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Gina Leisching, Ray-Dean Pietersen, Carel van Heerden, Paul van Helden, Ian Wiid, Bienyameen Baker
The distinguishing factors that characterize the host response to infection with virulent Mycobacterium tuberculosis (M.tb) are largely confounding. We present an infection study with two genetically closely related M.tb strains that have vastly different pathogenic characteristics. The early host response to infection with these detergent-free cultured strains was analysed through RNAseq in an attempt to provide information on the subtleties which may ultimately contribute to the virulent phenotype. Murine bone marrow derived macrophages (BMDMs) were infected with either a hyper- (R5527) or hypovirulent (R1507) Beijing M...
October 20, 2016: Virulence
Laura Bouché, Maria Panico, Paul Hitchen, Daniel Binet, Federico Sastre, Alexandra Faulds-Pain, Esmeralda Valiente, Evgeny Vinogradov, Annie Aubry, Kelly Fulton, Susan Twine, Susan M Logan, Brendan W Wren, Anne Dell, Howard R Morris
Glycosylation of flagellins is a well recognized property of many bacterial species. In this study we describe the structural characterization of novel flagellar glycans from a number of hypervirulent strains of C. difficile. We used mass spectrometry (nano LC- MS and MS/MS analysis) to identify a number of putative glycopeptides which carried a variety of glycoform substitutions each of which was linked through an initial HexNAc residue to Ser or Thr. Detailed analysis of a LLDGSSTEIR glycopeptide released by tryptic digestion, which carried two variant structures, revealed that the glycopeptide contained, in addition to carbohydrate moieties, a novel structural entity...
October 7, 2016: Journal of Biological Chemistry
Brenda Anna Kwambana-Adams, Franklin Asiedu-Bekoe, Badu Sarkodie, Osei Kuffour Afreh, George Khumalo Kuma, Godfred Owusu-Okyere, Ebenezer Foster-Nyarko, Sally-Ann Ohene, Charles Okot, Archibald Kwame Worwui, Catherine Okoi, Madikay Senghore, Jacob Kweku Otu, Chinelo Ebruke, Richard Bannerman, Kwame Amponsa-Achiano, David Opare, Gemma Kay, Timothy Letsa, Owen Kaluwa, Ebenezer Appiah-Denkyira, Victor Bampoe, Syed M A Zaman, Mark J Pallen, Umberto D'Alessandro, Jason M Mwenda, Martin Antonio
BACKGROUND: An outbreak of pneumococcal meningitis among non-infant children and adults occurred in the Brong-Ahafo region of Ghana between December 2015 and April 2016 despite the recent nationwide implementation of a vaccination programme for infants with the 13-valent pneumococcal conjugate vaccine (PCV13). METHODS: Cerebrospinal fluid (CSF) specimens were collected from patients with suspected meningitis in the Brong-Ahafo region. CSF specimens were subjected to Gram staining, culture and rapid antigen testing...
October 18, 2016: BMC Infectious Diseases
Cristina Rodriguez, Bernard Taminiau, Nicolas Korsak, Véronique Avesani, Johan Van Broeck, Philippe Brach, Michel Delmée, Georges Daube
BACKGROUND: Increasing age, several co-morbidities, environmental contamination, antibiotic exposure and other intestinal perturbations appear to be the greatest risk factors for C. difficile infection (CDI). Therefore, elderly care home residents are considered particularly vulnerable to the infection. The main objective of this study was to evaluate and follow the prevalence of C. difficile in 23 elderly care home residents weekly during a 4-month period. A C. difficile microbiological detection scheme was performed along with an overall microbial biodiversity study of the faeces content by 16S rRNA gene analysis...
October 1, 2016: BMC Microbiology
Catherine E Isom, Smita K Menon, Leonard M Thomas, Ann H West, George B Richter-Addo, Elizabeth A Karr
BACKGROUND: Clostridium difficile is a spore-forming obligate anaerobe that can remain viable for extended periods, even in the presence of antibiotics, which contributes to the persistence of this bacterium as a human pathogen during host-to-host transmission and in hospital environments. We examined the structure and function of a gene product with the locus tag CDR20291_0991 (cdPadR1) as part of our broader goal aimed at elucidating transcription regulatory mechanisms involved in virulence and antibiotic resistance of the recently emergent hypervirulent C...
October 4, 2016: BMC Microbiology
Sergio García-Fernández, María-Isabel Morosini, Marta Cobo, José Ramón Foruny, Antonio López-Sanromán, Javier Cobo, José Romero, Rafael Cantón, Rosa Del Campo
We report the fecal carriage eradication of a VIM-1-producing ST9 Klebsiella oxytoca strain in a pluripathological 84-year-old woman after fecal microbiota transplantation to control relapsing R027 hypervirulent Clostridium difficile infections. The donor was her son, in which the absence of fecal carbapenemase-producing bacteria was corroborated.
September 16, 2016: Diagnostic Microbiology and Infectious Disease
Esmeralda Valiente, Laura Bouché, Paul Hitchen, Alexandra Faulds-Pain, Mario Songane, Lisa F Dawson, Elizabeth Donahue, Richard A Stabler, Maria Panico, Howard R Morris, Mona Bajaj-Elliott, Susan M Logan, Anne Dell, Brendan W Wren
Clostridium difficile is the principal cause of nosocomial infectious diarrhoea worldwide. The pathogen modifies its flagellin with either a type A or type B O-linked glycosylation system, which has a contributory role in pathogenesis. We study the functional role of glycosyltransferases modifying type B flagellin in the 023 and 027 hypervirulent C. difficile lineages by mutagenesis of five putative glycosyltransferases and biosynthetic genes. We reveal their roles in the biosynthesis of the flagellin glycan chain and demonstrate that flagellar post-translational modification affects motility and adhesion-related bacterial properties of these strains...
October 4, 2016: Journal of Biological Chemistry
Bailey M Carignan, Kyle D Brumfield, Mike S Son
Vibrio cholerae is the etiological agent of the infectious disease cholera, which is characterized by vomiting and severe watery diarrhea. Recently, V. cholerae clinical isolates have demonstrated increased virulence capabilities, causing more severe symptoms with a much higher rate of disease progression than previously observed. We have identified single nucleotide polymorphisms (SNPs) in four virulence-regulatory genes (hapR, hns, luxO, and vieA) of a hypervirulent V. cholerae clinical isolate, MQ1795...
September 2016: MSphere
Margaret Ip, Irene Ang, Kitty Fung, Veranja Liyanapathirana, Ming Jing Luo, Raymond Lai
We describe a hypervirulent clone of group B Streptococcus serotype III, subtype 4, sequence type 283, that caused invasive disease with a predilection for meningitis in Hong Kong during 1993-2012. The organism is associated with high mortality and increased summer prevalence and is linked to diseased fish from freshwater fish farms.
October 2016: Emerging Infectious Diseases
Matteo Cerboneschi, Francesca Decorosi, Carola Biancalani, Maria Vittoria Ortenzi, Sofia Macconi, Luciana Giovannetti, Carlo Viti, Beatrice Campanella, Massimo Onor, Emilia Bramanti, Stefania Tegli
The plant pathogenic bacterium Pseudomonas savastanoi, the causal agent of olive and oleander knot disease, uses the so-called "indole-3-acetamide pathway" to convert tryptophan to indole-3-acetic acid (IAA) via a two-step pathway catalyzed by enzymes encoded by the genes in the iaaM/iaaH operon. Moreover, pathovar nerii of P. savastanoi is able to conjugate IAA to lysine to generate the less biologically active compound IAA-Lys via the enzyme IAA-lysine synthase encoded by the iaaL gene. Interestingly, iaaL is now known to be widespread in many Pseudomonas syringae pathovars, even in the absence of the iaaM and iaaH genes for IAA biosynthesis...
September 13, 2016: Research in Microbiology
Major Gooyit, Kim D Janda
Prolonged use of broad-spectrum antibiotics disrupts the indigenous gut microbiota, which consequently enables toxigenic Clostridium difficile species to proliferate and cause infection. The burden of C. difficile infections was exacerbated with the outbreak of hypervirulent strains that produce copious amounts of enterotoxins and spores. In recent past, membrane-active agents have generated a surge of interest due to their bactericidal property with a low propensity for resistance. In this study, we capitalized on the antimicrobial property and low oral bioavailability of salicylanilide anthelmintics (closantel, rafoxanide, niclosamide, oxyclozanide) to target the gut pathogen...
2016: Scientific Reports
Bing Wang, Samantha M Powell, Neda Hessami, Fares Z Najar, Leonard M Thomas, Elizabeth A Karr, Ann H West, George B Richter-Addo
Nitroreductases (NRs) are flavin mononucleotide (FMN)-dependent enzymes that catalyze the biotransformation of organic nitro compounds (RNO2; R = alkyl, aryl) to the nitroso RN=O, hydroxylamino RNHOH, or amine RNH2 derivatives. Metronidazole (Mtz) is a nitro-containing antibiotic that is commonly prescribed for lower-gut infections caused by the anaerobic bacterium Clostridium difficile. C. difficile infections rank number one among hospital acquired infections, and can result in diarrhea, severe colitis, or even death...
September 10, 2016: Nitric Oxide: Biology and Chemistry
Helen Campbell, Shamez Ladhani
Invasive meningococcal disease (IMD) is associated with high morbidity and mortality. Recently, use of the quadrivalent MenACWY conjugate vaccines has increased with the emergence of a hypervirulent MenW:cc11 strain in certain parts of the world, especially South America. In England, MenW:cc11 IMD cases increased rapidly after 2009 and was responsible for 24% of all IMD cases in 2014/15 compared to <5% previously, leading to the emergency introduction of a national teenage MenACWY conjugate vaccine programme in August 2015...
September 12, 2016: International Health
Zuowei Wu, Balamurugan Periaswamy, Orhan Sahin, Michael Yaeger, Paul Plummer, Weiwei Zhai, Zhangqi Shen, Lei Dai, Swaine L Chen, Qijing Zhang
Infections due to clonal expansion of highly virulent bacterial strains are clear and present threats to human and animal health. Association of genetic changes with disease is now a routine, but identification of causative mutations that enable disease remains difficult. Campylobacter jejuni is an important zoonotic pathogen transmitted to humans mainly via the foodborne route. C. jejuni typically colonizes the gut, but a hypervirulent and rapidly expanding clone of C. jejuni recently emerged, which is able to translocate across the intestinal tract, causing systemic infection and abortion in pregnant animals...
September 20, 2016: Proceedings of the National Academy of Sciences of the United States of America
Shuyi Chen, Huawei Gu, Chunli Sun, Haiying Wang, Jufang Wang
BACKGROUND: Clostridium difficile is an anaerobic, spore-forming and Gram-positive bacillus. It is the major cause of antibiotic-associated diarrhea prevailing in hospital settings. The morbidity and mortality of C. difficile infection (CDI) has increased significantly due to the emergence of hypervirulent strains. Because of the poor clinical different between CDI and other causes of hospital-acquired diarrhea, laboratory test for C. difficile is an important intervention for diagnosis of CDI...
September 6, 2016: Infection
Erin E McClelland, Udupi A Ramagopal, Johanna Rivera, James Cox, Antonio Nakouzi, Moses M Prabu, Steven C Almo, Arturo Casadevall
The pathogenic yeast Cryptococcus neoformans causes cryptococcosis, a life-threatening fungal disease. C. neoformans has multiple virulence mechanisms that are non-host specific, induce damage and interfere with immune clearance. Microarray analysis of C. neoformans strains serially passaged in mice associated a small gene (CNAG_02591) with virulence. This gene, hereafter identified as HVA1 (hypervirulence-associated protein 1), encodes a protein that has homologs of unknown function in plant and animal fungi, consistent with a conserved mechanism...
September 2016: PLoS Pathogens
Edmondo Campisi, Roberto Rosini, Wenjing Ji, Silvia Guidotti, Maricarmen Rojas-López, Guozhu Geng, Qiulian Deng, Huamin Zhong, Weidong Wang, Haiying Liu, Cassandra Nan, Immaculada Margarit, C D Rinaudo
Neonatal invasive disease caused by group B Streptococcus (GBS) represents a significant public health care concern globally. However, data related to disease burden, serotype distribution, and molecular epidemiology in China and other Asian countries are very few and specifically relative to confined regions. The aim of this study was to investigate the genetic characteristics of GBS isolates recovered from neonates with invasive disease during 2013-2014 at Guangzhou and Changsha hospitals in southern mainland China...
2016: Frontiers in Microbiology
Carrie A Cowardin, Erica L Buonomo, Mahmoud M Saleh, Madeline G Wilson, Stacey L Burgess, Sarah A Kuehne, Carsten Schwan, Anna M Eichhoff, Friedrich Koch-Nolte, Dena Lyras, Klaus Aktories, Nigel P Minton, William A Petri
Clostridium difficile is the most common hospital acquired pathogen in the USA, and infection is, in many cases, fatal. Toxins A and B are its major virulence factors, but expression of a third toxin, known as C. difficile transferase (CDT), is increasingly common. An adenosine diphosphate (ADP)-ribosyltransferase that causes actin cytoskeletal disruption, CDT is typically produced by the major, hypervirulent strains and has been associated with more severe disease. Here, we show that CDT enhances the virulence of two PCR-ribotype 027 strains in mice...
2016: Nature Microbiology
Hossein Gouran, Hyrum Gillespie, Rafael Nascimento, Sandeep Chakraborty, Paulo A Zaini, Aaron Jacobson, Brett S Phinney, David Dolan, Blythe P Durbin-Johnson, Elena S Antonova, Steven E Lindow, Matthew S Mellema, Luiz R Goulart, Abhaya M Dandekar
Pierce's disease (PD) is a deadly disease of grapevines caused by the Gram-negative bacterium Xylella fastidiosa. Though disease symptoms were formerly attributed to bacteria blocking the plant xylem, this hypothesis is at best overly simplistic. Recently, we used a proteomic approach to characterize the secretome of X. fastidiosa, both in vitro and in planta, and identified LesA as one of the pathogenicity factors of X. fastidiosa in grapevines that leads to leaf scorching and chlorosis. Herein, we characterize another such factor encoded by PD0956, designated as an antivirulence secreted protease "PrtA" that displays a central role in controlling in vitro cell proliferation, length, motility, biofilm formation, and in planta virulence...
2016: Scientific Reports
José M Vargas-Muñiz, Hilary Renshaw, Amber D Richards, Greg Waitt, Erik J Soderblom, Martin A Moseley, Yohannes Asfaw, Praveen R Juvvadi, William J Steinbach
Septins are a conserved family of GTPases that form hetero-oligomeric complexes and perform diverse functions in higher eukaryotes, excluding plants. Our previous studies in the human fungal pathogen Aspergillus fumigatus revealed that the core septin, AspB, a CDC3 ortholog, is required for septation, conidiation, and conidial cell wall organization. Although AspB is important for these cellular functions, nothing is known about the role of kinases or phosphatases in the posttranslational regulation and localization of septins in A...
2016: Frontiers in Microbiology
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