bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contemporary Seasonal Influenza A (H1N1) Virus Infection Primes for a More Robust Response To Split Inactivated Pandemic Influenza A (H1N1) Virus Vaccination in Ferrets
Authors: Ellebedy Ali H. , Fabrizio Thomas P. , Kayali Ghazi , Oguin Thomas H. , Brown Scott A. , Rehg Jerold , Thomas Paul G. , Webby Richard J. 
Published: October 2010

ABSTRACT

Human influenza pandemics occur when influenza viruses to which the population has little or no immunity emerge and acquire the ability to achieve human-to-human transmission. In April 2009, cases of a novel H1N1 influenza virus in children in the southwestern United States were reported. It was retrospectively shown that these cases represented the spread of this virus from an ongoing outbreak in Mexico. The emergence of the pandemic led to a number of national vaccination programs. Surprisingly, early human clinical trial data have shown that a single dose of nonadjuvanted pandemic influenza A (H1N1) 2009 monovalent inactivated vaccine (pMIV) has led to a seroprotective response in a majority of individuals, despite earlier studies showing a lack of cross-reactivity between seasonal and pandemic H1N1 viruses. Here we show that previous exposure to a contemporary seasonal H1N1 influenza virus and to a lesser degree a seasonal influenza virus trivalent inactivated vaccine is able to prime for a higher antibody response after a subsequent dose of pMIV in ferrets. The more protective response was partially dependent on the presence of CD8
+
cells. Two doses of pMIV were also able to induce a detectable antibody response that provided protection from subsequent challenge. These data show that previous infection with seasonal H1N1 influenza viruses likely explains the requirement for only a single dose of pMIV in adults and that vaccination campaigns with the current pandemic influenza vaccines should reduce viral burden and disease severity in humans.
Assessment of the IgA Immunoassay Diagnostic Potential of the
Mycobacterium tuberculosis
MT10.3-MPT64 Fusion Protein in Tuberculous Pleural Fluid
Authors: Araujo Leonardo Silva , Moraes Renata Maciel , Trajman Anete , Saad Maria Helena Féres 
Published: October 2010

ABSTRACT

Pleural tuberculosis (PL-TB) remains difficult to diagnose. An enzyme-linked immunosorbent assay (ELISA) was developed based on a construction containing the fusion of the
Rv3019c
(MT10.3) and
Rv1980c
(MPT64) gene sequences, and its performance was evaluated in an area where TB is endemic. A total of 92 pleural fluid (PF) samples at serial dilutions of 1:50 to 1:800 were included in the ELISA IgA MT10.3-MPT64 evaluation: 70 from TB patients and 22 from patients with other pleurisies. Confirmation of the expression and subsequent purification of the protein was made by SDS-PAGE and Western blot assays, resulting in a 36-kDa protein. ELISA IgA MT10.3-MPT64 showed sensitivities of 61.4%, 58.6%, 62.9%, 67.1%, and 70% at each PF dilution, respectively. The cumulative results of all dilutions increased sensitivity to 81.4% without jeopardizing specificity. Similar results were also obtained at the combined dilutions of 1:50, 1:200, and 1:800 or 1:50 plus 1:800 dilutions (80%). The overall sensitivity of the reference test, i.e., histopathological examination, was 74%. But, via the ELISA IgA MT10.3-MPT64 test, sensitivity was high for specimens with a negative culture (23/27; 85.2%) or nonspecific histopathology (17/18; 94.4%). Our findings demonstrated the promising use of this test as an adjunct in PL-TB diagnoses, particularly in cases with lower bacterial loads and false-negative results in the reference tests, since the new test includes such important features as quick and easy application, high sensitivity and, perhaps most importantly, affordability, which is so crucial for its widespread use in developing countries.
Molecular Probes for Diagnosis of Clinically Relevant Bacterial Infections in Blood Cultures
Authors: Hansen Wendy L. J. , Beuving Judith , Bruggeman Cathrien A. , Wolffs Petra F. G. 
Published: October 2010

ABSTRACT

Broad-range real-time PCR and sequencing of the 16S rRNA gene region is a widely known method for the detection and identification of bacteria in clinical samples. However, because of the need for sequencing, such identification of bacteria is time-consuming. The aim of our study was to develop a more rapid 16S real-time PCR-based identification assay using species- or genus-specific probes. The Gram-negative bacteria were divided into
Pseudomonas
species,
Pseudomonas aeruginosa
,
Escherichia coli
, and other Gram-negative species. Within the Gram-positive species, probes were designed for
Staphylococcus
species,
Staphylococcus aureus
,
Enterococcus
species,
Streptococcus
species, and
Streptococcus pneumoniae
. The assay also included a universal probe within the 16S rRNA gene region for the detection of all bacterial DNA. The assay was evaluated with a collection of 248 blood cultures. In this study, the universal probe and the probes targeting
Pseudomonas
spp.,
P. aeruginosa
,
E. coli
,
Streptococcus
spp.,
S. pneumoniae
,
Enterococcus
spp., and
Staphylococcus
spp. all had a sensitivity and specificity of 100%. The probe specific for
S. aureus
showed eight discrepancies, resulting in a sensitivity of 100% and a specificity of 93%. These data showed high agreement between conventional testing and our novel real-time PCR assay. Furthermore, this assay significantly reduced the time needed for identification. In conclusion, using pathogen-specific probes offers a faster alternative for pathogen detection and could improve the diagnosis of bloodstream infections.
Vancomycin Susceptibility Trends and Prevalence of Heterogeneous Vancomycin-Intermediate
Staphylococcus aureus
in Clinical Methicillin-Resistant
S. aureus
Isolates
Authors: Pitz Adam M. , Yu Fang , Hermsen Elizabeth D. , Rupp Mark E. , Fey Paul D. , Olsen Keith M. 
Published: October 2010

ABSTRACT

Due to the rise in methicillin-resistant
Staphylococcus aureus
(MRSA) infections and widespread use of vancomycin, MRSA isolates with reduced susceptibility to vancomycin are emerging (i.e., MIC creep). However, the prevalence of heterogeneous vancomycin-intermediate
S. aureus
(hVISA) is unknown due to the difficulty in detecting this phenotype. Recently, Etest glycopeptide resistance detection (GRD) strips have been developed to detect hVISA. This study assessed vancomycin susceptibility in MRSA isolates and determined the prevalence of hVISA by Etest GRD and population analysis profile-area under the curve ratio (PAP-AUC). The genetic backgrounds of 167 MRSA isolates collected from 2000 to 2008 were identified by pulsed-field gel electrophoresis. Vancomycin MICs were determined using Etest and two broth microdilution assays, MicroScan and Sensititre. Etest GRD was performed on all isolates, and those exhibiting a hVISA phenotype were further tested by PAP-AUC. The vancomycin MIC modes remained consistent at 1 μg/ml, as assessed by Sensititre and MicroScan. Etest reported a significant increase (mode MIC = 1.5 μg/ml) in the MIC between 2000 and 2008 (
P
< 0.01); however, this increase did not reflect a ≥2-fold change. In addition, the slight MIC increase did not increase linearly from 2000 to 2008, suggesting biological fluctuation, and is inconsistent with the concept of MIC creep. Etest GRD identified six hVISA isolates, two of which were confirmed to be hVISA by PAP-AUC. In conclusion, reduced vancomycin susceptibility was not detected in our hospital over a 9-year period using three different MIC methodologies, and the hVISA incidence was 1.2%, as determined by Etest GRD and PAP-AUC.
Evaluation of a New Chromogenic Medium (StrepB
Select
) for Detection of Group B
Streptococcus
from Vaginal-Rectal Specimens
Authors: Louie L. , Kotowich L. , Meaney H. , Vearncombe M. , Simor A. E. 
Published: October 2010

ABSTRACT

We compared StrepB
Select
medium (
Select
) after enrichment with conventional culture for the detection of Group B
Streptococcus
(GBS). Postenrichment sensitivities of
Select
and conventional culture were 98.8% and 92.2%, respectively (
P
< 0.05).
Select
was superior for detection of GBS from vaginal-rectal specimens. Growth of non-GBS colonies required additional work to exclude the presence of GBS, especially after 48 h of incubation. Incubation of
Select
beyond 24 h did not significantly increase the yield of GBS.
Evaluation of the BD GeneOhm Assay Using the Rotor-Gene 6000 Platform for Rapid Detection of Methicillin-Resistant
Staphylococcus aureus
from Pooled Screening Swabs
Authors: Smith Melvyn Howard , Hodgson Julian , Eltringham Ian Joseph 
Published: October 2010

ABSTRACT

As health services move toward universal methicillin-resistant
Staphylococcus aureus
(MRSA) screening for hospital admissions, the most cost-effective approach is yet to be defined. In this study, one of the largest to date, we evaluated the performance of the BD GeneOhm MRSA assay on the Rotor-Gene 6000 thermal cycler, using samples taken directly from pooled MRSA screens. Results were compared with the same assay performed on the Smart-Cycler II platform and overnight broth culture. Samples yielding discrepant results were subjected to detailed analysis with an in-house PCR and patient note review. A total of 1,428 pooled MRSA screens were tested. Sensitivities and specificities of 85.3% and 95.8% for the Rotor-Gene and 81% and 95.7% for the Smart-Cycler were obtained, compared with broth enrichment. The sensitivity of the BD GeneOhm assay was increased to 100% when the results of in-house PCR and patient note review were taken into account. This study demonstrates that the Rotor-Gene 6000 thermal cycler is a reliable platform for use with the BD GeneOhm assay. It also proves that commercial PCR can be performed direct on pooled samples in selective broth, without the need for overnight incubation.
Molecular Detection of Mixed Infections of
Mycobacterium tuberculosis
Strains in Sputum Samples from Patients in Karonga District, Malawi
Authors: Mallard Kim , McNerney Ruth , Crampin Amelia C. , Houben Rein , Ndlovu Richard , Munthali Lumbani , Warren Robin M. , French Neil , Glynn Judith R. 
Published: October 2010

ABSTRACT

The occurrence of mixed infections of
Mycobacterium tuberculosis
is no longer disputed. However, their frequency, and the impact they may have on our understanding of tuberculosis (TB) pathogenesis and epidemiology, remains undetermined. Most previous studies of frequency applied genotyping techniques to cultured
M. tuberculosis
isolates and found mixed infections to be rare. PCR-based techniques may be more sensitive for detecting multiple
M. tuberculosis
strains and can be applied to sputum. To date, one study in South Africa has used a PCR approach and suggested that mixed infection could be common. We investigated mixed infections in northern Malawi using two lineage-specific PCR assays targeting the Latin American-Mediterranean (LAM) and Beijing lineages. Compared with spoligotyping, the specificity and sensitivity of both assays was 100%. From 160 culture-positive sputa, mixed LAM and non-LAM strains were detected in 4 sputa belonging to 2 (2.8%) patients. Both patients were HIV positive, with no history of TB. Cultured isolates from both patients showed only LAM by PCR and spoligotyping. In a set of 377 cultured isolates, 4 were mixed LAM and non-LAM. Only one showed evidence of more than one
M. tuberculosis
strain using IS
6110
-based restriction fragment length polymorphism (IS
6110
-RFLP) and spoligotyping analyses. Corresponding sputa for the 4 isolates were unavailable. Mixed Beijing and non-Beijing strains were not detected in this study. Mixed infections appear to be rare in our setting and are unlikely to affect findings based on DNA fingerprinting data. Molecular methods, which avoid the selective nature of culture and target distinct strains, are well suited to detection of mixed infections.
False-Negative PCR Result Due to Gene Polymorphism: the Example of
Neisseria meningitidis
Authors: Jaton Katia , Ninet Béatrice , Bille Jacques , Greub Gilbert 
Published: October 2010

ABSTRACT

Early treatment of meningococcal meningitis is mandatory but may negate the cerebrospinal fluid culture. Etiological diagnosis then mainly relies on PCR. Here, we report a case of false-negative results for real-time PCR for a
Neisseria meningitidis
serogroup B isolate with a polymorphism in the
ctrA
gene.
Blood Myeloid Dendritic Cells from HIV-1-Infected Individuals Display a Proapoptotic Profile Characterized by Decreased Bcl-2 Levels and by Caspase-3+Frequencies That Are Associated with Levels of Plasma Viremia and T Cell Activation in an Exploratory Study
Authors: Dillon Stephanie M. , Friedlander Laura J. , Rogers Lisa M. , Meditz Amie L. , Folkvord Joy M. , Connick Elizabeth , McCarter Martin D. , Wilson Cara C. 
Published: October 2010

ABSTRACTReduced frequencies of myeloid and plasmacytoid dendritic cell (DC) subsets (mDCs and pDCs, respectively) have been observed in the peripheral blood of HIV-1-infected individuals throughout the course of disease. Accumulation of DCs in lymph nodes (LNs) may partly account for the decreased numbers observed in blood, but increased DC death may also be a contributing factor. We used multiparameter flow cytometry to evaluate pro- and antiapoptotic markers in blood mDCs and pDCs from untreated HIV-1-infected donors, from a subset of infected donors before and after receiving antiretroviral therapy (ART), and from uninfected control donors. Blood mDCs, but not pDCs, from untreated HIV-1-infected donors expressed lower levels of antiapoptotic Bcl-2 than DCs from uninfected donors. A subset of HIV-1-infected donors had elevated frequencies of proapoptotic caspase-3+blood mDCs, and positive correlations were observed between caspase-3+mDC frequencies and plasma viral load and CD8+T-cell activation levels. Caspase-3+mDC frequencies, but not mDC Bcl-2 expression, were reduced with viral suppression on ART. Apoptosis markers on DCs in blood and LN samples from a cohort of untreated, HIV-1-infected donors with chronic disease were also evaluated. LN mDCs displayed higher levels of Bcl-2 and lower caspase-3+frequencies than did matched blood mDCs. Conversely, LN pDCs expressed lower Bcl-2 levels than their blood counterparts. In summary, blood mDCs from untreated HIV-1-infected subjects displayed a proapoptotic profile that was partially reversed with viral suppression, suggesting that DC death may be a factor contributing to blood DC depletion in the setting of chronic, untreated HIV disease.
Yeast-Elicited Cross-Reactive Antibodies to HIV Env Glycans Efficiently Neutralize Virions Expressing Exclusively High-Mannose N-Linked Glycans
Authors: Agrawal-Gamse Caroline , Luallen Robert J. , Liu Bingfen , Fu Hu , Lee Fang-Hua , Geng Yu , Doms Robert W. 
Published: October 2010

ABSTRACT

The HIV envelope (Env) protein uses a dense coat of glycans to mask conserved domains and evade host humoral immune responses. The broadly neutralizing antibody 2G12, which binds a specific cluster of high-mannose glycans on HIV Env, shows that the glycan shield can also serve as a target for neutralizing antibodies. We have described a triple mutant
Saccharomyces cerevisiae
strain that expresses high-mannose glycoproteins that bind to 2G12. When used to immunize rabbits, this yeast elicits antibodies that bind to gp120-associated glycans but fail to neutralize virus. Here we sought to determine the reason for these discordant results. Affinity purification of sera over columns conjugated with three 2G12-reactive yeast glycoproteins showed that these proteins could adsorb 80% of the antibodies that bind to gp120 glycans. Despite binding to monomeric gp120, these mannose-specific antibodies failed to bind cell surface-expressed trimeric Env. However, when Env was expressed in the presence of the mannosidase inhibitor kifunensine to force retention of high-mannose glycans at all sites, the purified antibodies gained the abilities to bind trimeric Env and to strongly and broadly neutralize viruses produced under these conditions. Combined, these data show that the triple mutant yeast strain elicits antibodies that bind to high-mannose glycans presented on the HIV envelope, but only when they are displayed in a manner not found on native Env trimers. This implies that the underlying structure of the protein scaffold used to present the high-mannose glycans may be critical to allow elicitation of antibodies that recognize trimeric Env and neutralize virus.
Small-Molecule Inhibition of Human Immunodeficiency Virus Type 1 Infection by Virus Capsid Destabilization
Authors: Shi Jiong , Zhou Jing , Shah Vaibhav B. , Aiken Christopher , Whitby Kevin 
Published: October 2010

ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) infection is dependent on the proper disassembly of the viral capsid, or “uncoating,” in target cells. The HIV-1 capsid consists of a conical multimeric complex of the viral capsid protein (CA) arranged in a hexagonal lattice. Mutations in CA that destabilize the viral capsid result in impaired infection owing to defects in reverse transcription in target cells. We describe here the mechanism of action of a small molecule HIV-1 inhibitor, PF-3450074 (PF74), which targets CA. PF74 acts at an early stage of HIV-1 infection and inhibits reverse transcription in target cells. We show that PF74 binds specifically to HIV-1 particles, and substitutions in CA that confer resistance to the compound prevent binding. A single point mutation in CA that stabilizes the HIV-1 core also conferred strong resistance to the virus without inhibiting compound binding. Treatment of HIV-1 particles or purified cores with PF74 destabilized the viral capsid
in vitro
. Furthermore, the compound induced the rapid dissolution of the HIV-1 capsid in target cells. PF74 antiviral activity was promoted by binding of the host protein cyclophilin A to the HIV-1 capsid, and PF74 and cyclosporine exhibited mutual antagonism. Our data suggest that PF74 triggers premature HIV-1 uncoating in target cells, thereby mimicking the activity of the retrovirus restriction factor TRIM5α. This study highlights uncoating as a step in the HIV-1 life cycle that is susceptible to small molecule intervention.
The Magnitude of Local Immunity in the Lungs of Mice Induced by Live Attenuated Influenza Vaccines Is Determined by Local Viral Replication and Induction of Cytokines
Authors: Lau Yuk-Fai , Santos Celia , Torres-Vélez Fernando J. , Subbarao Kanta 
Published: October 2010

ABSTRACT

While live attenuated influenza vaccines (LAIVs) have been shown to be efficacious and have been licensed for human use, the surface glycoproteins hemagglutinin (HA) and neuraminidase (NA) have to be updated for optimal protective efficacy. Little is known about the effect of different HA and NA proteins on the immunogenicity of LAIVs developed using the same backbone. A panel of LAIVs that share the internal protein genes, with unique HA and NA gene segments from different influenza subtypes, was rescued by reverse genetics, and a comparative study of immune responses induced by these vaccines was conducted in mice. The results suggest that the magnitude of lung immunity, including pulmonary IgA antibody and memory CD8
+
T lymphocytes, induced by the vaccines depends on the replication efficiency of the LAIVs, as well as the induction of cytokines/chemokines in the lungs. However, these factors are not important in determining systemic immunity such as serum antibody titers and memory CD8
+
T cells in the spleen. A qualitative analysis of immune responses induced by a single dose of an H5N1 LAIV revealed that the vaccine induced robust systemic and mucosal immunity in mice. In addition, antibodies and memory lymphocytes established in the lungs following vaccination were required for protection against lethal challenge with homologous and heterologous H5N1 viruses. Our results highlight the different requirements for inducing systemic and lung immunity that can be explored for the development of pulmonary immunity for protection against respiratory pathogens.
Replicative and Transcriptional Activities of Hepatitis B Virus in Patients Coinfected with Hepatitis B and Hepatitis Delta Viruses
Authors: Pollicino Teresa , Raffa Giuseppina , Santantonio Teresa , Gaeta Giovanni Battista , Iannello Giuliano , Alibrandi Angela , Squadrito Giovanni , Cacciola Irene , Calvi Chiara , Colucci Giuseppe , Levrero Massimo , Raimondo Giovanni 
Published: October 2010

ABSTRACTHepatitis B virus (HBV) and hepatitis delta virus (HDV) interplay was investigated by examining liver and serum samples from 21 coinfected and 22 HBV-monoinfected patients with chronic liver disease. Different real-time PCR assays were applied to evaluate intrahepatic amounts of HBV DNA, covalently closed circular DNA (cccDNA), pregenomic RNA (pgRNA), pre-S/S RNAs, and HDV RNA. Besides HBV DNA and HDV RNA levels, HBsAg concentrations in the sera were also determined. HDV-coinfected cases showed significantly lower median levels of serum HBV DNA (−5 log), intrahepatic relaxed-circular DNA (−2 log), and cccDNA (−2 log) than those of HBV-monoinfected cases. Interestingly, pgRNA and pre-S/S RNA amounts were significantly lower (both −1 log) in HDV-positive patients, whereas serum HBsAg concentrations were comparable between the two patient groups. Pre-S/S RNA and HBsAg amounts per cccDNA molecule were higher in HDV-positive patients (3-fold and 1 log, respectively), showing that HBV replication was reduced, whereas synthesis of envelope proteins was not specifically decreased. The ratios of cccDNA to intracellular total HBV DNA showed a larger proportion of cccDNA molecules in HDV-positive cases. For these patients, both intrahepatic and serum HDV RNA amounts were associated with cccDNA but not with HBsAg or HBV DNA levels. Finally, HBV genomes with large deletions in the basal core promoter/precore region were detected in 5/21 HDV-positive patients but in no HDV-negative patients and were associated with lower viremia levels. These findings provide significant information about the interference exerted by HDV on HBV replication and transcription activities in the human liver.