bluuebunny/crossref_metadata_2025_split huggingface dataset:
Agrobacterium Bioassay Strain for Ultrasensitive Detection of
N
-Acylhomoserine Lactone-Type Quorum-Sensing Molecules: Detection of Autoinducers in
Mesorhizobium huakuii
Authors: Zhu Jun , Chai Yunrong , Zhong Zengtao , Li Shunpeng , Winans Stephen C. 
Published: November 2003

ABSTRACT

An ultrasensitive bioassay system for the detection of
N
-acylhomoserine lactones (AHLs) was constructed in
Agrobacterium tumefaciens
by using the T7 expression system to overproduce the AHL receptor TraR. This strain detected many diverse AHLs, some at extremely low concentrations. We used this strain to detect for the first time AHLs made by
Mesorhizobium huakuii
, which symbiotically fixes nitrogen in association with the legume
Astragalus sinicus
, a source of green manure throughout eastern Asia.
Site-Specific Manifestations of Invasive Group A Streptococcal Disease: Type Distribution and Corresponding Patterns of Virulence Determinants
Authors: Vlaminckx Bart J. M. , Mascini Ellen M. , Schellekens Joop , Schouls Leo M. , Paauw Armand , Fluit Ad C. , Novak Rodger , Verhoef Jan , Schmitz Franz Josef 
Published: November 2003

ABSTRACTAs part of a national surveillance program on invasive group A streptococci (GAS), isolates that caused specific manifestations of invasive GAS disease in The Netherlands were collected between 1992 and 1996. These site-specific GAS infections involved meningitis, arthritis, necrotizing fasciitis, and puerperal sepsis. An evaluation was performed to determine whether GAS virulence factors correlate with these different disease manifestations. PCRs were developed to detect 9 genes encoding exotoxins and 12 genes encoding fibronectin binding proteins. The genetic backgrounds of all isolates were determined by M genotyping and pulsed-field gel electrophoresis (PFGE) analysis. The predominant M types included M1, M2, M3, M4, M6, M9, M12, and M28. Most M types were associated with all manifestations of GAS disease. However, M2 was found exclusively in patients with puerperal sepsis, M6 predominated in patients with meningitis, and M12 predominated in patients with GAS arthritis. While characteristic gene profiles were detected in most M types, the resolution of detection of different gene profiles within M genotypes was enhanced by PFGE analysis, which clearly demonstrated the existence of some clonal lineages among invasive GAS isolates in The Netherlands. M1 isolates comprised a single clone carrying highly mitogenic toxin genes (speA,smeZ) and were associated with toxic shock-like syndrome. Toxin profiles were highly conserved among the most virulent strains, such as M1 and M3.
Comparison of Real-Time PCR and Culture for Detection of
Porphyromonas gingivalis
in Subgingival Plaque Samples
Authors: Boutaga Khalil , van Winkelhoff Arie Jan , Vandenbroucke-Grauls Christina M. J. E. , Savelkoul Paul H. M. 
Published: November 2003

ABSTRACT

Porphyromonas gingivalis
is a major pathogen in destructive periodontal disease in humans. Detection and quantification of this microorganism are relevant for diagnosis and treatment planning. The prevalence and quantity of
P. gingivalis
in subgingival plaque samples of periodontitis patients were determined by anaerobic culture and real-time PCR amplification of the 16S small-subunit rRNA gene. The PCR was performed with primers and a fluorescently labeled probe specific for the
P. gingivalis
16S rRNA gene. By the real-time PCR assay, as few as 1 CFU of
P. gingivalis
could be detected. Subgingival plaque samples from 259 adult patients with severe periodontitis were analyzed.
P. gingivalis
was detected in 111 (43%) of the 259 subgingival plaque samples by culture and in 138 (53%) samples by PCR. The sensitivity, specificity, and positive and negative predictive values of the real-time PCR were 100, 94, 94, and 100%, respectively. We conclude that real-time PCR confirms the results of quantitative culture of
P. gingivalis
and offers significant advantages with respect to the rapidity and sensitivity of detection of
P. gingivalis
in subgingival plaque samples.
Molecular Epidemiology of
Proteus mirabilis
Infections of the Catheterized Urinary Tract
Authors: Sabbuba N. A. , Mahenthiralingam E. , Stickler D. J. 
Published: November 2003

ABSTRACT

Proteus mirabilis
compromises the care of many patients undergoing long-term indwelling bladder catheterization. It forms crystalline bacterial biofilms in catheters which block the flow of urine, causing either incontinence due to leakage or painful distention of the bladder due to urinary retention. If it is not dealt with, catheter blockage can lead to pyelonephritis and septicemia. We have examined the epidemiology of catheter-associated
P. mirabilis
infections by use of pulsed-field gel electrophoresis (PFGE) of
Not
I restriction enzyme digests of bacterial DNA. This technique was shown to be more discriminatory than the classical phenotypic Dienes typing technique. We demonstrated that each of 42 isolates from diverse environmental sources and 10 of 12 isolates from blood, wound swabs, and mid-stream urine samples of hospitalized patients had distinct genotypes. Examination of a set of 55 isolates of
P. mirabilis
, each from a different clinical or environmental source, identified 49 distinct genotypes and 43 Dienes types. The index of discrimination was 0.993 for the PFGE method and 0.988 for the Dienes method. Applying the PFGE method to isolates from catheter-associated urinary tract infections confirmed that the strains present in the crystalline catheter biofilms were identical to those isolated from the same patient's urine. An analysis of samples taken during a prospective study of infections in catheterized nursing home patients revealed that a single genotype of
P. mirabilis
can persist in the urinary tract despite many changes of catheter, periods of noncatheterization, and antibiotic therapy.
Geographic Distribution and Clonal Diversity of
Streptococcus pneumoniae
Serotype 1 Isolates
Authors: Brueggemann Angela B. , Spratt Brian G. 
Published: November 2003

ABSTRACT
Serotype 1 pneumococci are a major cause of serious disease and have been associated with outbreaks but are rarely carried. The high attack rate and lack of coverage of this serotype by the heptavalent conjugate vaccine prompted the characterization of a geographically diverse collection of 166 serotype 1 isolates from recent cases of invasive disease. The isolates were resolved by multilocus sequence typing into 16 clones, which clustered into three major lineages with very different geographic distributions. Lineage A isolates were exclusively from Europe and North America, lineage B isolates were predominantly from Africa and Israel, and lineage C isolates were mainly from Chile. There was no clear association between the presence of individual clones within a country and the prevalence of serotype 1 disease.
Characterization of Isolates of Methicillin-Resistant
Staphylococcus aureus
from Hong Kong by Phage Typing, Pulsed-Field Gel Electrophoresis, and Fluorescent Amplified-Fragment Length Polymorphism Analysis
Authors: Ip M. , Lyon D. J. , Chio F. , Enright M. C. , Cheng A. F. 
Published: November 2003

ABSTRACT

The genetic relatedness of 127 methicillin-resistant
Staphylococcus aureus
(MRSA) isolates, belonging to five major types as identified by pulsed-field gel electrophoresis (PFGE) and antibiotic resistance profiles, was examined further using phage typing and fluorescent amplified fragment length polymorphism (FAFLP). The MRSA isolates were recovered from patients at the Prince of Wales Hospital (PWH), Hong Kong, over a 13-year period, 1988 to 2000. These strains were also compared with representatives of the well-described MRSA international clones and with epidemic MRSA strains (eMRSA) 1 to 16 from the United Kingdom. Phage typing distinguished two major “clones” at this hospital: all of the phage type 1 (PT1) isolates belonged to PFGE types A, C, D, and E, while most of the PT2 isolates were associated with PFGE type B, which exhibited a unique antibiotic resistance profile. MRSA isolates belonging to PFGE subtype A2 were indistinguishable from the British eMRSA-1, while isolates of PFGE type B were closely related to eMRSA-9 by PFGE. Based on FAFLP, all five predominant PFGE types at the PWH belonged to one group and fell into the same cluster as eMRSA-1, -4, -7, -9, and -11 isolates. Multilocus sequence typing and staphylococcal cassette chromosome
mec
typing classified representatives of our MRSA isolates as members of the same clone (ST239-MRSA-III). Thus, the predominant MRSA isolates frin the PWH in the last decade are closely related to early United Kingdom eMRSA clones 1, 4, and 11 and are members of a lineage that includes the Brazilian MRSA clone.
Enzyme-Linked Immunosorbent Assay Employing a Recombinant Antigen for Detection of Protective Antibody against Swine Erysipelas
Authors: Imada Yumiko , Mori Yasuyuki , Daizoh Masaji , Kudoh Kazuma , Sakano Tetsuya 
Published: November 2003

ABSTRACT

The specificities and sensitivities of five recombinant proteins of the surface protective antigen (SpaA) of
Erysipelothrix rhusiopathiae
were examined by indirect enzyme-linked immunosorbent assay (ELISA) with the aim of developing a reliable serological test for the detection of protective antibody against
E. rhusiopathiae
. Fully mature protein and the N-terminal 416 amino acids (SpaA416) showed sufficient antigenicities, and further examination was done with SpaA416 because of its higher yield. The antibody titers of pigs experimentally immunized with commercial live vaccine and two types of inactivated vaccines clearly increased after immunization, and all pigs were completely protected against challenge with virulent strains. On the other hand, the antibody titers of nonimmunized control pigs remained very low until they were challenged, and all showed severe symptoms or subsequently died. Interference with the production of antibody against live vaccine by maternal antibody or porcine respiratory and reproductive syndrome virus infection 1 week after vaccination was also clearly detected. Because the ELISA titer correlated well with the protection results, the specificity and sensitivity of the ELISA were further evaluated with sera collected from pigs reared on 1 farm on which animals had acute septicemia, 2 farms on which the animals were infected or free from infection, and 10 farms on which the animals were vaccinated with live vaccine, among others. The ELISA titers clearly revealed the conditions of the herds. These results indicate that the SpaA416 ELISA is an effective method not only for evaluating pigs for the presence of protective antibody levels resulting from vaccination or maternal antibody but also for detecting antibody produced by natural infection. This test has important potential for the effective control of swine erysipelas.
High Diversity ofankASequences ofAnaplasma phagocytophilumamongIxodes ricinusTicks in Germany
Authors: von Loewenich Friederike D. , Baumgarten Birgit U. , Schröppel Klaus , Geißdörfer Walter , Röllinghoff Martin , Bogdan Christian 
Published: November 2003

ABSTRACTIn Germany humans with acute granulocytic ehrlichiosis have not yet been described. Here, we characterized three different genes ofAnaplasma phagocytophilumstrains infecting GermanIxodes ricinusticks in order to test whether they differ from strains in other European countries and the United States. A total of 1,022I. ricinusticks were investigated for infection withA. phagocytophilumby nested PCR and sequence analysis. Forty-two (4.1%) ticks were infected. For all positive ticks, parts of the 16S rRNA andgroESLgenes were sequenced. The complete coding sequence of theankAgene could be determined in 24 samples. The 16S rRNA andgroESLgene sequences were as much as 100% identical to known sequences. FifteenankAsequences were ≥99.37% identical to sequences derived from humans with granulocytic ehrlichiosis in Europe and from a horse with granulocytic ehrlichiosis in Germany. Thus, GermanI. ricinusticks most likely harborA. phagocytophilumstrains that can cause disease in humans. Nine additional sequences were clearly different from knownankAsequences. Because these newly described sequences have never been obtained from diseased humans or animals, their biological significance is currently unknown. Based on this unexpected sequence heterogeneity, we propose to use theankAgene for further phylogenetic analyses ofA. phagocytophilumand to investigate the biology and pathogenicity of strains that differ in theankAgene.
Characterization of the Natural Population of
Bartonella henselae
by Multilocus Sequence Typing
Authors: Iredell J. , Blanckenberg D. , Arvand M. , Grauling S. , Feil E. J. , Birtles R. J. 
Published: November 2003

ABSTRACT

Investigations of the population genetics of
Bartonella henselae
have demonstrated a high level of diversity among strains, and the delineation of isolates into one of two subtypes, type I (Houston) and type II (Marseille), represented by specific 16S ribosomal DNA (rDNA) sequences, has long been considered the most significant genotypic division within the species. This belief is challenged by recent work suggesting a role for horizontal gene exchange in generating intraspecies diversity. We attempted to resolve this issue and extend exploration of the population structure of
B. henselae
by using multilocus sequence typing (MLST) to examine the distribution of polymorphisms within nine different genes in a sample of 37 human and feline isolates. MLST distinguished seven sequence types (STs) that resolved into three distinct lineages, suggesting a clonal population structure for the species, and support for these divisions was obtained by macrorestriction analysis using pulsed-field gel electrophoresis. The distribution of STs among isolates recovered from human infections was not random, and such isolates were significantly more often associated with one particular ST, lending further support to the suggestion that specific genotypes contribute disproportionately to the disease burden in humans. All but one isolate lay on lineages that bore the representative strain of either the Houston or Marseille subtype. However, the distribution of the two 16S rDNA alleles among the isolates was not entirely congruent with their lineage allocations, indicating that this is not a sensitive marker of the clonal divisions within the species. The inheritances of several of the genes studied could not be reconciled with one another, providing further evidence of horizontal gene transfer among
B. henselae
strains and suggesting that recombination has a role in shaping the genetic character of bartonellae.
Prevalence, Molecular Epidemiology, and Clinical Significance of Heterogeneous Glycopeptide-Intermediate
Staphylococcus aureus
in Liver Transplant Recipients
Authors: Bert Frédéric , Clarissou Juliette , Durand François , Delefosse Didier , Chauvet Chantal , Lefebvre Patricia , Lambert Nicole , Branger Catherine 
Published: November 2003

ABSTRACT

We investigated the prevalence, molecular epidemiology, and clinical significance of heterogeneous glycopeptide-intermediate
Staphylococcus aureus
(hGISA) isolates in 48 liver transplant recipients infected or colonized with methicillin-resistant
S. aureus
over a 5-year period. Strains were screened for hGISA on Mueller-Hinton agar containing 5 mg of teicoplanin per liter. Heterogeneous glycopeptide resistance was confirmed by the E-test method with a dense inoculum and a simplified method of population analysis. hGISA strains were found in 13 (27%) of the 48 patients studied. Eleven of the 13 strains shared a common multiresistant phenotype with homogeneous methicillin resistance and gentamicin resistance, and they were closely related according to the results of pulsed-field gel electrophoresis. Only 2 of the 13 patients infected or colonized with hGISA strains had previously received glycopeptide therapy. Most patients were successfully treated with vancomycin, but one patient who failed to respond to vancomycin subsequently died. These results suggest that the high prevalence of hGISA among our patients was due to the clonal spread of a multiresistant strain.
Comparison between Indirect Immunofluorescence Assay and Shell Vial Culture for Detection of Mumps Virus from Clinical Samples
Authors: Reina Jordi , Ballesteros Francisca , Ruiz de Gopegui Enrique , Munar Maria , Mari Margarita 
Published: November 2003

ABSTRACT

We report a prospective comparison of the efficacies of an indirect immunofluorescence assay (IFA) and shell vial culture (SVC) of throat swab and urine samples from patients with mumps. Throat swab samples were used for the IFA; the urine samples and throat swabs were inoculated into vials of Vero cells. We studied 62 patients by using 62 throat swabs and 50 urine samples (50 patients with both samples). Sixty (96.7%) throat samples were positive in the SVC, and 61 (98.3%) were positive in the IFA. For the 50 patients from whom both samples were available, the IFA was positive in 50 (100%) cases, the urine sample was positive in 49 (98%) cases, and the throat swab was positive in 48 (96%) cases (
P
> 0.05). This comparison of throat swabs and urine samples has shown that the two clinical samples are similar in efficacy.
Genetic Characterization of Newly Reintroduced Dengue Virus Type 3 in Martinique (French West Indies)
Authors: Peyrefitte Christophe N. , Couissinier-Paris Patricia , Mercier-Perennec Véronique , Bessaud Maël , Martial Jenny , Kenane Nadia , Durand Jean-Paul A. , Tolou Hugues J. 
Published: November 2003

ABSTRACT
Dengue type 3 viruses were isolated from patients in Martinique between 1999 and 2002. This serotype had not been detected on the island in the last 20 years. Genomic sequence determination and analysis showed great stability of the virus during the period studied.
Molecular Variation in the Variable-Length PCR Target and 120-Kilodalton Antigen Genes ofEhrlichia chaffeensisfrom White-Tailed Deer (Odocoileus virginianus)
Authors: Yabsley Michael J. , Little Susan E. , Sims Ethan J. , Dugan Vivien G. , Stallknecht David E. , Davidson William R. 
Published: November 2003

ABSTRACTGenes encoding two surface-expressed antigens ofEhrlichia chaffeensis, the variable-length PCR target (VLPT) and the 120-kDa antigen, which contain variable numbers of tandem repeats, were characterized forE. chaffeensisfrom white-tailed deer (Odocoileus virginianus). Both genes from infected deer contained numbers of repeats similar to those reported in genes from humans and ticks, although a new variant of the 120-kDa antigen gene containing five repeat units and coinfection with multiple VLPT and 120-kDa antigen gene genetic types were detected. Sequence analysis of both genes revealed more nucleotide variation than previously reported forE. chaffeensisfrom infected humans or ticks. This is the most extensive study ofE. chaffeensisVLPT and 120-kDa antigen gene genetic variation to date and is the first to examine genetic variation inE. chaffeensisfrom a nonhuman vertebrate host.
Performance of the Focus and Kalon Enzyme-Linked Immunosorbent Assays for Antibodies to Herpes Simplex Virus Type 2 Glycoprotein G in Culture-Documented Cases of Genital Herpes
Authors: Morrow Rhoda Ashley , Friedrich David , Krantz Elizabeth 
Published: November 2003

ABSTRACT
Glycoprotein G-based herpes simplex virus type 2 (HSV-2) enzyme-linked immunosorbent assays from Focus and Kalon were performed with specimens from 118 patients with culture-documented genital herpes episodes, and their results were compared. Sensitivity was 52% by Kalon and 86% by Focus for first HSV-2 episodes and 100% (for each of the two tests) for recurrent HSV-2. Median times to seroconversion were 120 days by the Kalon assay, 21 days by the Focus assay, and 68 days by Western blotting assay. Values for specificity were 100% (Kalon) and 93% (Focus).
Evaluation of Genotyping Large Numbers of
Escherichia coli
Isolates by Enterobacterial Repetitive Intergenic Consensus-PCR
Authors: Meacham Kiersten J. , Zhang Lixin , Foxman Betsy , Bauer Richard J. , Marrs Carl F. 
Published: November 2003

ABSTRACT

We analyzed a large collection of
Escherichia coli
isolates typed by enterobacterial repetitive intergenic consensus (ERIC)-PCR with BioNumerics gel analysis software. However, the interexperimental variation of ERIC-PCR caused the computer software to classify repeated isolates as different. ERIC-PCR should not be used as the sole determinant of genetic similarity when typing large numbers of bacterial isolates via computer software.
Frequency of Binary Toxin Genes among
Clostridium difficile
Strains That Do Not Produce Large Clostridial Toxins
Authors: Geric Barbara , Johnson Stuart , Gerding Dale N. , Grabnar Miklavz , Rupnik Maja 
Published: November 2003

ABSTRACT

Pathogenic strains of
Clostridium difficile
commonly produce two large clostridial toxins (LCTs), A and B, virulence factors responsible for
C. difficile
disease. Some strains have been reported to produce an additional toxin, a binary toxin designated CDT. Binary toxin has cytotoxic effects on cells in culture, but its role in human disease is not yet defined. In this study we examined the frequency of binary toxin genes (
cdtB
and
cdtA
) among
C. difficile
isolates that do not produce LCTs (A
−
B
−
) from a large United States-based collection organized by restriction endonuclease analysis (REA) typing. Of 58 strains tested, 9 (15.5%) were
cdtB
and
cdtA
positive, including 4 of 46 (8.7%) non-LCT-producing REA groups, with an estimated prevalence of at least 2% of all non-LCT-producing isolates within the collection. Five of the binary toxin-positive strains belonged to toxinotype XI, which does not produce LCTs but has minor parts of the LCT coding region or pathogenicity locus (PaLoc). We describe two new binary toxin-positive variants, one without any remnant of the LCT genes. This previously unknown variation was found in three isolates that were unrelated by REA typing. LCT-negative, binary toxin-positive strains were isolated from symptomatic and asymptomatic patients and from the hospital environment.
Restriction Enzyme Analysis of Ribosomal DNA Shows that
Candida inconspicua
Clinical Isolates Can Be Misidentified as
Candida norvegensis
with Traditional Diagnostic Procedures
Authors: Majoros L. , Kardos G. , Belák Á. , Maráz A. , Asztalos L. , Csánky E. , Barta Z. , Szabó B. 
Published: November 2003

ABSTRACT

We identified 29 yeast isolates from 22 patients using the API ID32C panel. Twenty-eight of these isolates were
Candida norvegensis
and one was
C. inconspicua
. Although
C. norvegensis
is considered a pseudohypha-producing species, only one isolate produced pseudohyphae. Restriction enzyme analysis of PCR-amplified ribosomal DNA with four different enzymes proved that all isolates were
C. inconspicua
.
Molecular Surveillance of
Cryptosporidium
spp. in Raw Wastewater in Milwaukee: Implications for Understanding Outbreak Occurrence and Transmission Dynamics
Authors: Zhou Ling , Singh Ajaib , Jiang Jianlin , Xiao Lihua 
Published: November 2003

ABSTRACT

Six
Cryptosporidium
spp. were found in 50 of 179 Milwaukee wastewater samples collected weekly over a year. Of the eight subtypes of
Cryptosporidium hominis
and
Cryptosporidium parvum
present, allele Ib was found in 14 of 16 samples, and its sequence was identical to that of the subtype in human samples from the 1993 Milwaukee outbreak of cryptosporidiosis.