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klebsiella pneumoniae polysaccharide capsule

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https://www.readbyqxmd.com/read/29153063/-investigation-of-various-virulence-factors-of-klebsiella-pneumoniae-strains-isolated-from-nosocomial-infections
#1
Halit Kuş, Uğur Arslan, Hatice Türk Dağı, Duygu Fındık
Klebsiella pneumoniae is an opportunistic pathogen that commonly affects immunosuppressed patients and causes nosocomial infections. K.pneumoniae has a variety of virulence factors, especially capsule polysaccharide, hypermucoviscosity (HV), fimbriae, toxins and determinants for iron acquisition. The aim of this study was to detect the virulence factors in K.pneumoniae strains isolated from nosocomial infections in two years. Fifty three K.pneumoniae strains isolated from the samples of patients with nosocomial infections in the Medical Microbiology Laboratory of Selcuk University Faculty of Medicine Hospital between 2011 and 2013 were included in the study...
October 2017: Mikrobiyoloji Bülteni
https://www.readbyqxmd.com/read/28731269/biofilm-formation-and-antibiotic-resistance-in-klebsiella-pneumoniae-urinary-strains
#2
C Vuotto, F Longo, C Pascolini, G Donelli, M P Balice, M F Libori, V Tiracchia, A Salvia, P E Varaldo
AIMS: Multidrug-resistant Klebsiella pneumoniae has become a relevant healthcare-associated pathogen. Capsule, type 1 and 3 fimbriae (mrkA gene), type 2 quorum-sensing system (luxS), synthesis of D-galactan I (wbbM), LPS transport (wzm) and poly-beta-1,6-N-acetyl-D-glucosamine (pgaA) seem involved in K. pneumoniae biofilm. Nonenzymatic antibiotic resistance is related to nonexpression or mutation of porins (OmpK35 and OmpK36), and efflux pump (acrB) overexpression. The aim of this study was to analyse some virulence factors of K...
July 21, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28729207/first-two-cases-of-severe-multifocal-infections-caused-by-klebsiella-pneumoniae-in-switzerland-characterization-of-an-atypical-non-k1-k2-serotype-strain-causing-liver-abscess-and-endocarditis
#3
Baharak Babouee Flury, Valentina Donà, Niccolò Buetti, Hansjakob Furrer, Andrea Endimiani
BACKGROUND: We describe the first two multifocal invasive infections due to Klebsiella pneumoniae recently observed in Switzerland. METHODS: Phenotypic (MIC assays and string test) and molecular analyses (PCR/Sequencing for bla, virulence factor genes and whole genome sequencing for one strain) were performed to characterize the causative K. pneumoniae isolates. RESULTS: Both K. pneumoniae isolates (Kp1 and Kp2) were pan-susceptible to antibiotics and produced narrow-spectrum SHV β-lactamases...
September 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28728189/spontaneous-globe-rupture-due-to-rapidly-evolving-endogenous-hypermucoid-klebsiella-pneumoniae-endophthalmitis
#4
Edward H Wood, Matthew A Powers, Darius M Moshfeghi
In this retrospective report, the authors describe a rare case of spontaneous globe rupture from Klebsiella pneumoniae endophthalmitis in a middle-aged man with poorly controlled type 2 diabetes mellitus. There have been only four previously reported cases of spontaneous globe rupture from endophthalmitis. Out of the now five reported cases, all have been due to endogenous endophthalmitis, four have been due to gram-negative bacteria, and three have been due to K. pneumoniae. K. pneumoniae, especially the hypermucoid variant with a protective polysaccharide capsule, is an emerging pathogen with remarkable virulence...
July 1, 2017: Ophthalmic Surgery, Lasers & Imaging Retina
https://www.readbyqxmd.com/read/28676686/two-t7-like-bacteriophages-k5-2-and-k5-4-each-encodes-two-capsule-depolymerases-isolation-and-functional-characterization
#5
Pei-Fang Hsieh, Hsiao-Hsuan Lin, Tzu-Lung Lin, Yi-Yin Chen, Jin-Town Wang
Two Klebsiella bacteriophages K5-2 and K5-4, which are able to infect and grow on either capsular types K30/K69 and K5 or K8 and K5 of Klebsiella strains, were isolated and characterized. Each phage contained two open reading frames (ORFs), which encoded two putative capsule depolymerases, respectively. The first ORF encoded tail fiber proteins, which have K30/K69 depolymerase and K8 depolymerase activities. The second ORF encoded hypothetical proteins, which are almost identical in amino acid sequences, and have K5 depolymerase activity...
July 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28486697/evolution-and-dissemination-of-the-klebsiella-pneumoniae-clonal-group-258-throughout-israeli-post-acute-care-hospitals-2008-13
#6
Amos Adler, Ziv Lifshitz, Michal Gordon, Debbie Ben-David, Efrat Khabra, Samira Masarwa, Orit Zion, Mitchell J Schwaber, Yehuda Carmeli
Objectives: The KPC-producing Klebsiella pneumoniae (KPC-KP) clonal group (CG) 258 has disseminated throughout Israeli post-acute care hospitals (PACHs). The objectives of the study were (i) to describe the evolution and (ii) to understand the dissemination modes of CG 258 in the PACH system in Israel. Methods: KPC-KP surveillance cultures isolates were collected in Israeli PACHs in three national point-prevalence surveys: 2008, 2011 and 2013. CG 258 was identified by pilv-l PCR...
August 1, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28437231/capsular-polysaccharide-types-and-virulence-related-traits-of-epidemic-kpc-producing-klebsiella-pneumoniae-isolates-in-a-chinese-university-hospital
#7
Yang Liu, Pan-Pan Liu, Lian-Hui Wang, Dan-Dan Wei, La-Gen Wan, Wei Zhang
Klebsiella pneumoniae is an important human pathogen associated with a variety of diseases and the prevalence of blaKPC carrying K. pneumoniae (KPC-Kp) is rapidly increasing. Capsule is an important virulence factor in K. pneumoniae. In this study, we determined to first systematically characterize capsular polysaccharide (CPS) and virulence traits in KPC-Kp strains. A total of 56 KPC-Kp isolates were recovered from clinical samples in a Chinese hospital, which were assigned to clonal lineages by multilocus sequence typing (MLST)...
October 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28348868/the-diversity-of-klebsiella-pneumoniae-surface-polysaccharides
#8
Rainer Follador, Eva Heinz, Kelly L Wyres, Matthew J Ellington, Michael Kowarik, Kathryn E Holt, Nicholas R Thomson
Klebsiella pneumoniae is considered an urgent health concern due to the emergence of multi-drug-resistant strains for which vaccination offers a potential remedy. Vaccines based on surface polysaccharides are highly promising but need to address the high diversity of surface-exposed polysaccharides, synthesized as O-antigens (lipopolysaccharide, LPS) and K-antigens (capsule polysaccharide, CPS), present in K. pneumoniae. We present a comprehensive and clinically relevant study of the diversity of O- and K-antigen biosynthesis gene clusters across a global collection of over 500 K...
August 2016: Microbial Genomics
https://www.readbyqxmd.com/read/28348840/identification-of-klebsiella-capsule-synthesis-loci-from-whole-genome-data
#9
Kelly L Wyres, Ryan R Wick, Claire Gorrie, Adam Jenney, Rainer Follador, Nicholas R Thomson, Kathryn E Holt
Klebsiella pneumoniae is a growing cause of healthcare-associated infections for which multi-drug resistance is a concern. Its polysaccharide capsule is a major virulence determinant and epidemiological marker. However, little is known about capsule epidemiology since serological typing is not widely accessible and many isolates are serologically non-typeable. Molecular typing techniques provide useful insights, but existing methods fail to take full advantage of the information in whole genome sequences. We investigated the diversity of the capsule synthesis loci (K-loci) among 2503 K...
December 2016: Microbial Genomics
https://www.readbyqxmd.com/read/28081233/differences-in-inflammatory-response-induced-by-two-representatives-of-clades-of-the-pandemic-st258-klebsiella-pneumoniae-clonal-lineage-producing-kpc-type-carbapenemases
#10
Giuseppe Castronovo, Ann Maria Clemente, Alberto Antonelli, Marco Maria D'Andrea, Michele Tanturli, Eloisa Perissi, Sara Paccosi, Astrid Parenti, Federico Cozzolino, Gian Maria Rossolini, Maria Gabriella Torcia
ST258-K. pneumoniae (ST258-KP) strains, the most widespread multidrug-resistant hospital-acquired pathogens, belong to at least two clades differing in a 215 Kb genomic region that includes the cluster of capsule genes. To investigate the effects of the different capsular phenotype on host-pathogen interactions, we studied representatives of ST258-KP clades, KKBO-1 and KK207-1, for their ability to activate monocytes and myeloid dendritic cells from human immune competent hosts. The two ST258-KP strains strongly induced the production of inflammatory cytokines...
2017: PloS One
https://www.readbyqxmd.com/read/27795303/antibody-based-immunotherapy-to-treat-and-prevent-infection-with-hypervirulent-klebsiella-pneumoniae
#11
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
https://www.readbyqxmd.com/read/27752727/a-nanomechanical-study-of-the-effects-of-colistin-on-the-klebsiella-pneumoniae-aj218-capsule
#12
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...
May 2017: European Biophysics Journal: EBJ
https://www.readbyqxmd.com/read/27715471/the-contribution-of-capsule-polysaccharide-genes-to-virulence-of-klebsiella-pneumoniae
#13
Kwan Soo Ko
No abstract text is available yet for this article.
July 4, 2017: Virulence
https://www.readbyqxmd.com/read/27683817/cd36-provides-host-protection-against-klebsiella-pneumoniae-intrapulmonary-infection-by-enhancing-lipopolysaccharide-responsiveness-and-macrophage-phagocytosis
#14
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. K. 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 K. pneumoniae pathogenicity. Despite differences in serum sensitivity and virulence of 3 distinct K. pneumoniae (hypermucoviscous K1, research K2, and carbapenemase-producing ST258) strains, the absence of CD36 significantly increased host susceptibility to acute intrapulmonary infection by K...
December 15, 2016: Journal of Infectious Diseases
https://www.readbyqxmd.com/read/27565716/effect-in-virulence-of-switching-conserved-homologous-capsular-polysaccharide-genes-from-klebsiella-pneumoniae-serotype-k1-into-k20
#15
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...
July 4, 2017: Virulence
https://www.readbyqxmd.com/read/26946245/atomic-force-microscopy-of-bacteria-reveals-the-mechanobiology-of-pore-forming-peptide-action
#16
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
https://www.readbyqxmd.com/read/26904512/h-ns-nucleoid-protein-controls-virulence-features-of-klebsiella-pneumoniae-by-regulating-the-expression-of-type-3-pili-and-the-capsule-polysaccharide
#17
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
https://www.readbyqxmd.com/read/26196384/genomic-analysis-of-the-emergence-and-rapid-global-dissemination-of-the-clonal-group-258-klebsiella-pneumoniae-pandemic
#18
Jolene R Bowers, Brandon Kitchel, Elizabeth M Driebe, Duncan R MacCannell, Chandler Roe, Darrin Lemmer, Tom de Man, J Kamile Rasheed, David M Engelthaler, Paul Keim, Brandi M Limbago
Multidrug-resistant Klebsiella pneumoniae producing the KPC carbapenemase have rapidly spread throughout the world, causing severe healthcare-associated infections with limited antimicrobial treatment options. Dissemination of KPC-producing K. pneumoniae is largely attributed to expansion of a single dominant strain, ST258. In this study, we explore phylogenetic relationships and evolution within ST258 and its clonal group, CG258, using whole genome sequence analysis of 167 isolates from 20 countries collected over 17 years...
2015: PloS One
https://www.readbyqxmd.com/read/26034816/role-of-capsular-polysaccharides-in-biofilm-formation-an-afm-nanomechanics-study
#19
Huabin Wang, Jonathan J Wilksch, Richard A Strugnell, Michelle L Gee
Bacteria form biofilms to facilitate colonization of biotic and abiotic surfaces, and biofilm formation on indwelling medical devices is a common cause of hospital-acquired infection. Although it is well-recognized that the exopolysaccharide capsule is one of the key bacterial components for biofilm formation, the underlying biophysical mechanism is poorly understood. In the present study, nanomechanical measurements of wild type and specific mutants of the pathogen, Klebsiella pneumoniae, were performed in situ using atomic force microscopy (AFM)...
June 17, 2015: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/26017037/unravelling-of-a-mechanism-of-resistance-to-colistin-in-klebsiella-pneumoniae-using-atomic-force-microscopy
#20
C Formosa, M Herold, C Vidaillac, R E Duval, E Dague
OBJECTIVES: In this study we focused on the mechanism of colistin resistance in Klebsiella pneumoniae. METHODS: We used two strains of K. pneumoniae: a colistin-susceptible strain (K. pneumoniae ATCC 700603, KpATCC) and its colistin-resistant derivative (KpATCCm, MIC of colistin 16 mg/L). We performed a genotypic analysis based on the expression of genes involved in LPS synthesis and L-Ara4N moiety addition. We also explored the status of the mgrB gene. Then, a phenotypic analysis was performed using atomic force microscopy (AFM)...
August 2015: Journal of Antimicrobial Chemotherapy
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