bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical Significance of Expression of Human Cytomegalovirus pp67 Late Transcript in Heart, Lung, and Bone Marrow Transplant Recipients as Determined by Nucleic Acid Sequence-Based Amplification
Authors: Gerna Giuseppe , Baldanti Fausto , Middeldorp Jaap M. , Furione Milena , Zavattoni Maurizio , Lilleri Daniele , Revello Maria Grazia 
Published: December 2019

ABSTRACT
Human cytomegalovirus (HCMV) infection was monitored retrospectively by qualitative determination of pp67 mRNA (a late viral transcript) by nucleic acid sequence-based amplification (NASBA) in a series of 50 transplant recipients, including 26 solid-organ (11 heart and 15 lung) transplant recipients (SOTRs) and 24 bone marrow transplant recipients (BMTRs). NASBA results were compared with those obtained by prospective quantitation of HCMV viremia and antigenemia and retrospective quantitation of DNA in leukocytes (leukoDNAemia). On the whole, 29 patients were NASBA positive, whereas 10 were NASBA negative, and the blood of 11 patients remained HCMV negative. NASBA detected HCMV infection before quantitation of viremia did but after quantitation of leukoDNAemia and antigenemia did. In NASBA-positive blood samples, median levels of viremia, antigenemia, and leukoDNAemia were significantly higher than the relevant levels detected in NASBA-negative HCMV-positive blood samples. By using the quantitation of leukoDNAemia as the “gold standard,” the analytical sensitivity (47.3%), as well as the negative predictive value (68.3%), of NASBA for the diagnosis of HCMV infection intermediate between that of antigenemia quantitation (analytical sensitivity, 72.3%) and that of viremia quantitation (analytical sensitivity, 28.7%), while the specificity and the positive predictive value were high (90 to 100%). However, with respect to the clinically relevant antigenemia cutoff of ≥100 used in this study for the initiation of preemptive therapy in SOTRs with reactivated HCMV infection, the clinical sensitivity of NASBA reached 100%, with a specificity of 68.9%. Upon the initiation of antigenemia quantitation-guided treatment, the actual median antigenemia level was 158 (range, 124 to 580) in SOTRs who had reactivated infection and who presented with NASBA positivity 3.5 ± 2.6 days in advance and 13.5 (range, 1 to 270) in the group that included BMTRs and SOTRs who had primary infection (in whom treatment was initiated upon the first confirmation of detection of HCMV in blood) and who presented with NASBA positivity 2.0 ± 5.1 days later. Following antiviral treatment, the durations of the presence of antigenemia and pp67 mRNA in blood were found to be similar. In conclusion, monitoring of the expression of HCMV pp67 mRNA appears to be a promising, well-standardized tool for determination of the need for the initiation and termination of preemptive therapy. Its overall clinical impact should be analyzed in future prospective studies.
Detection of Antibody to Avian Influenza A (H5N1) Virus in Human Serum by Using a Combination of Serologic Assays
Authors: Rowe Thomas , Abernathy Robert A. , Hu-Primmer Jean , Thompson William W. , Lu Xiuhua , Lim Wilina , Fukuda Keiji , Cox Nancy J. , Katz Jacqueline M. 
Published: December 2019

ABSTRACT
From May to December 1997, 18 cases of mild to severe respiratory illness caused by avian influenza A (H5N1) viruses were identified in Hong Kong. The emergence of an avian virus in the human population prompted an epidemiological investigation to determine the extent of human-to-human transmission of the virus and risk factors associated with infection. The hemagglutination inhibition (HI) assay, the standard method for serologic detection of influenza virus infection in humans, has been shown to be less sensitive for the detection of antibodies induced by avian influenza viruses. Therefore, we developed a more sensitive microneutralization assay to detect antibodies to avian influenza in humans. Direct comparison of an HI assay and the microneutralization assay demonstrated that the latter was substantially more sensitive in detecting human antibodies to H5N1 virus in infected individuals. An H5-specific indirect enzyme-linked immunosorbent assay (ELISA) was also established to test children’s sera. The sensitivity and specificity of the microneutralization assay were compared with those of an H5-specific indirect ELISA. When combined with a confirmatory H5-specific Western blot test, the specificities of both assays were improved. Maximum sensitivity (80%) and specificity (96%) for the detection of anti-H5 antibody in adults aged 18 to 59 years were achieved by using the microneutralization assay combined with Western blotting. Maximum sensitivity (100%) and specificity (100%) in detecting anti-H5 antibody in sera obtained from children less than 15 years of age were achieved by using ELISA combined with Western blotting. This new test algorithm is being used for the seroepidemiologic investigations of the avian H5N1 influenza outbreak.
Comparison of the Mycobacteria Growth Indicator Tube with MB Redox, Löwenstein-Jensen, and Middlebrook 7H11 Media for Recovery of Mycobacteria in Clinical Specimens
Authors: Somoskövi Ákos , Magyar Pál 
Published: December 2019

ABSTRACT

The rate of recovery and the mean time to detection of mycobacteria in clinical specimens were evaluated with two nonradiometric broth-based systems, the Mycobacteria Growth Indicator Tube (MGIT) and MB Redox systems. The data obtained for each system were compared with each other and with those obtained with the Löwenstein-Jensen (LJ) and Middlebrook 7H11 reference media. A total of 117 mycobacterial isolates (
Mycobacterium tuberculosis
,
n
= 112; nontuberculous mycobacteria,
n
= 5) were detected in 486 clinical specimens. The recovery rates for
M. tuberculosis
were 91 of 112 (81.3%) isolates with MGIT and 81 of 112 (72.3%) isolates with MB Redox. The combination of MGIT plus MB Redox recovered 104 of the 112 (92.9%)
M. tuberculosis
isolates. MGIT plus LJ plus Middlebrook 7H11 recovered 106 of the 112 (94.6%) isolates, MB Redox plus LJ plus Middlebrook 7H11 recovered 99 of the 112 (88.4%) isolates, and LJ plus Middlebrook 7H11 recovered 84 of the 112 (75.0%) isolates. The mean time to detection of
M. tuberculosis
in smear-positive specimens was 7.2 days with MGIT, 6.9 days with MB Redox, 20.4 days with LJ, and 17.6 days with Middlebrook 7H11. The mean time to detection of
M. tuberculosis
in smear-negative specimens was 19.1 days with MGIT, 15.5 days with MB Redox, 25.8 days with LJ, and 21.6 days with Middlebrook 7H11. The contamination rates were 4.4, 3.8, 2.1, and 2.7% for MGIT, MB Redox, LJ, and Middlebrook 7H11, respectively. In conclusion, MGIT and MB Redox can be viable tools in the routine mycobacteriology laboratory.
Characterization of Nonenterotoxigenic
Escherichia coli
Strains Producing F17 Fimbriae Isolated from Diarrheic Lambs and Goat Kids
Authors: Cid D. , Sanz R. , Marín I. , de Greve H. , Ruiz-Santa-Quiteria J. A. , Amils R. , de la Fuente R. 
Published: December 2019

ABSTRACT

Forty-five ovine and caprine nonenterotoxigenic
Escherichia coli
strains producing F17-related fimbriae were characterized with respect to the fimbrial structural subunit and adhesin subtypes produced. In addition, several characteristics related to the virulence of strains producing F17 fimbriae were studied. Most of the strains (73%) possessed the
f17cA
structural subunit gene, whereas the
f17aA
and
f17dA
genes were detected only on three (6%) and two (4%) strains, respectively. The
f17bA
gene was not detected. All but one of these strains possessed the
f17G
genes of the adhesin subfamily II. The only strain having the
f17G
gene of subfamily I possessed the structural subunit gene
f17dA
. Sequencing of the
f17A
and
f17G
genes of four selected strains confirmed the association of
f17cA
and
f17dA
structural subunit genes with the
f17G
genes of the adhesin subfamily II. These results indicated that adhesins of the subfamily II are prominent among ovine and caprine isolates and that they are indistinctly associated with the F17 structural subunit subtypes on these field strains. CS31A- and CNF2-related genes were not detected. Most of the strains adhered in vitro to ovine intestinal brush borders (36 of 45) and agglutinated the erythrocytes of different species in the presence of
d
-mannose (39 of 45). F17-positive strains produced colicin V (57%) and were resistant to the bactericidal effect of serum (91%) in significantly higher percentages than F17-negative strains (34% produced colicin V, and 66% were serum resistant). Thus, most of the studied ovine and caprine strains showed phenotypic characteristics of septicemic strains.
Detection by Enzyme Immunoassay of Serum Immunoglobulin G Antibodies That Recognize Specific
Cryptosporidium parvum
Antigens
Authors: Priest Jeffrey W. , Kwon James P. , Moss Delynn M. , Roberts Jacquelin M. , Arrowood Michael J. , Dworkin Mark S. , Juranek Dennis D. , Lammie Patrick J. 
Published: December 2019

ABSTRACT

Human infection with
Cryptosporidium parvum
usually elicits characteristic immunoglobulin G (IgG), IgA, and IgM antibody responses against two sporozoite surface antigens with apparent molecular masses of approximately 27 and 17 kDa. We have determined that these two antigens are actually complex families of related antigens. We have developed two new enzyme-linked immunosorbent assays (ELISAs) for the detection and quantitation of serum IgG antibodies against both antigens. The assays utilize a recombinant form of the 27-kDa antigen and a partially purified native fraction isolated from sonicated whole oocysts that contains 17-kDa antigen. An immunoblot assay previously developed in our laboratory served as the reference, or “gold standard,” seroassay for the assessment of the new ELISAs. Positive responses with the recombinant-27-kDa-antigen ELISA were correlated with the immunoblot results for the 27-kDa antigen, with a sensitivity and specificity of 90 and 92%, respectively. Similarly, positive responses with the partially purified native-17-kDa-antigen ELISA correlated with the immunoblot results for the 17-kDa antigen, with a sensitivity and specificity of 90 and 94%, respectively. For both ELISAs the median IgG antibody levels for serum sets collected during outbreaks of waterborne
C. parvum
infection were at least 2.5-fold higher than the levels determined for a nonoutbreak set. Using the immunoblot as the “gold standard,” the new ELISAs were more specific and, in the case of the 27-kDa-antigen ELISA, more sensitive than the crude oocyst antigen ELISA currently in use. These assays will be useful in future epidemiologic studies.
Abiotrophia
Species as a Cause of Endophthalmitis Following Cataract Extraction
Authors: Namdari Hassan , Kintner Kathleen , Jackson Barbara A. , Namdari Surena , Hughes Joan L. , Peairs Randall R. , Savage Donald J. 
Published: December 2019

ABSTRACT

Microorganisms of the genus
Abiotrophia
, members of the oral flora, are known as important causes of bacterial endocarditis. In this study, we report two individual cases of acute vitreous infection caused by
Abiotrophia adiacens
and
Abiotrophia defectiva
approximately a week after cataract extraction.
Abiotrophia
isolates were recovered by cultivation of vitreous humor on chocolate agar and identified via conventional and API 20 Strep identification systems. An 83-year-old male patient (A) and an 80-year-old female patient (B) demonstrated almost identical symptoms of infectious endophthalmitis manifested as hypopyon and opaque media. The vision of both patients was reduced to detection of hand motion in the left and the right eyes, respectively. An emergency pars plana core vitrectomy was performed, and intraocular antibiotics were administered to each patient, who presented 8 months apart in two different institutions. Patients A and B were treated with an intravitreal injection of vancomycin-amikacin and vancomycin-ceftazidime, respectively, which resulted in complete recovery.
Simultaneous Detection of
Bacteroides forsythus
and
Prevotella intermedia
by 16S rRNA Gene-Directed Multiplex PCR
Authors: Conrads Georg , Flemmig Thomas F. , Seyfarth Ilse , Lampert Friedrich , Lütticken Rudolf 
Published: December 2019

ABSTRACT

In a 16S rRNA gene-directed multiplex PCR,
Prevotella intermedia
- and
Bacteroides forsythus
-specific reverse primers were combined with a single conserved forward primer. A 660-bp fragment and an 840-bp fragment that were specific for both species could be amplified simultaneously. A total of 152 clinical samples, subgingival plaque and swabs of three different oral mucosae, from 38 periodontitis patients were used for the evaluation.
Assessment of Metronidazole Susceptibility in
Helicobacter pylori
: Statistical Validation and Error Rate Analysis of Breakpoints Determined by the Disk Diffusion Test
Authors: Chaves Sandra , Gadanho Mário , Tenreiro Rogério , Cabrita José 
Published: December 2019

ABSTRACT

Metronidazole susceptibility of 100
Helicobacter pylori
strains was assessed by determining the inhibition zone diameters by disk diffusion test and the MICs by agar dilution and PDM Epsilometer test (E test). Linear regression analysis was performed, allowing the definition of significant linear relations, and revealed correlations of disk diffusion results with both E-test and agar dilution results (
r
2
= 0.88 and 0.81, respectively). No significant differences (
P
= 0.84) were found between MICs defined by E test and those defined by agar dilution, taken as a standard. Reproducibility comparison between E-test and disk diffusion tests showed that they are equivalent and with good precision. Two interpretative susceptibility schemes (with or without an intermediate class) were compared by an interpretative error rate analysis method. The susceptibility classification scheme that included the intermediate category was retained, and breakpoints were assessed for diffusion assay with 5-μg metronidazole disks. Strains with inhibition zone diameters less than 16 mm were defined as resistant (MIC > 8 μg/ml), those with zone diameters equal to or greater than 16 mm but less than 21 mm were considered intermediate (4 μg/ml < MIC ≤ 8 μg/ml), and those with zone diameters of 21 mm or greater were regarded as susceptible (MIC ≤ 4 μg/ml). Error rate analysis applied to this classification scheme showed occurrence frequencies of 1% for major errors and 7% for minor errors, when the results were compared to those obtained by agar dilution. No very major errors were detected, suggesting that disk diffusion might be a good alternative for determining the metronidazole sensitivity of
H. pylori
strains.
Improved Mg2+-Based Reverse Transcriptase Assay for Detection of Primate Retroviruses
Authors: Sears Johnna F. , Repaske Roy , Khan Arifa S. 
Published: December 2019

ABSTRACTThe reverse transcriptase (RT) assay is a simple, relatively inexpensive, widely used assay that can detect all retroviruses (known and novel retroviruses as well as infectious and defective retroviruses) on the basis of the divalent cation requirement of their RT enzyme, i.e., Mg2+or Mn2+. Descriptions of various RT assays have been published; however, they cannot be directly applied to the analysis of biological products or clinical samples without further standardization to determine the lower limit of virus detection (sensitivity), assay variability (reproducibility), or ability to detect different retroviruses (specificity). We describe the detection of type E and type D primate retroviruses, which may be pathogenic for humans, by a new32P-based, Mg2+-containing RT assay. The results show that the sensitivity of detection is <3.2 50% tissue culture infective doses (TCID50s) for human immunodeficiency virus type 1 (HIV-1) and <1 TCID50for simian immunodeficiency virus isolated from a rhesus macaque (SIVmac). Analysis of recombinant HIV-1 RT enzyme indicated that 10−5U, which is equivalent to 4.25 × 104virions, could be detected. Additionally, genetically distinct type D retroviruses such as simian AIDS retrovirus and squirrel monkey retrovirus were also detected in the assay with similar sensitivities. Thus, the improved RT assay can be used to detect genetically divergent Mg2+-dependent retroviruses of human and simian origin that can infect human cells and that therefore pose a potential health risk to humans.
Characterization of Antimicrobial Resistance in
Streptococcus pyogenes
Isolates from the San Francisco Bay Area of Northern California
Authors: York Mary K. , Gibbs Laurel , Perdreau-Remington Francoise , Brooks G. F. 
Published: December 2019

ABSTRACT

During 1994 and 1995, 157 isolates of
Streptococcus pyogenes
from patients with invasive disease were consecutively collected in the San Francisco Bay area to determine the frequency of antimicrobial resistance. Susceptibility testing was performed according to the guidelines of the National Committee for Clinical Laboratory Standards by the disk method and by broth microdilution. For comparison of susceptibility patterns, an additional 149 strains were randomly collected from patients with pharyngitis. For San Francisco County, 32% of the isolates from invasive-disease-related specimens but only 9% of the isolates from throat cultures from the same period were resistant to erythromycin (
P
= 0.0007). Alameda County and Contra Costa County had rates of resistance of ≤10% from isolates from all cultures. When the data were analyzed by hospital, the San Francisco County Hospital had a statistically higher rate of erythromycin resistance (39%) among the strains from serious infections compared to those from other counties (P = <0.0003). For tetracycline, high rates of resistance were observed in San Francisco County for both isolates from patients with invasive disease (34%) and pharyngitis (21%) in the same period. Using pulsed-field gel electrophoresis, two clones, one at the San Francisco County Hospital and a second in the entire area, were identified. The latter clone exhibited resistance to bacitracin. Of 146 strains that were tested by microdilution, all were susceptible to penicillin. Clindamycin resistance was not seen among the erythromycin-susceptible strains, but two of the 39 erythromycin-resistant strains were also resistant to clindamycin. An additional 34 strains showed resistance to clindamycin when exposed to an erythromycin disk in the double-disk diffusion test, suggesting that the mechanism of erythromycin resistance is due to an
erm
gene. This study demonstrates a high rate of resistance to macrolides and tetracycline among
S. pyogenes
isolates in San Francisco County and shows that macrolide resistance is more common in strains from patients with invasive disease than in strains from those with pharyngitis.
Rapid Identification of Fungi by Using the ITS2 Genetic Region and an Automated Fluorescent Capillary Electrophoresis System
Authors: Turenne Christine Y. , Sanche Steven E. , Hoban Daryl J. , Karlowsky James A. , Kabani Amin M. 
Published: December 2019

ABSTRACT

Invasive fungal disease often plays an important role in the morbidity and mortality of immunocompromised patients. The poor sensitivity of current fungal blood culture and histological practices has led to the development of highly sensitive and specific molecular techniques, such as the PCR. Sequence variability of the internal transcribed spacer 2 (ITS2) region of fungi is potentially useful in rapid and accurate diagnosis of clinical fungal isolates. PCR with fungus-specific primers targeted toward conserved sequences of the 5.8S and 28S ribosomal DNA (rDNA) results in amplification of the species-specific ITS2 regions, which are variable in amplicon length. We have made use of the ABI PRISM 310 genetic analyzer and the ABI PRISM 310 GeneScan analysis software for the determination of variable size differences of the ITS2 region of clinically important fungi, including
Candida
and non-
Candida
yeasts,
Aspergillus
species, and a variety of dermatophytes. No cross-reaction occurred when samples were tested against human and bacterial genomic DNA. We have found that most clinically significant fungal isolates can be differentiated by this method, and it therefore serves to be a promising tool for the rapid (<7 h) diagnosis of fungemia and other invasive fungal infections.
Molecular Relationships and Antimicrobial Susceptibilities of Viridans Group Streptococci Isolated from Blood of Neutropenic Cancer Patients
Authors: Wisplinghoff H. , Reinert R. R. , Cornely O. , Seifert H. 
Published: December 2019

ABSTRACT

From January 1995 to May 1998, 57 episodes of bacteremia due to viridans group streptococci were identified in 50 febrile neutropenic patients with hematologic malignancies. Four patients experienced two separate episodes of streptococcal bacteremia, and one patient had four separate episodes of streptococcal bacteremia. Strains were identified to species level as
Streptococcus mitis
(
n
= 37),
Streptococcus oralis
(
n
= 19), and
Streptococcus salivarius
(
n
= 1). Epidemiologic relatedness of these strains was studied by using PCR-based fingerprinting with M13 and ERIC-2 primers and pulsed-field gel electrophoresis with restriction enzyme
Sma
I. All strains that were isolated from different patients exhibited unique fingerprint patterns, thus suggesting that viridans group streptococcal bacteremia usually derives from an endogenous source. Cross-transmission of strains between patients could not be established. Four
S. mitis
isolates recovered during four separate bacteremic episodes in a single patient had identical fingerprint patterns. Susceptibility testing was carried out by broth microdilution technique according to National Committee for Clinical Laboratory Standards guidelines. The MICs at which 90% of the isolates are inhibited were (in milligrams per liter) as follows: 0.5 (penicillin), 0.5 (amoxicillin), 0.25 (cefotaxime), 2 (chloramphenicol), 4 (erythromycin), 0.5 (clindamycin), ≥32 (tetracycline), ≥32 (trimethoprim-sulfamethoxazole), 4 (ciprofloxacin), 0.5 (sparfloxacin), 0.5 (vancomycin), 0.25 (teicoplanin), and 1 (quinupristin-dalfopristin). High-level penicillin resistance (MIC, ≥4 mg/liter) was found in one isolate only, but intermediate penicillin resistance was noted in 11 isolates (19%). Resistance rates to other drugs were as follows: 7% (amoxicillin), 4% (cefotaxime), 4% (chloramphenicol), 32% (erythromycin), 9% (clindamycin), 39% (tetracycline), 68% (trimethoprim-sulfamethoxazole), 23% (ciprofloxacin), 0% (sparfloxacin), 0% (vancomycin), 0% (teicoplanin), and 0% (quinupristin-dalfopristin).
High-Resolution Genotyping of
Streptococcus pyogenes
Serotype M1 Isolates by Fluorescent Amplified-Fragment Length Polymorphism Analysis
Authors: Desai Meeta , Efstratiou Androulla , George Robert , Stanley John 
Published: December 2019

ABSTRACT

We have used fluorescent amplified-fragment length polymorphism (FAFLP) analysis to subtype clinical isolates of
Streptococcus pyogenes
serotype M1. Established typing methods define most M1 isolates as members of a clone that has a worldwide distribution and that is strongly associated with invasive diseases. FAFLP analysis simultaneously sampled 90 to 120 loci throughout the M1 genome. Its discriminatory power, precision, and reproducibility were compared with those of other molecular typing methods. Irrespective of disease symptomatology or geographic origin, the majority of the clinical M1 isolates shared a single ribotype, pulsed-field gel electrophoresis macrorestriction profile, and
emm
1 gene sequence. Nonetheless, among these isolates, FAFLP analysis could differentiate 17 distinct profiles, including seven multi-isolate groups. The FAFLP profiles of M1 isolates reproducibly exhibited between 1 and more than 20 amplified fragment differences. The high discriminatory power of genotyping by FAFLP analysis revealed genetic microheterogeneity and differentiated otherwise “identical” M1 isolates as members of a clone complex.