bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Infections Attributable to thed-Tartrate-Fermenting Variant of Salmonella enterica Serovar Paratyphi B in Germany Originate in Reptiles and, on Rare Occasions, Poultry
Authors: Toboldt Anne , Tietze Erhard , Helmuth Reiner , Fruth Angelika , Junker Ernst , Malorny Burkhard
Published: August 2012

In this study, the population structure, incidence, and potential sources of human infection caused by thed-tartrate-fermenting variant ofSalmonella entericaserovar Paratyphi B [S. Paratyphi B (dT+)] was investigated. In Germany, the serovar is frequently isolated from broilers. Therefore, a selection of 108 epidemiologically unrelatedS. entericaserovar Paratyphi B (dT+) strains isolated in Germany between 2002 and 2010 especially from humans, poultry/poultry meat, and reptiles was investigated by phenotypic and genotypic methods. Strains isolated from poultry and products thereof were strongly associated with multilocus sequence type ST28 and showed antimicrobial multiresistance profiles. Pulsed-field gel electrophoresis XbaI profiles were highly homogeneous, with only a few minor XbaI profile variants. All strains isolated from reptiles, except one, were strongly associated with ST88, another distantly related type. Most of the strains were susceptible to antimicrobial agents, and XbaI profiles were heterogeneous. Strains isolated from humans yielded seven sequence types (STs) clustering in three distantly related lineages. The first lineage, comprising five STs, represented mainly strains belonging to ST43 and ST149. The other two lineages were represented only by one ST each, ST28 and ST88. The relatedness of strains based on the pathogenicity gene repertoire (102 markers tested) was mostly in agreement with the multilocus sequence type. Because ST28 was frequently isolated from poultry but rarely in humans over the 9-year period investigated, overall, this study indicates that in GermanyS. entericaserovar Paratyphi B (dT+) poses a health risk preferentially by contact with reptiles and, to a less extent, by exposure to poultry or poultry meat.
Yeast Communities of Diverse Drosophila Species: Comparison of Two Symbiont Groups in the Same Hosts
Authors: Chandler James Angus , Eisen Jonathan A. , Kopp Artyom
Published: August 2012

The combination of ecological diversity with genetic and experimental tractability makes
Drosophila
a powerful model for the study of animal-associated microbial communities. Despite the known importance of yeasts in
Drosophila
physiology, behavior, and fitness, most recent work has focused on
Drosophila
-bacterial interactions. In order to get a more complete understanding of the
Drosophila
microbiome, we characterized the yeast communities associated with different
Drosophila
species collected around the world. We focused on the phylum Ascomycota because it constitutes the vast majority of the
Drosophila
-associated yeasts. Our sampling strategy allowed us to compare the distribution and structure of the yeast and bacterial communities in the same host populations. We show that yeast communities are dominated by a small number of abundant taxa, that the same yeast lineages are associated with different host species and populations, and that host diet has a greater effect than host species on yeast community composition. These patterns closely parallel those observed in
Drosophila
bacterial communities. However, we do not detect a significant correlation between the yeast and bacterial communities of the same host populations. Comparative analysis of different symbiont groups provides a more comprehensive picture of host-microbe interactions. Future work on the role of symbiont communities in animal physiology, ecological adaptation, and evolution would benefit from a similarly holistic approach.
Influence of Light on Carbon Utilization in Aerobic Anoxygenic Phototrophs
Authors: Hauruseu Dzmitry , Koblížek Michal
Published: August 2012

Aerobic anoxygenic phototrophs contain photosynthetic reaction centers composed of bacteriochlorophyll. These organisms are photoheterotrophs, as they require organic carbon substrates for their growth whereas light-derived energy has only an auxiliary function. To establish the contribution of light energy to their metabolism, we grew the phototrophic strain
Erythrobacter
sp. NAP1 in a carbon-limited chemostat regimen on defined carbon sources (glutamate, pyruvate, acetate, and glucose) under conditions of different light intensities. When grown in a light-dark cycle, these bacteria accumulated 25% to 110% more biomass in terms of carbon than cultures grown in the dark. Cultures grown on glutamate accumulated the most biomass at moderate light intensities of 50 to 150 μmol m
−2
s
−1
but were inhibited at higher light intensities. In the case of pyruvate, we did not find any inhibition of growth by high irradiance. The extent of anaplerotic carbon fixation was detemined by radioactive bicarbonate incorporation assays. While the carboxylation activity provided 4% to 11% of the cellular carbon in the pyruvate-grown culture, in the glutamate-grown cells it provided only approximately 1% of the carbon. Additionally, we tested the effect of light on respiration and photosynthetic electron flow. With increasing light intensity, respiration decreased to approximately 25% of its dark value and was replaced by photophosphorylation. The additional energy from light allows the aerobic anoxygenic phototrophs to accumulate the supplied organic carbon which would otherwise be respired. The higher efficiency of organic carbon utilization may provide an important competitive advantage during growth under carbon-limited conditions.
Detailed Assessment of the Kinetics of Hg-Cell Association, Hg Methylation, and Methylmercury Degradation in Several Desulfovibrio Species
Authors: Graham Andrew M. , Bullock Allyson L. , Maizel Andrew C. , Elias Dwayne A. , Gilmour Cynthia C.
Published: August 2012

The kinetics of inorganic Hg [Hg(II)
i
] association, methylation, and methylmercury (MeHg) demethylation were examined for a group of
Desulfovibrio
species with and without MeHg production capability. We employed a detailed method for assessing MeHg production in cultures, including careful control of medium chemistry, cell density, and growth phase, plus mass balance of Hg(II)
i
and MeHg during the assays. We tested the hypothesis that differences in Hg(II)
i
sorption and/or uptake rates drive observed differences in methylation rates among
Desulfovibrio
species. Hg(II)
i
associated rapidly and with high affinity to both methylating and nonmethylating species. MeHg production by Hg-methylating strains was rapid, plateauing after ∼3 h. All MeHg produced was rapidly exported. We also tested the idea that all
Desulfovibrio
species are capable of Hg(II)
i
methylation but that rapid demethylation masks its production, but we found this was not the case. Therefore, the underlying reason why MeHg production capability is not universal in the
Desulfovibrio
is not differences in Hg affinity for cells nor differences in the ability of strains to degrade MeHg. However, Hg methylation rates varied substantially between Hg-methylating
Desulfovibrio
species even in these controlled experiments and after normalization to cell density. Thus, biological differences may drive cross-species differences in Hg methylation rates. As part of this study, we identified four new Hg methylators (
Desulfovibrio aespoeensis
,
D. alkalitolerans
,
D. psychrotolerans
, and
D. sulfodismutans
) and four nonmethylating species (
Desulfovibrio alcoholivorans
,
D. tunisiensis
,
D. carbinoliphilus
, and
D. piger
) in our ongoing effort to generate a library of strains for Hg methylation genomics.
Correlation of Intracellular Trehalose Concentration with Desiccation Resistance of Soil Escherichia coli Populations
Authors: Zhang Qian , Yan Tao
Published: August 2012

Naturalized soilEscherichia colipopulations need to resist common soil desiccation stress in order to inhabit soil environments. In this study, four representative soilE. colistrains and one lab strain, MG1655, were tested for desiccation resistance via die-off experiments in sterile quartz sand under a potassium acetate-induced desiccation condition. The desiccation stress caused significantly lower die-off rates of the four soil strains (0.17 to 0.40 day−1) than that of MG1655 (0.85 day−1). Cellular responses, including extracellular polymeric substance (EPS) production, exogenous glycine betaine (GB) uptake, and intracellular compatible organic solute synthesis, were quantified and compared under the desiccation and hydrated control conditions. GB uptake appeared not to be a specific desiccation response, while EPS production showed considerable variability among theE. colistrains. AllE. colistrains produced more intracellular trehalose, proline, and glutamine under the desiccation condition than the hydrated control, and only the trehalose concentration exhibited a significant correlation with the desiccation-contributed die-off coefficients (Spearman's ρ = −1.0;P= 0.02).De novotrehalose synthesis was further determined for 15E. colistrains from both soil and nonsoil sources to determine its prevalence as a specific desiccation response. MostE. colistrains (14/15) synthesized significantly more trehalose under the desiccation condition, and the soilE. colistrains produced more trehalose (106.5 ± 44.9 μmol/mg of protein [mean ± standard deviation]) than the nonsoil reference strains (32.5 ± 10.5 μmol/mg of protein).
Stability of Sponge-Associated Bacteria over Large Seasonal Shifts in Temperature and Irradiance
Authors: Erwin Patrick M. , Pita Lucía , López-Legentil Susanna , Turon Xavier
Published: August 2012

Complex microbiomes reside in marine sponges and consist of diverse microbial taxa, including functional guilds that may contribute to host metabolism and coastal marine nutrient cycles. Our understanding of these symbiotic systems is based primarily on static accounts of sponge microbiota, while their temporal dynamics across seasonal cycles remain largely unknown. Here, we investigated temporal variation in bacterial symbionts of three sympatric sponges (Irciniaspp.) over 1.5 years in the northwestern (NW) Mediterranean Sea, using replicated terminal restriction fragment length polymorphism (T-RFLP) and clone library analyses of bacterial 16S rRNA gene sequences. Bacterial symbionts inIrciniaspp. exhibited host species-specific structure and remarkable stability throughout the monitoring period, despite large fluctuations in temperature and irradiance. In contrast, seawater bacteria exhibited clear seasonal shifts in community structure, indicating that different ecological constraints act on free-living and on symbiotic marine bacteria. Symbiont profiles were dominated by persistent, sponge-specific bacterial taxa, notably affiliated with phylogenetic lineages capable of photosynthesis, nitrite oxidation, and sulfate reduction. Variability in the sponge microbiota was restricted to rare symbionts and occurred most prominently in warmer seasons, coincident with elevated thermal regimes. Seasonal stability of the sponge microbiota supports the hypothesis of host-specific, stable associations between bacteria and sponges. Further, the core symbiont profiles revealed in this study provide an empirical baseline for diagnosing abnormal shifts in symbiont communities. Considering that these sponges have suffered recent, episodic mass mortalities related to thermal stresses, this study contributes to the development of model sponge-microbe symbioses for assessing the link between symbiont fluctuations and host health.
Rapid and Sensitive Quantification of Vibrio cholerae and Vibrio mimicus Cells in Water Samples by Use of Catalyzed Reporter Deposition Fluorescence
In Situ
Hybridization Combined with Solid-Phase Cytometry
Authors: Schauer Sonja , Sommer Regina , Farnleitner Andreas H. , Kirschner Alexander K. T.
Published: August 2012

A new protocol for rapid, specific, and sensitive cell-based quantification of
Vibrio cholerae
/
Vibrio mimicus
in water samples was developed. The protocol is based on catalyzed reporter deposition fluorescence
in situ
hybridization (CARD-FISH) in combination with solid-phase cytometry. For pure cultures, we were able to quantify down to 6
V. cholerae
cells on one membrane with a relative precision of 39% and down to 12 cells with a relative precision of 17% after hybridization with the horseradish peroxidase (HRP)-labeled probe Vchomim1276 (specific for
V. cholerae
and
V. mimicus
) and signal amplification. The corresponding position of the probe on the 16S rRNA is highly accessible even when labeled with HRP. For the first time, we were also able to successfully quantify
V. cholerae
/
V. mimicus
via solid-phase cytometry in extremely turbid environmental water samples collected in Austria. Cell numbers ranged from 4.5 × 10
1
cells ml
−1
in the large saline lake Neusiedler See to 5.6 × 10
4
cells ml
−1
in an extremely turbid shallow soda lake situated nearby. We therefore suggest CARD-FISH in combination with solid-phase cytometry as a powerful tool to quantify
V. cholerae
/
V. mimicus
in ecological studies as well as for risk assessment and monitoring programs.
Farnesol and Cyclic AMP Signaling Effects on the Hypha-to-Yeast Transition in Candida albicans
Authors: Lindsay Allia K. , Deveau Aurélie , Piispanen Amy E. , Hogan Deborah A.
Published: August 2012

Candida albicans
, a fungal pathogen of humans, regulates its morphology in response to many environmental cues and this morphological plasticity contributes to virulence. Farnesol, an autoregulatory molecule produced by
C. albicans
, inhibits the induction of hyphal growth by inhibiting adenylate cyclase (Cyr1). The role of farnesol and Cyr1 in controlling the maintenance of hyphal growth has been less clear. Here, we demonstrate that preformed hyphae transition to growth as yeast in response to farnesol and that strains with increased cyclic AMP (cAMP) signaling exhibit more resistance to farnesol. Exogenous farnesol did not induce the hypha-to-yeast transition in mutants lacking the Tup1 or Nrg1 transcriptional repressors in embedded conditions. Although body temperature is not required for embedded hyphal growth, we found that the effect of farnesol on the hypha-to-yeast transition varies inversely with temperature. Our model of Cyr1 activity being required for filamentation is also supported by our liquid assay data, which show increased yeast formation when preformed filaments are treated with farnesol. Together, these data suggest that farnesol can modulate morphology in preformed hyphal cells and that the repression of hyphal growth maintenance likely occurs through the inhibition of cAMP signaling.
A Candida albicans Temperature-Sensitive
cdc12-6
Mutant Identifies Roles for Septins in Selection of Sites of Germ Tube Formation and Hyphal Morphogenesis
Authors: Li Lifang , Zhang Chengda , Konopka James B.
Published: August 2012

Septins were identified for their role in septation in
Saccharomyces cerevisiae
and were subsequently implicated in other morphogenic processes. To study septins in
Candida albicans
hyphal morphogenesis, a temperature-sensitive mutation was created that altered the C terminus of the essential Cdc12 septin. The
cdc12-6
cells grew well at room temperature, but at 37°C they displayed expected defects in septation, nuclear localization, and bud morphogenesis. Although serum stimulated the
cdc12-6
cells at 37°C to form germ tube outgrowths, the mutant could not maintain polarized hyphal growth and instead formed chains of elongated cell compartments. Serum also stimulated the
cdc12-6
mutant to induce a hyphal reporter gene (
HWP1-GFP
) and a characteristic zone of filipin staining at the leading edge of growth. Interestingly,
cdc12-6
cells shifted to 37°C in the absence of serum gradually displayed enriched filipin staining at the tip, which may be due to the altered cell cycle regulation. A striking difference from the wild type was that the
cdc12-6
cells frequently formed a second germ tube in close proximity to the first. The mutant cells also failed to form the diffuse band of septins at the base of germ tubes and hyphae, indicating that this septin band plays a role in preventing proximal formation of germ tubes in a manner analogous to bud site selection. These studies demonstrate that not only are septins important for cytokinesis, but they also promote polarized morphogenesis and selection of germ tube sites that may help disseminate an infection in host tissues.
Fur-Mediated Global Regulatory Circuits in Pathogenic Neisseria Species
Authors: Yu Chunxiao , Genco Caroline Attardo
Published: August 2012

The
f
erric
u
ptake
r
egulator (Fur) protein has been shown to function as a repressor of transcription in a number of diverse microorganisms. However, recent studies have established that Fur can function at a global level as both an activator and a repressor of transcription through both direct and indirect mechanisms. Fur-mediated indirect activation occurs via the repression of additional repressor proteins, or small regulatory RNAs, thereby activating transcription of a previously silent gene. Fur mediates direct activation through binding of Fur to the promoter regions of genes. Whereas the repressive mechanism of Fur has been thoroughly investigated, emerging studies on direct and indirect Fur-mediated activation mechanisms have revealed novel global regulatory circuits.
The β-Lactam Resistance Protein Blr, a Small Membrane Polypeptide, Is a Component of the Escherichia coli Cell Division Machinery
Authors: Karimova Gouzel , Davi Marilyne , Ladant Daniel
Published: August 2012

In
Escherichia coli
, cell division is performed by a multimolecular machinery called the divisome, made of 10 essential proteins and more than 20 accessory proteins. Through a bacterial two-hybrid library screen, we identified the
E. coli
β-lactam resistance protein Blr, a short membrane polypeptide of 41 residues, as an interacting partner of the essential cell division protein FtsL. In addition to FtsL, Blr was found to associate with several other divisomal proteins, including FtsI, FtsK, FtsN, FtsQ, FtsW, and YmgF. Using fluorescently tagged Blr, we showed that this peptide localizes to the division septum and that its colocalization requires the presence of the late division protein FtsN. Although Blr is not essential, previous studies have shown that the inactivation of the
blr
gene increased the sensitivity of bacteria to β-lactam antibiotics or their resistance to cell envelope stress. Here, we found that Blr, when overproduced, restores the viability of
E. coli ftsQ1
(Ts) cells, carrying a thermosensitive allele of the
ftsQ
gene, during growth under low-osmotic-strength conditions (e.g., in synthetic media or in Luria-Bertani broth without NaCl). In contrast, the inactivation of
blr
increases the osmosensitivity of
ftsQ1
(Ts) cells, and
blr ftsQ1
double mutants exhibit filamentous growth in LB broth even at a moderate salt concentration (0.5% NaCl) compared to parental
ftsQ1
(Ts) cells. Altogether, our results suggest that the small membrane polypeptide Blr is a novel component of the
E. coli
cell division apparatus involved in the stabilization of the divisome under certain stress conditions.
The Accessory Sec Protein Asp2 Modulates GlcNAc Deposition onto the Serine-Rich Repeat Glycoprotein GspB
Authors: Seepersaud Ravin , Bensing Barbara A. , Yen Yihfen T. , Sullam Paul M.
Published: August 2012

The accessory Sec system is a specialized transport system that exports serine-rich repeat (SRR) glycoproteins of Gram-positive bacteria. This system contains two homologues of the general secretory (Sec) pathway (SecA2 and SecY2) and several other essential proteins (Asp1 to Asp5) that share no homology to proteins of known function. In
Streptococcus gordonii
, Asp2 is required for the transport of the SRR adhesin GspB, but its role in export is unknown. Tertiary structure predictions suggest that the carboxyl terminus of Asp2 resembles the catalytic region of numerous enzymes that function through a Ser-Asp-His catalytic triad. Sequence alignment of all Asp2 homologues identified a highly conserved pentapeptide motif (Gly-X-Ser
362
-X-Gly) typical of most Ser-Asp-His catalytic triads, where Ser forms the reactive residue. Site-directed mutagenesis of residues comprising the predicted catalytic triad of Asp2 of
S. gordonii
had no effect upon GspB transport but did result in a marked change in the electrophoretic mobility of the protein. Lectin-binding studies and monosaccharide content analysis of this altered glycoform revealed an increase in glucosamine deposition. Random mutagenesis of the Asp2 region containing this catalytic domain also disrupted GspB transport. Collectively, our findings suggest that Asp2 is a bifunctional protein that is essential for both GspB transport and correct glycosylation. The catalytic domain may be responsible for controlling the glycosylation of GspB, while other surrounding regions are functionally required for glycoprotein transport.
Diversity and Versatility of the Thermotoga maritima Sugar Kinome
Authors: Rodionova Irina A. , Yang Chen , Li Xiaoqing , Kurnasov Oleg V. , Best Aaron A. , Osterman Andrei L. , Rodionov Dmitry A.
Published: August 2012

Sugar phosphorylation is an indispensable committed step in a large variety of sugar catabolic pathways, which are major suppliers of carbon and energy in heterotrophic species. Specialized sugar kinases that are indispensable for most of these pathways can be utilized as signature enzymes for the reconstruction of carbohydrate utilization machinery from microbial genomic and metagenomic data. Sugar kinases occur in several structurally distinct families with various partially overlapping as well as yet unknown substrate specificities that often cannot be accurately assigned by homology-based techniques. A subsystems-based metabolic reconstruction combined with the analysis of genome context and followed by experimental testing of predicted gene functions is a powerful approach of functional gene annotation. Here we applied this integrated approach for functional mapping of all sugar kinases constituting an extensive and diverse sugar kinome in the thermophilic bacterium
Thermotoga maritima
. Substrate preferences of 14 kinases mainly from the FGGY and PfkB families were inferred by bioinformatics analysis and biochemically characterized by screening with a panel of 45 different carbohydrates. Most of the analyzed enzymes displayed narrow substrate preferences corresponding to their predicted physiological roles in their respective catabolic pathways. The observed consistency supports the choice of kinases as signature enzymes for genomics-based identification and reconstruction of sugar utilization pathways. Use of the integrated genomic and experimental approach greatly speeds up the identification of the biochemical function of unknown proteins and improves the quality of reconstructed pathways.
The CRISPR/Cas Adaptive Immune System of Pseudomonas aeruginosa Mediates Resistance to Naturally Occurring and Engineered Phages
Authors: Cady Kyle C. , Bondy-Denomy Joe , Heussler Gary E. , Davidson Alan R. , O'Toole George A.
Published: August 2012

Here we report the isolation of 6 temperate bacteriophages (phages) that are prevented from replicating within the laboratory strain
Pseudomonas aeruginosa
PA14 by the endogenous CRISPR/Cas system of this microbe. These phages are only the second identified group of naturally occurring phages demonstrated to be blocked for replication by a nonengineered CRISPR/Cas system, and our results provide the first evidence that the
P. aeruginosa
type I-F CRISPR/Cas system can function in phage resistance. Previous studies have highlighted the importance of the
p
rotospacer
a
djacent
m
otif (PAM) and a proximal 8-nucleotide seed sequence in mediating CRISPR/Cas-based immunity. Through engineering of a protospacer region of phage DMS3 to make it a target of resistance by the CRISPR/Cas system and screening for mutants that escape CRISPR/Cas-mediated resistance, we show that nucleotides within the PAM and seed sequence and across the non-seed-sequence regions are critical for the functioning of this CRISPR/Cas system. We also demonstrate that
P. aeruginosa
can acquire spacer content in response to lytic phage challenge, illustrating the adaptive nature of this CRISPR/Cas system. Finally, we demonstrate that the
P. aeruginosa
CRISPR/Cas system mediates a gradient of resistance to a phage based on the level of complementarity between CRISPR spacer RNA and phage protospacer target. This work introduces a new
in vivo
system to study CRISPR/Cas-mediated resistance and an additional set of tools for the elucidation of CRISPR/Cas function.
An interesting cause of faecal occult blood
Authors: Rabb Nicolas , Kitsanta Panagiota , Hunt Lesley , Riley Stuart
Published: August 2012

A 69-year-old man presented to bowel cancer screening after testing for faecal occult blood. Initial colonoscopy had been limited by a sigmoid stricture and a barium enema had revealed a suspicious mass in the corresponding area. He was referred for repeat colonoscopy, which showed a hard structure crossing the mid sigmoid colon, with both ends impacted into the bowel wall. A CT scan revealed what appeared to be a small bone impacted in a diverticulum with evidence of recent inflammation and a sealed perforation. The patient had recently been managed conservatively for an episode of diverticulitis at his local hospital but was currently asymptomatic. Owing to the possibility of future complications he underwent a laparoscopic sigmoid colectomy to remove the offending foreign body.
Sports in extreme conditions: The impact of exercise in cold temperatures on asthma and bronchial hyper-responsiveness in athletes
Authors: Carlsen Kai-Håkon
Published: August 2012

Exercise-induced asthma (EIA) and bronchial hyper-responsiveness (BHR) are frequently reported among elite athletes of outdoor endurance winter sports, particularly in cross-country and biathlon skiers. The pathogenesis of EIA is related to water loss and heat-loss through the increased respiration during exercise, leading to mediator release, airways inflammation and increased parasympathetic nervous activity in the airways, causing bronchial constriction and BHR. In the competing elite athlete this is presently considered to be due to the frequently repeated increased ventilation during training and competitions in combination with the repeated environmental exposure to cold air in outdoor winter sports. It is important that athletes at risk of asthma and BHR are monitored through regular medical control with assessment of lung function and BHR, and when BHR or asthma is diagnosed, optimal controlling treatment through anti-inflammatory treatment by inhaled steroids should be started and relieving treatment (inhaled ipratropium bromide and inhaled β2-agonists) should be used to relieve bronchial constriction if present.
Development of a predictive model to identify inpatients at risk of re-admission within 30 days of discharge (PARR-30)
Authors: Billings John , Blunt Ian , Steventon Adam , Georghiou Theo , Lewis Geraint , Bardsley Martin
Published: August 2012

Objectives

To develop an algorithm for identifying inpatients at high risk of re-admission to a National Health Service (NHS) hospital in England within 30 days of discharge using information that can either be obtained from hospital information systems or from the patient and their notes.

Design

Multivariate statistical analysis of routinely collected hospital episode statistics (HES) data using logistic regression to build the predictive model. The model's performance was calculated using bootstrapping.

Setting

HES data covering all NHS hospital admissions in England.

Participants

The NHS patients were admitted to hospital between April 2008 and March 2009 (10% sample of all admissions, n=576 868).

Main outcome measures

Area under the receiver operating characteristic curve for the algorithm, together with its positive predictive value and sensitivity for a range of risk score thresholds.

Results

The algorithm produces a ‘risk score’ ranging (0–1) for each admitted patient, and the percentage of patients with a re-admission within 30 days and the mean re-admission costs of all patients are provided for 20 risk bands. At a risk score threshold of 0.5, the positive predictive value (ie, percentage of inpatients identified as high risk who were subsequently re-admitted within 30 days) was 59.2% (95% CI 58.0% to 60.5%); representing 5.4% (95% CI 5.2% to 5.6%) of all inpatients who would be re-admitted within 30 days (sensitivity). The area under the receiver operating characteristic curve was 0.70 (95% CI 0.69 to 0.70).

Conclusions

We have developed a method of identifying inpatients at high risk of unplanned re-admission to NHS hospitals within 30 days of discharge. Though the models had a low sensitivity, we show how to identify subgroups of patients that contain a high proportion of patients who will be re-admitted within 30 days. Additional work is necessary to validate the model in practice.
Junior doctors and patient safety: evaluating knowledge, attitudes and perception of safety climate
Authors: Durani Piyush , Dias Joseph , Singh Harvinder P , Taub Nicholas
Published: August 2012

Introduction

Engagement of junior doctors in patient safety initiatives is high on the national agenda, but there is a lack of studies evaluating patient safety attitudes among junior doctors.

Methods

The Junior Doctor–Patient Safety Attitudes and Climate Questionnaire is a multidimensional scale created using items from already-validated scales and inclusion of new items based on further review. It consists of three subscales: ‘knowledge and training’ (10 items), ‘attitudes to patient safety’ (15 items) and ‘perception of workplace safety climate’ (15 items). This was disseminated to foundation trainees, general practice trainees and hospital core and speciality trainees via the Deanery distribution lists and responses were collected anonymously.

Results

A total of 527 complete responses were collected; although self-declared knowledge in patient safety concepts was high, there was less declared understanding of a ‘high reliability organisation’ (74% no/unsure) and the concept of active failures/latent conditions (60% no/unsure). The greatest agreement was demonstrated for the statement ‘Even the most experienced and competent doctors make errors’ (p<0.01). However, more senior trainees and surgical trainees (vs medical trainees) demonstrated greater agreement with ‘Medical error is a sign of incompetence’ (p<0.01). More junior trainees demonstrated greater agreement with ‘Management is more interested in meeting performance targets than focusing on patient safety issues’ (p<0.01).

Conclusions

This study demonstrates subtle differences in attitudes to patient safety among junior doctors of different grades and specialities. These should be taken into account when designing interventions to improve patient safety education and culture among junior doctors.
Prehospital delay in acute stroke and TIA
Authors: Faiz Kashif Waqar , Sundseth Antje , Thommessen Bente , Rønning Ole Morten
Published: August 2012

Background

Early management improves outcome in acute stroke. This study was designed to assess the prehospital path from symptom onset to arrival in hospital and to identify factors associated with prehospital delay.

Methods

A prospective study was conducted including patients with acute ischaemic stroke, intracerebral haemorrhage and transient ischaemic attack admitted to hospital. Time intervals for prehospital delay, background data, severity, type of first medical contact and mode of transport were recorded. Univariate and multivariate analyses were performed to identify factors influencing prehospital delay.

Results

A total of 440 patients were included, with a mean age of 71.4±13.0 years (44.3% female subjects), consisting of 65.9% patients with ischaemic stroke, 11.4% with intracerebral haemorrhage and 22.7% with transient ischaemic attack. The median time from symptom onset to admission was 3.0 h (179 min; IQR 77–542). The median decision delay was 1.5 h (92 min, IQR 25–405) and accounted for 55.1% (median value) of the prehospital delay. 310 (70.5%) patients arrived by ambulance. In the multivariate linear regression analysis, high National Institute of Health Stroke Scale score (p<0.001), transport by ambulance (p<0.001) and lower age (p=0.048) were significantly associated with early admission.

Conclusions

Severe strokes, use of ambulance and lower age are associated with reduced prehospital delay. The present study shows that more than half of the delay is caused by the hesitation to contact medical services. Public information campaigns should focus on fast symptom recognition and the importance of immediately contacting the Emergency Medical Services upon symptom onset.
Ultrasound guidance for difficult peripheral venous access: systematic review and meta-analysis
Authors: Egan Grace , Healy Donagh , O'Neill Heidi , Clarke-Moloney Mary , Grace Pierce A , Walsh Stewart R
Published: August 2012

Background

Establishing intravenous access is often vital in an acute hospital setting but can be difficult. Ultrasound-guided cannulation increases success rates in prospective studies. However, these studies have often lacked a comparative group. This systematic review and meta-analysis aimed to determine the clinical effectiveness of Ultrasound-guided peripheral intravenous cannulation compared with the standard technique in patients known to have difficult access.

Methods

Electronic abstract databases, trial registries, article reference lists and internet repositories were searched using the following search terms: ‘peripheral venous cannulation’, ‘peripheral venous access’. Studies meeting the following criteria were included: randomised controlled trial patients of all ages who required peripheral intravenous access; interventions were Ultrasound-guided versus standard cannulation technique; patients were identified as having difficult venous access; inclusion of at least one defined outcome (procedural success time to cannula placement; number of attempts).

Results

7 trials were identified (289 participants). Ultrasound guidance increases the likelihood of successful cannulation (pooled OR 2.42; 95% CI 1.26 to 4.68; p=0.008). There were no differences in time to successful cannulation, or number of percutaneous skin punctures.

Conclusion

Ultrasound guidance increases the likelihood of successful peripheral cannulation in difficult access patients. We recommend its use in patients who have difficult venous access, and have failed venous cannulation by standard methods. Further randomised controlled trials (RCTs) with larger sample sizes would be of benefit to investigate if Ultrasound has any additional advantages in terms of reducing the procedure time and the number of skin punctures required for successful venous cannulation.
Approach of the patient with a liver mass
Authors: Rodríguez de Lope Carlos , Reig María E , Darnell Anna , Forner Alejandro
Published: August 2012

The widespread use of imaging techniques has led to an increased diagnosis of incidental liver tumours. The differential diagnosis is extremely broad since it may range from benign asymptomatic lesions to malignant neoplasms. The correct characterisation of a liver mass has become a diagnostic challenge for most clinicians. They can be divided in two major categories; cystic lesions, usually benign with excellent long-term outcome, and solid lesions, in which malignancy should be excluded. A particular population is those patients with cirrhosis, who have high risk for hepatocellular carcinoma development. Dynamic imaging techniques have a pivotal role in the diagnostic work-up of liver tumours, allowing a confident diagnosis in most cases. If imaging is not conclusive, a biopsy should be requested to obtain a definitive diagnosis.
Feasibility of small bowel capsule endoscopy in children under the age of 4 years: a single centre experience
Authors: Vadamalayan Babu , Hii Michael , Kark Justin , Bjarnason Ingvar
Published: August 2012

Data on the use of wireless capsule endoscopy (WCE) in younger children remain limited. However, this single centre study suggests that it is a relatively complication-free procedure that may be considered in younger children below 4 years of age, when small bowel pathology is suspected. We retrospectively reviewed the King's College Hospital WCE database between August 2009 and August 2011. Patients aged 4 years or younger were included in the study. Six children fulfilled the inclusion criteria. The indications for WCE were unexplained gastrointestinal tract (GIT) bleeding (n=4), chronic diarrhoea with (n=1) and without (n=1) GIT bleeding (n=1). All had an oesophagogastroduodenoscopy and an ileocolonoscopy before WCE. The mean age at the time of WCE was 2 years 6 months (range 1 year 7 months to 3 years 7 months). The mean weight at WCE was 13.3 kg (range 9–17 kg). Four children had a complete study.
Coeliac disease in Asians in a single centre in southern Derbyshire
Authors: Holmes Geoffrey KT , Moor Fiona
Published: August 2012

Background

Coeliac disease affects adult Asians from north India, Pakistan and Bangladesh in the UK but how commonly this occurs is unknown. An audit of coeliac disease was therefore conducted in a well-defined area in southern Derbyshire.

Methods

All white and Asian patients with biopsy-confirmed coeliac disease diagnosed between 1958 and 2008 were identified. Population data from the Office of National Statistics allowed the calculation of prevalence. Presenting symptoms, adherence to a gluten-free diet and follow-up record were determined for Asians and compared with matched white patients.

Results

Among 1305 coeliac patients diagnosed between 1958 and 2008, 82 were Asian. Coeliac disease occurred significantly more frequently in Asian than white individuals and this could be attributed to the significantly higher prevalence in women 16 years and older and under 60 years of age. No Asian man over the age of 65 years was diagnosed with coeliac disease. Asians are more likely to present with anaemia and less likely to present with diarrhoea than white individuals. Asians are less likely to adhere to a strict gluten-free diet than white patients.

Conclusions

This baseline audit indicates that increased efforts should be directed towards diagnosing coeliac disease in Asian men over the age of 65 years, in whom at present it is unrepresented. Strategies also need to be developed to help more Asian patients adhere strictly to the gluten-free diet.
Do we know how to use corticosteroids in acute severe ulcerative colitis?
Authors: Islam Mohammed S , Grainger Stephen L
Published: August 2012

Options for the treatment of acute severe ulcerative colitis have broadened with the use of ciclosporin and infliximab, but corticosteroids remain first-line treatment. However, an optimum regimen for drug, dose and duration has not been established in the 57 years since Truelove and Witts first reported their value. In the absence of evidenced-based guidance this study sought to discover how gastroenterology units in the UK manage patients with acute severe colitis. In January 2010 a questionnaire was sent to all members of the inflammatory bowel disease section of the British Society of Gastroenterology enquiring about their use of corticosteroids in a typical patient with acute severe colitis. One hundred and two responses were obtained, representing more than 50% of the UK gastroenterology units. No consensus, and a wide variation in practice was found between these units. Over 70% of responders initially treat patients with intravenous hydrocortisone (400 mg/day), although some units prefer methylprednisolone and dexamethasone. On transfer to oral treatment, all units use prednisolone, most starting with 40 mg/day. There are no agreed national or international guidelines on the reducing regimen or duration of oral treatment—the area of greatest variation in our survey. Most units reduce prednisolone by 5 mg/week, but because of variations in the timing and magnitude of dose reduction, total exposure to prednisolone varies by 2.6-fold. To minimise harm from undertreatment or overtreatment of acute severe colitis a controlled study of prednisolone dose and duration is needed.
Developing an endoscopic mucosal resection service in a district general hospital
Authors: Lamb Chris A , Barbour Jamie A
Published: August 2012

Objective

To describe the implementation of a formal single-operator led endoscopic mucosal resection (EMR) service in a district general hospital, and the effect on patient outcome of this service development.

Design

Prospective audit during initiation and subsequent development of EMR service.

Setting

District general hospital.

Patients

All patients referred to EMR service between 1 January 2008 and 31 December 2011.

Interventions

Nil in addition to clinical care.

Main outcomes measured

The number of EMRs per year including polyp size and histology, recurrence of polyp tissue at 3 months following EMR, and complications including early/delayed bleeding and perforation.

Results

Following service implementation, the number of EMRs rose from 11 in 2008 to 35 in 2011, with the number of large polyps (>30 mm) rising from four in 2008 to 24 in 2011. Recurrent or residual adenomatous tissue fell from 75% in 2008 to 4.76% in 2011. Only one perforation occurred over the 4 years (0.8% perforation rate: 1 in 120 polypectomies). A reduction in surgical intervention for adenomatous polyp removal was observed during the audit period.

Conclusions

Professional engagement and support by medical, surgical and nursing members of the endoscopy team promoted development of skill and confidence in EMR. Exposure to higher volumes of EMR procedures allowed successful removal of larger lesions, while maintained patient safety and reduced the need for surgical removal of benign polyps.
Electronic chemical pathology consultation service and dried blood spot metabolic screening in hospital patients
Authors: Mak Chloe Miu , Siu Wai-Kwan , Law Chun-Yiu , Wong Chi-Keung , Lee Hon-Kit , Yeung Sam , Sham Chak-On , Tse Kong , Lee Hencher Han-Chih , Chen Sammy Pak-Lam , Ching Chor-Kwan , Au Chui-Kwan , Poon Wing-Tat , Lam Ching-Wan , Kwong Ngai-Shan , Chan Albert Yan-Wo
Published: August 2012

Aim

Inborn errors of metabolism (IEM) are an unpopular and difficult subject and most clinicians are unfamiliar with them. Although chemical pathologists have a long-standing practice in advising test strategy and result interpretation especially from primary care, such consultations are usually informal, unstructured and those related to IEM are infrequently requested. This study aims to provide a formal electronic consultation service and to apply tandem mass spectrometry-based dried blood spot metabolic screening (DBSM) as a rapid first-line test for patients suspected of IEM.

Methods

DBSM and a chemical pathology consultation were ordered through the hospital computer terminals. DBSM detected 29 metabolic disorders. The clinical data and metabolic results for the 12-month period were reviewed.

Results

There were 279 consultations of which 209 were initiated by paediatricians and 70 by adult physicians. The main reasons for consultation were developmental delay, neurological abnormalities, unexplained biochemical abnormalities and monitoring of patients with IEM. There were 158 DBSM requests. One positive case of isovaleric acidaemia was detected.

Conclusions

All high-risk paediatric patients should have a DBSM and a timely electronic chemical pathology consultation as a rapid and cost-effective first-line screening. Provision of a visible, accessible and helpful consultation service enables professional reimbursement.
Variation in postmortem liver sampling: implications for postmortem toxicology interpretation
Authors: Morley Stephen R , Bolton Jennifer
Published: August 2012

Aims

To investigate the sites for postmortem liver sampling when toxicological analysis is required and to compare these to published guidelines which recommend sampling from deep within the right lobe of the liver.

Methods

A questionnaire was sent to all pathologists who had supplied liver samples to the Sheffield toxicology laboratory in 2011. Practices were audited against published standards.

Results

79 liver samples had been provided from 39 pathologists. 30 pathologists replied. 15/30 pathologists had sampled from deep within the liver, but only 7/30 pathologists sampled from the deep within the right lobe.

Conclusions

The published guidelines for liver sampling were either not known or not being followed by pathologists. Although this did not directly affect any of the cases audited, such a lack of knowledge of the recommended site of liver sampling may lead to incorrect interpretation if the site of liver sample is unknown by the receiving laboratory.
SINGLE-MACHINE SCHEDULING WITH PROPORTIONALLY DETERIORATING JOBS SUBJECT TO AVAILABILITY CONSTRAINTS
Authors: LI SHISHENG , FAN BAOQIANG
Published: August 2012

We address the nonresumable version of the scheduling problem with proportionally deteriorating jobs on a single machine subject to availability constraints. The objective is to minimize the total weighted completion time. We show that there exists no polynomial-time algorithm with a constant worst-case ratio for the problem with two nonavailability intervals unless [Formula: see text]. Furthermore, we propose a pseudo-polynomial-time algorithm and a fully polynomial-time approximation scheme for the problem with a single nonavailability interval.
REDUNDANCY IN FUNCTIONAL BRAIN CONNECTIVITY FROM EEG RECORDINGS
Authors: DE VICO FALLANI FABRIZIO , TOPPI JLENIA , DI LANZO CLAUDIA , VECCHIATO GIOVANNI , ASTOLFI LAURA , BORGHINI GIANLUCA , MATTIA DONATELLA , CINCOTTI FEBO , BABILONI FABIO
Published: August 2012

The concept of redundancy is a critical resource of the brain enhancing the resilience to neural damages and dysfunctions. In the present work, we propose a graph-based methodology to investigate the connectivity redundancy in brain networks. By taking into account all the possible paths between pairs of nodes, we considered three complementary indexes, characterizing the network redundancy (i) at the global level, i.e. the scalar redundancy (ii) across different path lengths, i.e. the vectorial redundancy (iii) between node pairs, i.e. the matricial redundancy. We used this procedure to investigate the functional connectivity estimated from a dataset of high-density EEG signals in a group of healthy subjects during a no-task resting state. The statistical comparison with a benchmark dataset of random networks, having the same number of nodes and links of the EEG nets, revealed a significant (p < 0.05) difference for all the three indexes. In particular, the redundancy in the EEG networks, for each frequency band, appears radically higher than random graphs, thus revealing a natural tendency of the brain to present multiple parallel interactions between different specialized areas. Notably, the matricial redundancy showed a high (p < 0.05) redundancy between the scalp sensors over the parieto-occipital areas in the Alpha range of EEG oscillations (7.5–12.5 Hz), which is known to be the most responsive channel during resting state conditions.