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klebsiella pneumoniae capsule

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...
October 26, 2016: Clinical and Vaccine Immunology: CVI
Hsi-Hsu Lin, Yao-Shen Chen, Hao-Wen Hsiao, Pei-Tan Hsueh, Wei-Fen Ni, Ya-Lei Chen
Here, we report the whole-genome sequences of Klebsiella pneumoniae ED2 and ED23, isolated, respectively, from bacteremic patients with liver abscesses (ED2) and patients with primary liver abscess and metastatic meningitis (ED23). Both strains were of multilocus sequence type 23 with capsule serotype K1.
October 20, 2016: Genome Announcements
Anna Mularski, Jonathan Wilksch, Eric Hanssen, Jian Li, Takehiro Tomita, Sacha James Pidot, Tim Stinear, Frances Separovic, Dick Strugnell
Atomic force microscopy measurements of capsule thickness revealed that that the wild-type Klebsiella pneumoniae AJ218 capsular polysaccharides were rearranged by exposure to colistin. The increase in capsule thickness measured near minimum inhibitory/bactericidal concentration (MIC/MBC) is consistent with the idea that colistin displaces the divalent cations that cross-bridge adjacent lipopolysaccharide (LPS) molecules through the capsule network. Cryo-electron microscopy demonstrated that the measured capsule thickness at near MIC/MBC of 1...
October 17, 2016: European Biophysics Journal: EBJ
Reza Ranjbar, Hamed Memariani, Rahim Sorouri, Mojtaba Memariani
Klebsiella pneumoniae is one of the most important agents of community-acquired urinary tract infection (CA-UTI). In addition to extended-spectrum β-lactamases (ESBLs), a number of virulence factors have been shown to play an important role in the pathogenesis of K. pneumoniae, including capsule, siderophores, and adhesins. Little is known about the genetic diversity and virulence content of the CTX-M-15-producing K. pneumoniae isolated from CA-UTI in Iran. A total of 152 K. pneumoniae isolates were collected from CA-UTI patients in Tehran from September 2015 through April 2016...
October 7, 2016: Microbial Pathogenesis
Kwan Soo Ko
No abstract text is available yet for this article.
October 7, 2016: Virulence
Tolani F Olonisakin, Huihua Li, Zeyu Xiong, Elizabeth J K Kochman, Minting Yu, Yanyan Qu, Mei Hulver, Jay K Kolls, Claudette St Croix, Yohei Doi, Minh-Hong Nguyen, Robert M Q Shanks, Rama K Mallampalli, Valerian E Kagan, Anuradha Ray, Roy L Silverstein, Prabir Ray, Janet S Lee
Klebsiella pneumoniae remains an important cause of intrapulmonary infection and invasive disease worldwide. Klebsiella pneumoniae can evade serum killing and phagocytosis primarily through the expression of a polysaccharide capsule, but its pathogenicity is also influenced by host factors. We examined whether CD36, a scavenger receptor that recognizes pathogen and modified-self ligands, is a host determinant of Klebsiella pneumoniae pathogenicity. Despite differences in serum sensitivity and virulence of three distinct Klebsiella pneumoniae (hypermucoviscous K1, research K2, carbapenemase-producing ST258) strains utilized, the absence of CD36 significantly increased host susceptibility to acute intrapulmonary infection by K...
September 28, 2016: Journal of Infectious Diseases
Chii-Lan Lin, Fei-Hsu Chen, Li-Yueh Huang, Jen-Chang Chang, Jiun-Han Chen, Yu-Kuo Tsai, Feng-Yee Chang, Jung-Chung Lin, L Kristopher Siu
The capsular polysaccharides in different serotypes of Klebsiella pneumoniae (KP) coded by the (CPS) gene cluster are characterized by a conserved and a hyper-variable region. We performed a virulence study by switching genes in the highly conserved region of the CPS cluster between strains. Six genes in the CPS conserved region in serotype K20, including galF, acidPPc, wzi, wza, wzb and wzc, were knocked out and replaced by the homologous genes from serotype K1. Compared to the parental K20 strain, the mutants showed a decline in lethality (LD50) in mice from 10-fold to > 10(5)-fold and were categorized in terms of the effect on virulence as low (L) for galF and acidPPC, moderate (M) for wzi, and high (H) for wza, wzb and wzc...
August 26, 2016: Virulence
Jolene R Bowers, Darrin Lemmer, Jason W Sahl, Talima Pearson, Elizabeth M Driebe, Bette Wojack, Michael A Saubolle, David M Engelthaler, Paul Keim
Health care-acquired infections (HAIs) kill tens of thousands of people each year and add significantly to health care costs. Multidrug-resistant and epidemic strains are a large proportion of HAI agents, and multidrug-resistant strains of Klebsiella pneumoniae, a leading HAI agent, have caused an urgent public health crisis. In the health care environment, patient colonization by K. pneumoniae precedes infection, and transmission via colonization leads to outbreaks. Periodic patient screening for K. pneumoniae colonization has the potential to curb the number of HAIs...
October 2016: Journal of Clinical Microbiology
I Russel Lee, James S Molton, Kelly L Wyres, Claire Gorrie, Jocelyn Wong, Chu Han Hoh, Jeanette Teo, Shirin Kalimuddin, David C Lye, Sophia Archuleta, Kathryn E Holt, Yunn-Hwen Gan
Hypervirulent Klebsiella pneumoniae is an emerging cause of community-acquired pyogenic liver abscess. First described in Asia, it is now increasingly recognized in Western countries, commonly afflicting those with Asian descent. This raises the question of genetic predisposition versus geospecific strain acquisition. We leveraged on the Antibiotics for Klebsiella Liver Abscess Syndrome Study (A-KLASS) clinical trial ongoing in ethnically diverse Singapore, to prospectively examine the profiles of 70 patients together with their isolates' genotypic and phenotypic characteristics...
July 13, 2016: Scientific Reports
Wen-Liang Yu, Mei-Feng Lee, Chi-Chung Chen, Hung-Jen Tang, Chung-Han Ho, Yin-Ching Chuang
We investigated the implications of hypervirulence determinants on clinical features of 48 adult patients with bacteremia caused by extended-spectrum β-lactamase-producing Klebsiella pneumoniae. Isolates in the hypervirulence group included any of the following virulence determinants: K1/K2 capsule serotypes, hypermucoviscosity phenotype, rmpA gene, or rmpA2 gene. Nonhypervirulence group isolates were negative for all of the above virulence factors. In this study, all isolates used were non-K1/K2 strains. Statistically significant differences were observed in clinical features of patients between the two groups...
July 5, 2016: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
Joseph S Schoeniger, Corey M Hudson, Zachary W Bent, Anupama Sinha, Kelly P Williams
Virulence genes on mobile DNAs such as genomic islands (GIs) and plasmids promote bacterial pathogen emergence. Excision is an early step in GI mobilization, producing a circular GI and a deletion site in the chromosome; circular forms are also known for some bacterial insertion sequences (ISs). The recombinant sequence at the junctions of such circles and deletions can be detected sensitively in high-throughput sequencing data, using new computational methods that enable empirical discovery of mobile DNAs...
August 19, 2016: Nucleic Acids Research
Michelle K Paczosa, Joan Mecsas
Klebsiella pneumoniae causes a wide range of infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Historically, K. pneumoniae has caused serious infection primarily in immunocompromised individuals, but the recent emergence and spread of hypervirulent strains have broadened the number of people susceptible to infections to include those who are healthy and immunosufficient. Furthermore, K. pneumoniae strains have become increasingly resistant to antibiotics, rendering infection by these strains very challenging to treat...
September 2016: Microbiology and Molecular Biology Reviews: MMBR
Anis Barati, Aziz Ghaderpour, Li Lee Chew, Chui Wei Bong, Kwai Lin Thong, Ving Ching Chong, Lay Ching Chai
Klebsiella pneumoniae is an opportunistic pathogen that is responsible for causing nosocomial and community-acquired infections. Despite its common presence in soil and aquatic environments, the virulence potential of K. pneumoniae isolates of environmental origin is largely unknown. Hence, in this study, K. pneumoniae isolated from the estuarine waters and sediments of the Matang mangrove estuary were screened for potential virulence characteristics: antibiotic susceptibility, morphotype on Congo red agar, biofilm formation, presence of exopolysaccharide and capsule, possession of virulence genes (fimH, magA, ugE, wabG and rmpA) and their genomic fingerprints...
April 2016: International Journal of Environmental Research and Public Health
Steven Clegg, Caitlin N Murphy
Strains of Klebsiella pneumoniae are frequently opportunistic pathogens implicated in urinary tract and catheter-associated urinary-tract infections of hospitalized patients and compromised individuals. Infections are particularly difficult to treat since most clinical isolates exhibit resistance to several antibiotics leading to treatment failure and the possibility of systemic dissemination. Infections of medical devices such as urinary catheters is a major site of K. pneumoniae infections and has been suggested to involve the formation of biofilms on these surfaces...
February 2016: Microbiology Spectrum
Anna Mularski, Jonathan J Wilksch, Eric Hanssen, Richard A Strugnell, Frances Separovic
Time-resolved AFM images revealed that the antimicrobial peptide (AMP) caerin 1.1 caused localised defects in the cell walls of lysed Klebsiella pneumoniae cells, corroborating a pore-forming mechanism of action. The defects continued to grow during the AFM experiment, in corroboration with large holes that were visualised by scanning electron microscopy. Defects in cytoplasmic membranes were visualised by cryo-EM using the same peptide concentration as in the AFM experiments. At three times the minimum inhibitory concentration of caerin, 'pores' were apparent in the outer membrane...
June 2016: Biochimica et Biophysica Acta
Miguel A Ares, José L Fernández-Vázquez, Roberto Rosales-Reyes, Ma Dolores Jarillo-Quijada, Kristine von Bargen, Javier Torres, Jorge A González-Y-Merchand, María D Alcántar-Curiel, Miguel A De la Cruz
Klebsiella pneumoniae is an opportunistic pathogen causing nosocomial infections. Main virulence determinants of K. pneumoniae are pili, capsular polysaccharide, lipopolysaccharide, and siderophores. The histone-like nucleoid-structuring protein (H-NS) is a pleiotropic regulator found in several gram-negative pathogens. It has functions both as an architectural component of the nucleoid and as a global regulator of gene expression. We generated a Δhns mutant and evaluated the role of the H-NS nucleoid protein on the virulence features of K...
2016: Frontiers in Cellular and Infection Microbiology
Changlong Pang, Ang Li, Di Cui, Jixian Yang, Fang Ma, Haijuan Guo
Klebsiella pneumoniae J1 is a Gram-negative strain, which belongs to a protein-based microbial flocculant-producing bacterium. However, little genetic information is known about this species. Here we carried out a whole-genome sequence analysis of this strain and report the complete genome sequence of this organism and its genetic basis for carbohydrate metabolism, capsule biosynthesis and transport system.
February 20, 2016: Journal of Biotechnology
Esra Deniz Candan, Nilüfer Aksöz
Klebsiella pneumoniae, known as a major threat to public health, is the most common factor of nosocomial and community acquired infections. In this study, 50 K. pneumoniae clinical specimens isolated from bronchial, urea, blood, catheter, rectal, bile, tracheal and wound cultures were collected. These isolates were identified and carbapenem resistance was determined via an automated system, CHROMagar Orientation and CHROMagar KPC. The carbapenemase gene regions (blaIMP, blaVIM, blaOXA, blaNDM and blaKPC) and presence of virulence factors (magA, k2A, rmpA, wabG, uge, allS, entB, ycfM, kpn, wcaG, fimH, mrkD, iutA, iroN, hly ve cnf-1) of these isolates were determined by using Multiplex-PCR...
2015: Acta Biochimica Polonica
David A Rosen, Julia K Hilliard, Kristin M Tiemann, Elizabeth M Todd, S Celeste Morley, David A Hunstad
Klebsiella pneumoniae, a chief cause of nosocomial pneumonia, is a versatile and commonly multidrug-resistant human pathogen for which further insight into pathogenesis is needed. We show that the pilus regulatory gene fimK promotes the virulence of K. pneumoniae strain TOP52 in murine pneumonia. This contrasts with the attenuating effect of fimK on urinary tract virulence, illustrating that a single factor may exert opposing effects on pathogenesis in distinct host niches. Loss of fimK in TOP52 pneumonia was associated with diminished lung bacterial burden, limited innate responses within the lung, and improved host survival...
February 15, 2016: Journal of Infectious Diseases
Duyen Thi Ngoc Huynh, Ah-Young Kim, In-Hye Seol, Samuel Jung, Min-Cheol Lim, Jeong-A Lee, Mi-Rae Jo, Soo-Jin Choi, Borim Kim, Jinwon Lee, Wooki Kim, Young-Rok Kim
The microbiological production of 2,3-butanediol (2,3-BDO) has attracted considerable attention as an alternative way to produce high-value chemicals from renewable sources. Among the number of 2,3-BDO-producing microorganisms, Klebsiella pneumoniae has been studied most extensively and is known to produce large quantity of 2,3-BDO from a range of substrates. On the other hand, the pathogenic characteristics of the bacteria have limited its industrial applications. In this study, two major virulence traits, outer core LPS and fimbriae, were removed through homologous recombination from 2,3-BDO-producing K...
November 2015: Applied Microbiology and Biotechnology
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