Browsing by Author "Ferrés, Marcela"

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    An Open One-Step RT-qPCR for SARS-CoV-2 detection
    (Public Library Science, 2024) Cerda Rojas, Ariel Patricio; Rivera, Maira; Armijo, Grace; Ibarra-Henríquez, Catalina; Reyes, Javiera; Blázquez Sánchez, Paula; Avilés, Javiera; Arce, Anibal; Seguel, Aldo; Brown, Alexander J.; Vásquez, Yesseny; Cortez-San Martín, Marcelo; Cubillos, Francisco A.; García, Patricia; Ferrés, Marcela; Ramírez Sarmiento, César Antonio; Federici, Fernan; Gutiérrez, Rodrigo A.
    The COVID-19 pandemic has resulted in millions of deaths globally, and while several diagnostic systems were proposed, real-time reverse transcription polymerase chain reaction (RT-PCR) remains the gold standard. However, diagnostic reagents, including enzymes used in RT-PCR, are subject to centralized production models and intellectual property restrictions, which present a challenge for less developed countries. With the aim of generating a standardized One-Step open RT-qPCR protocol to detect SARS-CoV-2 RNA in clinical samples, we purified and tested recombinant enzymes and a non-proprietary buffer. The protocol utilized M-MLV RT and Taq DNA pol enzymes to perform a Taqman probe-based assay. Synthetic RNA samples were used to validate the One-Step RT-qPCR components, demonstrating sensitivity comparable to a commercial kit routinely employed in clinical settings for patient diagnosis. Further evaluation on 40 clinical samples (20 positive and 20 negative) confirmed its comparable diagnostic accuracy. This study represents a proof of concept for an open approach to developing diagnostic kits for viral infections and diseases, which could provide a cost-effective and accessible solution for less developed countries.
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    Correlation between female sex, IL28B genotype, and the clinical severity of bronchiolitis in pediatric patients
    (2020) Astudillo, P.; Angulo, J.; Pino, K.; de Carvalho, J. B.; de Morais, G. L.; Perez, S.; de Vasconcelos, A. T. R.; Ferrés, Marcela; López Lastra, Marcelo Andrés
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    Hantavirus in humans: a review of clinical aspects and management
    (2023) Vial Clavo, Pablo Agustín; Ferrés, Marcela; Vial, Cecilia; Klingstrom, Jonás; Ahlm, Clas; López, René; Le Corre Pérez, Monique Nicole; Mertz J., Gregory
    Hantavirus infections are part of the broad group of viral haemorrhagic fevers. They are also recognised as a distinct model of an emergent zoonotic infection with a global distribution. Many factors influence their epidemiology and transmission, such as climate, environment, social development, ecology of rodent hosts, and human behaviour in endemic regions. Transmission to humans occurs by exposure to infected rodents in endemic areas; however, Andes hantavirus is unique in that it can be transmitted from person to person. As hantaviruses target endothelial cells, they can affect diverse organ systems; increased vascular permeability is central to pathogenesis. The main clinical syndromes associated with hantaviruses are haemorrhagic fever with renal syndrome (HFRS), which is endemic in Europe and Asia, and hantavirus cardiopulmonary syndrome (HCPS), which is endemic in the Americas. HCPS and HFRS are separate clinical entities, but they share several features and have many overlapping symptoms, signs, and pathogenic alterations. For HCPS in particular, clinical outcomes are highly associated with early clinical suspicion, access to rapid diagnostic testing or algorithms for presumptive diagnosis, and prompt transfer to a facility with critical care units. No specific effective antiviral treatment is available.
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    Mother-to-child transmission of Andes virus through breast milk, Chile
    (2020) Ferrés, Marcela; Martínez Valdebenito, Constanza; Angulo, J.; Henríquez, C.; Vera Otarola, Jorge Andrés; Vergara, M. J.; Vial Cox, María Cecilia; Vial Claro, Pablo; Pérez, J.; Le Corre Pérez, Monique Nicole; Fernández, J.; Sotomayor, V.; Valdés, M. F.; González-Candia, D.; Tischler, N. D.; Mertz, G.
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    Reconocimiento de influenza-A como etiología de síndrome febril e insuficiencia respiratoria en adultos hospitalizados durante brote en la comunidad
    (2004) Rabagliati Borie, Ricardo Miguel; Benítez Gómez, Rosana; Fernández Montenegro, María Alicia; Gaete Gutiérrez, Pablo Antonio; Guzmán Durán, Ana María; García Cañete, Patricia; Ferrés, Marcela; Pérez Cortés, Carlos Miguel; Labarca L., Jaime
    Background: Influenza-A (IA) occurs every winter, is mostly observed among outpatients. Aim: To describe the clinical and epidemiological characteristics of cases that required hospital admission during an outbreak in Chile in 1999. Patients and methods: Adults subjects, with Influenza A confirmed by antigen detection test, hospitalized in the clinical hospital of the «Hospital Clínico de la Universidad Católica de Chile» between May and June, with fever or respiratory symptoms were studied. A special record was designed to register clinical, microbiological and therapeutic data. Results: Fifty five cases, 26 males, aged 15 to 91 years, were studied. Eighty four percent had chronic concomitant diseases and 9.1% were immunosuppressed. Clinical findings were fever in 87.3%, asthenia in 83.6%, cough in 93.6%, abnormal pulmonary signs in 69%, an elevated C-reactive protein (mean value of 11.6 ± 7.1 mg/dL) and acute respiratory insufficiency in 54.5%. Cases were isolated in cohort or individual rooms and 38.2% were admitted to intensive or intermediate care units. Amantadine was prescribed to 52 patients and was well tolerated. Thirty three percent of cases developed pneumonia. These subjects were older, had more dyspnea and respiratory insufficiency than patients without pneumonia. Conclusions: IA should be borne in mind when dealing with hospitalized adults, during epidemic outbreaks in the community. The clinical picture can resemble a serious bacterial infection. An early diagnosis allows the use of specific treatments, to decrease the risk of nosocomial spread and to avoid unnecessary use of antibiotics.
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    Symptom Profiles and Risk Factors for Hospitalization in Patients With SARS-CoV-2 and COVID-19 : A Large Cohort From South America
    (2020) Díaz Piga, Luis Antonio; García-Salum, T.; Fuentes López, Eduardo; Ferrés, Marcela; Medina, Rafael; Riquelme Pérez, Arnoldo
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    Utilidad de la reacción de polimerasa en cadena en tiempo real en el diagnóstico de infecciones por virus respiratorio sincicial en adultos
    (Sociedad Chilena de Infectología, 2007) Rabagliati Borie, Ricardo Miguel; Serri Venegas, Michel André; Montecinos Perret, Luisa Paola; Azócar Azócar, Teresa Del Carmen; Ferrés, Marcela
    Introducción: Las infecciones respiratorias virales (IRV) son causa importante de morbilidad en adultos. Virus respiratorio sincicial (VRS) causa hasta 20% de las IRV en esta edad; sin embargo, su diagnóstico es subestimado debido a una menor sensibilidad de las técnicas diagnosticas convencionales (IF y ELISA). Objetivos: Evaluar el impacto del uso de reacción de la polimerasa en cadena en tiempo real (TR-RPC en tiempo real) en el diagnóstico de IRV por VRS en adultos y caracterizar su perfil clínico. Pacientes y Métodos: Durante ocho semanas del año 2005, los adultos hospitalizados en Hospital Clínico de la Universidad Católica con sospecha de IRV, e IFD negativa para VRS, FLU-A, -B, paraFLU-1, 2, 3 y ADV de muestra de hisopado nasofaríngeo, fueron sometidos a detección de VRS por TR-RPC en tiempo real. Se confeccionó una base de datos con los antecedentes clínicos, laboratorio y evolución de cada paciente. Resultados: De 114 pacientes con IFD negativa en 17 (14,9%) se detectó VRS. Fiebre, congestión faríngea, tos y signos de obstrucción bronquial, configuraron en más de 80% de los casos el perfil clínico de los pacientes. Treinta por ciento presentaba enfermedad crónica y 47% eran inmunocomprometidos. Tres de 17 (18%) presentaron descompensación de la enfermedad de base y 1/17 (6%) requirió ventilación mecánica. No hubo mortalidad asociada. Conclusiones: El uso de TR-RPC en tiempo real permitió duplicar la detección de infecciones por VRS en adultos hospitalizados respecto a las diagnosticadas por IFD. Se recomienda considerar el empleo la técnica de TR-RPC en tiempo real en aquellos pacientes con sospecha clínica de VRS durante la temporada de VRS y estudio viro lógico negativo por métodos convencionales.