Browsing by Author "Balcells Marty, María Elvira"

Now showing 1 - 20 of 45
  • Thumbnail Image
    Item
    A comparative study of two different methods for the detection of latent tuberculosis in HIV-positive individuals in Chile
    (Elsevier Ltd, 2008) Balcells Marty, María Elvira; Pérez Cortes, Carlos Miguel; Chanqueo Cornejo, Leonardo Andrés; Lasso Barreto, Martin Francisco; Villanueva, Marcela; Espinoza Concha, Mónica Ximena; Villarroel Del Pino, Luis Antonio; García Cañete, Patricia Del Carmen
    Objective: To compare the performance of two tests for diagnosing latent tuberculosis (TB) infection in the HIV-positive population in Chile, in order to better identify the subjects who might benefit from TB chemoprophylaxis. Design: This was a cross-sectional study among individuals attending three HIV outpatient clinics in Santiago, tested with a 2-TU purified protein derivative, QuantiFERON ® -TB Gold ‘in-tube’ (QFT-G), and a chest X-ray. Results: A total of 116 subjects were enrolled in the study, having a mean CD4 count of 393 cells/μl (range 100–977). The tuberculin skin text (TST; 5 mm cutoff) and QFT-G results were positive in 10.9% and 14.8% of the individuals, respectively, with moderate agreement between both tests (kappa = 0.59). A history of both known TB exposure (odds ratio (OR) 3.46, 95% confidence interval (CI) 1.02–11.22) and past TB (OR 4.31, 95% CI 1.13–15.5) were associated with a positive QFT-G result. Only past TB was significantly associated with a positive TST result (OR 6.63, 95% CI 1.62–26.3). Among the subjects with TST < 5 mm, 8.2% were positive by QFT-G test. These individuals had a lower mean CD4 cell count than those detected positive by both tests (328 cells/μl and 560 cells/μl, respectively, p = 0.03). Conclusions: In this population of HIV-infected individuals, QFT-G and TST showed an acceptable level of agreement, although QFT-G appears less affected by more advanced immunosuppression.
  • Thumbnail Image
    Item
    A First Insight on the Population Structure of Mycobacterium tuberculosis Complex as Studied by Spoligotyping and MIRU-VNTRs in Santiago, Chile
    (2015) Balcells Marty, María Elvira; García Cañete, Patricia; Meza, P.; Pena, C.; Cifuentes, M.; Couvin, D.; Rastogi, N.
  • Thumbnail Image
    Item
    Angiomatosis bacilar por Bartonella quintana como primera manifestación de infección por VIH
    (SOC MEDICA SANTIAGO, 2012) Uribe González, Pablo Francisco; Balcells Marty, María Elvira; Giesen Flaskamp, Laura; Cardenas De La Torre, Consuelo Paz; Garcia Muñoz, Patricia Alejandra; González Bombardiere, Sergio
    Bacillary angiomatosis is an unusual infectious disease, with angioproliferative lesions, typical of immunocompromised patients. It is caused by Bartonella quintana and Bartonella henselae, two infectious agents of the genus Bartonella, which trigger variable clinical manifestations, including cutaneous vascular and purpuric lesions, and regional lymphadenopathy, and even a systemic disease with visceral involvement. We report a 38-year-old HIV positive male presenting with a history of six months of cutaneous growing purple angiomatous lesions, located also in nasal fossae, rhinopharynx and larynx. The skin biopsy was compatible with bacillary angiomatosis. Polymerase chain reaction of a tissue sample showed homology with B. quintana strain Toulouse. The patient was treated with azithromycin and ciprofloxacin with a favorable evolution. (Rev Med Chile 2012; 140: 910-914).
  • Thumbnail Image
    Item
    Association of vitamin D deficiency, season of the year, and latent tuberculosis infection among household contacts
    (2017) Balcells Marty, María Elvira; García Cañete, Patricia; Tiznado, Camila; Villarroel del Pino, Luis A.
  • Thumbnail Image
    Item
    Clinical standards for the diagnosis, treatment and prevention of TB infection
    (International Union Against Tuberculosis and Lung Disease, 2022) Migliori, G. B.; Wu, S. J.; Matteelli, A.; Zenner, D.; Goletti, D.; Ahmedov, S.; Al Abri, S.; Allen, D. M.; Balcells Marty, María Elvira; Garcia Basteiro, A. L.; Cambau, E.; Chaisson, R. E.; Chee, C. B. E.; Dalcolmo, M. P.; Denholm, J. T.; Erkens, C.; Esposito, S.; Farnia, P.; Friedland, J. S.; Graham, S.; Hamada, Y.; Harries, A. D.; Kay, A. W.; Kritski, A.; Manga, S.; Marais, B. J.; Menzies, D.; Ng, D.; Petrone, L.; Rendon, A.; Silva, D. R.; Schaaf, H. S.; Skrahina, A.; Sotgiu, G.; Thwaites, G.; Tiberi, S.; Tukvadze, N.; Zellweger, J P; Ambrosio, L. D.; Centis, R.; Ong, C. W. M.
    BACKGROUND: Tuberculosis (TB) preventive therapy (TPT) decreases the risk of developing TB disease and its associated morbidity and mortality. The aim of these clinical standards is to guide the assessment, management of TB infection (TBI) and implementation of TPT. METHODS: A panel of global experts in the field of TB care was identified; 41 participated in a Delphi process. A 5-point Likert scale was used to score the initial standards. After rounds of revision, the document was approved with 100% agreement. RESULTS: Eight clinical standards were defined: Standard 1, all individuals belonging to at-risk groups for TB should undergo testing for TBI; Standard 2, all individual candidates for TPT (including caregivers of children) should undergo a counselling/health education session; Standard 3, testing for TBI: timing and test of choice should be optimised; Standard 4, TB disease should be excluded prior to initiation of TPT; Standard 5, all candidates for TPT should undergo a set of baseline examinations; Standard 6, all individuals initiating TPT should receive one of the recommended regimens; Standard 7, all individuals who have started TPT should be monitored; Standard 8, a TBI screening and testing register should be kept to inform the cascade of care. CONCLUSION: This is the first consensus-based set of Clinical Standards for TBI. This document guides clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage TBI.
  • Thumbnail Image
    Item
    Cluster of imported vivax malaria in travelers returning from Peru
    (2015) Weitzel, Thomas; Labarca L., Jaime; Cortes, Claudia P.; Rosas, Reinaldo; Balcells Marty, María Elvira; Perret Pérez, Cecilia
  • Thumbnail Image
    Item
    Comparación de adenosina deaminasa y detección de anticuerpos anti-antígeno A60 para el diagnóstico de meningitis tuberculosa
    (SOC CHILENA INFECTOLOGIA, 2012) García Cañete, Patricia; Bahamondes, Laura; Reyes Ortega, Paula Soledad; Román Gómez, Juan Carlos; Poblete, Haydé; Balcells Marty, María Elvira
    Antecedentes: El diagnóstico de meningitis tuberculosa (MTBC) se ve limitado por la ausencia de técnicas diagnósticas rápidas y precisas en líquido cefalorraquídeo (LCR). En este estudio evaluamos la respuesta inmunoló-gica de anticuerpos anti-antígeno A60 de Mycobacterium tuberculosis en LCR en comparación a la determinación de adenosina deaminasa (ADA). Métodos: Un total de 63 muestras de LCR fueron estudiadas mediante ELISA indirecto para detección de IgG, IgM e IgA anti-A60. Estas muestras incluyeron 17 casos de MTBC confirmada y 46 controles con otras infecciones. Resultados: Los títulos de IgG, IgM e IgA anti A-60 resultaron significativamente superiores en casos de MTBC versus controles (p > 0,01). El anticuerpo con mej or poder discriminatorio resultó IgM, con un área bajo la curva ROC de 0,928 (95%IC 0,8340,978), comparado a 0,863 (95% IC: 0,752-0,936) para ADA (p = NS). La sensibilidad de IgM anti-A60 (nivel de corte > 0,06 U/ml) fue de 94,1% versus 88,2% para ADA (nivel de corte > 6,2 U/ml), p = NS. Ambos IgM anti-A60 y ADA presentaron la misma especificidad baja-moderada (80,4%). Dos casos de MMTBC fueron correctamente identificados por IgM anti-A60 pero no por ALDA. Conclusión: La detección de anticuerpos anti-A60 (IgM) puede ser de ayuda en el diagnostico de MTBC en forma complementaria a la determinación de ALDA. La baja especificidad de ambos tests constituye su principal limitante.
  • Thumbnail Image
    Item
    Convalescent plasma in COVID-19. Mortality-safety first results of the prospective multicenter FALP 001-2020 trial
    (2020) Gazitúa, R.; Briones, J. L.; Selman, C.; Villarroel Espíndola, F.; Aguirre, A.; González Steigmaier, R.; Cereceda, K.; Mahave, M.; Rubio, B.; Ferrer Rosende, P.; Sapunar, J.; Marsiglia, H.; Morales, R.; Yarad, F.; Balcells Marty, María Elvira; Rojas, Luis; Nervi Nattero, Bruno; Nien, J. K.; Garate, J.; Prieto, C.; Palma, S.; Escobar, C.; Bascuñan, J.; Muñoz, R.; Pinto, M.; Cardemil, D.; Navarrete, M.; Reyes, S.; Espinosa, V.; Yáñez, N.; Caglevic, C.
  • Thumbnail Image
    Item
    Diagnostic accuracy of the Xpert® MTB/RIF cycle threshold level to predict smear positivity : a meta-analysis
    (2017) Lange, B.; Khan, P.; Kalmambetova, G.; Al-Darraji H. A.; Alland, D.; Antonenka, U.; Brown, T.; Balcells Marty, María Elvira; Blakemore, R.; Denkinger, C. M.|Dheda, K.; Hoffmann, H.; Kadyrov, A.
  • Thumbnail Image
    Item
    Diagnostic performance of GM-CSF and IL-2 in response to long-term specific-antigen cell stimulation in patients with active and latent tuberculosis infection
    (2018) Balcells Marty, María Elvira; Ruiz-Tagle, Cinthya; Tiznado, Camila; García Cañete, Patricia; Naves, Rodrigo
  • Thumbnail Image
    Item
    Endemic Scrub Typhus-like Illness, Chile
    (Centers for Disease Control an Prevention, 2011) Balcells Marty, María Elvira; Rabagliati Borie, Ricardo Miguel; García Cañete, Patricia Del Carmen; Poggi Mayorga, Helena Loreto; Oddo Benavides, Carlos David; Concha Rogazy, Marcela Andrea; Abarca Villaseca, Katia; Jiang, Ju; Kelly, Daryl J.; Richards, Allen L.; Fuerst, Paul A.
    We report a case of scrub typhus in a 54-year-old man who was bitten by several terrestrial leeches during a trip to Chiloe Island in southern Chile in 2006. A molecular sample, identified as related to Orientia tsutsugamushi based on the sequence of the 16S rRNA gene, was obtained from a biopsy specimen of the eschar on the patient's leg. Serologic analysis showed immunoglobulin G conversion against O. tsutsugamushi whole cell antigen. This case and its associated molecular analyses suggest that an Orientia-like agent is present in the Western Hemisphere that can produce scrub typhus-like illness. The molecular analysis suggests that the infectious agent is closely related, although not identical, to members of the Orientia sp. from Asia.
  • Thumbnail Image
    Item
    Estrategia de pesquisa sistemática y seguimiento prolongado revela alto número de nuevas infecciones tuberculosas en contactos adultos en la Región Metropolitana, Chile
    (2020) Balcells Marty, María Elvira; Carvajal, Camila; Fernández, Paula; Ruiz-Tagle, Cinthya; Pizarro, Alejandra; García, Patricia; Peña, Carlos; Cuevas, Gerardo; Naves, Rodrigo
    Background: Contact investigation is cardinal in the control of tuberculosis (TB) since it helps to stop its transmission. In Chile, the National TB Program strategy does not include latent TB infection testing, regular chemoprophylaxis or follow-up in adults. Active TB was found in only 1.2% of contacts at country-level during 2018. Aim: To evaluate the performance of a systematic screening ofadult household contacts with targeted chemoprophylaxis and prolonged active follow-up. Material and Methods: Prospective cohort of household contacts in Santiago. Two face-to-face visits (at 0 and 12 weeks) that included QuantiFERON TB-Gold plus tests (QFT), chest radiography (CXR) at 0 and 24 weeks and, periodic text messaging or phone call follow-up for up to 48 weeks were implemented. Contacts with positive QFT were referred for TB chemoprophylaxis. Results: A total of 200 contacts were enrolled, 69% were migrants. At baseline evaluation, 45% had a positive QFT result and 1.6% had co-prevalent active TB. At follow-up, 13% contacts further converted to QFT (+), and 5.1% more were diagnosed with active TB (mean follow-up time 32 weeks). Of these 10 further active TB cases, 6 (60%) had a negative QFT and all (100%) had normal CXR at baseline; while three cases occurred in QFT converters. Conclusions: In this cohort of household contacts, 6.7 % were diagnosed with active TB (more than 2/3 at follow-up) and 13% had a late QFT (+) conversion. Active and prolonged contacts’ follow-up are essential to detect new infections and tackle the TB epidemic in Chile.
  • Thumbnail Image
    Item
    Evaluation of concordance of new QuantiFERON-TB Gold Plus platforms for Mycobacterium tuberculosis infection diagnosis in a prospective cohort of household contacts
    (2024) Ruiz-Tagle Seguel, Cinthya Grace; García Cañete, Patricia Del Carmen; Hernández, Mariluz; Balcells Marty, María Elvira
    Interferon-gamma (IFN-γ) release assays play a pivotal role in tuberculosis infection (TBI) diagnosis, with QuantiFERON-TB Gold Plus—an enzyme-linked immunosorbent assay (ELISA)—among the most widely utilized. Newer QuantiFERON-TB platforms with shorter turnaround times were recently released. We aimed to evaluate these platforms’ agreement in the diagnosis of TBI. Blood samples from a prospective cohort of tuberculosis household contacts were collected at baseline and after 12 weeks of follow-up, and tested with LIAISON, an automated chemiluminescence immunoassay (CLIA) system, QIAreach, a lateral flow (QFT-LF) semi-automated immunoassay, and the ELISA QuantiFERON-TB Gold Plus platform. Test concordances were analyzed. ELISA vs CLIA overall agreement was 83.3% for all tested samples (120/144) [Cohen’s kappa coefficient (κ): 0.66 (95% CI: 0.54–0.77)]. Samples positive with CLIA provided consistently higher IFN-γ levels than with ELISA (P < 0.001). Twenty-four (16.7%) discordant pairs were obtained, all CLIA-positive/ELISA-negative: 15 (62.5%) had CLIA IFN-γ levels within borderline values (0.35–0.99 IU/mL) and 9 (37.5%) >0.99 IU/mL. QFT-LF showed only 76.4% (68/89) overall agreement with ELISA [κ: 0.53 (95% CI: 0.37–0.68)] with 21 (23.6%) discordant results obtained, all QFT-LF-positive/ELISA-negative. Overall concordance between ELISA and CLIA platforms was substantial, and only moderate between ELISA and QFT-LF. The CLIA platform yielded higher IFN-γ levels than ELISA, leading to an almost 17% higher positivity rate. The techniques do not seem interchangeable, and validation against other gold standards, such as microbiologically-confirmed tuberculosis disease, is required to determine whether these cases represent true new infections or whether CLIA necessitates a higher cutoff.
  • Thumbnail Image
    Item
  • No Thumbnail Available
    Item
    Humoral immune-response to a SARS-CoV-2- BNT162b2 booster in inflammatory arthritis patients who received an inactivated virus vaccine
    (BMJ PUBLISHING GROUP, 2022) Durán Santa Cruz, Josefina Gracia; Burgos Cañete, Paula Isabel; Le Corre Pérez, Monique Nicole; Ruiz-Tagle, Cinthya; Martínez Valdebenito, Constanza; Castro, Mauricio; Metcalfe Torres, Valentina Estrella; Niemann Concha, Paula Valentina; Balcells Marty, María Elvira
  • Thumbnail Image
    Item
    Identificación de especies de micobacterias mediante espectrometría de masas (MALDI-TOF)
    (2020) Contreras, Samuel; Rodriguez, David; Vera, Francisco; Balcells Marty, María Elvira; Celis, Luis; Legarraga Raddatz, Paulette; Carlos Roman, Juan; García Cañete, Patricia
    Introducción: Las enfermedades producidas por micobacterias son de gran importancia clínica y epidemiológica presentando el complejo Mycobacterium tuberculosis (MTBc) una morbi-mortalidad mayor que la producida por micobacterias no tuberculosas (MNTB). La identificación tradicional está basada en sus características fenotípicas mediante procesos laboriosos e incapaces en algunos casos de distinguir entre especies. Actualmente, la mayoría de las técnicas utilizadas se basan en métodos moleculares que tienen alta veracidad, pero son complejas y de alto costo. La espectrometría de masas con desorción/ionización láser asistida por una matriz asociada a tiempo de vuelo (MALDI-TOF MS) se basa en la comparación del espectro proteico producido con respecto al de una base de datos de referencia. Objetivo: Evaluar el rendimiento de MALDI-TOF MS en la identificación de micobacterias comparado con métodos moleculares: Material y Métodos: Se analizaron 28 aislados de nueve especies distintas mediante MALDI-TOF MS. Resultados: Se identificó correctamente 78,5% de las aislados (22/28), concordante en 100% (9/9) de MNTB de crecimiento rápido, 60% (9/15) en las MNTB de crecimiento lento y 100% (4/4) de MTBc. Todas las especies no identificadas (6/6) pertenecen al complejo M. avium/intracellulare. Conclusión: MALDI-TOD MS es una metodología rápida, fácil y de bajo costo, con adecuada veracidad respecto a los métodos moleculares.
  • Thumbnail Image
    Item
    In reply
    (The International Journal of Tuberculosis and Lung Disease, 2016) Balcells Marty, María Elvira
  • No Thumbnail Available
    Item
    Influence of SARS-CoV-2 mRNA Vaccine Booster among Cancer Patients on Active Treatment Previously Immunized with Inactivated versus mRNA Vaccines: A Prospective Cohort Study
    (2023) Mondaca Contreras, Sebastián Patricio; Walbaum, Benjamín; Corre, Nicole Le; Ferrés Garrido, Marcela Viviana; Valdés, Alejandro; Martínez-Valdebenito, Constanza; Ruiz-Tagle, Cinthya; Macanas Pirard, Patricia; Ross, Patricio; Cisternas, Betzabé; Pérez, Patricia; Cabrera, Olivia; Cerda, Valentina; Ormazábal, Ivana; Barrera Vásquez, Aldo Vincen; Prado, María E.; Venegas, María I.; Palma, Silvia; Broekhuizen, Richard; Kalergis, Alexis; Bueno, Susan M.; Espinoza, Manuel A.; Balcells Marty, María Elvira; Nervi Nattero, Bruno
    Cancer patients on chemotherapy have a lower immune response to SARS-CoV-2 vaccines. Therefore, through a prospective cohort study of patients with solid tumors receiving chemotherapy, we aimed to determine the immunogenicity of an mRNA vaccine booster (BNT162b2) among patients previously immunized with an inactivated (CoronaVac) or homologous (BNT162b2) SARS-CoV-2 vaccine. The primary outcome was the proportion of patients with anti-SARS-CoV-2 neutralizing antibody (NAb) seropositivity at 8–12 weeks post-booster. The secondary end points included IgG antibody (TAb) seropositivity and specific T-cell responses. A total of 109 patients were included. Eighty-four (77%) had heterologous vaccine schedules (two doses of CoronaVac followed by the BNT162b2 booster) and twenty-five had (23%) homologous vaccine schedules (three doses of BNT162b2). IgG antibody positivity for the homologous and heterologous regimen were 100% and 96% (p = 0.338), whereas NAb positivity reached 100% and 92% (p = 0.13), respectively. Absolute NAb positivity and Tab levels were associated with the homologous schedule (with a beta coefficient of 0.26 with p = 0.027 and a geometric mean ratio 1.41 with p = 0.044, respectively). Both the homologous and heterologous vaccine regimens elicited a strong humoral and cellular response after the BNT162b2 booster. The homologous regimen was associated with higher NAb positivity and Tab levels after adjusting for relevant covariates.
  • Thumbnail Image
    Item
    Insights into neutralizing antibody responses in individuals exposed to SARS-CoV-2 in Chile
    (2021) Beltrán Pavez, Carolina; Riquelme Barrios, Sebastián; Oyarzún Arrau, Aarón; Gaete Argel, Aracelly; González Stegmaier, Roxana; Cereceda Solis, Karina; Aguirre, Adam; Travisany, Dante; Palma Vejares, Ricardo; Barriga, Gonzalo P.; Gaggero, Aldo; Martínez Valdebenito, Constanza; Le Corre Pérez, Monique Nicole; Ferrés, Marcela; Balcells Marty, María Elvira; Fernández, Jorge; Ramírez, Eugenio; Villarroel, Franz; Valiente Echeverría, Fernando; Soto Rifo, Ricardo
    Chile has one of the worst numbers worldwide in terms of SARS-CoV-2 positive cases and COVID-19-related deaths per million inhabitants; thus, characterization of neutralizing antibody (NAb) responses in the general population is critical to understanding of immunity at the local level. Given our inability to perform massive classical neutralization assays due to the scarce availability of BSL-3 facilities in the country, we developed and fully characterized an HIV-based SARS-CoV-2 pseudotype, which was used in a 96-well plate format to investigate NAb responses in samples from individuals exposed to SARS-CoV-2 or treated with convalescent plasma. We also identified samples with decreased or enhanced neutralization activity against the D614G spike variant compared with the wild type, indicating the relevance of this variant in host immunity. The data presented here represent the first insights into NAb responses in individuals from Chile, serving as a guide for future studies in the country.
  • Thumbnail Image
    Item
    Isoniazid preventive therapy and risk for resistant tuberculosis
    (Centers for Disease Control and Prevention (CDC), 2006) Balcells Marty, María Elvira; Thomas, Sara L.; Godfrey Faussett, Peter; Grant, Allison D.
    In the context of tuberculosis (TB) resurgence, isoniazid preventive therapy (IPT) is increasingly promoted, but concerns about the risk for development of isoniazid-resistant tuberculosis may hinder its widespread implementation. We conducted a systematic review of data published since 1951 to assess the effect of primary IPT on the risk for isoniazid-resistant TB. Different definitions of isoniazid resistance were used, which affected summary effect estimates; we report the most consistent results. When all 13 studies (N = 18,095 persons in isoniazid groups and N = 17,985 persons in control groups) were combined, the summary relative risk for resistance was 1.45 (95% confidence interval 0.85-2.47). Results were similar when studies of HIV-uninfected and HIV-infected persons were considered separately. Analyses were limited by small numbers and incomplete testing of isolates, but findings do not exclude an increased risk for isoniazid-resistant TB after IPT. The diagnosis of active TB should be excluded before IPT. Continued surveillance for isoniazid resistance is essential.