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https://www.readbyqxmd.com/read/28318472/antimicrobial-resistance-penicillin-binding-protein-sequences-and-pilus-islet-carriage-in-relation-to-clonal-evolution-of-streptococcus-pneumoniae-serotype-19a-in-russia-2002-2013
#1
N Mayanskiy, T Savinova, N Alyabieva, O Ponomarenko, E Brzhozovskaya, A Lazareva, L Katosova, R Kozlov
Clonal changes of serotype 19A pneumococci have been appreciated in conjunction with growing prevalence of this serotype after implementation of the seven-valent pneumococcal conjugate vaccine (PCV7). In the present study, we characterized serotype 19A pneumococci collected in Russia within a decade preceding the implementation of PCV vaccination and described their clonal evolution. We retrospectively analyzed non-invasive serotype 19A isolates collected in 2002-2013. All isolates were subjected to multilocus sequence typing, antimicrobial susceptibility testing, determination of macrolide resistance genotype, molecular detection of pilus islet (PI) carriage, sequencing of penicillin-binding protein (PBP) genes...
March 20, 2017: Epidemiology and Infection
https://www.readbyqxmd.com/read/28278175/pneumococcal-infection-of-respiratory-cells-exposed-to-welding-fumes-role-of-oxidative-stress-and-hif-1-alpha
#2
Jonathan Grigg, Lisa Miyashita, Reetika Suri
Welders are more susceptible to pneumococcal pneumonia. The mechanisms are yet unclear. Pneumococci co-opt the platelet activating factor receptor (PAFR) to infect respiratory epithelial cells. We previously reported that exposure of respiratory cells to welding fumes (WF), upregulates PAFR-dependent pneumococcal infection. The signaling pathway for this response is unknown, however, in intestinal cells, hypoxia-inducible factor-1 α (HIF 1α) is reported to mediate PAFR-dependent infection. We sought to assess whether oxidative stress plays a role in susceptibility to pneumococcal infection via the platelet activating factor receptor...
2017: PloS One
https://www.readbyqxmd.com/read/28265264/role-of-streptococcus-pneumoniae-proteins-in-evasion-of-complement-mediated-immunity
#3
REVIEW
Greiciely O Andre, Thiago R Converso, Walter R Politano, Lucio F C Ferraz, Marcelo L Ribeiro, Luciana C C Leite, Michelle Darrieux
The complement system plays a central role in immune defense against Streptococcus pneumoniae. In order to evade complement attack, pneumococci have evolved a number of mechanisms that limit complement mediated opsonization and subsequent phagocytosis. This review focuses on the strategies employed by pneumococci to circumvent complement mediated immunity, both in vitro and in vivo. At last, since many of the proteins involved in interactions with complement components are vaccine candidates in different stages of validation, we explore the use of these antigens alone or in combination, as potential vaccine approaches that aim at elimination or drastic reduction in the ability of this bacterium to evade complement...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28264558/a-natural-lipotrisaccharide-and-its-derivatives-selectively-lyse-streptococcus-pneumoniae-via-interaction-with-cell-membrane
#4
Bo Liu, Xue Liu, Jing-Ren Zhang, Gang Liu
A natural lipotrisaccharide (NP000778, 1a), a new triglycosidic tri-O-substituted glycolipid isolated from the Morinda citrifolia plant, and its chemical derivatives were identified to be active against major Gram-positive pathogens, particularly Streptococcus pneumoniae. Additional evidence indicated that 1a and its synthetic derivatives exerted their bactericidal activities against S. pneumoniae by selectively targeting the bacterial membrane, leading to the rapid lysis of the pneumococci. Efficient synthesis of 1a and its derivatives was performed using an application of the intramolecular aglycon delivery (IAD) reaction to establish its structure-activity relationships (SARs)...
March 14, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/28252438/-sensitivity-study-of-antimicrobial-pneumococci-in-central-kazakhstan
#5
I Belyaev, A Belyaev
To determine the epidemiological pattern of antibiotic resistance strains of S. Pneumoniae studied the sensitivity of nasopharyngeal isolates of pneumococci isolated from healthy children attending sports clubs Karaganda region. The frequency of allocation of pneumococci was 35.57%. In accordance with the values of the minimum inhibitory concentration resistant pneumococci was: penicillin - 5.41%, erythromycin - 8.1%, clindamycin - 4.05%, amoxicillin-6.76%, tetracycline 28.38%. Resistance to beta-lactam antibiotics in the studied children is not a significant problem...
January 2017: Georgian Medical News
https://www.readbyqxmd.com/read/28251028/empyema-due-to-streptococcus-pneumoniae-serotype-9v-in-a-child-immunized-with-13-valent-conjugated-pneumococcal-vaccine
#6
Murat Sütçü, Hacer Aktürk, Fatih Karagözlü, Ayper Somer, Nezahat Gürler, Nuran Salman
BACKGROUND: Clinical vaccine failure is the occurence of the specific vaccine-preventable disease in an appropriately and fully vaccinated person after enough time has elapsed for protection against the antigens of the vaccine to develop. Fully immunized cases with pneumoccal vaccine may sometimes develop a complicated pneumonia with empyema caused by a vaccine serotype. CASE REPORT: A 2 year-old male patient was admitted with the complaints of fever. On the basis of findings and laboratory results, the patient was diagnosed as having empyema...
January 2017: Balkan Medical Journal
https://www.readbyqxmd.com/read/28241127/vitamin-d-promotes-pneumococcal-killing-and-modulates-inflammatory-responses-in-primary-human-neutrophils
#7
Karthik Subramanian, Peter Bergman, Birgitta Henriques-Normark
Streptococcus pneumoniae is a major human pathogen and a leading cause of pneumonia, septicemia, and meningitis worldwide. Despite clinical studies linking vitamin D deficiency and pneumonia, molecular mechanisms behind these observations remain unclear. In particular, the effects of vitamin D on neutrophil responses remain unknown. Using pneumococcal strains, primary neutrophils isolated from human blood, and sera from patients with frequent respiratory tract infections (RTIs), we investigated the effects of vitamin D on neutrophil bactericidal and inflammatory responses, including pattern recognition receptors, antimicrobial peptides, and cytokine regulation...
February 28, 2017: Journal of Innate Immunity
https://www.readbyqxmd.com/read/28235635/cephalosporin-no-donor-prodrug-pyrro-c3d-shows-%C3%AE-lactam-mediated-activity-against-streptococcus-pneumoniae-biofilms
#8
Raymond N Allan, Michael J Kelso, Ardeshir Rineh, Nageshwar R Yepuri, Martin Feelisch, Odel Soren, Sanjita Brito-Mutunayagam, Rami J Salib, Paul Stoodley, Stuart C Clarke, Jeremy S Webb, Luanne Hall-Stoodley, Saul N Faust
Bacterial biofilms show high tolerance towards antibiotics and are a significant problem in clinical settings where they are a primary cause of chronic infections. Novel therapeutic strategies are needed to improve anti-biofilm efficacy and support reduction in antibiotic use. Treatment with exogenous nitric oxide (NO) has been shown to modulate bacterial signaling and metabolic processes that render biofilms more susceptible to antibiotics. We previously reported on cephalosporin-3'-diazeniumdiolates (C3Ds) as NO-donor prodrugs designed to selectively deliver NO to bacterial infection sites following reaction with β-lactamases...
May 1, 2017: Nitric Oxide: Biology and Chemistry
https://www.readbyqxmd.com/read/28235386/characteristics-of-ci-children-with-complicated-middle-ear-infections
#9
Søren Hoberg, Christian Danstrup, Bjarke Laursen, Niels Krintel Petersen, Nichlas Udholm, Gintaras Audrius Kamarauskas, Therese Ovesen
OBJECTIVE: To describe cases of complicated middle ear infections in children with cochlear implants (CI), i.e., episodes of acute otitis media (AOM) and acute mastoiditis (AM), resulting in hospitalization. METHODS: A total of 206 children under 16 years (300 implantations) were implanted between 1 January 2008 and 31 December 2014 at the West Danish CI Center, Department of Otorhinolaryngology Head and Neck Surgery, Aarhus, Denmark. By means of two prospective local databases, episodes of AOM or AM and demographics were retrieved including biochemistry, microbiology, length of follow- up, and variable treatment modalities (intravenous (IV) antibiotics, revision mastoidectomy, and insertion of ventilation tubes)...
February 24, 2017: Cochlear Implants International
https://www.readbyqxmd.com/read/28223347/intact-pneumococci-trigger-transcription-of-interferon-related-genes-in-human-monocytes-while-fragmented-autolyzed-bacteria-subvert-this-response
#10
Susann Skovbjerg, Rickard Nordén, Anna Martner, Ebba Samuelsson, Lars Hynsjö, Agnes E Wold
A peculiar trait of pneumococci (Streptococcus pneumoniae) is their propensity to undergo spontaneous lysis during stationary growth due to activation of the enzyme autolysin (LytA) that fragments the peptidoglycan cell wall. The fragments that are generated upon autolysis impair phagocytosis and reduce production of IL-12 and IFN-γ by human leukocytes in response to intact pneumococci, thereby impeding crucial host defenses. The objective was to identify additional monocyte genes whose transcription is induced by intact pneumococci, and subverted by autolyzed bacteria...
February 21, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28218261/pneumococcal-prophages-are-diverse-but-not-without-structure-or-history
#11
Angela B Brueggemann, Caroline L Harrold, Reza Rezaei Javan, Andries J van Tonder, Angus J McDonnell, Ben A Edwards
Bacteriophages (phages) infect many bacterial species, but little is known about the diversity of phages among the pneumococcus, a leading global pathogen. The objectives of this study were to determine the prevalence, diversity and molecular epidemiology of prophages (phage DNA integrated within the bacterial genome) among pneumococci isolated over the past 90 years. Nearly 500 pneumococcal genomes were investigated and RNA sequencing was used to explore prophage gene expression. We revealed that every pneumococcal genome contained prophage DNA...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28215918/molecular-detection-of-genes-responsible-for-macrolide-resistance-among-streptococcus-pneumoniae-isolated-in-north-lebanon
#12
Salam El Ashkar, Marwan Osman, Rayane Rafei, Hassan Mallat, Marcel Achkar, Fouad Dabboussi, Monzer Hamze
In recent years, the increased use of macrolides was linked with the emergence of resistance Streptococcus pneumoniae worldwide. The main aim of this study was to determine the prevalence of S. pneumoniae resistant to macrolides and to identify the macrolide resistance genotypes among clinical isolates collected in North Lebanon. Disk diffusion susceptibility method was performed for 132 strains of S. pneumoniae isolated over a period of 5 years in North Lebanon. Polymerase Chain Reaction followed by pyrosequencing was carried out for confirmation of phenotypic diagnosis...
February 16, 2017: Journal of Infection and Public Health
https://www.readbyqxmd.com/read/28209832/complete-genome-sequences-of-three-multidrug-resistant-clinical-isolates-of-streptococcus-pneumoniae-serotype-19a-with-different-susceptibilities-to-the-myxobacterial-metabolite-carolacton
#13
Jannik Donner, Boyke Bunk, Isabel Schober, Cathrin Spröer, Simone Bergmann, Michael Jarek, Jörg Overmann, Irene Wagner-Döbler
The full-genome sequences of three drug- and multidrug-resistant Streptococcus pneumoniae clinical isolates of serotype 19A were determined by PacBio single-molecule real-time sequencing, in combination with Illumina MiSeq sequencing. A comparison to the genomes of other pneumococci indicates a high nucleotide sequence identity to strains Hungary19A-6 and TCH8431/19A.
February 16, 2017: Genome Announcements
https://www.readbyqxmd.com/read/28209711/serotype-3-pneumococci-sequester-platelet-derived-human-thrombospondin-1-via-the-adhesin-and-immune-evasion-protein-hic
#14
Ulrike Binsker, Thomas P Kohler, Krystin Krauel, Sylvia Kohler, Johanna Habermeyer, Hansjörg Schwertz, Sven Hammerschmidt
Streptococcus pneumoniae serotype 3 strains emerge frequently within clinical isolates of invasive diseases. Bacterial invasion into deeper tissues is associated with colonization and immune evasion mechanisms. Thus, pneumococci express a versatile repertoire of surface proteins sequestering and interacting specifically with components of the human extracellular matrix and serum. Hic, a PspC-like pneumococcal surface protein possesses vitronectin and Factor H binding activity. Here, we show that heterologously expressed Hic domains interact, similar to the classical PspC molecule, with human matricellular thrombospondin-1 (hTSP-1)...
February 16, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28193634/purified-streptococcus-pneumoniae-endopeptidase-o-pepo-enhances-particle-uptake-by-macrophages-in-a-tlr2-and-mir-155-dependent-manner
#15
Hua Yao, Hong Zhang, Kai Lan, Hong Wang, Yufeng Su, Dagen Li, Zhixin Song, Fang Cui, Yibing Yin, Xuemei Zhang
Insights into the host-microbial virulence factors interaction, especially the immune-signaling mechanisms, could provide novel prevention and treatment options for pneumococcal diseases. Streptococcus pneumoniae endopeptidase O (PepO) is a newly discovered and ubiquitously expressed pneumococcal virulence protein. A PepO-mutant strain showed impaired adherence to and invasion of host cells compared with their isogenic wild-type strains. It is still unknown whether PepO is involved in host defense response against pneumococcal infection...
February 13, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28161422/il-17a-and-complement-contribute-to-killing-of-pneumococci-following-immunization-with-a-pneumococcal-whole-cell-vaccine
#16
Ivana B Campos, Muriel Herd, Kristin L Moffitt, Ying-Jie Lu, Michelle Darrieux, Richard Malley, Luciana C C Leite, Viviane M Gonçalves
The pneumococcal whole cell vaccine (PWCV) has been investigated as an alternative to polysaccharide-based vaccines currently in use. It is a non-encapsulated killed vaccine preparation that induces non-capsular antibodies protecting mice against invasive pneumococcal disease (IPD) and reducing nasopharyngeal (NP) carriage via IL-17A activation of mouse phagocytes. Here, we show that PWCV induces antibody and IL-17A production to protect mice against challenge in a fatal aspiration-sepsis model after only one dose...
February 1, 2017: Vaccine
https://www.readbyqxmd.com/read/28134792/from-immunologically-archaic-to-neoteric-glycovaccines
#17
REVIEW
Marco Cavallari, Gennaro De Libero
Polysaccharides (PS) are present in the outermost surface of bacteria and readily come in contact with immune cells. They interact with specific antibodies, which in turn confer protection from infections. Vaccines with PS from pneumococci, meningococci, Haemophilus influenzae type b, and Salmonella typhi may be protective, although with the important constraint of failing to generate permanent immunological memory. This limitation has in part been circumvented by conjugating glycovaccines to proteins that stimulate T helper cells and facilitate the establishment of immunological memory...
January 27, 2017: Vaccines
https://www.readbyqxmd.com/read/28133541/putatively-novel-serotypes-and-the-potential-for-reduced-vaccine-effectiveness-capsular-locus-diversity-revealed-among-5405-pneumococcal-genomes
#18
Andries J van Tonder, James E Bray, Sigríður J Quirk, Gunnsteinn Haraldsson, Keith A Jolley, Martin C J Maiden, Steen Hoffmann, Stephen D Bentley, Ásgeir Haraldsson, Helga Erlendsdóttir, Karl G Kristinsson, Angela B Brueggemann
The pneumococcus is a leading global pathogen and a key virulence factor possessed by the majority of pneumococci is an antigenic polysaccharide capsule ('serotype'), which is encoded by the capsular (cps) locus. Approximately 100 different serotypes are known, but the extent of sequence diversity within the cps loci of individual serotypes is not well understood. Investigating serotype-specific sequence variation is crucial to the design of sequence-based serotyping methodology, understanding pneumococcal conjugate vaccine (PCV) effectiveness and the design of future PCVs...
October 1, 2016: Microbial Genomics
https://www.readbyqxmd.com/read/28132873/detection-of-macrolide-resistance-genes-in-culture-negative-specimens-from-bangladeshi-children-with-invasive-pneumococcal-diseases
#19
Md Hasanuzzaman, Roly Malaker, Maksuda Islam, Abdullah H Baqui, Gary L Darmstadt, Cynthia G Whitney, Samir K Saha
OBJECTIVES: In recent years, an increasing prevalence of macrolide resistance among pneumococci in Bangladesh has been observed. However, the scenario remains incomplete, as few isolates (<1%) are available from pneumonia cases and most pneumococcal meningitis cases (>80%) are culture-negative. This study optimised a triplex PCR method to detect macrolide resistance genes (MRGs) (mefA and ermB) and cpsA from culture-negative pneumococcal cases to predict the prevalence and level of macrolide resistance...
January 26, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28125588/comparison-of-serotype-prevalence-of-pneumococci-isolated-from-middle-ear-lower-respiratory-tract-and-invasive-disease-prior-to-vaccination-in-iceland
#20
Martha Á Hjálmarsdóttir, Sigríður Júlía Quirk, Gunnsteinn Haraldsson, Helga Erlendsdóttir, Ásgeir Haraldsson, Karl G Kristinsson
BACKGROUND: Information on pneumococcal serotype distribution before vaccination is a prerequisite for evaluation of vaccine effect. The aim was to investigate the prevalence of pneumococcal serotypes isolated from middle ear (ME), lower respiratory tract (LRT) and from invasive disease (IPD) in Iceland prior to implementation of ten-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV-10) into the infant vaccination program (April 2011). METHODS AND FINDINGS: All isolates cultured 2007-2011 from ME, LRT and IPD identified as pneumococci were serotyped and tested for susceptibility at the Clinical Microbiology Department, Landspitali University Hospital that serves approximately 85% of the Icelandic population...
2017: PloS One
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