Browsing by Author "Silva, Francisco"
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Item A 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; Spencer, María; Martínez, Rodrigo; lam, Marusella; Rojas, Pamela; Porte, Lorena; Silva, Francisco; Braun, Estefanía; Valdivieso, Francisca; Lhauser, Margareta; Lafourcade, Mónica; Miller, Guillermo; García, Patricia; Arias, César; Munita, JoséCeftaroline (CPT) is a broad-spectrum agent with potent activity against methicillin-resistant Staphylococcus aureus (MRSA). The sequence type 5 (ST5) Chilean-Cordobés clone, associated with CPT nonsusceptibility, is dominant in Chile, a region with high rates of MRSA infections. Here, we assessed the in vitro activity of CPT against a collection of MRSA isolates collected between 1999 and 2018 from nine hospitals (n = 320) and community settings (n = 41) in Santiago, Chile, and evaluated performance across testing methodologies. We found that our hospital-associated isolates exhibited higher CPT MIC distributions (MIC50 and MIC90 of 2 mg/liter) than the community isolates (MIC50 and MIC90 of 0.5 mg/liter), a finding that was consistent across time and independent of the culture source. High proportions (64%) of isolates were CPT nonsusceptible despite the absence of CPT use in Chile. Across methodologies, the Etest underestimated the MIC relative to the gold standard broth microdilution (BMD) test (MIC50 and MIC90 of 1 and 1.5 mg/liter, respectively). There was low (∼51%) categorical agreement (CA) between Etest and BMD results across CLSI and EUCAST breakpoints. The recent revision of CLSI guidelines abolished "very major error" (VME) from the previous guidelines (81%), which perform similarly to the EUCAST guidelines. The level of concordance between CLSI and EUCAST for BMD testing and Etest was >95%. Disk diffusion performed poorly relative to BMD under CLSI (CA, 55%) and EUCAST (CA, 36%) guidelines. Comparison of EUCAST to CLSI for disk diffusion (with EUCAST used as the reference) showed low agreement (CA, 25%; VME, 70%). In summary, CPT-nonsusceptible MRSA are dominant in clinical settings in Chile. Our results provide data to support the reevaluation of CPT breakpoints and to improve agreement across methodologies and agencies.Item Clinical Utility of Serial Measurements of Antineutrophil Cytoplasmic Antibodies Targeting Proteinase 3 in ANCA-Associated Vasculitis(2020) Thompson, Gwen E; Fussner, Lynn A; Hummel, Amber M; Schroeder, Darrell R; Silva, Francisco; Snyder, Melissa R; Langford, Carol A; Merkel, Peter A; Monach, Paul A; Seo, Philip; Spiera, Robert F; St Clair, E William; Stone, John H; Specks, UlrichBackground: The utility of ANCA testing as an indicator of disease activity in ANCA-associated vasculitis (AAV) remains controversial. This study aimed to determine the association of ANCA testing by various methods and subsequent remission and examine the utility of a widely used automated addressable laser-bead immunoassay (ALBIA) to predict disease relapses. Methods: Data from the Rituximab vs. Cyclophosphamide for ANCA-Associated Vasculitis (RAVE) trial were used. ANCA testing was performed by direct ELISA, capture ELISA, and ALBIA. Cox proportional hazards regression models were used to evaluate the association of PR3-ANCA level and subsequent remission or relapse. The ALBIA results are routinely reported as >8 when the value is high. For this study, samples were further titrated. A decrease and increase in PR3-ANCA were defined as a halving or doubling in value, respectively. Results: A decrease in ANCA by ALBIA at 2 months was associated with shorter time to sustained remission (HR 4.52, p = 0.035). A decrease in ANCA by direct ELISA at 4 months was associated with decreased time to sustained remission (HR 1.77, p = 0.050). There were no other associations between ANCA decreases or negativity and time to remission. An increase in PR3-ANCA by ALBIA was found in 78 of 93 subjects (84%). Eleven (14%) had a PR3-ANCA value which required titration for detection of an increase. An increase of ANCA by ALBIA was associated with severe relapse across various subgroups. Conclusions: A decrease in ANCA by ALBIA at 2 months and by direct ELISA at 4 months may be predictive of subsequent remission. These results should be confirmed in a separate cohort with similarly protocolized sample and clinical data collection. A routinely used automated ALBIA for PR3-ANCA measurement is comparable to direct ELISA in predicting relapse in PR3-AAV. Without titration, 14% of the increases detected by ALBIA would have been missed. Titration is recommended when this assay is used for disease monitoring. The association of an increase in PR3-ANCA with the risk of subsequent relapse remains complex and is affected by disease phenotype and remission induction agent.Publication Creación del primer biorrepositorio nacional de bacterias multirresistentes disponible para el estudio de la resistencia bacteriana en Chile(2022) García, Patricia; Rivas Jiménez, Lina María; Peters, Anne Sophie; Henríquez, Paola; Castillo, Loriana; Illesca, Vijna; Maripani, Andrea; Moreno, Juan; Mühlhause, Margareta; Porte, Lorena; Rioseco, María Luisa; Rojas, Pamela; Silva, Francisco; Suazo, Patricio; Munita, Jose M.La disponibilidad de cepas bacteriana para el estudio de la resis tencia bacteriana es clave para los avances en la investigación básica y clínica respecto del tema. Existen pocos biorrepositorios o bancos de bacterias con mecanismos de resistencia conocidos, aisladas de infecciones clínicamente significativas. Una revisión de la literatura revela que sólo en los Estados Unidos de América existe un biobanco de aislados resistentes disponibles para estudios. En esta publicación se cuenta cómo se creó el primer biorrepositorio de bacterias resistentes en Chile asociados a la Red de Laboratorios MICROB-R, con la participación de 11 centros distribuidos a lo largo del país, que a la fecha cuenta con más de 3.500 aislados bacterianos estudiados fenotípica y genotípicamente, disponibles para la comunidad científica chilenaPublication Enfermedad relacionada a IgG4. Serie clínica de pacientes chilenos(2022) Cuéllar, María C.; Gutiérrez, Miguel; Herrera, Alejandra; Elgueta, Fabián; Wurmann, Pamela; Badilla, Natalia; Mansilla, Bellanides; Basualdo, Javier; Vega, Jorge; Erlij, Daniel; Labarca, Cristian; Vergara, Cristian; Mezzano, Verónica; Méndez, Ignacio; Stange, Lilith; Michalland, Susana; Silva, Francisco; Jara, Aquiles; Goecke, Annelise; Burgos, Paula; Iruretagoyena, Mirentxu; Fernández, Cristina; Landeros, Carolina; Neira Quiroga, OscarBackground: IgG4-related disease (IgG4 RD) is an immune-mediated fibro-inflammatory disorder, with tissue infiltration of IgG4+ plasma cells. It causes pseudotumors, tumors, and a wide spectrum of clinical manifestations. Aim: To report the clinical, laboratory, histopathological and treatment characteristics of a group of Chilean patients with IgG4 RD. Material and Methods: Review of medical records of 52 patients aged 18 to 76 years with IgG4 RD seen at six medical centers. Results: Elevated IgG4 serum levels (> 135 mg/dl) were found in 18 of 44 (41%) patients. There was histological confirmation of the disease in 46 patients. The most common sites of involvement were lungs, eyes and kidneys. Eighteen (35%) patients had only one organ involved, 34 (65%) patients had two organs and 13 (25%) patients had three or more organs. The involvement of two organs was significantly more common in men (p < 0.05). In patients with only one organ involvement, the most frequent location was orbital and meningeal. All patients with kidney or lung disease had multiorgan involvement. All patients received corticosteroid therapy, 67% synthetic immunosuppressants, and 16% rituximab. Conclusions: ER-IgG4 can affect any tissue. Multiorgan involvement was more common in this series, with preference for lungs, eyes and kidneys. An excellent response to steroids is characteristic of the disease, but with a high relapse rate that requires additional immunosuppression.Item Factors determining the clinical utility of serial measurements of antineutrophil cytoplasmic antibodies targeting proteinase 3(Wiley, 2017) Fussner, Lynn A.; Hummel, Amber M.; Schroeder, Darrell R.; Silva, Francisco; Cartin-Ceba, Rodrigo; Snyder, Melissa; Hoffman, Gary S.; Kallenberg, Cees G. M.; Langford, Carol A.; Merkel, Peter A.; Monach, Paul A.; Seo, Philip; Spiera, Robert F.; St.Clair, E. William; Tchao, Nadia K.; Stone, John H.; Specks, UlrichOBJECTIVE: Relapse following remission is common in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), particularly with ANCAs directed at proteinase 3 (PR3). This study was undertaken to evaluate the association of an increase in PR3-ANCA level with subsequent relapse. METHODS: Data from the Rituximab versus Cyclophosphamide for ANCA-Associated Vasculitis (RAVE) trial were used. Starting from the time of achieving complete remission, serial measurements by direct and capture enzyme-linked immunosorbent assays (ELISAs) were analyzed in 93 patients with PR3-ANCA, using Cox proportional hazards regression. RESULTS: An increase in PR3-ANCA level was identified in 58 of 93 subjects (62.4%) by direct ELISA and in 59 of 93 (63.4%) by capture ELISA. Relapses occurred in 55 of 93 subjects (59.1%), with 25 and 21 occurring within 1 year after an increase by direct ELISA and capture ELISA, respectively. An increase by direct ELISA was associated with subsequent severe relapses (hazard ratio [HR] 4.57; P < 0.001), particularly in patients presenting with renal involvement (HR 7.94; P < 0.001) and alveolar hemorrhage (HR 24.19; P < 0.001). Both assays identified increased risk for severe relapse in the rituximab group (HR 5.80; P = 0.002 for direct ELISA and HR 4.54; P = 0.007 for capture ELISA) but not the cyclophosphamide/azathioprine group (P = 0.103 and P = 0.197, respectively). CONCLUSION: The association of an increase in PR3-ANCA level with the risk of subsequent relapse is partially affected by the PR3-ANCA detection methodology, disease phenotype, and remission induction treatment. An increase in PR3-ANCA level during complete remission conveys an increased risk of relapse, particularly severe relapse, among patients with renal involvement or alveolar hemorrhage and those treated with rituximab. Serial measurements of PR3-ANCA may be informative in this subset of patients, but the risk of relapse must be weighed carefully against the risks associated with therapy.Item Hydroxychloroquine and chloroquine in COVID-19: should they be used as standard therapy?(2020) Ibáñez, Sebastián; Martínez, Oriela; Valenzuela, Francisca; Silva, Francisco; Valenzuela, OmarThe pandemic of the new coronavirus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has urged the nations to an unprecedented world-wide reaction, including an accelerated exploration of therapeutic options. In the absence of a vaccine and specifically designed antivirals, the medical community has proposed the use of various previously available medications in order to reduce the number of patients requiring prolonged hospitalizations, oxygen therapy, and mechanical ventilation and to decrease mortality from coronavirus disease 2019 (COVID-19). Hydroxychloroquine and chloroquine are among the proposed drugs and are the most widely used so far, despite the lack of robust evidence on their usefulness. The objective of this article is to review and discuss the possible role of these drugs in the therapy of COVID-19.Publication Trends and socioeconomic, demographic, and environmental factors associated with antimicrobial resistance: a longitudinal analysis in 39 hospitals in Chile 2008-2017(2023) Allel , Kasim; Labarca, Jaime; Carvajal, Camila; Garcia, Patricia; Cifuentes, Marcela; Silva, Francisco; Munita, Jose M.; Undurraga, EduardoBackground: Antimicrobial resistance (AMR) is among the most critical global health threats of the 21st century. AMR is primarily driven by the use and misuse of antibiotics but can be affected by socioeconomic and environmental factors. Reliable and comparable estimates of AMR over time are essential to making public health decisions, defining research priorities, and evaluating interventions. However, estimates for developing regions are scant. We describe the evolution of AMR for critical priority antibiotic-bacterium pairs in Chile and examine their association with hospital and community-level characteristics using multivariate rate-adjusted regressions. Methods: Drawing on multiple data sources, we assembled a longitudinal national dataset to analyse AMR levels for critical priority antibiotic-bacterium combinations in 39 private and public hospitals (2008-2017) throughout the country and characterize the population at the municipality level. We first described trends of AMR in Chile. Second, we used multivariate regressions to examine the association of AMR with hospital characteristics and community-level socioeconomic, demographic, and environmental factors. Last, we estimated the expected distribution of AMR by region in Chile. Findings: Our results show that AMR for priority antibiotic-bacterium pairs steadily increased between 2008 and 2017 in Chile, driven primarily by Klebsiella pneumoniae resistant to third-generation cephalosporins and carbapenems, and vancomycin-resistant Enterococcus faecium. Higher hospital complexity, a proxy for antibiotic use, and poorer local community infrastructure were significantly associated with greater AMR. Interpretation: Consistent with research in other countries in the region, our results show a worrisome increase in clinically relevant AMR in Chile and suggest that hospital complexity and living conditions in the community may affect the emergence and spread of AMR. Our results highlight the importance of understanding AMR in hospitals and their interaction with the community and the environment to curtail this ongoing public health crisis. Funding: This research was supported by the Agencia Nacional de Investigación y Desarrollo (ANID), Fondo Nacional de Desarrollo Científico y Tecnológico FONDECYT, The Canadian Institute for Advanced Research (CIFAR), and Centro UC de Políticas Públicas, Pontificia Universidad Católica de Chile.