Browsing by Author "Valdivieso, Francisca"
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- ItemA Multicenter Study To Evaluate Ceftaroline Breakpoints : Performance in an Area with High Prevalence of Methicillin-Resistant Staphylococcus aureus Sequence Type 5 Lineage(2019) Khan, Ayesha; Rivas, Lina M.; Spencer, María; Martínez, Rodrigo; Lam, Marusella; Rojas, Pamela; Porte, Lorena; Silva, Francisco; Braun, Stephanie; García Cañete, Patricia; Valdivieso, Francisca; Mvlhauser, Margareta; Lafourcade, Mónica; Miller, William R.; Arias, César A.; Munita, José M.
- ItemA non-randomized multicentre trial of human immune plasma for treatment of hantavirus cardiopulmonary syndrome caused by Andes virus(2015) Vial, Pablo A.; Valdivieso, Francisca; Calvo, Mario; Rioseco, M. Luisa; Riquelme, Raul; Araneda, Andres; Tomicic, V.; Graf, Jerónimo; Paredes, Laura; Florenzano, Matias
- ItemHigh-dose intravenous methylprednisolone for hantavirus cardiopulmonary syndrome in Chile : a double-blind, randomized controlled clinical trial(2013) Vial, Pablo A.; Valdivieso, Francisca; Ferrés Garrido, Marcela Viviana; Riquelme, Raúl; Rioseco, M. Luisa; Calvo, Mario; Castillo, Constanza; Díaz, Ricardo; Scholz, Luis; Cuiza, Analia
- ItemHighly Differentiated, Resting Gn-Specific Memory CD8(+) T Cells Persist Years after Infection by Andes Hantavirus(PUBLIC LIBRARY SCIENCE, 2010) Manigold, Tobias; Mori, Andres; Graumann, Rebecca; Llop, Elena; Simon, Valeska; Ferres, Marcela; Valdivieso, Francisca; Castillo, Constanza; Hjelle, Brian; Vial, PabloIn man, infection with South American Andes virus (ANDV) causes hantavirus cardiopulmonary syndrome (HCPS). HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-gamma ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gn-derived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3(+)CD8(+) T cells were specific for the single HLA-B*3501-restricted epitope Gn(465-473) years after the acute infection. Remarkably, Gn(465-473)-specific cells readily secreted IFN-gamma, granzyme B and TNF-alpha but not IL-2 upon stimulation and showed a 'revertant' CD45RA(+)CD27(-)CD28(-)CCR7(-)CD127(-) effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T cells are critical for viral control and protective immunity. If so, Gn-derived immunodominant epitopes could be of high value for future ANDV vaccines.
- ItemIncubation period of hantavirus cardiopulmonary syndrome(CENTERS DISEASE CONTROL & PREVENTION, 2006) Vial, Pablo A.; Valdivieso, Francisca; Mertz, Gregory; Castillo, Constanza; Belmar, Edith; Delgado, Iris; Tapia, Mauricio; Ferres, MarcelaThe potential incubation period from exposure to onset of symptoms was 7-39 days (median 18 days) in 20 patients with a defined period of exposure to Andes virus in a high-risk area. This period was 14-32 days (median 18 days) in 11 patients with exposure for <= 48 hours.
- ItemPerformance of the VITEK MS System for the Identification of Filamentous Fungi in a Routine Microbiological Laboratory in Chile(2024) Porte, Lorena; Cruz, Rodrigo; Pérez, Inia; Varela, Carmen; Díaz, Cristina; García Cañete, Patricia; Legarraga, Paulette; Valdivieso, Francisca; Weitzel, ThomasBackground: Filamentous fungi are an emergent cause of severe infections in immunocompromised patients. Timely and accurate identification is crucial to initiate appropriate therapy. Traditional identification methods are time-consuming, labor-intensive, and operator-dependent. Ma-trix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry is a rapid and easy-to-perform identification method. This study evaluates the effectiveness of a commercial MALDI-TOF MS platform to identify filamentous fungi in a routine laboratory. Material and Methods: We included 67 fungal isolates from 35 species/species complexes within 15 genera, confirmed in mycology reference laboratories. 33 were from clinical samples and 34 from strain collections. The study used the VITEK MS system (v3.2.0 database), after sample extraction by VITEK MS Mould Kit. Results were classified into categories: ‘correct species’, ‘correct species complex’, ‘correct genus’, ‘incorrect identification’, and ‘no identification’. We also evaluated the practicality of the kit. Results: VITEK MS correctly identified 91.0% of isolates (58.2% to species, 29.9% to species complex, and 1.5% to genus level). In 82%, the result matched the species/species complex identified by reference methods. No misidentifications were observed. The kit was rapid and easy to use. Conclusion: The VITEK MS system showed a high capability to accurately identify filamentous fungi in a routine laboratory.
- ItemYellow fever vaccination for Chilean tourists visiting Brazil. Practical considerations(SOC CHILENA INFECTOLOGIA, 2018) Weitzel, Thomas; Perret, Cecilia; Valdivieso, Francisca; Abarca, Katia; Vial, PabloDue to the recent yellow fever outbreak affecting the costal region of Brazil, including main touristic destinations, there is a high demand of yellow fever vaccination. This publication addresses the most relevant practical issues regarding this vaccine for tourists visiting Brazil and aims to serve as a guideline for non-expert physicians in Chile and elsewhere.