bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of the C Terminus of FtsK in
Escherichia coli
Chromosome Segregation
Authors: Yu Xuan-Chuan , Weihe Elizabeth K. , Margolin William 
Published: March 2020

ABSTRACT

FtsK is essential for
Escherichia coli
cell division. We report that cells lacking the C terminus of FtsK are defective in chromosome segregation as well as septation, often exhibiting asymmetrically positioned nucleoids and large anucleate regions. Combining the corresponding truncated
ftsK
gene with a
mukB
null mutation resulted in a synthetic lethal phenotype. When the truncated
ftsK
was combined with a
minCDE
deletion, chains of minicells were generated, many of which contained DNA. These results suggest that the C terminus of FtsK has an important role in chromosome partitioning.
Rapid Detection of
mecA
-Positive and
mecA
-Negative Coagulase-Negative Staphylococci by an Anti-Penicillin Binding Protein 2a Slide Latex Agglutination Test
Authors: Hussain Zafar , Stoakes Luba , Garrow Shaunalee , Longo Susan , Fitzgerald Viivi , Lannigan Robert 
Published: March 2020

ABSTRACT

A rapid slide latex agglutination (LA) test, MRSA-Screen (Denka Seiken Co., Niigata, Japan), which detects PBP 2a, was tested for its ability to differentiate between
mecA
-positive and -negative coagulase-negative staphylococci. A total of 463 isolates from 13 species were included in the study. The
mecA
gene was detected by PCR, and the oxacillin MIC was determined by the agar dilution method according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). The LA test was performed with oxacillin-induced isolates. The true-positive and true-negative results were defined on the basis of the presence or the absence of the
mecA
gene. By PCR, 251 isolates were
mecA
positive and 212 were
mecA
negative. The sensitivities, specificities, and positive and negative predictive values for the LA test compared to the NCCLS breakpoint for oxacillin resistance (≥0.5 mg/liter) were as follows: for the LA test, 100, 99.5, 99.6, and 100%, respectively; for the NCCLS breakpoint, 100, 60.8, 75.1, and 100%, respectively. One hundred twenty-five
mecA
-positive isolates were also tested by the LA test without induction of PBP 2a; only 72 (57.6%) gave a positive result and required 3 to 15 min for reaction. With induction, all 251 isolates were positive within 3 min. The LA test was reliable in classifying
mecA
-negative isolates, but it classified isolates for which the oxacillin MIC was ≥0.5 mg/liter as oxacillin susceptible. For the reliable detection of oxacillin resistance by the MRSA-Screen in coagulase-negative staphylococci, induction of the
mecA
gene appears to be necessary.
A Multicenter Study Evaluation of the Digene Hybrid Capture II Signal Amplification Technique for Detection of Hepatitis B Virus DNA in Serum Samples and Testing of EUROHEP Standards
Authors: Niesters Hubert G. M. , Krajden Mel , Cork Lynda , de Medina Maria , Hill Mary , Fries Edwin , Osterhaus Albert D. M. E. 
Published: March 2020

ABSTRACT

We have evaluated the new Digene Hybrid Capture II HBV DNA Test (HCII HBV), which is a 96-well microtiter plate-based signal amplification assay. This test uses hybrid capture technology that specifically detects RNA-DNA hybrids. HCII HBV is able to quantify hepatitis B virus (HBV) DNA at between 1.4 × 10
5
and 1.7 × 10
9
HBV copies per ml in a standard format. By using a modified sample preparation method, which allows the input of 30-fold more serum for an ultrasensitive format, the sensitivity of the assay can be increased reproducibly to approximately 8,000 copies of HBV per ml. By using a combination of these two formats, the assay can quantify over a total range of 6 logs. In our multicenter evaluation study, the mean laboratory-to-laboratory coefficients of variation were 22, 7, and 12% at the three sites, respectively, with a combined specificity of 98.4%. The linearities of both the standard test and the ultrasensitive test were excellent, with Spearman correlation coefficients of 0.997 and 0.999, respectively. Furthermore, the intra-assay reproducibility for the standard assay gave coefficients of variation of from 13 to 33, 9 to 21, and 3 to 8% at the three sites, respectively. HCII HBV was shown to be genotype independent when the EUROHEP standards for genotypes A and D were used. This assay allows the accurate measurement of HBV DNA levels in serum and can be clinically used for the monitoring of responses to antiviral agents for patients chronically infected with HBV.
A Filamentous Phage Associated with Recent Pandemic
Vibrio parahaemolyticus
O3:K6 Strains
Authors: Nasu Hatsumi , Iida Tetsuya , Sugahara Tomomi , Yamaichi Yoshiharu , Park Kwon-Sam , Yokoyama Katsushi , Makino Kozo , Shinagawa Hideo , Honda Takeshi 
Published: March 2020

ABSTRACT

A specific serotype, O3:K6, of
Vibrio parahaemolyticus
has recently been causing epidemics of gastroenteritis in Southeast Asia, Japan, and North America. To examine whether the new O3:K6 strains possess characteristics that may exacerbate outbreaks, we compared
V. parahaemolyticus
O3:K6 strains with non-O3:K6 strains using strains isolated from individuals with traveler's diarrhea at Kansai Airport Quarantine Station, Osaka, Japan. All 24 O3:K6 strains possessed a common plasmid, pO3K6 (DNA size, 8,782 bp, with 10 open reading frames [ORFs]). The gene organization of pO3K6 was similar to that of Vf33, a filamentous phage previously described in
V. parahaemolyticus
. We isolated a phage (phage f237) from the culture supernatant of
V. parahaemolyticus
O3:K6 strain KXV237, which formed a turbid plaque on an indicator strain. The genome of f237 was single-stranded DNA, and the double-stranded DNA obtained by treatment of the genome with DNA polymerase was identical to that of pO3K6 when analyzed by agarose gel electrophoresis after
Hin
dIII digestion. Furthermore, the N-terminal amino acid sequence of the f237 major coat protein was found in ORF4 of pO3K6. Our results showed that pO3K6 is a replicative form of f237. Among the ORFs found in the f237 genome, the sequence of ORF8 had no significant homology to those of any proteins in databases. ORF8 was located on a region corresponding to the distinctive region of Vf33, and its G+C content was apparently lower than that of the remaining DNA sequence of f237. By colony hybridization, ORF8 was detected only in O3:K6 strains isolated since 1996 and was not found in O3:K6 strains isolated before 1996 and clinical
V. parahaemolyticus
strains other than those of serotype O3:K6. Thus, this study shows that f237 is exclusively associated with recent
V. parahaemolyticus
O3:K6 strains. The ORF8 gene can be a useful genetic marker for the identification of the recently widespread O3:K6 strains of
V. parahaemolyticus
.
Cloning, Characterization, and Expression of a 200-Kilodalton Diagnostic Antigen of
Babesia bigemina
Authors: Tebele N. , Skilton R. A. , Katende J. , Wells C. W. , Nene V. , McElwain T. , Morzaria S. P. , Musoke A. J. 
Published: March 2020

ABSTRACT

Current serological tests for
Babesia bigemina
use semipurified merozoite antigens derived from infected erythrocytes. One of the major drawbacks of these tests is that antigen quality can vary from batch to batch. Since the quality of the antigen contributes to the sensitivity and specificity of serological tests, the use of standardized recombinant antigens should ensure consistency in assay quality. Previously, a 200-kDa merozoite antigen (p200) was identified as a candidate diagnostic antigen for use in a serological assay for the detection of
B. bigemina
antibodies in infected cattle. In this study, we have cloned, characterized, and expressed p200. A 3.5-kbp cDNA clone encoding p200 was isolated and shown to be almost full length, lacking approximately 300 bp at the 5′ end. The predicted amino acid sequence shows that p200 consists of a long, highly charged central repeat region of an uninterrupted α helix, indicative of a fibrous protein. Immunoelectron microscopy localized p200 to the merozoite cytoplasm, suggesting that the antigen may be a structural protein involved in forming filament structures within the cytoskeleton. The 3.5-kbp cDNA was expressed in bacteria as a fusion protein with glutathione
S
-transferase (GST), but the yield was poor. To improve the yield, cDNA fragments encoding antigenic domains of p200 were expressed as fusions with GST. One of these fusion proteins, C1A-GST, is composed of a 7-kDa fragment of the p200 repeat region and contains epitopes that react strongly with sera from cattle experimentally infected with
B. bigemina
. Recombinant C1A-GST should permit the development of an improved enzyme-linked immunosorbent assay for the detection of antibodies against
B. bigemina.
Development of Antigen Detection Assay for Diagnosis of Tuberculosis Using Sputum Samples
Authors: Pereira Arias-Bouda Lenka M. , Nguyen Lan N. , Ho Ly M. , Kuijper Sjoukje , Jansen Henk M. , Kolk Arend H. J. 
Published: March 2020

ABSTRACT

The rising incidence of tuberculosis worldwide means an increasing burden on diagnostic facilities, so tests simpler than Ziehl-Neelsen staining are needed. Such tests should be objective, reproducible, and have at least as good a detection limit as 10
4
bacteria/ml. A capture enzyme-linked immunosorbent assay (ELISA) was developed for detection of lipoarabinomannan (LAM) in human sputum samples. As a capture antibody, we used a murine monoclonal antibody against LAM, with rabbit antiserum against
Mycobacterium tuberculosis
as a source of detector antibodies. The sensitivity of the capture ELISA was evaluated by using purified LAM and
M. tuberculosis
whole cells. We were able to detect 1 ng of purified LAM/ml and 10
4
M. tuberculosis
whole cells/ml. LAM could also be detected in culture filtrate of a 3-week-old culture of
M. tuberculosis
. The culture filtrate contained approximately 100 μg of LAM/ml. The detection limit in sputum pretreated with
N
-acetyl-
l
-cysteine and proteinase K was 10
4
M. tuberculosis
whole cells per ml. Thirty-one (91%) of 34 sputum samples from 18 Vietnamese patients with tuberculosis (32 smear positive and 2 smear negative) were positive in the LAM detection assay. In contrast, none of the 25 sputum samples from 21 nontuberculous patients was positive. This specific and sensitive assay for the detection of LAM in sputum is potentially useful for the diagnosis of tuberculosis.
Intestinal Lesions Associated with Disseminated Candidiasis in an Experimental Animal Model
Authors: Andrutis Karl A. , Riggle Perry J. , Kumamoto Carol A. , Tzipori Saul 
Published: March 2020

ABSTRACT

In human patients, disseminated candidiasis, a life-threatening disease for immunocompromised patients, is often associated with intestinal lesions. In this study, we demonstrate that immunosuppressed gnotobiotic (IGB) piglets orally inoculated with wild-type
Candida albicans
developed extensive intestinal lesions and disseminated infection. Severe ulceration of the ileal mucosa was observed overlying regions of colonization and necrosis of the gut-associated lymphoid tissue. Despite the high susceptibility of IGB piglets to many microbial pathogens, an avirulent mutant strain of
C. albicans
failed to produce intestinal lesions and exhibited poor dissemination, demonstrating that these effects required virulent organisms. It is likely that in IGB piglets, as in human patients, intestinal lesions provide the mechanism for escape of
C. albicans
from the gastrointestinal tract. Multinucleated giant cells containing fungal organisms were observed within lymph nodes and lymphatic vessels, and as with other pathogens, such cells could provide a mechanism for dissemination of
C. albicans
.
Diagnostic Potential of Puumala Virus Nucleocapsid Protein Expressed in
Drosophila melanogaster
Cells
Authors: Brus Sjölander Katarina , Golovljova Irina , Plyusnin Alexander , Lundkvist Åke 
Published: March 2020

ABSTRACT
Puumala virus (PUU) nucleocapsid protein (N) was expressed in insect cells by using the Drosophila Expression System (DES; Invitrogen BV, Groningen, The Netherlands). Stable transfectants were established by hygromycin B selection and showed continuous expression of the recombinant protein (DES-PUU-N) for at least 5 months. The antigenic property of DES-PUU-N was shown to be identical to that of native PUU N when examined with a panel of hantavirus-specific monoclonal antibodies. Enzyme-linked immunosorbent assays (ELISAs) for detection of human immunoglobulin M (IgM) and IgG antibodies were established by using DES-PUU-N as antigen and were compared to assays based on native N. The ELISAs were evaluated for patient diagnosis and seroepidemiological purposes with panels of sera collected from patients with hemorrhagic fever with renal syndrome (HFRS) and from healthy blood donors. Equally high sensitivities and specificities for detection of PUU-specific IgM in acute-phase HFRS patient sera were obtained by the ELISA based on DES-PUU-N and the assay based on the native antigen. For detection of PUU-specific IgG, the ELISA based on monoclonal antibody-captured DES-PUU-N antigen showed optimal sensitivity and specificity.
Diagnosis of Invasive Amebiasis by Enzyme-Linked Immunosorbent Assay of Saliva To Detect Amebic Lectin Antigen and Anti-Lectin Immunoglobulin G Antibodies
Authors: Abd-Alla Mohamed D. , Jackson Terry F. H. G. , Reddy Selvan , Ravdin Jonathan I. 
Published: March 2020

ABSTRACT

Saliva from subjects with amebic liver abscess (ALA), acute amebic colitis, asymptomatic infection with
Entamoeba histolytica
or
Entamoeba dispar
, and uninfected controls was tested by enzyme-linked immunosorbent assay (ELISA) for the presence of
E. histolytica
galactose-inhibitable lectin antigen and salivary immunoglobulin (IgG) antibodies to a recombinant cysteine-rich lectin-derived protein (LC3). Salivary lectin antigen was found in 65.8% of subjects with acute colitis, compared to 22.2% of those convalescent from ALA, 10.0% with asymptomatic
E. histolytica
infection, 9.8% with
E. dispar
infection, and 2.6% of controls (subjects from the United States and study patients with nonamebic diarrhea) (
P
< 0.001 for each compared to values for subjects with colitis). Salivary anti-LC3 IgG antibodies were found in 92% of ALA patients regardless of duration of illness and in 83.3% of colitis patients who were symptomatic for at least 7 days (
P
< 0.001 compared to other study groups). Serum anti-LC3 IgG antibodies were detected in 56.3% of subjects with acute colitis, 100% of subjects with ALA or prolonged colitis, 45% of subjects with asymptomatic
E. histolytica
infection, 32.3% of subjects with
E. dispar
infection, and 23.4% of diarrhea controls. In comparison to ELISA for serum anti-LC3 IgG antibodies, the salivary lectin antigen assay is a more sensitive and specific test for acute amebic colitis. Detection of salivary anti-LC3 IgG antibodies by ELISA is an effective means for the diagnosis of ALA and prolonged cases of amebic colitis.
Quantitative Real-Time PCR for
Porphyromonas gingivalis
and Total Bacteria
Authors: Lyons Sharon R. , Griffen Ann L. , Leys Eugene J. 
Published: March 2020

ABSTRACT

Accurate quantitation of the number of cells of individual bacterial species in dental plaque samples is needed for understanding the bacterial etiology of periodontitis. Real-time PCR offers a sensitive, efficient, and reliable approach to quantitation. Using the TaqMan system we were able to determine both the amount of
Porphyromonas gingivalis
and the total number of bacterial cells present in plaque samples. Using species-specific primers and a fluorescent probe, detection of DNA from serial dilutions of
P. gingivalis
cells was linear over a large range of DNA concentrations (correlation coefficient = 0.96). No difference was observed between
P. gingivalis
DNA alone and the same DNA mixed with DNA isolated from dental plaque, indicating that
P. gingivalis
levels can be determined accurately from clinical samples. The total number of cells of all bacterial species was determined using universal primers and a fluorescent probe. Standard curves using four different bacterial species gave similar results (correlation coefficient = 0.86). Levels of both
P. gingivalis
and total bacteria were determined from a series of human plaque samples. High levels of
P. gingivalis
were observed in several of the samples from subjects with periodontitis and none of those from healthy subjects. Real-time quantitative PCR provided a sensitive and reliable method for quantitating
P. gingivalis
. In addition, it allowed the determination of the total number of bacterial cells present in a complex sample so that the percentage of
P. gingivalis
cells could be determined.
Isolation of
Acanthamoeba
-Specific Antibodies from a Bacteriophage Display Library
Authors: Khan Naveed A. , Greenman John , Topping Katherine P. , Hough Victoria C. , Temple Graham S. , Paget Timothy A. 
Published: March 2020

ABSTRACT

Acanthamoeba
causes opportunistic eye infections in humans, which can lead to severe keratitis and may ultimately result in blindness. Current methods for identifying this organism rely on culture and microscopy. In this paper, we describe the isolation of antibody fragments that can be used for the unequivocal identification of
Acanthamoeba
. A bacteriophage antibody display library was used to isolate antibody fragments that bind specifically to
Acanthamoeba
. Individual clones were studied by enzyme-linked immunosorbent assay, flow cytometry, and immunofluorescence. Four antibody clones that specifically bind to
Acanthamoeba
spp. were identified.
Epidemiology of Recurrences or Reinfections of
Clostridium difficile
-Associated Diarrhea
Authors: Barbut Frédéric , Richard Anne , Hamadi Kheira , Chomette Valérie , Burghoffer Béatrice , Petit Jean-Claude 
Published: March 2020

ABSTRACT

Approximately 15 to 35% of patients with a first episode of
Clostridium difficile
-associated diarrhea relapse within 2 months. Between 1994 and 1997, strains from 93 hospitalized patients with
C. difficile
recurrences were fingerprinted by using both serotyping and PCR-ribotyping. The results showed that 48.4% of clinical recurrences were, in fact, reinfections with a different strain of
C. difficile
. Rates of clinical recurrences could therefore be reduced by implementing strict isolation precautions.
Molecular Characterization of the
vanD
Gene Cluster and a Novel Insertion Element in a Vancomycin-Resistant Enterococcus Isolated in Canada
Authors: Boyd D. A. , Conly J. , Dedier H. , Peters G. , Robertson L. , Slater E. , Mulvey M. R. 
Published: March 2020

ABSTRACT

A single
vanD
-containing
Enterococcus faecium
strain (N97-330) was isolated in Canada. The
vanD
-containing region was cloned and sequenced. Although the proteins have more than 96% identity to a previously described
vanD
region in BM4339, the

vanS
D

gene contains a frameshift mutation that leads to a predicted truncated protein. Furthermore, sequence analysis of the
ddl
gene revealed the presence of an IS
982
-like element (IS
Efm1
) which interrupted the
d
-Ala–
d
-Ala ligase. This suggested the constitutive expression of the
vanD
operon, which was confirmed. Pulsed-field gel electrophoresis fingerprinting demonstrated that BM4339 was not related to N97-330 (>15 band differences). Both strains contained multiple copies of the IS
982
-like element.
Survival of the Human Granulocytic Ehrlichiosis Agent under Refrigeration Conditions
Authors: Kalantarpour Fatemeh , Chowdhury Ishraq , Wormser Gary P. , Aguero-Rosenfeld Maria E. 
Published: March 2020

ABSTRACT
The human granulocytic ehrlichiosis (HGE) agent in infected blood specimens remained viable during refrigeration at 4°C for up to 18 days. These findings suggest that blood specimens submitted for culture may withstand transportation to a remote laboratory. HGE should be added to the list of infections potentially transmitted by blood transfusion.
High Prevalence of TT Virus DNA in Human Saliva and Semen
Authors: Inami Tomoko , Konomi Nami , Arakawa Yasuyuki , Abe Kenji 
Published: March 2020

ABSTRACT
Using the PCR assay, we found a high prevalence of TT virus (TTV) DNA in saliva and semen from patients who were seropositive for TTV. This finding suggests that the presence of TTV in body fluids other than serum may affect the routes of viral transmission.
Genetic Similarity among One
Aspergillus flavus
Strain Isolated from a Patient Who Underwent Heart Surgery and Two Environmental Strains Obtained from the Operating Room
Authors: Diaz-Guerra Teresa M. , Mellado Emilia , Cuenca-Estrella Manuel , Gaztelurrutia Lourdes , Navarro Jose Ignacio Villate , Tudela Juan L. Rodríguez 
Published: March 2020

ABSTRACT

We report the simultaneous isolation of one
Aspergillus flavus
strain from the aortic prosthesis of a heart surgery patient and another two isolates recovered from a dual-reservoir cooler-heater used in the operating room where this patient was operated on. Genetic typing of these three isolates by randomly amplified polymorphic DNA (RAPD) revealed identical genotypes. Eight unrelated control strains of
A. flavus
had eight different genotypes. These results clearly indicated the nosocomial origin of the
A. flavus
strain isolated from the patient. We suggest that the RAPD technique is a rapid and reliable tool to ascertain the epidemiology of infections caused by
A. flavus
.
Comparison of Quantitations of Viral Load in Varicella and Zoster
Authors: Kimura Hiroshi , Kido Shinji , Ozaki Takao , Tanaka Naoko , Ito Yoshinori , Williams Richard K. , Morishima Tsuneo 
Published: March 2020

ABSTRACT
The pathogenesis of varicella and zoster and the effects of antiviral treatment were investigated using real-time PCR for varicella-zoster virus (VZV) DNA in skin lesions and peripheral blood. A higher occurrence of viremic VZV DNA was observed in varicella than in zoster. Acyclovir treatment resulted in marked suppression of viremia in varicella.
Corrective steps to enhance ventilation in the delivery room
Authors: Yang Kesi C , te Pas Arjan B , Weinberg Danielle D , Foglia Elizabeth E 
Published: March 2020

ObjectiveThe clinical impact of ventilation corrective steps for delivery room positive pressure ventilation (PPV) is not well studied. We aimed to characterise the performance and effect of ventilation corrective steps (MRSOPA (Mask adjustment, Reposition airway, Suction mouth and nose, Open mouth, Pressure increase and Alternative airway)) during delivery room resuscitation of preterm infants.DesignProspective observational study of delivery room PPV using video and respiratory function monitor recordings.SettingTertiary academic delivery hospital.PatientsPreterm infants <32 weeks gestation.Main outcome measureMean exhaled tidal volume (Vte) of PPV inflations before and after MRSOPA interventions, categorised as inadequate (<4 mL/kg); appropriate (4–8 mL/kg), or excessive (>8 mL/kg). Secondary outcomes were leak (>30%) and obstruction (Vte <1 mL/kg), and infant heart rate.ResultsThere were 41 corrective interventions in 30 infants, with a median duration of 15 (IQR 7–29) s. The most frequent intervention was a combination of Mask/Reposition and Suction/Open. Mean Vte was inadequate before 16/41 interventions and became adequate following 6/16. Mean Vte became excessive after 6/41 interventions. Mask leak, present before 13/41 interventions, was unchanged after 4 and resolved after 9. Obstruction was present before five interventions and was subsequently resolved only once. MRSOPA interventions introduced leak in two cases and led to obstruction in one case. The heart rate was <100 beats per minute before 31 interventions and rose to >100 beats per minute after 14/31 of these.ConclusionsVentilation correction interventions improve tidal volume delivery in some cases, but lead to ineffective or excessive tidal volumes in others. Mask leak and obstruction can be induced by MRSOPA manoeuvres.