bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of
Streptococcus pneumoniae
Revisited
Authors: Kellogg James A. , Bankert David A. , Elder Carol J. , Gibbs Joanne L. , Smith Marie C. 
Published: July 2002

ABSTRACT

The sensitivities and specificities of several different diagnostic assays for
Streptococcus pneumoniae
were assessed using 99 clinical isolates of
S. pneumoniae
and 101 viridans streptococci and were as follows: Pneumoslide, 99 and 87%, respectively; Directigen, 100 and 85%, respectively; Phadebact, 100 and 98%, respectively; deoxycholate drop test, 99 and 98%, respectively; deoxycholate tube test, 100 and 99%, respectively; optochin, 99 and 98%, respectively; and Gram Positive Identification Card, 90 and 96%, respectively. Identification of clinical isolates of
S. pneumoniae
should be confirmed using one or more diagnostic assays with well-documented high (e.g., ≥95%) sensitivities and specificities.
Association of
cagA
and
vacA
Genotypes of
Helicobacter pylori
with Gastric Diseases in Estonia
Authors: Andreson Helena , Lõivukene Krista , Sillakivi Toomas , Maaroos Heidi-Ingrid , Ustav Mart , Peetsalu Ants , Mikelsaar Marika 
Published: July 2002

ABSTRACT

Gastric biopsy specimens from 156 adult patients from southern Estonia suffering from chronic gastritis, peptic ulcer disease, and perforated peptic ulcer were analyzed by PCR. The
cagA
gene was evenly distributed throughout 87% of the specimens from the patients with the different gastric diseases. The presence of the
cagA
gene correlated with that of
vacA
signal sequence type s1a (99%). However, no clear differences were found in the distribution of
cagA
and
vacA
genotypes among patients in Estonia with severe perforated peptic ulcer, uncomplicated peptic ulcer, or chronic gastritis.
Immunofluorescence Technique Using HeLa Cells Expressing Recombinant Nucleoprotein for Detection of Immunoglobulin G Antibodies to Crimean-Congo Hemorrhagic Fever Virus
Authors: Saijo Masayuki , Qing Tang , Niikura Masahiro , Maeda Akihiko , Ikegami Tetsuro , Sakai Koji , Prehaud Christophe , Kurane Ichiro , Morikawa Shigeru 
Published: July 2002

ABSTRACT
A HeLa cell line continuously expressing recombinant nucleoprotein (rNP) of the Crimean-Congo hemorrhagic fever virus (CCHFV) was established by transfection with an expression vector containing the cDNA of CCHFV NP (pKS336-CCHFV-NP). These cells were used as antigens for indirect immunofluorescence (IF) to detect immunoglobulin G antibodies to CCHFV. The sensitivity and specificity of this IF technique were examined by using serum samples and were compared to those of the IF technique using CCHFV-infected Vero E6 cells (authentic antigen). Staining of the CCHFV rNP expressed in HeLa cells showed a unique granular pattern similar to that of CCHFV-infected Vero E6 cells. Positive staining could easily be distinguished from a negative result. All 13 serum samples determined to be positive by using the authentic antigen were also determined to be positive by using CCHFV rNP-expressing HeLa cells (recombinant antigen). The 108 serum samples determined to be negative by using the authentic antigen were also determined to be negative by using the recombinant antigen. Thus, both the sensitivity and the specificity of this IF technique were 100% compared to the IF with authentic antigen. The novel IF technique using CCHFV rNP-expressing HeLa cells can be used not only for diagnosis of CCHF but also for epidemiological studies on CCHFV infections.
Molecular Characterization of Extended-Spectrum β-Lactamases Produced by Nosocomial Isolates of
Enterobacteriaceae
from an Italian Nationwide Survey
Authors: Perilli Mariagrazia , Dell'Amico Emanuela , Segatore Bernardetta , de Massis Maria Rosaria , Bianchi Ciro , Luzzaro Francesco , Rossolini Gian Maria , Toniolo Antonio , Nicoletti Giuseppe , Amicosante Gianfranco 
Published: July 2002

ABSTRACT

Extended-spectrum β-lactamases (ESBLs) are widespread in hospital settings worldwide. The present investigation was undertaken to assess the distribution and prevalence of ESBLs belonging to the TEM and SHV families in 448 ESBL-producing clinical isolates of
Enterobacteriaceae
collected from 10 different Italian hospitals. The natures of TEM and SHV determinants were identified by direct sequencing of PCR-amplified genes. TEM-52 and SHV-12 were the most common variants, and they were found in most hospitals and in several different species. Other less frequent variants included TEM-5, TEM-12, TEM-15, TEM-19, TEM-20, TEM-24, TEM-26, TEM-43, TEM-60, TEM-72, TEM-87, SHV-2a, SHV-5, and SHV-11.
Proteus mirabilis
was the most common producer of TEM-type ESBLs, while
Klebsiella pneumoniae
was the most common producer of SHV-type ESBLs. The distribution of TEM- and SHV-type ESBL variants in
Enterobacteriaceae
from Italian hospitals exhibited notable differences from those from other geographical settings.
Diffusely Adherent
Escherichia coli
as a Cause of Acute Diarrhea in Young Children in Northeast Brazil: a Case-Control Study
Authors: Scaletsky Isabel C. A. , Fabbricotti Sandra H. , Carvalho Rozane L. B. , Nunes Claudia R. , Maranhão Helcio S. , Morais Mauro B. , Fagundes-Neto Ulysses 
Published: July 2002

ABSTRACT

In a prospective study carried out in two urban centers in northeastern Brazil, 195 HEp-2-adherent
Escherichia coli
strains were isolated; 110 were identified as the only pathogen in stools of children with diarrhea, and 85 were from controls. Enteropathogenic
E. coli
isolates were identified in 21 children with diarrhea (8.9%) and 7 children without diarrhea (3.0%), and they were significantly associated with diarrhea (
P
< 0.01). Enteroaggregative
E. coli
strains were isolated from 40 children with diarrhea (16.9%) and 38 children without diarrhea (16.4%) and showed no correlation with diarrhea (
P
> 0.5). In 49 children with diarrhea (20.7%) and 40 children without diarrhea (17.3%), diffusely adherent
E. coli
(DAEC) isolates were detected and were not found to be associated with diarrhea (
P
= 0.41). However, after stratification, for children older than 12 months of age a significant correlation between DAEC infection and diarrhea was detected (
P
= 0.01). These results suggest that DAEC isolates should be considered potential pathogens in northeastern Brazil and also confirm the association of DAEC with age-dependent diarrhea.
Genotyping of Clinical Methicillin-Susceptible
Staphylococcus aureus
Isolates in a Dutch Teaching Hospital
Authors: Van Dijk Yvonne , Wielders Camiel L. C. , Fluit Ad C. , Paauw Armand , Diepersloot Rob J. A. , Mascini Ellen M. 
Published: July 2002

ABSTRACT

Methicillin-susceptible
Staphylococcus aureus
isolates, recovered from 204 patients in our hospital in a 22-month period, were characterized by pulsed-field gel electrophoresis. Among the multiple
S. aureus
types six clonal lineages dominated, comprising isolates from 158 patients. Despite the limited genetic variation, cross-transmission was made plausible only sporadically.
Susceptibility Testing of Fluconazole by the NCCLS Broth Macrodilution Method, E-Test, and Disk Diffusion for Application in the Routine Laboratory
Authors: Vandenbossche Inge , Vaneechoutte Mario , Vandevenne Marleen , De Baere Thierry , Verschraegen Gerda 
Published: July 2002

ABSTRACT

Antifungal susceptibility testing may be an important aid in the treatment of patients with life-threatening yeast infections. In order to establish the suitability of different susceptibility test methods for fluconazole with yeasts, the Rosco tablet and the E-test were compared with the gold standard NCCLS broth macrodilution method for 106 yeast strains. These included 102 clinical isolates of
Candida
spp., including
Candida glabrata
(
n
= 30),
Candida albicans
(
n
= 20),
Candida tropicalis
(
n
= 13),
Candida parapsilosis
(
n
= 10),
Candida krusei
(
n
= 8), plus
Cryptococcus neoformans
(
n
= 3),
Saccharomyces cerevisiae
(
n
= 2), and 16 strains belonging to other
Candida
spp. Four American Type Culture Collection strains of
Candida
were included as quality controls. The NCCLS method was found to be too complex and labor-intensive for routine testing. The E-test is an accurate alternative, but experience in determining MICs and careful attention to procedural details are critically important. The Rosco tablet showed the best agreement with the NCCLS reference method, especially when newly established breakpoints of
R
≤ 10 mm and
S
≥ 21 mm were used.
Molecular Characterization of Vancomycin-Resistant Enterococci Repopulating the Gastrointestinal Tract following Treatment with a Novel Glycolipodepsipeptide, Ramoplanin
Authors: Baden L. R. , Critchley I. A. , Sahm D. F. , So W. , Gedde M. , Porter S. , Moellering R. C. , Eliopoulos G. 
Published: July 2002

ABSTRACT

We characterized baseline and repopulating stool isolates recovered during a phase II trial of ramoplanin for the treatment of patients with stool carriage of vancomycin-resistant enterococci (VRE). Repopulation with a strain with a related genotype was found in 74, 60, and 53% of individuals in groups treated with placebo, 100 mg of ramoplanin, and 400 mg of ramoplanin, respectively. All ramoplanin-treated patients with a culture positive for VRE at day 7 had a relapse caused by a genotypically related isolate. In ramoplanin-treated patients, antibiotics with activities against anaerobic organisms were associated with positive cultures on day 7 (relative risk [RR] = 8.8;
P
= 0.004), and the avoidance of such antibiotics was significantly associated with culture negativity through day 21 (RR = 0.16;
P
= 0.02).
Real-Time PCR Coupled with Automated DNA Extraction and Detection of Galactomannan Antigen in Serum by Enzyme-Linked Immunosorbent Assay for Diagnosis of Invasive Aspergillosis
Authors: Costa Catherine , Costa Jean-Marc , Desterke Christophe , Botterel Françoise , Cordonnier Catherine , Bretagne Stéphane 
Published: July 2002

ABSTRACT

To improve the diagnosis of invasive aspergillosis (IA), we developed a LightCycler PCR assay targeted to
Aspergillus fumigatus
and
A. flavus
mitochondrial DNA. To avoid contamination, fully automated nucleic acid extraction with the MagNA Pure LC apparatus was used. The linearity of the results was achieved over a 6-log range of input
A. fumigatus
DNA, from 0.3 ng to 3 fg/10 μl of water. We retrospectively compared the LightCycler PCR and an enzyme-linked immunosorbent assay for the detection of galactomannan (GM) in serum from 14 patients with IA. The GM assay was more frequently positive (57 of 109; 52%) than the PCR assay (49 of 109; 45%). The LightCycler PCR assay, combined with automated DNA extraction, could be used in association with the GM assay to improve the reliability of IA diagnosis.
H-2Db−/−Mice Are Susceptible to Persistent Infection by Theiler's Virus
Authors: Azoulay-Cayla Arièle , Dethlefs Sven , Pérarnau Béatrice , Larsson-Sciard Eva-Lotta , Lemonnier François A. , Brahic Michel , Bureau Jean-François 
Published: July 2002

ABSTRACTH-2bmice are resistant to persistent infection of the central nervous system by Theiler's virus. They clear the infection 7 to 10 days after intracranial inoculation. Resistance maps to theH-2Dgene and not to theH-2Kgene and is associated with a potent antiviral cytotoxic T-lymphocyte (CTL) response. We usedH-2bmice in which theH-2Dor theH-2Kgene had been inactivated to dissect the respective roles of these genes in resistance. We report thatH-2D−/−but notH-2K−/−mice were susceptible to persistent infection. Furthermore, whereasH-2K−/−mice mounted a vigorous virus-specific CTL response, similar to that of control C57BL/6 mice, the CTL response ofH-2D−/−mice was nil or minimal. Using target cells transfected with theH-2Dbor theH-2Kbgene, we showed that theH-2K-restricted CTL response against the virus was minimal inH-2D−/−mice. These results demonstrate that theH-2DbandH-2Kbgenes play nonredundant roles in the resistance to this persistent infection.
Mutations in the E1 Hydrophobic Domain of Rubella Virus Impair Virus Infectivity but Not Virus Assembly
Authors: Qiu Zhiyong , Yao Jiansheng , Cao Hanwei , Gillam Shirley 
Published: July 2002

ABSTRACTRubella virus (RV) virions contain three structural proteins, a capsid protein that interacts with viral genomic RNA to form a nucleocapsid and two membrane glycoproteins, E2 and E1. We found that substitution of either an aspartic acid residue at Gly93 (G93D) or a glycine residue at Pro104 (P104G) in the internal hydrophobic domain of E1 affected virus infectivity but not virus assembly. Viruses carrying G93D and P104G mutations had impaired infectivity, reduced 1,000-fold and 10-fold, respectively. A revertant was isolated from the G93D mutant. Sequencing analysis showed that the substituted aspartic acid residue in G93D mutant had reverted to the original glycine residue, suggesting the involvement of Gly93 in membrane fusion during viral entry.
Efficient Translation of Rotavirus mRNA Requires Simultaneous Interaction of NSP3 with the Eukaryotic Translation Initiation Factor eIF4G and the mRNA 3′ End
Authors: Vende Patrice , Piron Maria , Castagné Nathalie , Poncet Didier 
Published: July 2002

ABSTRACT
In contrast to the vast majority of cellular proteins, rotavirus proteins are translated from capped but nonpolyadenylated mRNAs. The viral nonstructural protein NSP3 specifically binds the 3′-end consensus sequence of viral mRNAs and interacts with the eukaryotic translation initiation factor eIF4G. Here we show that expression of NSP3 in mammalian cells allows the efficient translation of virus-like mRNA. A synergistic effect between the cap structure and the 3′ end of rotavirus mRNA was observed in NSP3-expressing cells. The enhancement of viral mRNA translation by NSP3 was also observed in a rabbit reticulocyte lysate translation system supplemented with recombinant NSP3. The use of NSP3 mutants indicates that its RNA- and eIF4G-binding domains are both required to enhance the translation of viral mRNA. The results reported here show that NSP3 forms a link between viral mRNA and the cellular translation machinery and hence is a functional analogue of cellular poly(A)-binding protein.
Characterization of a Novel Respiratory Syncytial Virus-Specific Human Cytotoxic T-Lymphocyte Epitope
Authors: Goulder Philip J. R. , Lechner Franziska , Klenerman Paul , McIntosh Kenneth , Walker Bruce D. 
Published: July 2002

ABSTRACTRespiratory syncytial virus (RSV) infection is a major cause of morbidity in childhood worldwide. The first human RSV-specific cytotoxic T-lymphocyte epitope to be defined is described. This HLA B7-restricted epitope in nucleoprotein (NP) was detectable in four healthy, B7-positive adult subjects using B7-RSV-NP tetrameric complexes to stain CD8+T cells.
Coinfection of SCID-hu Thy/Liv Mice with Human Herpesvirus 6 and Human Immunodeficiency Virus Type 1
Authors: Gobbi Alberto , Stoddart Cheryl A. , Locatelli Giuseppe , Santoro Fabio , Bare Christopher , Linquist-Stepps Valerie , Moreno Mary E. , Abbey Nancy W. , Herndier Brian G. , Malnati Mauro S. , McCune Joseph M. , Lusso Paolo 
Published: July 2002

ABSTRACTHuman herpesvirus 6 (HHV-6) has been proposed as a potential cofactor in the progression of human immunodeficiency virus type 1 (HIV-1) disease. We used the SCID-hu Thy/Liv mouse model to evaluate the in vivo interactions between HHV-6 and HIV-1. Our results demonstrate that HHV-6 and HIV-1 can simultaneously replicate in the human thymus in vivo. In this model, however, the presence of one virus appears not to modify the replication or cytopathicity of the other.
Viral Vascular Endothelial Growth Factor Plays a Critical Role in Orf Virus Infection
Authors: Savory Loreen J. , Stacker Steven A. , Fleming Stephen B. , Niven Brian E. , Mercer Andrew A. 
Published: July 2002

ABSTRACT
Infection by the parapoxvirus orf virus causes proliferative skin lesions in which extensive capillary proliferation and dilation are prominent histological features. This infective phenotype may be linked to a unique virus-encoded factor, a distinctive new member of the vascular endothelial growth factor (VEGF) family of molecules. We constructed a recombinant orf virus in which the VEGF-like gene was disrupted and show that inactivation of this gene resulted in the loss of three VEGF activities expressed by the parent virus: mitogenesis of vascular endothelial cells, induction of vascular permeability, and activation of VEGF receptor 2. We used the recombinant orf virus to assess the contribution of the viral VEGF to the vascular response seen during orf virus infection of skin. Our results demonstrate that the viral VEGF, while recognizing a unique profile of the known VEGF receptors (receptor 2 and neuropilin 1), is able to stimulate a striking proliferation of blood vessels in the dermis underlying the site of infection. Furthermore, the data demonstrate that the viral VEGF participates in promoting a distinctive pattern of epidermal proliferation. Loss of a functional viral VEGF resulted in lesions with markedly reduced clinical indications of infection. However, viral replication in the early stages of infection was not impaired, and only at later times did it appear that replication of the recombinant virus might be reduced.
Molecular Correlates of Influenza A H5N1 Virus Pathogenesis in Mice
Authors: Katz Jacqueline M. , Lu Xiuhua , Tumpey Terrence M. , Smith Catherine B. , Shaw Michael W. , Subbarao Kanta 
Published: July 2002

ABSTRACT
Highly pathogenic avian influenza A H5N1 viruses caused an outbreak of human respiratory illness in Hong Kong. Of 15 human H5N1 isolates characterized, nine displayed a high-, five a low-, and one an intermediate-pathogenicity phenotype in the BALB/c mouse model. Sequence analysis determined that five specific amino acids in four proteins correlated with pathogenicity in mice. Alone or in combination, these specific residues are the likely determinants of virulence of human H5N1 influenza viruses in this model.
Glycoprotein Exchange Vectors Based on Vesicular Stomatitis Virus Allow Effective Boosting and Generation of Neutralizing Antibodies to a Primary Isolate of Human Immunodeficiency Virus Type 1
Authors: Rose Nina F. , Roberts Anjeanette , Buonocore Linda , Rose John K. 
Published: July 2002

ABSTRACT
Live recombinant vesicular stomatitis viruses (VSVs) expressing foreign antigens are highly effective vaccine vectors. However, these vectors induce high-titer neutralizing antibody directed at the single VSV glycoprotein (G), and this antibody alone can prevent reinfection and boosting with the same vector. To determine if efficient boosting could be achieved by changing the G protein of the vector, we have developed two new recombinant VSV vectors based on the VSV Indiana serotype but with the G protein gene replaced with G genes from two other VSV serotypes, New Jersey and Chandipura. These G protein exchange vectors grew to titers equivalent to wild-type VSV and induced similar neutralizing titers to themselves but no cross-neutralizing antibodies to the other two serotypes. The effectiveness of these recombinant VSV vectors was illustrated in experiments in which sequential boosting of mice with the three vectors, all encoding the same primary human immunodeficiency virus (HIV) envelope protein, gave a fourfold increase in antibody titer to an oligomeric HIV envelope compared with the response in animals receiving the same vector three times. In addition, only the animals boosted with the exchange vectors produced antibodies neutralizing the autologous HIV primary isolate. These VSV envelope exchange vectors have potential as vaccines in immunizations when boosting of immune responses may be essential.
Jembrana Disease Virus Tat Can Regulate Human Immunodeficiency Virus (HIV) Long Terminal Repeat-Directed Gene Expression and Can Substitute for HIV Tat in Viral Replication
Authors: Chen Hexin , He Jun , Fong Steven , Wilcox Graham , Wood Charles 
Published: July 2002

ABSTRACTJembrana disease virus (JDV) is a bovine lentivirus genetically similar to bovine immunodeficiency virus; it causes an acute and sometimes fatal disease in infected animals. This virus carries a very potent Tat that can strongly activate not only its own long terminal repeat (LTR) but also the human immunodeficiency virus (HIV) LTR. In contrast, HIV Tat cannot reciprocally activate the JDV LTR (H. Chen, G. E. Wilcox, G. Kertayadnya, and C. Wood, J. Virol. 73:658–666, 1999). This indicates that in transactivation JDV Tat may utilize a mechanism similar to but not the same as that of the HIV Tat. To further study the similarity of JDV and HIVtatin transactivation, we first tested the responses of a series of HIV LTR mutants to the JDV Tat. Cross-transactivation of HIV LTR by JDV Tat was impaired by mutations that disrupted the HIV type 1 transactivation response element (TAR) RNA stem-loop structure. Our results demonstrated that JDV Tat, like HIV Tat, transactivated the HIV LTR at least partially in a TAR-dependent manner. However, the sequence in the loop region of TAR was not as critical for the function of JDV Tat as it was for HIV Tat. The competitive inhibition of Tat-induced transactivation by the truncated JDV or HIV Tat, which consisted only of the activation domain, suggested that similar cellular factors were involved in both JDV and HIV Tat-induced transactivation. Based on the one-round transfection assay with HIVtatmutant proviruses, the cotransfected JDVtatplasmid can functionally complement the HIVtatdefect. To further characterize the effect of JDV Tat on HIV, a stable chimeric HIV carrying the JDVtatgene was generated. This chimeric HIV replicated in a T-cell line, C8166, and in peripheral blood mononuclear cells, which suggested that JDV Tat can functionally substitute for HIV Tat. Further characterization of this chimeric virus will help to elucidate how JDV Tat functions and to explain the differences between HIV and JDV Tat transactivation.
In Vivo T-Lymphocyte Activation and Transient Reduction of Viral Replication in Macaques Infected with Simian Immunodeficiency Virus
Authors: Chen Zheng W. , Shen Yun , Zhou Dejiang , Simon Meredith , Kou ZhongChen , Lee-Parritz David , Shen Ling , Sehgal Prabhat , Letvin Norman L. 
Published: July 2002

ABSTRACTWhile it is well established that cellular activation can increase human immunodeficiency virus (HIV) replication in T lymphocytes, it is also clear that both activated CD8+and CD4+T lymphocytes mediate anti-HIV activity. To assess the relative importance of these contrary effects on HIV replication in vivo, we evaluated the consequences ofMycobacterium bovisBCG and staphylococcal enterotoxin B (SEB) inoculation in vivo in rhesus monkeys chronically infected with simian immunodeficiency virus of macaques (SIVmac). BCG inoculation induced as much as a 2.5-log reduction of plasma and intracellular SIV RNA in SIVmac-infected monkeys. This down-regulation of virus replication persisted as long as 4 weeks after BCG inoculation. Similarly, SEB injection resulted in up to a 3-log decrease in plasma and intracellular SIV RNA in SIVmac-infected macaques. Interestingly, the short-term reduction of viremia in these monkeys correlated with the peak in vivo production of SEB- and BCG-induced cytokine responses. However, no long-term clinical benefit was observed in the SIVmac-infected macaques. These studies provide in vivo evidence that potent T-cell stimulation driven by antigens other than the virus itself can, under some circumstances, mediate short-term reduction of viremia in AIDS virus-infected individuals.