yasuhiko Takemoto, Yukihiro Kaneko, Taichi Shuto, Hiroshi Kakeya
BACKGROUND: A few Japanese cases of hypermucoviscous Klebsiella pneumoniae (K. pneumoniae) invasive syndrome have recently been reported. Although extrahepatic complications from bacteremic dissemination have been observed, infected aneurysms are rare. Furthermore, the primary source of infection is generally a liver abscess, and is rarely the prostate. Therefore, we report two atypical cases of hypermucoviscous K. pneumoniae invasive syndrome. CASE PRESENTATION: The first case was an 81-year-old Japanese man with no significant medical history, who was referred to our hospital for vision loss in his right eye...
November 16, 2016: BMC Infectious Diseases
Elizabeth Diago-Navarro, Isabel Calatayud-Baselga, Donglei Sun, Camille Khairallah, Inderjit Mann, Amaia Ulacia-Hernando, Brian Sheridan, Meiqing Shi, Bettina C Fries
Hypervirulent Klebsiella pneumoniae (hvKp) strains are predicted to become a major threat in Asia if antibiotic resistance continues to spread. Anticapsular antibodies (Abs) were developed because disseminated infections caused by hvKp are associated with significant morbidity and mortality, even with antibiotic-sensitive strains. K1-serotype polysaccharide capsules (K1-CPS) are expressed by the majority of hvKp strains. In this study, K1-CPS-specific IgG Abs were generated by conjugation of K1-CPS to immunogenic anthrax protective antigen (PA) protein...
January 2017: Clinical and Vaccine Immunology: CVI
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...
November 16, 2015: 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
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