Detection of Plant DNA in the Bronchoalveolar Lavage of Patients with Ventilator-Associated Pneumonia

BACKGROUND: Hospital-acquired infections such as nosocomial pneumonia are a serious cause of mortality for hospitalized patients, especially for those admitted to intensive care units (ICUs). Despite the number of the studies reported to date, the causative agents of pneumonia are not completely known. Herein, we found by molecular technique that vegetable and tobacco DNA may be detected in the bronchoalveolar lavage from patients with ventilator-associated pneumonia (VAP). METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we studied bronchoalveolar lavage (BAL) from patients admitted to ICUs with ventilator-associated pneumonia. BAL fluids were assessed with molecular tests, culture and blood culture. We successfully identified plant DNA in six patients out of 106 (6%) with ventilator-associated pneumonia. Inhalation was confirmed in four cases and suspected in the other two cases. Inhalation was significantly frequent in patients with plant DNA (four out of six patients) than those without plant DNA (three out of 100 patients) (P<0.001). Nicotiana tabacum chloroplast DNA was identified in three patients who were smokers (cases 2, 3 and 6). Cucurbita pepo, Morus bombycis and Triticum aestivum DNA were identified in cases 1, 4 and 5 respectively. Twenty-three different bacterial species, two viruses and five fungal species were identified from among these six patients by using molecular and culture techniques. Several of the pathogenic microorganisms identified are reported to be food-borne or tobacco plant-associated pathogens. CONCLUSIONS/SIGNIFICANCE: Our study shows that plants DNA may be identified in the BAL fluid of pneumonia patients, especially when exploring aspiration pneumonia, but the significance of the presence of plant DNA and its role in the pathogenesis of pneumonia is unknown and remains to be investigated. However, the identification of these plants may be a potential marker of aspiration in patients with pneumonia

Repertoire of Intensive Care Unit Pneumonia Microbiota

Despite the considerable number of studies reported to date, the causative agents of pneumonia are not completely identified. We comprehensively applied modern and traditional laboratory diagnostic techniques to identify microbiota in patients who were admitted to or developed pneumonia in intensive care units (ICUs). During a three-year period, we tested the bronchoalveolar lavage (BAL) of patients with ventilator-associated pneumonia, community-acquired pneumonia, non-ventilator ICU pneumonia and aspiration pneumonia, and compared the results with those from patients without pneumonia (controls). Samples were tested by amplification of 16S rDNA, 18S rDNA genes followed by cloning and sequencing and by PCR to target specific pathogens. We also included culture, amoeba co-culture, detection of antibodies to selected agents and urinary antigen tests. Based on molecular testing, we identified a wide repertoire of 160 bacterial species of which 73 have not been previously reported in pneumonia. Moreover, we found 37 putative new bacterial phylotypes with a 16S rDNA gene divergence ≥98% from known phylotypes. We also identified 24 fungal species of which 6 have not been previously reported in pneumonia and 7 viruses. Patients can present up to 16 different microorganisms in a single BAL (mean ± SD; 3.77±2.93). Some pathogens considered to be typical for ICU pneumonia such as Pseudomonas aeruginosa and Streptococcus species can be detected as commonly in controls as in pneumonia patients which strikingly highlights the existence of a core pulmonary microbiota. Differences in the microbiota of different forms of pneumonia were documented

Progressive dementia associated with ataxia or obesity in patients with Tropheryma whipplei encephalitis

<p>Abstract</p> <p>Background</p> <p><it>Tropheryma whipplei</it>, the agent of Whipple's disease, causes localised infections in the absence of histological digestive involvement. Our objective is to describe <it>T. whipplei </it>encephalitis.</p> <p>Methods</p> <p>We first diagnosed a patient presenting dementia and obesity whose brain biopsy and cerebrospinal fluid specimens contained <it>T. whipplei </it>DNA and who responded dramatically to antibiotic treatment. We subsequently tested cerebrospinal fluid specimens and brain biopsies sent to our laboratory using <it>T. whipplei </it>PCR assays. PAS-staining and <it>T. whipplei </it>immunohistochemistry were also performed on brain biopsies. Analysis was conducted for 824 cerebrospinal fluid specimens and 16 brain biopsies.</p> <p>Results</p> <p>We diagnosed seven patients with <it>T. whipplei </it>encephalitis who demonstrated no digestive involvement. Detailed clinical histories were available for 5 of them. Regular PCR that targeted a monocopy sequence, PAS-staining and immunohistochemistry were negative; however, several highly sensitive and specific PCR assays targeting a repeated sequence were positive. Cognitive impairments and ataxia were the most common neurologic manifestations. Weight gain was paradoxically observed for 2 patients. The patients' responses to the antibiotic treatment were dramatic and included weight loss in the obese patients.</p> <p>Conclusions</p> <p>We describe a new clinical condition in patients with dementia and obesity or ataxia linked to <it>T. whipplei </it>that may be cured with antibiotics.</p

Uncertainty and sensitivity analyses of the Kozloduy pump trip test using coupled Thermal-Hydraulic 3D Kinetics code

The modeling of complex transients in nuclear power plants (NPP) remains a challenging topic for best estimate three-dimensional coupled code computational tools. This technique is, nowadays, extensively used since it allows decreasing conservatism in the calculation models and performs more realistic simulation and more precise consideration of multidimensional effects under complex transients in NPPs. Therefore, large international activities are in progress aiming to assess the capabilities of coupled codes and the new frontiers for the nuclear technology that could be opened by this technique. In the current paper, a contribution to the assessment and validation of coupled code technique through the Kozloduy VVER100 pump trip test is performed. For this purpose, the coupled RELAP5/3.3-PARCS/2.6 code is used. The code results were assessed against experimental data. Deviations between code predictions and measurements are mainly due to the used models for evaluating and modeling of the Doppler feedback effect. Further investigations through the use of two “antagonist” uncertainty GRS and the CIAU methods, were considered in order to evaluate and quantify the origin of the observed discrepancies. It was revealed on one hand that relative error quantification discrepancies exist between the two approaches, and further enhancements for both methods are needed

Assessment of 12 CHF prediction methods, for an axially non-uniform heat flux distribution, with the RELAP5 computer code

The present article covers the evaluation of the performance of twelve critical heat flux methods/correlations published in the open literature. The study concerns the imulation of an axially non-uniform heat flux istribution with the RELAP5 computer code in a single boilingwater reactor channel benchmark problem. The nodalization scheme employed for the considered particular geometry, as modelled in RELAP5 code, is described. For this purpose a review of critical heat flux models/correlations applicable to non-uniform axial heat profile is provided. Simulation results using the RELAP5 code and those obtained from our computer program, based on three type redictions methods such as local conditions, F-factor and boiling length average approaches were compare

Assessment of 12 CHF Prediction Methods, for an Axially Non-Uniform Heat Flux Distribution, with the RELAP5 Computer Code

The present article covers the evaluation of the performance of twelve critical heat flux methods/ correlations published in the open literature. The study concerns the simulation of an axially non-uniform heat flux distribution with the RELAP5 computer code in a single boilingwater reactor channel benchmark problem. The nodalization scheme employed for the considered particular geometry, as modelled in RELAP5 code, is described. For this purpose a review of critical heat flux models/correlations applicable to non-uniform axial heat profile is provided. Simulation results using the RELAP5 code and those obtained from our computer program, based on three type predictions methods such as local conditions, F-factor and boiling length average approaches were compared

An Electrothermal Model for GaInP/GaAs Power HBTs with Enhanced Convergence Capabilities

International audienceA new model for GaInP/GaAs power heterojunction bipolar transistors (HBT) is proposed. This non-linear electrothermal and fully scalable model was designed with closed-form equations in order to reduce simulation times in complex circuits like high power amplifiers (HPA) and to have good convergence capabilities at high compression levels. This paper presents model topology and shows parameters extraction from pulsed I-V, pulsed [S]-parameters measurements. Simulations performed on a two-stage HPA with 20 HBTs devices have demonstrated the good convergence properties as well as a good correlation with measurement

Application of coupled code technique to a safety analysis of a standard MTR research reactor

Accident analyses in nuclear research reactors have been performed, up to now, using simple computational tools based on conservative physical models. These codes, developed to focus on specific phenomena in the reactor, were widely used for licensing purposes. Nowadays, the advances in computer technology make it possible to switch to a new generation of computational tools that provides more realistic description of the phenomena occurring in a nuclear research reactor. Recent International Atomic Energy Agency (IAEA) activities have emphasized the maturity in using Best Estimate (BE) Codes in the analysis of accidents in research reactors. Indeed, some assessments have already been performed using BE thermal–hydraulic system codes such as RELAP5/Mod3. The challenge today is oriented to the application of coupled code techniques for research reactors safety analyses. Within the framework of the current study, a Three-Dimensional Neutron Kinetics Thermal–Hydraulic Model (3D-NKTH) based on coupled PARCS and RELAP5/Mod3.3 codes has been developed for the IAEA High Enriched Uranium (HEU) benchmark core. The results of the steady state calculations are sketched by comparison to tabulated results issued from the IAEA TECDOC 643. These data were obtained using conventional diffusion codes as well as Monte Carlo codes. On the other hand, the transient analysis was assessed with conventional coupled point kinetics–thermal–hydraulic channel codes such as RELAP5 stand alone, RETRAC-PC, and PARET codes. Through this study, the applicability of the coupled code technique is emphasized with an outline of some remaining challenges