Evidence-based radiography : a new methodology or the systematisation of an old practice?

Introduction: Evidence based radiography (EBR) is the logical development of evidence based practice applied to radiography. The aim of this study was to investigate the opinion of a cohort of Portuguese radiographers in Southern Portugal working in public hospitals regarding evidence based practice (EBP), namely about the levels of knowledge about EBR, how they access information and how they use it within daily practice. Methods: A self-administered questionnaire was applied to a sample of 40 radiographers in the Portuguese region of Algarve. This questionnaire was validated for Portuguese speakers using the translation-retranslation method. Results: The final response rate was 69% (40/58). Results suggest that most radiographers trained EBR during their undergraduate training. Although, no statistically significant correlations were found in the practice of EBR against participant gender, age, training, career level, reading papers and workplace. The most frequent reason to read papers is the “interest” to do so, and national professional journals are read more often. It was found that radiographers that read scientific papers more frequently know more about research (p=0.005), understand the importance of research for the professional activity (p=0.023), and know more on how to conduct research papers (p=0.034). Conclusion: EBR within radiography is not yet well established, and radiographers’ have varying viewpoints. Radiographers that read scientific papers more frequently understand better the philosophy behind this concept but it is very important to deepen the knowledge on this area. Implications for Practice: When practicing radiography based on the best available scientific knowledge, professionals are ensuring the best for patients and for profession. To achieve this, and before taking any action, it is important to evaluate the current situation, and this research presents a way to do so

Population Genomic Analysis of a Bacterial Plant Pathogen: Novel Insight into the Origin of Pierce's Disease of Grapevine in the U.S.

Invasive diseases present an increasing problem worldwide; however, genomic techniques are now available to investigate the timing and geographical origin of such introductions. We employed genomic techniques to demonstrate that the bacterial pathogen causing Pierce's disease of grapevine (PD) is not native to the US as previously assumed, but descended from a single genotype introduced from Central America. PD has posed a serious threat to the US wine industry ever since its first outbreak in Anaheim, California in the 1880s and continues to inhibit grape cultivation in a large area of the country. It is caused by infection of xylem vessels by the bacterium Xylella fastidiosa subsp. fastidiosa, a genetically distinct subspecies at least 15,000 years old. We present five independent kinds of evidence that strongly support our invasion hypothesis: 1) a genome-wide lack of genetic variability in X. fastidiosa subsp. fastidiosa found in the US, consistent with a recent common ancestor; 2) evidence for historical allopatry of the North American subspecies X. fastidiosa subsp. multiplex and X. fastidiosa subsp. fastidiosa; 3) evidence that X. fastidiosa subsp. fastidiosa evolved in a more tropical climate than X. fastidiosa subsp. multiplex; 4) much greater genetic variability in the proposed source population in Central America, variation within which the US genotypes are phylogenetically nested; and 5) the circumstantial evidence of importation of known hosts (coffee plants) from Central America directly into southern California just prior to the first known outbreak of the disease. The lack of genetic variation in X. fastidiosa subsp. fastidiosa in the US suggests that preventing additional introductions is important since new genetic variation may undermine PD control measures, or may lead to infection of other crop plants through the creation of novel genotypes via inter-subspecific recombination. In general, geographically mixing of previously isolated subspecies should be avoided

Population Structure of the Bacterial Pathogen Xylella fastidiosa among Street Trees in Washington D.C.

Funding for Open Access provided by the UMD Libraries Open Access Publishing Fund.Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multilocus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship

Winter curing of Prunus dulcis cv ‘Butte,’ P. webbii and their interspecific hybrid in response to Xylella fastidiosa infections

Clonal replicates of Prunus dulcis cv ‘Butte,’ P. webbii and their interspecific hybrid P 63-61 were inoculated with Xylella fastidiosa strain M23 and evaluated for almond leaf scorch disease and subsequent winter curing of infections during three growing seasons. Initial inoculations established greater than 90% infection in each of the accessions, based on PCR diagnoses from petiole tissues sampled near the inoculation site. Classic leaf scorch symptoms were evident in each population during the first growing season in a controlled greenhouse environment. Trees were removed from the greenhouse during the winters to accumulate chill hours and to provide the possibility of winter curing X. fastidiosa infections. Both PCR diagnostics and in vitro cultivation were used during the second and third growing seasons to determine the persistence of X. fastidiosa in clones among the three populations. Tree survival and the degree of winter cured infections differed among the three populations, with P. webbii and P 63-61 demonstrating enhanced levels of survivorship over ‘Butte.’ After two cycles of ambient winter temperatures and subsequent growth, ‘Butte’ averaged 21.2% winter cured trees with 73.1% mean survival. Tree survival and winter cured infections were nearly 100% for both P. webbii and P 63-61, demonstrating the utility of P. webbii in almond breeding efforts aimed at reducing tree vulnerability to X. fastidiosa infections

The Complex Biogeography of the Plant Pathogen Xylella fastidiosa: Genetic Evidence of Introductions and Subspecific Introgression in Central America

Datos y artículo incluido por Lisela Moreira Carmona, responsable de depósitos de publicaciones del área de Patógenos y Plagas del CIBCMThe bacterium Xylella fastidiosa is a plant pathogen with a history of economically damaging introductions of subspecies to regions where its other subspecies are native. Genetic evidence is presented demonstrating the introduction of two new taxa into Central America and their introgression into the native subspecies, X. fastidiosa subsp. fastidiosa. The data are from 10 genetic outliers detected by multilocus sequence typing (MLST) of isolates from Costa Rica. Six (five from oleander, one from coffee) defined a new sequence type (ST53) that carried alleles at six of the eight loci sequenced (five of the seven MLST loci) diagnostic of the South American subspecies Xylella fastidiosa subsp. pauca which causes two economically damaging plant diseases, citrus variegated chlorosis and coffee leaf scorch. The two remaining loci of ST53 carried alleles from what appears to be a new South American form of X. fastidiosa. Four isolates, classified as X. fastidiosa subsp. fastidiosa, showed a low level of introgression of non-native DNA. One grapevine isolate showed introgression of an allele from X. fastidiosa subsp. pauca while the other three (from citrus and coffee) showed introgression of an allele with similar ancestry to the alleles of unknown origin in ST53. The presence of X. fastidiosa subsp. pauca in Central America is troubling given its disease potential, and establishes another route for the introduction of this economically damaging subspecies into the US or elsewhere, a threat potentially compounded by the presence of a previously unknown form of X. fastidiosa.Universidad de Costa Rica/[801-B2-516]/UCR/Costa RicaUniversidad de Costa Rica/[801-A1-801]/UCR/Costa RicaInternational Foundation for Science/[grant C/5152-1]/IFS/SueciaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM

Previsual symptoms of Xylella fastidiosa infection revealed in spectral plant-trait alterations

Plant pathogens cause significant losses to agricultural yields, and increasingly threaten food security, ecosystem integrity, and societies in general. Xylella fastidiosa (Xf) is one of the most dangerous plant bacteria worldwide, causing several diseases with profound impacts on agriculture and the environment. Primarily occurring in the Americas, its recent discovery in Asia and Europe demonstrates a dramatically broadened geographic range. The Xf pathogen has thus re-emerged as a global threat, with its poorly contained expansion in Europe creating a socio-economic, cultural, and political disaster. Xf represents a threat of global proportion because it can infect over 350 plant species worldwide, and the early detection of Xf has been identified as a critical need for its eradication. Here, we show that changes in plant functional traits retrieved from airborne imaging spectroscopy and thermography reveal Xf infection in trees before symptoms are visible. We obtained accuracies of disease detection exceeding 80% when high-resolution solar-induced fluorescence quantified by 3D simulations and thermal-based stress indicators were coupled with photosynthetic traits sensitive to rapid pigment dynamics and degradation. Moreover, we found that the visually asymptomatic trees originally scored as affected via spectral plant trait alterations (presumed false positives) developed Xf symptoms four months later at almost double the rate of the asymptomatic trees classified as not affected by remote sensing. We demonstrate that spectral plant trait alterations caused by Xf infection are detectable at the landscape scale before symptoms are visible, a critical requirement to help eradicate some of the most devastating plant diseases worldwide.JRC.D.1-Bio-econom

Use of beneficial bacteria and their secondary metabolites to control grapevine pathogen diseases

Grapevine is one of the most important economic crops yielding berries, wine products as well as derivates. However, due to the large array of pathogens inducing diseases on this plant, considerable amounts of pesticides—with possible negative impact on the environment and health—have been used and are currently used in viticulture. To avoid negative impacts of such products and to ensure product quality, a substantial fraction of pesticides needs to be replaced in the near future. One solution can be related to the use of beneficial bacteria inhabiting the rhizo- and/or the endosphere of plants. These biocontrol bacteria and their secondary metabolites can reduce directly or indirectly pathogen diseases by affecting pathogen performance by antibiosis, competition for niches and nutrients, interference with pathogen signaling or by stimulation of host plant defenses. Due to the large demand for biocontrol of grapevine diseases, such biopesticides, their modes of actions and putative consequences of their uses need to be described. Moreover, the current knowledge on new strains from the rhizo- and endosphere and their metabolites that can be used on grapevine plants to counteract pathogen attack needs to be discussed. This is in particular with regard to the control of root rot, grey mould, trunk diseases, powdery and downy mildews, pierce’s disease, grapevine yellows as well as crown gall. Future prospects on specific beneficial microbes and their secondary metabolites that can be used as elicitors of plant defenses and/or as biocontrol agents with potential use in a more sustainable viticulture will be further discussed