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klebsiella pneumoniae polysaccharide capsule

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
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
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
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
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
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
Anna Tomás, Leticia Lery, Verónica Regueiro, Camino Pérez-Gutiérrez, Verónica Martínez, David Moranta, Enrique Llobet, Mar González-Nicolau, Jose L Insua, Juan M Tomas, Philippe J Sansonetti, Régis Tournebize, José A Bengoechea
Klebsiella pneumoniae is an etiologic agent of community-acquired and nosocomial pneumonia. It has been shown that K. pneumoniae infections are characterized by reduced early inflammatory response. Recently our group has shown that K. pneumoniae dampens the activation of inflammatory responses by antagonizing the activation of the NF-κB canonical pathway. Our results revealed that K. pneumoniae capsule polysaccharide (CPS) was necessary but not sufficient to attenuate inflammation. To identify additional Klebsiella factors required to dampen inflammation, we standardized and applied a high-throughput gain-of-function screen to examine a Klebsiella transposon mutant library...
July 3, 2015: Journal of Biological Chemistry
Kelly L Wyres, Claire Gorrie, David J Edwards, Heiman F L Wertheim, Li Yang Hsu, Nguyen Van Kinh, Ruth Zadoks, Stephen Baker, Kathryn E Holt
Klebsiella pneumoniae clonal group (CG) 258, comprising sequence types (STs) 258, 11, and closely related variants, is associated with dissemination of the K. pneumoniae carbapenemase (KPC). Hospital outbreaks of KPC CG258 infections have been observed globally and are very difficult to treat. As a consequence, there is renewed interest in alternative infection control measures such as vaccines and phage or depolymerase treatments targeting the K. pneumoniae polysaccharide capsule. To date, 78 immunologically distinct capsule variants have been described in K...
May 2015: Genome Biology and Evolution
Hsin-An Lin, Ya-Li Huang, Kao-Ming Yeh, L K Siu, Jung-Chung Lin, Feng-Yee Chang
BACKGROUND: To determine whether the presence of a capsule regulator gene [i.e., regulator of mucoid phenotype A (rmpA) gene] contributes to virulence on extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) with serotype non-K1/K2 strains. METHODS: Twenty-eight ESBL-KP and non-ESBL-KP isolates were collected from the Tri-Service General Hospital (Taipei, Taiwan). The impact of the virulent rmpA gene in different capsular polysaccharide serotypes on ESBL-KP and non-ESBL-KP isolates was studied by a neutrophil phagocytosis reaction, a serum bactericidal assay, and an animal survival model...
August 2016: Journal of Microbiology, Immunology, and Infection, Wei Mian Yu Gan Ran za Zhi
Liang Chen, Barun Mathema, Johann D D Pitout, Frank R DeLeo, Barry N Kreiswirth
UNLABELLED: Carbapenem-resistant Enterobacteriaceae (CRE), especially Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae, pose an urgent threat in health facilities in the United States and worldwide. K. pneumoniae isolates classified as sequence type 258 (ST258) by multilocus sequence typing are largely responsible for the global spread of KPC. A recent comparative genome study revealed that ST258 K. pneumoniae strains are two distinct genetic clades; however, the molecular origin of ST258 largely remains unknown, and our understanding of the evolution of the two genetic clades is incomplete...
2014: MBio
I Kanevsky-Mullarky, A J Nedrow, S Garst, W Wark, M Dickenson, C S Petersson-Wolfe, R N Zadoks
Klebsiella pneumoniae mastitis in dairy cattle is generally due to an opportunistic infection from the environment, resulting in large heterogeneity among mastitis-causing strains within a herd. However, in mastitis outbreaks in 4 herds, several strains of K. pneumoniae were identified as the cause of infection in multiple cows, suggesting increased ability to either cause disease or evade host defenses. In this study, differences in capsule formation and immune evasion were compared in 5 pairs of K. pneumoniae strains, where one strain in each pair was associated with multiple cases of mastitis and the other with a single case of mastitis...
2014: Journal of Dairy Science
Tzu-Wen Huang, Irene Lam, Hwan-You Chang, Shih-Feng Tsai, Bernhard O Palsson, Pep Charusanti
BACKGROUND: Klebsiella pneumoniae is a leading cause of hospital-acquired urinary tract infections and pneumonia worldwide, and is responsible for many cases of pyogenic liver abscess among diabetic patients in Asia. A defining characteristic of this pathogen is the presence of a thick, exterior capsule that has been reported to play a role in biofilm formation and to protect the organism from threats such antibiotics and host immune challenge. FINDINGS: We constructed two knockout mutants of K...
2014: BMC Research Notes
Yi-Jiun Pan, Tzu-Lung Lin, Yen-Hua Chen, Chun-Ru Hsu, Pei-Fang Hsieh, Meng-Chuan Wu, Jin-Town Wang
Capsule is an important virulence factor in bacteria. A total of 78 capsular types have been identified in Klebsiella pneumoniae. However, there are limitations in current typing methods. We report here the development of a new genotyping method based on amplification of the variable regions of the wzc gene. Fragments corresponding to the variable region of wzc were amplified and sequenced from 76 documented capsular types of reference or clinical strains. The remaining two capsular types (reference strains K15 and K50) lacked amplifiable wzc genes and were proven to be acapsular...
2013: PloS One
Shruti Bansal, Sanjeev Kumar Soni, Kusum Harjai, Sanjay Chhibber
Formation of dense, highly hydrated biofilm structures pose a risk for public and environmental health. Extracellular polymeric substances encompassing biofilms offer 1000-fold greater resistance as compared to the planktonic cells. Using enzymes as anti-biofouling agents, will improve penetration of antimicrobials and increase susceptibility of biofilms to components of immune system. The challenge of using enzymes derived from unrelated bacteria for the degradation of capsular matrix of Klebsiella pneumoniae has not been dealt in the past...
July 2014: Journal of Basic Microbiology
Chun-Ru Hsu, Tzu-Lung Lin, Yi-Jiun Pan, Pei-Fang Hsieh, Jin-Town Wang
BACKGROUND: Klebsiella pneumoniae is one of the major pathogens causing hospital-acquired multidrug-resistant infections. The capsular polysaccharide (CPS) is an important virulence factor of K. pneumoniae. With 78 capsular types discovered thus far, an association between capsular type and the pathogenicity of K. pneumoniae has been observed. METHODOLOGY/PRINCIPAL FINDINGS: To investigate an initially non-typeable K. pneumoniae UTI isolate NTUH-K1790N, the cps gene region was sequenced...
2013: PloS One
Ching-Jou Huang, Zhe-Chong Wang, Hsi-Yuan Huang, Hsien-Da Huang, Hwei-Ling Peng
This study shows that the expression of yjcC, an in vivo expression (IVE) gene, and the stress response regulatory genes soxR, soxS, and rpoS are paraquat inducible in Klebsiella pneumoniae CG43. The deletion of rpoS or soxRS decreased yjcC expression, implying an RpoS- or SoxRS-dependent control. After paraquat or H2O2 treatment, the deletion of yjcC reduced bacterial survival. These effects could be complemented by introducing the ΔyjcC mutant with the YjcC-expression plasmid pJR1. The recombinant protein containing only the YjcC-EAL domain exhibited phosphodiesterase (PDE) activity; overexpression of yjcC has lower levels of cyclic di-GMP...
2013: PloS One
José Luis Insua, Enrique Llobet, David Moranta, Camino Pérez-Gutiérrez, Anna Tomás, Junkal Garmendia, José A Bengoechea
The implementation of infection models that approximate human disease is essential for understanding pathogenesis at the molecular level and for testing new therapies before they are entered into clinical stages. Insects are increasingly being used as surrogate hosts because they share, with mammals, essential aspects of the innate immune response to infections. We examined whether the larva of the wax moth Galleria mellonella could be used as a host model to conceptually approximate Klebsiella pneumoniae-triggered pneumonia...
October 2013: Infection and Immunity
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