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https://www.readbyqxmd.com/read/28904998/parallel-evolution-of-group-b-streptococcus-hypervirulent-clonal-complex-17-unveils-new-pathoadaptive-mutations
#1
Alexandre Almeida, Isabelle Rosinski-Chupin, Céline Plainvert, Pierre-Emmanuel Douarre, Maria J Borrego, Claire Poyart, Philippe Glaser
Group B Streptococcus (GBS) is a commensal of the gastrointestinal and genitourinary tracts, while a prevailing cause of neonatal disease worldwide. Of the various clonal complexes (CCs), CC17 is overrepresented in GBS-infected newborns for reasons that are still largely unknown. Here, we report a comprehensive genomic analysis of 626 CC17 isolates collected worldwide, identifying the genetic traits behind their successful adaptation to humans and the underlying differences between carriage and clinical strains...
September 2017: MSystems
https://www.readbyqxmd.com/read/28898618/-klebsiella-pneumoniae-from-k1-and-hypervirulent-clone-st23-first-documented-case-in-portugal
#2
Aida Pereira, Tiago Petrucci, Maria João Simões
The hypervirulent K1 serotype Klebsiella pneumoniae is responsible for a new invasive syndrome, typically associated to hepatic abscesses with extra-hepatic complications. Initially described in Taiwan, it has significantly spread to several Asian countries and more recently to Europe and North America, thus constituting an emerging and global problem. The authors describe a case report of a 64-years-old portuguese caucasian woman without any previous diseases or epidemiological risk factors such as trips or contact with Asian products or population, diagnosed with a pyogenic liver abscess with pleural effusion caused by this hyper-virulent strain...
June 30, 2017: Acta Médica Portuguesa
https://www.readbyqxmd.com/read/28877927/protective-vaccine-efficacy-of-the-complete-form-of-ppe39-protein-from-mycobacterium-tuberculosis-beijing-k-strain-in-mice
#3
Ahreum Kim, Yun-Gyoung Hur, Sunwha Gu, Sang-Nae Cho
The aim of this study was to evaluate the protective efficacy of MTBK_24820, a complete form of PPE39 protein derived from a predominant Beijing/K strain of Mycobacterium tuberculosis in South Korea. Mice were immunized with MTKB_24820, M. bovis Bacilli Calmette-Guérin, or adjuvant prior to a high-dosed Beijing/K strain aerosol infection. After 4 and 9 weeks, bacterial loads were determined and histopathologic and immunologic features in the lungs and spleens of the M. tb-infected mice were analyzed. Putative immunogenic T-cell epitopes were examined using synthetic overlapping peptides...
September 6, 2017: Clinical and Vaccine Immunology: CVI
https://www.readbyqxmd.com/read/28874555/a-trans-acting-leader-rna-from-a-salmonella-virulence-gene
#4
Eunna Choi, Yoontak Han, Yong-Joon Cho, Daesil Nam, Eun-Jin Lee
Bacteria use flagella to move toward nutrients, find its host, or retract from toxic substances. Because bacterial flagellum is one of the ligands that activate the host innate immune system, its synthesis should be tightly regulated during host infection, which is largely unknown. Here, we report that a bacterial leader mRNA from the mgtCBR virulence operon in the intracellular pathogen Salmonella enterica serovar Typhimurium binds to the fljB coding region of mRNAs in the fljBA operon encoding the FljB phase 2 flagellin, a main component of bacterial flagella and the FljA repressor for the FliC phase 1 flagellin, and degrades fljBA mRNAs in an RNase E-dependent fashion during infection...
September 5, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28864030/a-fatal-outbreak-of-st11-carbapenem-resistant-hypervirulent-klebsiella-pneumoniae-in-a-chinese-hospital-a-molecular-epidemiological-study
#5
Danxia Gu, Ning Dong, Zhiwei Zheng, Di Lin, Man Huang, Lihua Wang, Edward Wai-Chi Chan, Lingbin Shu, Jiang Yu, Rong Zhang, Sheng Chen
BACKGROUND: Hypervirulent Klebsiella pneumoniae strains often cause life-threatening community-acquired infections in young and healthy hosts, but are usually sensitive to antibiotics. In this study, we investigated a fatal outbreak of ventilator-associated pneumonia caused by a new emerging hypervirulent K pneumoniae strain. METHODS: The outbreak occurred in the integrated intensive care unit of a new branch of the Second Affiliated Hospital of Zhejiang University (Hangzhou, China)...
August 29, 2017: Lancet Infectious Diseases
https://www.readbyqxmd.com/read/28864028/convergence-of-carbapenem-resistance-and-hypervirulence-in-klebsiella-pneumoniae
#6
Liang Chen, Barry N Kreiswirth
No abstract text is available yet for this article.
August 29, 2017: Lancet Infectious Diseases
https://www.readbyqxmd.com/read/28861076/case-of-meningitis-in-a-neonate-caused-by-an-extended-spectrum-beta-lactamase-producing-strain-of-hypervirulent-klebsiella-pneumoniae
#7
Khalit S Khaertynov, Vladimir A Anokhin, Yuri N Davidyuk, Irina V Nicolaeva, Svetlana V Khalioullina, Dina R Semyenova, Evgeny Y Alatyrev, Natalia N Skvortsova, Levon G Abrahamyan
Klebsiella pneumoniae is one of the most important infectious agents among neonates. This pathogen has a potential to develop an increased antimicrobial resistance and virulence. The classic non-virulent strain of K. pneumoniae, producing an extended-spectrum beta-lactamases (ESBL), is associated with nosocomial infection mainly in preterm neonates. Hypervirulent K. pneumoniae strains are associated with invasive infection among previously healthy ambulatory patients, and most of them exhibit antimicrobial susceptibility...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28859312/phase-variation-of-dna-methyltransferases-and-the-regulation-of-virulence-and-immune-evasion-in-the-pathogenic-neisseria
#8
Kate L Seib, Freda E-C Jen, Adeana L Scott, Aimee Tan, Michael P Jennings
The pathogenic Neisseria provide textbook examples of phase variation: the high frequency, random and reversible switching of gene expression. Typically, phase variable gene expression is observed in genes required for the expression of surface proteins and carbohydrate structures. All Neisseria gonorrhoeae and N. meningitidis strains also express phase variable DNA methyltransferases that are components of DNA restriction-modification systems. Phase variation of these DNA methyltransferases (Mod) alters global DNA methylation patterns...
August 31, 2017: Pathogens and Disease
https://www.readbyqxmd.com/read/28832534/transcriptional-analysis-allows-genome-reannotation-and-reveals-that-cryptococcus-gattii-vgii-undergoes-nutrient-restriction-during-infection
#9
Patrícia Aline Gröhs Ferrareze, Rodrigo Silva Araujo Streit, Patricia Ribeiro Dos Santos, Francine Melise Dos Santos, Rita Maria Cunha de Almeida, Augusto Schrank, Livia Kmetzsch, Marilene Henning Vainstein, Charley Christian Staats
Cryptococcus gattii is a human and animal pathogen that infects healthy hosts and caused the Pacific Northwest outbreak of cryptococcosis. The inhalation of infectious propagules can lead to internalization of cryptococcal cells by alveolar macrophages, a niche in which C. gattii cells can survive and proliferate. Although the nutrient composition of macrophages is relatively unknown, the high induction of amino acid transporter genes inside the phagosome indicates a preference for amino acid uptake instead of synthesis...
August 23, 2017: Microorganisms
https://www.readbyqxmd.com/read/28830806/an-outbreak-of-clostridium-difficile-infections-due-to-a-new-pcr-ribotype-826-epidemiological-and-microbiological-analyses
#10
Monique J T Crobach, Anne F Voor In 't Holt, Cornelis W Knetsch, Sofie M van Dorp, Willeke Bras, Celine Harmanus, Ed J Kuijper, Margreet C Vos
OBJECTIVES: The aim was to investigate an unusual outbreak of 5 patients with in total 8 episodes of a Clostridium difficile infection (CDI) on a gastro intestinal surgical ward of a Dutch tertiary care university affiliated hospital. METHODS: Clinical case investigations and laboratory analyses were performed. Laboratory analyses included PCR ribotyping, MLVA typing, toxinotyping, antimicrobial susceptibility testing and whole genome sequencing. RESULTS: The outbreak was associated with recurrent and severe disease in 2 out of 5 patients...
August 19, 2017: Clinical Microbiology and Infection
https://www.readbyqxmd.com/read/28813461/epidemiology-of-clostridium-difficile-in-infants-in-oxfordshire-uk-risk-factors-for-colonization-and-carriage-and-genetic-overlap-with-regional-c-difficile-infection-strains
#11
Nicole Stoesser, David W Eyre, T Phuong Quan, Heather Godwin, Gemma Pill, Emily Mbuvi, Alison Vaughan, David Griffiths, Jessica Martin, Warren Fawley, Kate E Dingle, Sarah Oakley, Kazimierz Wanelik, John M Finney, Melina Kachrimanidou, Catrin E Moore, Sherwood Gorbach, Thomas V Riley, Derrick W Crook, Tim E A Peto, Mark H Wilcox, A Sarah Walker
BACKGROUND: Approximately 30-40% of children <1 year of age are Clostridium difficile colonized, and may represent a reservoir for adult C. difficile infections (CDI). Risk factors for colonization with toxigenic versus non-toxigenic C. difficile strains and longitudinal acquisition dynamics in infants remain incompletely characterized. METHODS: Predominantly healthy infants (≤2 years) were recruited in Oxfordshire, UK, and provided ≥1 fecal samples. Independent risk factors for toxigenic/non-toxigenic C...
2017: PloS One
https://www.readbyqxmd.com/read/28809435/first-case-report-of-non-human-primates-alouatta-clamitans-with-the-hypervirulent-klebsiella-pneumoniae-serotype-k1-strain-st-23-a-possible-emerging-wildlife-pathogen
#12
Eleine Kuroki Anzai, Júlio César de Souza Júnior, Amanda Rezende Peruchi, Juliana Mello Fonseca, Elke Kreuscher Gumpl, Antônio Carlos Campos Pignatari, Zelinda Maria Braga Hirano, Alessandro Conrado de Oliveira Silveira
BACKGROUND: Hypervirulent strain of Klebsiella pneumoniae genotype K1 isolates have recently emerged, causing severe pyogenic liver abscess complicated by devastating metastatic infections in humans. METHODS: We describe a short outbreak of the non-human primate (NHP) research center, associated with a hypervirulent K. pneumoniae. The genetic similarity of the strains was evaluated by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) techniques, and virulence encoding genes were detected by polymerase chain reaction (PCR)...
August 15, 2017: Journal of Medical Primatology
https://www.readbyqxmd.com/read/28776043/amino-acid-differences-in-the-1753-to-1851-region-of-tcdb-influence-variations-in-tcdb1-and-tcdb2-cell-entry
#13
Jonathan J Hunt, Jason L Larabee, Jimmy D Ballard
Clostridium difficile TcdB2 enters cells with a higher efficiency than TcdB1 and exhibits an overall higher level of toxicity. However, the TcdB2-specific sequences that account for more efficient cell entry have not been reported. In this study, we examined the contribution of carboxy-terminal sequence differences to TcdB activity by comparing the binding, uptake, and endosomal localization of TcdB1 and TcdB2 or selected recombinant fragments of these proteins. Our findings suggest that sequence differences in the amino acid 1753 to 1851 region proximal to the combined repetitive oligopeptide domain (CROP) support enhanced uptake of TcdB2 and localization of toxin in acidified endosomes...
July 2017: MSphere
https://www.readbyqxmd.com/read/28769806/a-red-blood-cell-membrane-camouflaged-nanoparticle-counteracts-streptolysin-o-mediated-virulence-phenotypes-of-invasive-group-a-streptococcus
#14
Tamara Escajadillo, Joshua Olson, Brian T Luk, Liangfang Zhang, Victor Nizet
Group A Streptococcus (GAS), an important human-specific Gram-positive bacterial pathogen, is associated with a broad spectrum of disease, ranging from mild superficial infections such as pharyngitis and impetigo, to serious invasive infections including necrotizing fasciitis and streptococcal toxic shock syndrome. The GAS pore-forming streptolysin O (SLO) is a well characterized virulence factor produced by nearly all GAS clinical isolates. High level expression of SLO is epidemiologically linked to intercontinental dissemination of hypervirulent clonotypes and poor clinical outcomes...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/28753640/mycobacterium-tuberculosis-universal-stress-protein-rv2623-interacts-with-the-putative-atp-binding-cassette-abc-transporter-rv1747-to-regulate-mycobacterial-growth
#15
Lisa N Glass, Ganduri Swapna, Sivagami Sundaram Chavadi, JoAnn M Tufariello, Kaixia Mi, Joshua E Drumm, TuKiet T Lam, Guofeng Zhu, Chenyang Zhan, Catherine Vilchéze, Jesus Arcos, Yong Chen, Lijun Bi, Simren Mehta, Steven A Porcelli, Steve C Almo, Syun-Ru Yeh, William R Jacobs, Jordi B Torrelles, John Chan
We have previously shown that the Mycobacterium tuberculosis universal stress protein Rv2623 regulates mycobacterial growth and may be required for the establishment of tuberculous persistence. Here, yeast two-hybrid and affinity chromatography experiments have demonstrated that Rv2623 interacts with one of the two forkhead-associated domains (FHA I) of Rv1747, a putative ATP-binding cassette transporter annotated to export lipooligosaccharides. FHA domains are signaling protein modules that mediate protein-protein interactions to modulate a wide variety of biological processes via binding to conserved phosphorylated threonine (pT)-containing oligopeptides of the interactors...
July 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28729708/new-mycobacterium-tuberculosis-beijing-clonal-complexes-in-china-revealed-by-phylogenetic-and-bayesian-population-structure-analyses-of-24-loci-miru-vntrs
#16
Chao Zheng, Yann Reynaud, Changsong Zhao, Thierry Zozio, Song Li, Dongxia Luo, Qun Sun, Nalin Rastogi
Beijing lineage of Mycobacterium tuberculosis constitutes the most predominant lineage in East Asia. Beijing epidemiology, evolutionary history, genetics are studied in details for years revealing probable origin from China followed by worldwide expansion, partially linked to higher mutation rate, hypervirulence, drug-resistance, and association with cases of mixed infections. Considering huge amount of data available for 24-loci Mycobacterial Interspersed Repetitive Units-Variable Number of Tandem Repeats, we performed detailed phylogenetic and Bayesian population structure analyses of Beijing lineage strains in mainland China and Taiwan using available 24-loci MIRU-VNTR data extracted from publications or the SITVIT2 database (n = 1490)...
July 20, 2017: Scientific Reports
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
#17
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/28728202/-pyogenic-liver-abscess-changes-of-organisms-and-consequences-for-diagnosis-and-therapy
#18
REVIEW
Alexander Mischnik, Winfried Vincenz Kern, Robert Thimme
Liver abscess is a rare but potentially fatal disease with mortality rates of 2 - 12 %. The spectrum of causative microorganisms varies across the world and is changing due to increasing worldwide travel activity. As a result, previously less frequent pathogens must increasingly be considered in the differential diagnosis. The most common pathogens of liver abscess are so-called abscess streptococci, anaerobes and Gram-negative bacteria such as Escherichia coli and Klebsiella pneumoniae. Certain clones among the Gram-negatives, typically among Klebsiella spp...
July 2017: Deutsche Medizinische Wochenschrift
https://www.readbyqxmd.com/read/28717029/the-metabolite-transporter-peg344-is-required-for-the-full-virulence-of-the-hypervirulent-klebsiella-pneumoniae-strain-hvkp1-after-pulmonary-but-not-subcutaneous-challenge
#19
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
https://www.readbyqxmd.com/read/28713783/streptococcus-pyogenes-phospholipase-a2-induces-the-expression-of-adhesion-molecules-on-human-umbilical-vein-endothelial-cells-and-aorta-of-mice
#20
Masataka Oda, Hisanori Domon, Mie Kurosawa, Toshihito Isono, Tomoki Maekawa, Masaya Yamaguchi, Shigetada Kawabata, Yutaka Terao
The Streptococcus pyogenes phospholipase A2 (SlaA) gene is highly conserved in the M3 serotype of group A S. pyogenes, which often involves hypervirulent clones. However, the role of SlaA in S. pyogenes pathogenesis is unclear. Herein, we report that SlaA induces the expression of intercellular adhesion molecule 1 (ICAM1) and vascular cell adhesion molecule 1 (VCAM1) via the arachidonic acid signaling cascade. Notably, recombinant SlaA induced ICAM1 and VCAM1 expression in human umbilical vein endothelial cells (HUVECs), resulting in enhanced adhesion of human monocytic leukemia (THP-1) cells...
2017: Frontiers in Cellular and Infection Microbiology
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