bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Survey of the Dissemination of Two
bla
KPC
-Harboring IncFIA Plasmids in New Jersey and New York Hospitals
Authors: Chen Liang , Chavda Kalyan D. , Melano Roberto G. , Hong Tao , Rojtman Albert D. , Jacobs Michael R. , Bonomo Robert A. , Kreiswirth Barry N. 
Published: February 2014

ABSTRACT

Klebsiella pneumoniae
carbapenemase (KPC)-producing
K. pneumoniae
strains have spread worldwide and become a major threat in health care facilities. Transmission of
bla
KPC
, the plasmid-borne KPC gene, can be mediated by clonal spread and horizontal transfer. Here, we report the complete nucleotide sequences of two novel
bla
KPC-3
-harboring IncFIA plasmids, pBK30661 and pBK30683. pBK30661 is 74 kb in length, with a mosaic plasmid structure; it exhibits homologies to several other plasmids but lacks the plasmid transfer operon (
tra
) and the origin of transfer (
oriT
) that are required for plasmid transfer. pBK30683 is a conjugative plasmid with a cointegrated plasmid structure, comprising a 72-kb element that highly resembles pBK30661 (>99.9% nucleotide identities) and an extra 68-kb element that harbors
tra
and
oriT
. A PCR scheme was designed to detect the distribution of
bla
KPC
-harboring IncFIA (pBK30661-like and pBK30683-like) plasmids in a collection of clinical
Enterobacteriaceae
isolates from 10 hospitals in New Jersey and New York. KPC-harboring IncFIA plasmids were found in 20% of 491
K. pneumoniae
isolates, and all carried
bla
KPC-3
. pBK30661-like plasmids were identified mainly in the epidemic sequence type 258 (ST258)
K. pneumoniae
clone, while pBK30683-like plasmids were widely distributed in ST258 and other
K. pneumoniae
sequence types and among non-
K. pneumoniae Enterobacteriaceae
species. This suggests that both clonal spread and horizontal plasmid transfer contributed to the dissemination of
bla
KPC
-harboring IncFIA plasmids in our area. Further studies are needed to understand the distribution of this plasmid group in other health care regions and to decipher the origins of pBK30661-like and pBK30683-like plasmids.
Matrix Metalloproteinase Inhibition Lowers Mortality and Brain Injury in Experimental Pneumococcal Meningitis
Authors: Liechti Fabian D. , Grandgirard Denis , Leppert David , Leib Stephen L. 
Published: February 2014

ABSTRACT

Pneumococcal meningitis (PM) results in high mortality rates and long-lasting neurological deficits. Hippocampal apoptosis and cortical necrosis are histopathological correlates of neurofunctional sequelae in rodent models and are frequently observed in autopsy studies of patients who die of PM. In experimental PM, inhibition of matrix metalloproteinases (MMPs) and/or tumor necrosis factor (TNF)-converting enzyme (TACE) has been shown to reduce brain injury and the associated impairment of neurocognitive function. However, none of the compounds evaluated in these studies entered clinical development. Here, we evaluated two second-generation MMP and TACE inhibitors with higher selectivity and improved oral availability. Ro 32-3555 (Trocade, cipemastat) preferentially inhibits collagenases (MMP-1, -8, and -13) and gelatinase B (MMP-9), while Ro 32-7315 is an efficient inhibitor of TACE. PM was induced in infant rats by the intracisternal injection of live
Streptococcus pneumoniae
. Ro 32-3555 and Ro 32-7315 were injected intraperitoneally, starting at 3 h postinfection. Antibiotic (ceftriaxone) therapy was initiated at 18 h postinfection, and clinical parameters (weight, clinical score, mortality rate) were recorded. Myeloperoxidase activities, concentrations of cytokines and chemokines, concentrations of MMP-2 and MMP-9, and collagen concentrations were measured in the cerebrospinal fluid. Animals were sacrificed at 42 h postinfection, and their brains were assessed by histomorphometry for hippocampal apoptosis and cortical necrosis. Both compounds, while exhibiting disparate MMP and TACE inhibitory profiles, decreased hippocampal apoptosis and cortical injury. Ro 32-3555 reduced mortality rates and cerebrospinal fluid TNF, interleukin-1β (IL-1β) and collagen levels, while Ro 32-7315 reduced weight loss and cerebrospinal fluid TNF and IL-6 levels.
Protein Kinase C Mediates Enterohemorrhagic Escherichia coli O157:H7-Induced Attaching and Effacing Lesions
Authors: Shen-Tu Grace , Kim Hyunhee , Liu Mingyao , Johnson-Henry Kathene C. , Sherman Philip M. 
Published: February 2014

ABSTRACT

Enterohemorrhagic
Escherichia coli
serotype O157:H7 causes outbreaks of diarrhea, hemorrhagic colitis, and the hemolytic-uremic syndrome.
E. coli
O157:H7 intimately attaches to epithelial cells, effaces microvilli, and recruits F-actin into pedestals to form attaching and effacing lesions. Lipid rafts serve as signal transduction platforms that mediate microbe-host interactions. The aims of this study were to determine if protein kinase C (PKC) is recruited to lipid rafts in response to
E. coli
O157:H7 infection and what role it plays in attaching and effacing lesion formation. HEp-2 and intestine 407 tissue culture epithelial cells were challenged with
E. coli
O157:H7, and cell protein extracts were then separated by buoyant density ultracentrifugation to isolate lipid rafts. Immunoblotting for PKC was performed, and localization in lipid rafts was confirmed with an anti-caveolin-1 antibody. Isoform-specific PKC small interfering RNA (siRNA) was used to determine the role of PKC in
E. coli
O157:H7-induced attaching and effacing lesions. In contrast to uninfected cells, PKC was recruited to lipid rafts in response to
E. coli
O157:H7. Metabolically active bacteria and cells with intact lipid rafts were necessary for the recruitment of PKC. PKC recruitment was independent of the intimin gene, type III secretion system, and the production of Shiga toxins. Inhibition studies, using myristoylated PKCζ pseudosubstrate, revealed that atypical PKC isoforms were activated in response to the pathogen. Pretreating cells with isoform-specific PKC siRNA showed that PKCζ plays a role in
E. coli
O157:H7-induced attaching and effacing lesions. We concluded that lipid rafts mediate atypical PKC signal transduction responses to
E. coli
O157:H7. These findings contribute further to the understanding of the complex array of microbe-eukaryotic cell interactions that occur in response to infection.
Role of Pht Proteins in Attachment of Streptococcus pneumoniae to Respiratory Epithelial Cells
Authors: Kallio Anna , Sepponen Kirsi , Hermand Philippe , Denoël Philippe , Godfroid Fabrice , Melin Merit 
Published: February 2014

ABSTRACT

Pneumococcal adherence to mucosal surfaces is a critical step in nasopharyngeal colonization, but so far few pneumococcal adhesins involved in the interaction with host cells have been identified. PhtA, PhtB, PhtD, and PhtE are conserved pneumococcal surface proteins that have proven promising as vaccine candidates. One suggested virulence function of Pht proteins is to mediate adherence at the respiratory mucosa. In this study, we assessed the role of Pht proteins in pneumococcal binding to respiratory epithelial cells. Pneumococci were incubated with human nasopharyngeal epithelial cells (Detroit-562) and lung epithelial cells (A549 and NCI-H292), and the proportion of bound bacteria was measured by plating viable counts. Strains R36A (unencapsulated), D39 (serotype 2), 43 (serotype 3), 4-CDC (serotype 4), and 2737 (serotype 19F) with one or more of the four homologous Pht proteins deleted were compared with their wild-type counterparts. Also, the effect of anti-PhtD antibodies on the adherence of strain 2737 to the respiratory epithelial cells was studied. Our results suggest that Pht proteins play a role in pneumococcal adhesion to the respiratory epithelium. We also found that antibody to PhtD is able to inhibit bacterial attachment to the cells, suggesting that antibodies against PhtD present at mucosal surfaces might protect from pneumococcal attachment and subsequent colonization. However, the relative significance of Pht proteins to the ability of pneumococci to bind
in vitro
to epithelial cells depends on the genetic background and the capsular serotype of the strain.
Suppression of Antimicrobial Peptide Expression by Ureaplasma Species
Authors: Xiao Li , Crabb Donna M. , Dai Yuling , Chen Yuying , Waites Ken B. , Atkinson T. Prescott 
Published: February 2014

ABSTRACT

Ureaplasma
species commonly colonize the adult urogenital tract and are implicated in invasive diseases of adults and neonates. Factors that permit the organisms to cause chronic colonization or infection are poorly understood. We sought to investigate whether host innate immune responses, specifically, antimicrobial peptides (AMPs), are involved in determining the outcome of
Ureaplasma
infections. THP-1 cells, a human monocytoid tumor line, were cocultured with
Ureaplasma parvum
and
U. urealyticum
. Gene expression levels of a variety of host defense genes were quantified by real-time PCR.
In vitro
antimicrobial activities of synthetic AMPs against
Ureaplasma
spp. were determined using a flow cytometry-based assay. Chromosomal histone modifications in host defense gene promoters were tested by chromatin immunoprecipitation (ChIP). DNA methylation status in the AMP promoter regions was also investigated. After stimulation with
U. parvum
and
U. urealyticum
, the expression of cell defense genes, including the AMP genes (
DEFB1
,
DEFA5
,
DEFA6
, and
CAMP
), was significantly downregulated compared to that of
TNFA
and
IL-8
, which were upregulated.
In vitro
flow cytometry-based antimicrobial assay revealed that synthetic peptides LL-37, hBD-3, and hBD-1 had activity against
Ureaplasma
spp. Downregulation of the AMP genes was associated with chromatin modification alterations, including the significantly decreased histone H3K9 acetylation with
U. parvum
infection. No DNA methylation status changes were detected upon
Ureaplasma
infection. In conclusion, AMPs have
in vitro
activity against
Ureaplasma
spp., and suppression of AMP expression might be important for the organisms to avoid this aspect of the host innate immune response and to establish chronic infection and colonization.
Enhanced Interaction of Vibrio cholerae Virulence Regulators TcpP and ToxR under Oxygen-Limiting Conditions
Authors: Fan Fenxia , Liu Zhi , Jabeen Nusrat , Birdwell L. Dillon , Zhu Jun , Kan Biao 
Published: February 2014

ABSTRACT

Vibrio cholerae
is the causative agent of the diarrheal disease cholera. The ability of
V. cholerae
to colonize and cause disease requires the intricately regulated expression of a number of virulence factors during infection. One of the signals sensed by
V. cholerae
is the presence of oxygen-limiting conditions in the gut. It has been shown that the virulence activator AphB plays a key role in sensing low oxygen concentrations and inducing the transcription of another key virulence activator, TcpP. In this study, we used a bacterial two-hybrid system to further examine the effect of oxygen on different virulence regulators. We found that anoxic conditions enhanced the interaction between TcpP and ToxR, identified as the first positive regulator of
V. cholerae
virulence genes. We further demonstrated that the TcpP-ToxR interaction was dependent on the primary periplasmic protein disulfide formation enzyme DsbA and cysteine residues in the periplasmic domains of both ToxR and TcpP. Furthermore, we showed that in
V. cholerae
, an interaction between TcpP and ToxR is important for virulence gene induction. Under anaerobic growth conditions, we detected ToxR-TcpP heterodimers, which were abolished in the presence of the reducing agent dithiothreitol. Our results suggest that
V. cholerae
may sense intestinal anoxic signals by multiple components to activate virulence.
Mucosal Immunization with Recombinant Fusion Protein DnaJ-ΔA146Ply Enhances Cross-Protective Immunity against Streptococcus pneumoniae Infection in Mice via Interleukin 17A
Authors: Liu Yusi , Wang Hong , Zhang Shuai , Zeng Lingbin , Xu Xiuyu , Wu Kaifeng , Wang Wei , Yin Nanlin , Song Zhixin , Zhang Xuemei , Yin Yibing 
Published: February 2014

ABSTRACT

Pneumolysin (Ply) and its variants are protective against pneumococcal infections in animal models, and as a Toll-like receptor 4 agonist, pneumolysin has been reported to be a mucosal adjuvant. DnaJ has been approved as a useful candidate vaccine protein; we therefore designed novel fusion proteins of DnaJ with a form of Ply that has a deletion of A146 (ΔA146Ply-DnaJ [the C terminus of ΔA146Ply connected with the N terminus of DnaJ] and DnaJ-ΔA146Ply [the C terminus of DnaJ connected with the N terminus of ΔA146Ply]) to test whether they are protective against focal and lethal pneumococcal infections and their potential protective mechanisms. The purified proteins were used to intranasally immunize the animals without additional adjuvant. Immunization with DnaJ-ΔA146Ply or DnaJ plus ΔA146Ply (Ply with a single deletion of A146) could significantly reduce
S. pneumoniae
colonization in the nasopharynx and lung relative with DnaJ alone. Additionally, we observed the best protection for DnaJ-ΔA146Ply-immunized mice after challenge with lethal doses of
S. pneumoniae
strains, which was comparable to that achieved by PPV23. Mice immunized with DnaJ-ΔA146Ply produced significantly higher levels of anti-DnaJ IgG in serum and secretory IgA (sIgA) in saliva than those immunized with DnaJ alone. The production of IL-17A was also striking in DnaJ-ΔA146Ply-immunized mice. IL-17A knockout (KO) mice did not benefit from DnaJ-ΔA146Ply immunization in colonization experiments, and sIgA production was impaired in IL-17A KO mice. Collectively, our results indicate a mucosal adjuvant potential for ΔA146Ply and that, without additional adjuvant, DnaJ-ΔA146Ply fusion protein exhibits extensive immune stimulation and is effective against pneumococcal challenges, properties which are partially attributed to the IL-17A-mediated immune responses.
The δ Subunit of RNA Polymerase Guides Promoter Selectivity and Virulence in Staphylococcus aureus
Authors: Weiss Andy , Ibarra J. Antonio , Paoletti Jessica , Carroll Ronan K. , Shaw Lindsey N. 
Published: February 2014

ABSTRACT

In Gram-positive bacteria, and particularly the
Firmicutes
, the DNA-dependent RNA polymerase (RNAP) complex contains an additional subunit, termed the δ factor, or RpoE. This enigmatic protein has been studied for more than 30 years for various organisms, but its function is still not well understood. In this study, we investigated its role in the major human pathogen
Staphylococcus aureus
. We showed conservation of important structural regions of RpoE in
S. aureus
and other species and demonstrated binding to core RNAP that is mediated by the β and/or β′ subunits. To identify the impact of the δ subunit on transcription, we performed transcriptome sequencing (RNA-seq) analysis and observed 191 differentially expressed genes in the
rpoE
mutant. Ontological analysis revealed, quite strikingly, that many of the downregulated genes were known virulence factors, while several mobile genetic elements (SaPI5 and prophage ϕSA3usa) were strongly upregulated. Phenotypically, the
rpoE
mutant had decreased accumulation and/or activity of a number of key virulence factors, including alpha toxin, secreted proteases, and Panton-Valentine leukocidin (PVL). We further observed significantly decreased survival of the mutant in whole human blood, increased phagocytosis by human leukocytes, and impaired virulence in a murine model of infection. Collectively, our results demonstrate that the δ subunit of RNAP is a critical component of the
S. aureus
transcription machinery and plays an important role during infection.
A Broadly Implementable Research Course in Phage Discovery and Genomics for First-Year Undergraduate Students
Authors: Jordan Tuajuanda C. , Burnett Sandra H. , Carson Susan , Caruso Steven M. , Clase Kari , DeJong Randall J. , Dennehy John J. , Denver Dee R. , Dunbar David , Elgin Sarah C. R. , Findley Ann M. , Gissendanner Chris R. , Golebiewska Urszula P. , Guild Nancy , Hartzog Grant A. , Grillo Wendy H. , Hollowell Gail P. , Hughes Lee E. , Johnson Allison , King Rodney A. , Lewis Lynn O. , Li Wei , Rosenzweig Frank , Rubin Michael R. , Saha Margaret S. , Sandoz James , Shaffer Christopher D. , Taylor Barbara , Temple Louise , Vazquez Edwin , Ware Vassie C. , Barker Lucia P. , Bradley Kevin W. , Jacobs-Sera Deborah , Pope Welkin H. , Russell Daniel A. , Cresawn Steven G. , Lopatto David , Bailey Cheryl P. , Hatfull Graham F. 
Published: February 2014

ABSTRACT
Engaging large numbers of undergraduates in authentic scientific discovery is desirable but difficult to achieve. We have developed a general model in which faculty and teaching assistants from diverse academic institutions are trained to teach a research course for first-year undergraduate students focused on bacteriophage discovery and genomics. The course is situated within a broader scientific context aimed at understanding viral diversity, such that faculty and students are collaborators with established researchers in the field. The Howard Hughes Medical Institute (HHMI) Science Education Alliance Phage Hunters Advancing Genomics and Evolutionary Science (SEA-PHAGES) course has been widely implemented and has been taken by over 4,800 students at 73 institutions. We show here that this alliance-sourced model not only substantially advances the field of phage genomics but also stimulates students’ interest in science, positively influences academic achievement, and enhances persistence in science, technology, engineering, and mathematics (STEM) disciplines. Broad application of this model by integrating other research areas with large numbers of early-career undergraduate students has the potential to be transformative in science education and research training.

IMPORTANCE
Engagement of undergraduate students in scientific research at early stages in their careers presents an opportunity to excite students about science, technology, engineering, and mathematics (STEM) disciplines and promote continued interests in these areas. Many excellent course-based undergraduate research experiences have been developed, but scaling these to a broader impact with larger numbers of students is challenging. The Howard Hughes Medical Institute (HHMI) Science Education Alliance Phage Hunting Advancing Genomics and Evolutionary Science (SEA-PHAGES) program takes advantage of the huge size and diversity of the bacteriophage population to engage students in discovery of new viruses, genome annotation, and comparative genomics, with strong impacts on bacteriophage research, increased persistence in STEM fields, and student self-identification with learning gains, motivation, attitude, and career aspirations.
Climate change effects on human health: projections of temperature-related mortality for the UK during the 2020s, 2050s and 2080s
Authors: Hajat Shakoor , Vardoulakis Sotiris , Heaviside Clare , Eggen Bernd 
Published: February 2014

BackgroundThe most direct way in which climate change is expected to affect public health relates to changes in mortality rates associated with exposure to ambient temperature. Many countries worldwide experience annual heat-related and cold-related deaths associated with current weather patterns. Future changes in climate may alter such risks. Estimates of the likely future health impacts of such changes are needed to inform public health policy on climate change in the UK and elsewhere.MethodsTime-series regression analysis was used to characterise current temperature-mortality relationships by region and age group. These were then applied to the local climate and population projections to estimate temperature-related deaths for the UK by the 2020s, 2050s and 2080s. Greater variability in future temperatures as well as changes in mean levels was modelled.ResultsA significantly raised risk of heat-related and cold-related mortality was observed in all regions. The elderly were most at risk. In the absence of any adaptation of the population, heat-related deaths would be expected to rise by around 257% by the 2050s from a current annual baseline of around 2000 deaths, and cold-related mortality would decline by 2% from a baseline of around 41 000 deaths. The cold burden remained higher than the heat burden in all periods. The increased number of future temperature-related deaths was partly driven by projected population growth and ageing.ConclusionsHealth protection from hot weather will become increasingly necessary, and measures to reduce cold impacts will also remain important in the UK. The demographic changes expected this century mean that the health protection of the elderly will be vital.
Impact of chronic obstructive pulmonary disease on morbidity and mortality after myocardial infarction
Authors: Andell Pontus , Koul Sasha , Martinsson Andreas , Sundström Johan , Jernberg Tomas , Smith J Gustav , James Stefan , Lindahl Bertil , Erlinge David 
Published: February 2014

AimTo gain a better understanding of the impact of chronic obstructive pulmonary disease (COPD) on long-term mortality in patients with myocardial infarction (MI) and identify areas where the clinical care for these patients may be improved.MethodsPatients hospitalised for MI between 2005 and 2010 were identified from the nationwide Swedish SWEDEHEART registry. Patients with MI and a prior COPD hospital discharge diagnosis were compared to patients with MI without a prior COPD hospital discharge diagnosis for the primary endpoint of all-cause mortality at 1 year after MI. Secondary endpoints included rates of reinfarction, new-onset stroke, new-onset bleeding and new-onset heart failure at 1 year.ResultsA total of 81 191 MI patients were included, of which 4867 (6%) had a COPD hospital discharge diagnosis at baseline. Patients with COPD showed a significantly higher unadjusted 1-year mortality (24.6 vs 13.8%) as well as a higher rate of reinfarction, new-onset bleeding and new-onset heart failure post-MI. After adjustment for potential confounders, including comorbidities and treatment, the patients with COPD still showed a significantly higher 1-year mortality (HR 1.14, 95% CI 1.07 to 1.21) as well as a higher rate of new-onset heart failure (HR 1.35, 95% CI 1.24 to 1.47), whereas no significant association between COPD and myocardial reinfarction or new-onset bleeding remained.ConclusionsIn this nationwide contemporary study, patients with COPD frequently had an atypical presentation, less often underwent revascularisation and less often received guideline-recommended secondary preventive medications of established benefit. Prior COPD was associated with a higher 1-year mortality and a higher risk of subsequent new-onset heart failure after MI. The association seems to be mainly explained by differences in background characteristics, comorbidities and treatment, although a minor part might be explained by COPD in itself. Improved in-hospital MI treatment and post-MI secondary prevention according to the guidelines may lower the mortality in this high-risk population.