bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of Serum Bactericidal Activity Specific forHaemophilus influenzaeType b by Using a Chromogenic and Fluorescent Metabolic Indicator
Authors: Romero-Steiner Sandra , Spear Willie , Brown Nekeidra , Holder Patricia , Hennessy Thomas , Gomez de Leon Patricia , Carlone George M. 
Published: January 2004

ABSTRACTWe evaluated alamarBlue as a metabolic indicator in a standardized assay for the measurement of serum bactericidal activity (SBA) toHaemophilus influenzaetype b (Hib) using sera containing natural and vaccine-induced anticapsular (polyribosylribitol phosphate) antibodies. SBA assays with a colorimetric and a fluorometric end point in the presence of alamarBlue were developed and compared to a standard SBA assay, where colony counts are performed to determine the titer (12). A colorimetric end point required a spectrophotometer, whereas a fluorometric end point required a fluorometer. Prevaccination sera (n= 27) and postvaccination sera (n= 13) were tested by all three methodologies, and the SBA titers obtained in the presence of alamarBlue were compared to those from the standard method. Both the colorimetric and the fluorometric SBA titers were significantly correlated (r= 0.87 andr= 0.95, respectively) with those of the standard assay (≥50% killing as the SBA titer end point), and titers were not significantly different when compared to those of the standard assay (P> 0.68). However, the fluorometric end point had superior performance and ease of titer determination compared to the colorimetric end point (95 versus 87% of SBA titers were within 2 dilutions of the standard titer). Hib SBA assays with alamarBlue are reproducible, faster (same-day assay), and easier to perform than the standardized assay, which requires manual or automated colony counts. These semiautomated methodologies result in increased sample throughput and collection of data in digital formats that can be exported to data analysis programs for determination of SBA titers.
Immunoglobulin A (IgA) and IgG Immune Responses against P-90 Antigen for Diagnosis of Pulmonary Tuberculosis and Screening for
Mycobacterium tuberculosis
Infection
Authors: Conde Marcus B. , Suffys Philip , Lapa e Silva Jose Roberto , Kritski Afranio L. , Dorman Susan E. 
Published: January 2004

ABSTRACT

The purpose of the present study was to evaluate the usefulness of detection of serum immunoglobulin A (IgA) and IgG antibodies directed against the mycobacterial P-90 antigen for the diagnosis of active pulmonary tuberculosis (PTB) among symptomatic individuals and for the detection of
Mycobacterium tuberculosis
infections among close contacts of PTB patients. Two commercially available enzyme immunoassay (EIA) kits (IgA EIA-TB [EIA-IgA] and IgG EIA-TB [EIA-IgG]; Kreatech Diagnostics) were evaluated in a blinded fashion by using stored serum samples from 268 individuals, including 69 patients with PTB, 41 patients with diseases other than tuberculosis (TB), 12 subjects with healed PTB, 39 close contacts of PTB patients, and 107 healthy volunteers. For the EIA-IgA, the sensitivity was 74% and the specificity was 68% when a cutoff determined by a receiver operator characteristic curve was used. For the EIA-IgG, the sensitivity was 69% and the specificity was 64%. The EIA-IgA was positive for 54% of healthy close contacts of PTB patients but only 8% of healthy controls without contact with a PTB patient or a prior personal history of TB (
P
< 0.001). The relatively low sensitivities and specificities of these serologic tests make them poor tools for the diagnosis of PTB among patients with suspected PTB. However, the relatively high prevalence of positive EIA-IgA results among healthy close contacts of PTB patients warrants further evaluation of this test with close contacts and other populations at risk for recent
M. tuberculosis
exposure and development of disease.
Evaluation of the Determine Rapid Syphilis TP Assay Using Sera
Authors: Diaz Theresa , de Gloria Bonecini Almeida Maria , Georg Ingebourg , de Carvalho Maia Suely , Valls de Souza Rogerio , Markowitz Lauri E. 
Published: January 2004

ABSTRACT

The Abbott Determine Rapid Syphilis TP assay is a treponemal test that can be used in resource-poor settings that lack laboratory facilities. However, this test has not been extensively evaluated. We measured its sensitivity and specificity by using stored serum specimens (
n
= 567) from all persons who tested
Treponema pallidum
hemagglutination assay (TPHA) positive (
n
= 250) or TPHA indeterminate (
n
= 17) in the year 2001 and the first 300 patients in 2001 who tested TPHA negative at the Evandro Chagas Research Institute in Rio de Janeiro, Brazil. This rapid assay was independently interpreted by three different observers. With TPHA results as the reference, sensitivity ranged between readers from 95.6 to 98.4% and specificity ranged from 97.3 to 95.7%. There was little interreader variability in the interpretation of results, with approximately 98% agreement for all reader combinations. Of samples from persons with human immunodeficiency virus (HIV) infection (
n
= 198), sensitivity was 96.9 to 99.2% and it was 94.4 to 96.3% among HIV-negative persons (
n
= 127). Specificity was 92.4 to 95.5% among HIV-positive persons and 97.2 to 100% among HIV-negative persons. We found this test to have high sensitivity and specificity and little interreader variability, indicating that it may be easily used in resource-poor settings without laboratory facilities. Further studies are needed using this test on whole blood and under the clinical conditions for which it is intended.
Expression and Immunogenicity of Proteins Encoded by Sequences Specific toMycobacterium aviumsubsp.paratuberculosis
Authors: Bannantine John P. , Hansen Janis K. , Paustian Michael L. , Amonsin Alongkorn , Li Ling-Ling , Stabel Judith R. , Kapur Vivek 
Published: January 2004

ABSTRACTThe development of immunoassays specific for the diagnosis of Johne's disease in cattle requires antigens specific toMycobacterium aviumsubsp.paratuberculosis. However, because of genetic similarity to other mycobacteria comprising theM. aviumcomplex, no such antigens have been found. Through a comparative genomics approach, 21 potential coding sequences ofM. aviumsubsp.paratuberculosisthat are not represented in any other mycobacterial species tested (n= 9) were previously identified (J. P. Bannantine, E. Baechler, Q. Zhang, L. Li, and V. Kapur, J. Clin. Microbiol.40:1303-1310, 2002). Here we describe the cloning, heterologous expression, and antigenic analysis of theseM. aviumsubsp.paratuberculosis-specific sequences inEscherichia coli. Nucleotide sequences representing each unique predicted coding region were amplified and cloned into two differentE. coliexpression vectors encoding polyhistidine or maltose binding protein (MBP) affinity purification tags. All 21 of the MBP fusion proteins were successfully purified under denaturing conditions and were evaluated in immunoblotting studies with sera from rabbits and mice immunized withM. aviumsubsp.paratuberculosis. These studies showed that 5 of the 21 gene products are produced byM. aviumsubsp.paratuberculosisand are antigenic. Immunoblot analysis with a panel of sera from 9 healthy cattle and 10 cattle with clinical disease shows that the same fiveM. aviumsubsp.paratuberculosisproteins are also detected within the context of infection. Collectively, these studies have used a genomic approach to identify novelM. aviumsubsp.paratuberculosisantigens that are not present in any other mycobacteria. These findings may have a major impact on improved diagnostics for Johne's disease.
Direct Comparison of the BACTEC 9240 and BacT/ALERT 3D Automated Blood Culture Systems for
Candida
Growth Detection
Authors: Horvath Lynn L. , George Benjamin J. , Murray Clinton K. , Harrison Linda S. , Hospenthal Duane R. 
Published: January 2004

ABSTRACT

A direct comparison of two automated blood culture systems was conducted to compare their ability to detect
Candida
growth. The systems evaluated were the BACTEC 9240 (Bactec) and BacT/ALERT 3D (BacT). The aerobic, anaerobic, and mycology media for each system were evaluated: Bactec Plus Aerobic/F, Plus Anaerobic/F, and Myco/F Lytic bottles,, respectively, and BacT FA, SN, and MB bottles, respectively. Each blood culture bottle was inoculated with fresh blood from healthy donors. Fifty isolates of
Candida
spp. were used. The six different blood culture bottles were each inoculated with 1,000 yeasts per bottle and then incubated in the corresponding automated system. The BacT detected growth of 90% (135 of 150) of
Candida
pathogens, while Bactec detected 66% (100 of 150). Growth was detected in all BacT and Bactec mycology bottles, all BacT aerobic bottles, and by terminal subculture of all bottles. Sixty-five of 300 (22%) bottles had no growth detected; 50 from the Bactec (5 aerobic and 45 anaerobic) and 15 from the BacT (all anaerobic). Terminal subculture of “negative” bottles demonstrated viable yeast growth from all 65 bottles, representing 65 false-negatives. The mean time to growth detection in the BacT system was 25.62 h while the Bactec was 27.30 h (
P
< 0.01). Both automated blood culture systems detected all episodes of simulated candidemia when specialized mycology media were used. However, when only standard aerobic and anaerobic media were used, the BacT performed better than the Bactec in overall growth detection, time to growth detection, and number of false-negatives.
Molecular Analysis of
Mycobacterium kansasii
Isolates from the United States
Authors: Zhang Yansheng , Mann Linda B. , Wilson Rebecca W. , Brown-Elliott Barbara A. , Vincent Véronique , Iinuma Yoshitsugu , Wallace Richard J. 
Published: January 2004

ABSTRACT

We studied the population genetics of
Mycobacterium kansasii
isolates from the United States by PCR restriction enzyme analysis (PRA) of the 441-bp Telenti fragment of the
hsp
-65 gene and pulsed-field gel electrophoresis (PFGE) of genomic DNA with the restriction endonucleases
Ase
I,
Dra
I, and
Xba
I, and we compared the patterns to those previously reported from France and Japan. By PRA, 78 of 81 clinical isolates (96%) from the United States belonged to subspecies I. With PFGE, 28
Ase
I patterns, 32
Dra
I patterns, and 35
Xba
I patterns were produced. PFGE showed marked clonality of the U.S. isolates, with differences between genotypes involving only one or two bands. Isolates within Texas showed lower pattern diversity than those from different states. With
Dra
I, 31 of 71 isolates (44%) had the same common PFGE pattern, which matched the predominant pattern in France (pattern Ia), determined by Picardeau et al. (M. Picardeau, G. Prod'hom, L. Raskine, M. P. LePennec, and V. Vincent, J. Clin. Microbiol.
35:
25-32, 1997), and in Japan (type M), determined by Iinuma et al. (Y. Iinuma, S. Ichiyama, Y. Hasegawa, K. Shimokata, S. Kawahara, and T. Matsushima, J. Clin. Microbiol.
35:
596-599, 1997). With
Ase
I, 42% of isolates produced a common pattern indistinguishable from the common pattern seen in French isolates (Ia) and with only one band difference from the common pattern (type M) in Japan. This study demonstrates that subspecies I is the predominant subspecies of
M. kansasii
among clinical isolates in the United States, as it is in Europe and Japan, and that genotype I is highly clonal worldwide, with the same major genotype responsible for human infection. The fact that a single clone of
M. kansasii
is responsible for most cases of human disease suggests that specific virulence factors may be associated with this specific genotype.
Utility of the Focus Technologies West Nile Virus Immunoglobulin M Capture Enzyme-Linked Immunosorbent Assay for Testing Cerebrospinal Fluid
Authors: Prince Harry E. , Lape'-Nixon Mary , Moore Ronald J. , Hogrefe Wayne R. 
Published: January 2004

ABSTRACT
Focus Technologies has developed an immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA) kit that utilizes recombinant West Nile virus (WNV) antigens to detect WNV IgM in serum. We evaluate here the utility of the kit for detecting WNV IgM in cerebrospinal fluid (CSF). The sensitivity was evaluated by using 52 CSF specimens from the 2002 WNV season that were positive in both the Public Health Service Laboratories WNV IgM ELISA and an in-house WNV IgM ELISA with native WNV antigen. The specificity was evaluated with two groups of specimens: (i) 73 CSF specimens submitted for in-house WNV IgM ELISA testing from February through April 2003 and yielding a negative WNV IgM result and (ii) 60 CSF specimens determined to be positive for another virus by PCR testing. Using these 185 CSF specimens at a screening dilution of 1:2, the kit was determined to be 100% sensitive and 100% specific. Endpoint titers were determined for 20 IgM-positive CSF specimens by testing serial twofold dilutions and ranged from 1:8 to 1:512. Index values (specimen absorbance value/calibrator absorbance value) for the screening dilution (1:2) showed no correlation with IgM titers, whereas index values for higher dilutions showed significant correlation with IgM titers. CSF screening dilutions of greater than 1:2 are not recommended, however, due to the risk of obtaining false-negative results. These findings show that the Focus Technologies WNV IgM capture ELISA, when utilized as recommended, offers accurate qualitative detection of WNV IgM in CSF specimens.
Human Metapneumovirus Infection in Japanese Children
Authors: Ebihara Takashi , Endo Rika , Kikuta Hideaki , Ishiguro Nobuhisa , Ishiko Hiroaki , Hara Michimaru , Takahashi Yutaka , Kobayashi Kunihiko 
Published: January 2004

ABSTRACT
Human metapneumovirus (hMPV) has been recently discovered as an etiological agent of acute respiratory infections. Our purpose was to asses the virological and clinical features of children with respiratory infections caused by hMPV. We examined 658 nasopharyngeal swab samples obtained from 637 children with respiratory infections for hMPV by using reverse transcription-PCR (RT-PCR). A total of 268 samples from 637 children were inoculated onto tertiary monkey kidney cells. A total of 36 serum samples (26 in the acute phase and 10 in the convalescent phase) from the 26 hMPV-positive children were tested for immunoglobulin G (IgG) and IgM antibodies to hMPV by using an indirect immunofluorescence assay. We detected hMPV in 57 (8.9%) of the 637 samples by using RT-PCR and isolated 7 (2.6%) hMPV strains of the 268 samples in cell cultures. A total of 12 (46.2%) of 26 hMPV-positive children were suspected to have primary infection with hMPV as determined by an indirect immunofluorescence assay. The infected children were diagnosed as having wheezy bronchitis (36.8%), upper respiratory tract infection (26.3%), bronchitis (22.8%), and pneumonia (14.0%). We showed that two hMPV groups were circulating in different regions during the same period and that reinfection with hMPV frequently occurs in childhood. The RT-PCR test is the most sensitive test for detection of hMPV, and a serological test may be useful to differentiate between primary infection and reinfection with hMPV.
Typical Enteroaggregative
Escherichia coli
Is the Most Prevalent Pathotype among
E. coli
Strains Causing Diarrhea in Mongolian Children
Authors: Sarantuya Jav , Nishi Junichiro , Wakimoto Naoko , Erdene Shirchin , Nataro James P. , Sheikh Jalaluddin , Iwashita Mayumi , Manago Kunihiro , Tokuda Koichi , Yoshinaga Masao , Miyata Koichiro , Kawano Yoshifumi 
Published: January 2004

ABSTRACT

Diarrhea remains one of the main sources of morbidity and mortality in the world, and a large proportion is caused by diarrheagenic
Escherichia coli
. In Mongolia, the epidemiology of diarrheagenic
E. coli
has not been well studied. A total of 238
E. coli
strains from children with sporadic diarrhea and 278
E. coli
strains from healthy children were examined by PCR for 10 virulence genes: enteropathogenic
E. coli
(EPEC)
eae
,
tir
, and
bfpA
; enterotoxigenic
E. coli
(ETEC)
lt
and
st
; enteroinvasive
E. coli
(EIEC)
ipaH
; enterohemorragic
E. coli stx1
and
stx2
; and enteroaggregative
E. coli
(EAEC)
aggR
and
astA
. EAEC strains without AggR were identified by the HEp-2 cell adherence test. The detection of EAEC, ETEC, EPEC, and EIEC was significantly associated with diarrhea. The incidence of EAEC (15.1%), defined by either a molecular or a phenotypic assay, was higher in the diarrheal group than any other category (0 to 6.0%). The incidence of AggR-positive EAEC in the diarrheal group was significantly higher than in the control group (8.0 versus 1.4%;
P
= 0.0004), while that of AggR-negative EAEC was not (7.1 versus 4.3%). Nineteen AggR-positive EAEC strains harbored other EAEC virulence genes—
aggA
, 2 (5.5%);
aafA
, 4 (11.1%);
agg-3a
, 5 (13.8%);
aap
, 8 (22.2%);
aatA
, 11 (30.5%);
capU
, 9 (25.0%);
pet
, 6 (16.6%); and
set
, 3 (8.3%)—and showed 15 genotypes. EAEC may be an important pathogen of sporadic diarrhea in Mongolian children. Genetic analysis showed the heterogeneity of EAEC but illustrated the importance of the AggR regulon (denoting typical EAEC) as a marker for virulent EAEC strains.
Rapid Diagnosis of Human Herpesvirus 6 Infection by a Novel DNA Amplification Method, Loop-Mediated Isothermal Amplification
Authors: Ihira Masaru , Yoshikawa Tetsushi , Enomoto Yoshihiko , Akimoto Shiho , Ohashi Masahiro , Suga Sadao , Nishimura Naoko , Ozaki Takao , Nishiyama Yukihiro , Notomi Tsugunori , Ohta Yoshinori , Asano Yoshizo 
Published: January 2004

ABSTRACTA novel nucleic acid amplification method, termed loop-mediated isothermal amplification (LAMP), which amplifies DNA with high specificity, efficiency, and rapidity under isothermal conditions, may be a valuable tool for the rapid detection of infectious agents. LAMP was developed for human herpesvirus 6 (HHV-6), and its reliability was evaluated in this study. Although LAMP products were detected in HHV-6 B and HHV-6 A DNA, they were not detected in HHV-7 and human cytomegalovirus DNA. The sensitivity of the original HHV-6 LAMP protocol was 50 copies/tube. In order to increase the method's sensitivity, HHV-6 LAMP was modified by increasing the primer concentration. As a result of the modification, sensitivity increased to 25 copies/tube. After these initial validation studies, 13 patients with fever were tested for HHV-6 by viral isolation, serological analysis, and HHV-6 LAMP. In three of the eight patients with primary HHV-6 infection, HHV-6 DNA was detected in whole blood by the original HHV-6 LAMP protocol in not only the acute phase but also the convalescent phase. HHV-6 DNA was detected by modified HHV-6 LAMP in all eight plasma samples collected in the acute phase; however, no HHV-6 DNA was detected in plasma samples collected in the convalescent phase. Although HHV-6 DNA was detected in both the acute and convalescent phases of whole-blood samples in patients with past HHV-6 infection, it was not detected in plasma samples that did not contain latent viral DNA. Thus, detection of HHV-6 DNA in plasma by using this modified HHV-6 LAMP protocol is appropriate for diagnosis of active HHV-6 infection.
Comparison of DNA Dot Blot Hybridization and Lancefield Capillary Precipitin Methods for Group B Streptococcal Capsular Typing
Authors: Borchardt Stephanie M. , Foxman Betsy , Chaffin Donald O. , Rubens Craig E. , Tallman Patricia A. , Manning Shannon D. , Baker Carol J. , Marrs Carl F. 
Published: January 2004

ABSTRACT

Group B streptococci (GBS) (
Streptococcus agalactiae
) are a major cause of sepsis and meningitis in neonates and infants and of invasive disease in pregnant women, nonpregnant, presumably immunocompromised adults, and the elderly. Nine GBS serotypes based on capsular polysaccharide antigens have been described. The serotype distributions among invasive and colonizing isolates differ between pediatric and adult populations and have changed over time. Thus, periodic monitoring of GBS serotype distributions is necessary to ensure the proper formulation and application of an appropriate GBS vaccine for human use and to detect the emergence of novel serotypes. Since the mid-1990s, the proportion of GBS isolates that are nontypeable by standard serologic methods has increased, creating a need for more sensitive typing methods. We describe a typing method that uses DNA dot blot hybridization with probes generated by PCR from the GBS capsular genes for serotypes Ia, Ib, and II to VIII. PCR primers were designed to amplify type-specific GBS capsular gene sequences. Gene probes were constructed from the PCR products and used to classify isolates based on hybridization profiles. A total of 306 previously serotyped invasive and colonizing isolates were used to compare our dot blot capsular typing (DBCT) identification method with Lancefield serotyping (LS). A dot blot capsular type was assigned to 99% (303 of 306) of the isolates, whereas 273 of 306 isolates (89%) were assigned a Lancefield serotype. The overall agreement between the methods was 95% (256 of 270 isolates typeable by both methods). We conclude that the DBCT method is a specific and useful alternative to the commonly used LS method.
Prevalence and Genetic Diversity of Human Astroviruses in Mexican Children with Symptomatic and Asymptomatic Infections
Authors: Méndez-Toss Martha , Griffin Dixie D. , Calva Juan , Contreras Juan F. , Puerto Fernando I. , Mota Felipe , Guiscafré Héctor , Cedillo Roberto , Muñoz Onofre , Herrera Ismael , López Susana , Arias Carlos F. 
Published: January 2004

ABSTRACT
The prevalence and type diversity of human astroviruses (HAstV) in children with symptomatic and asymptomatic infections were determined in five localities of Mexico. HAstV were detected in 4.6 (24 of 522) and 2.6% (11 of 428) of children with and without diarrhea, respectively. Genotyping of the detected strains showed that at least seven (types 1 to 4 and 6 to 8) of the eight known HAstV types circulated in Mexico between October 1994 and March 1995. HAstV types 1 and 3 were the most prevalent in children with diarrhea, although they were not found in all localities studied. HAstV type 8 was found in Mexico City, Monterrey, and Mérida; in the last it was as prevalent (40%) as type 1 viruses, indicating that this astrovirus type is more common than previously recognized. A correlation between the HAstV infecting type and the presence or absence of diarrheic symptoms was not observed. Enteric adenoviruses were also studied, and they were found to be present in 2.3 (12 of 522) and 1.4% (6 of 428) of symptomatic and asymptomatic children, respectively.
Hepatitis C Genotyping by Denaturing High-Performance Liquid Chromatography
Authors: Liew Michael , Erali Maria , Page Sam , Hillyard David , Wittwer Carl 
Published: January 2004

ABSTRACTDetermination of the hepatitis C virus (HCV) genotype for infected patients increasingly has become accepted as the standard of care. Genotype assignment helps in assessing disease prognosis and assists in establishing the appropriate duration of treatment. The great genetic diversity of HCV, with 11 major genotypes and >70 subtypes, contributes to the technical difficulty of genotype testing. While the “gold standard” for testing is nucleic acid sequencing, a variety of hybridization assays, including the line probe assay, have been developed to provide more rapid and accessible forms of testing. The aim of this study was to determine whether denaturing high-performance liquid chromatography (dHPLC) could be used as a clinical method for distinguishing HCV genotypes 1, 2, 3, and 4. A portion of the 5′ untranslated region of the HCV genome was amplified by heminested multiplex reverse transcription PCR. The two amplicons then were analyzed by dHPLC analysis and compared to the genotypes determined by sequence analysis. After 115 specimens were analyzed as standards, 200 masked specimens (specimens whose identity was not known before testing) were analyzed to determine the concordance of the assay. The assay had a concordance of 96% at the genotype level and a concordance of 87% at the subtype level. However, the dHPLC method was not as accurate as other reported methods of HCV genotyping. This is the first time that HCV genotyping has been performed by dHPLC.