Browsing by Author "García Cañete, Patricia Del Carmen"

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    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.
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    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.
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    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.
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    Perfil clínico y epidemiológico de los casos de tuberculosis atendidos en una red de salud universitaria en Santiago de Chile entre los años 2000-2010
    (2012) Morgado Ahumada, Álvaro Esteban; Köhnenkampf, Ruth; Balcells Marty, María Elvira; Navarrete, Pablo; García Cañete, Patricia Del Carmen
    Background: The incidence and epidemiological profile of tuberculosis (TB) has changed significantly in the recent years in Chile. Aim: To evaluate the clinical and epidemiological characteristics of TB cases diagnosed in the last decade at a university hospital in Santiago. Material and Methods: The Mycobacterium tuberculosis culture registry of the microbiology laboratory was reviewed. Medical records of patients with a positive culture registered between 2000 and 2010 were retrieved and analyzed. Results: Two hundred forty positive Mycobacterium tuberculosis cultures were identified and the medical records of 158 of these patients were accessed for analysis. The median age was 53 years (range: 3 to 89), 55.1% were female and nearly 42% had extra-pulmonary TB. Among known risk factors, 32.9% of patients were older than 65 years, 4.4% were health care workers and 3.9% immigrants. Twenty eight percent (41/145) had some type of immunosuppression at diagnosis: 11.7% HIV infection and 16.6% were using immunosuppressive drugs. In this group, a previous tuberculin skin test was done in only 5 cases (12.2%). Adverse events related to TB treatment were reported in 21.3% of cases (17/80). No cases of fulminant hepatitis or death from this cause were identified. Four of 92 patients that had a complete follow up during treatment, died. Two of these patients were receiving steroids. Conclusions: Almost one third of TB cases occurred among immunosuppressed patients and 42% were extra-pulmonary forms. The prevention of TB reactivation in this group should be strengthened.