Sistema de Gestión del Conocimiento ANLIS MALBRÁN
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Influence of different storage conditions on the performance of spray-dried yogurt used as inoculum for milk fermentation
Get PDFFil: Bater, Caterina. Pontificia Universidad Católica Argentina. Facultad de Ingeniería y Ciencias Agrarias, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Santos, Mauricio. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas.Fil: Galmarini, Mara V. Pontificia Universidad Católica Argentina. Facultad de Ingeniería y Ciencias Agrarias, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Gómez-Zavaglia, Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Chirife, Jorge. Pontificia Universidad Católica Argentina. Facultad de Ingeniería y Ciencias Agrarias, Ciudad Autónoma de Buenos Aires; Argentina.A commercial drinkable yogurt with and without 4% of added trehalose (as cell protectant) was spray-dried obtaining a powder with low water activity (aw). Total bacterial count in the powder was between 8.48-8.90 log cfu/g. The dried yogurt was stored: (i) at 38 °C and aw = 0.33; (ii) at 38 °C in hermetically sealed flasks (aw = 0.21/0.22); (iii) in a cyclic temperature chamber (10-20 °C) in hermetically sealed flasks (aw = 0.21/0.22). Whole milk was then fermented by adding an inoculum of spray-dried yogurt after storage under these different conditions. The kinetics of acidification showed the presence of a lag time which was strongly dependent on storage conditions. The data was fitted with a logistic type equation from which the lag time was calculated. To evaluate structural differences among samples, Fourier Transform Infrared spectra (FTIR) were recorded. Partial Least Squares (PLS) models enabled a good correlation between lag time of fermentation and FTIR spectra. The lag time for yogurt powder stored at aw about 0.21/0.22 and cyclic temperature 10-20 °C remained approximately constant over the 12 weeks of storage, while all the other conditions resulted in a dramatic increase. The addition of trehalose had a small influence on lag time and, therefore, as a protectant of lactobacilli
First case report of cryptococcosis due to Cryptococcus decagattii in a pediatric patient in Argentina
No full textFil: Berejnoi, Ana. Hospital Público Materno Infantil; Argentina.Fil: Taverna, Constanza Giselle. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Micología; Argentina.Fil: Mazza, Mariana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Micología; Argentina.Fil: Vivot, Matías. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Micología; Argentina.Fil: Isla, Guillermina. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Micología; Argentina.Fil: Córdoba, Susana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Micología; Argentina.Fil: Davel, Graciela. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Micología; Argentina.We report the first case of cryptococcosis due to Cryptococcus decagattii in an immunocompetent pediatric patient from an indigenous community in Argentina with a successful outcome. Two isolates (blood, cerebrospinal fluid) were genotyped by restriction fragment length polymorphism of the orotidine monophosphate pyrophosphorylase (URA5) gene as VGIV and identified by multi-locus sequence typing as C. decagattii. Matrix-assisted laser desorption/ionization time of flight mass spectrometry identification indicated genotype VGIII. The minimum inhibitory concentration of amphotericin B, fluconazole, itraconazole, and voriconazole was determined (cerebrospinal fluid: 0.25, 16, 0.12, and 0.12, blood: 0.25, 4, 0.12, and 0.06, respectively, all in mg/L)
Timing of respiratory syncytial virus and influenza epidemic activity in five regions of Argentina, 2007-2016
Get PDFFil: Baumeister, Elsa. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratoria; Argentina.Fil: Duque, Jazmin. Influenza Division, National Center for Immunization and Respiratory Diseases, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia; Estados Unidos.Fil: Varela, Teresa. Sistema Nacional de Vigilancia por Laboratorio, Sistema Nacional de Vigilancia de la Salud, Ministerio de Salud de la Nación, Buenos Aires; Argentina.Fil: Palekar, Rakhee. Influenza Division, National Center for Immunization and Respiratory Diseases, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia; Estados Unidos.Fil: Couto, Paula. Pan American Health Organization, Washington, District of Columbia; Estados Unidos.Fil: Savy, Vilma L. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratoria; Argentina.Fil: Giovacchini, Carlos. Pan American Health Organization, Washington, District of Columbia; Estados Unidos.Fil: Haynes, Amber K. Division of Viral Diseases, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia; Estados Unidos.Fil: Rha, Brian. Division of Viral Diseases, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia; Estados Unidos.Fil: Arriola, Carmen S. Influenza Division, National Center for Immunization and Respiratory Diseases, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia; Estados Unidos.Fil: Gerber, Susan I. Division of Viral Diseases, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia; Estados Unidos.Fil: Azziz-Baumgartner, Eduardo. Influenza Division, National Center for Immunization and Respiratory Diseases, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia; Estados Unidos.Within-country differences in the timing of RSV and influenza epidemics have not been assessed in Argentina, the eighth largest country in the world by area
Vector competence of Aedes aegypti for different strains of Zika virus in Argentina
Get PDFFil: Bonica, Melisa Berenice. Centro de Estudios Parasitológicos y de Vectores (CEPAVE-CONICET), Universidad Nacional de La Plata, La Plata, Buenos Aires; Argentina.Fil: Goenaga, Silvina. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Martin, María Laura. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Feroci, Mariel. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Luppo, Victoria. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Muttis, Evangelina. Centro de Estudios Parasitológicos y de Vectores (CEPAVE-CONICET), Universidad Nacional de La Plata, La Plata, Buenos Aires; Argentina.Fil: Fabbri, Cintia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Morales, María Alejandra. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Enria, Delia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Micieli, María Victoria. Centro de Estudios Parasitológicos y de Vectores (CEPAVE-CONICET), Universidad Nacional de La Plata, La Plata, Buenos Aires; Argentina.Fil: Levis, Silvana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.The importance of Zika virus (ZIKV) has increased noticeably since the outbreak in the Americas in 2015, when the illness was associated with congenital disorders. Although there is evidence of sexual transmission of the virus, the mosquito Aedes aegypti is believed to be the main vector for transmission to humans. This species of mosquito has not only been found naturally infected with ZIKV, but also has been the subject of study in many vector competence assays that employ different strains of ZIKV around the world. In Argentina, the first case was reported in February 2016 and a total of 278 autochthonous cases have since been confirmed, however, ZIKV virus has not been isolated from any mosquito species yet in Argentina. In order to elucidate if Argentinian Ae. aegypti populations could be a possible vector of ZIKV, we conducted vector competence studies that involved a local strain of ZIKV from Chaco province, and a Venezuelan strain obtained from an imported case. For this purpose, Ae. aegypti adults from the temperate area of Argentina (Buenos Aires province) were fed with infected blood. Body, legs and saliva were harvested and tested by plaque titration on plates of Vero cells for ZIKV at 7, 11 and 14 days post infection (DPI) in order to calculate infection, transmission, and dissemination rates, respectively. Both strains were able to infect mosquitoes at all DPIs, whereas dissemination and transmission were observed at all DPIs for the Argentinian strain but only at 14 DPI for the Venezuelan strain. This study proves the ability of Ae. aegypti mosquitoes from Argentina to become infected with two different strains of ZIKV, both belonging to the Asian lineage, and that the virus can disseminate to the legs and salivary glands
Development and validation of an extended database for yeast identification by MALDI-TOF MS in Argentina
No full textMatrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has revolutionized the identification of microorganisms in clinical laboratories because it is rapid, relatively simple to use, accurate, and can be used for a wide number of microorganisms. Several studies have demonstrated the utility of this technique in the identification of yeasts; however, its performance is usually improved by the extension of the database. Here we developed an in-house database of 143 strains belonging to 42 yeast species in the MALDI Biotyper platform, and we validated the extended database with 388 regional strains and 15 reference strains belonging to 55 yeast species. We also performed an intra- and interlaboratory study to assess reproducibility and analyzed the use of the cutoff values of 1.700 and 2.000 to correctly identify at species level. The creation of an in-house database that extended the manufacturer's database was successful in view of no incorrect identification was introduced. The best performance was observed by using the extended database and a cutoff value of 1.700 with a sensitivity of .94 and specificity of .96. A reproducibility study showed utility to detect deviations and could be used for external quality control. The extended database was able to differentiate closely related species and it has potential in distinguishing the molecular genotypes of Cryptococcus neoformans and Cryptococcus gattii
Utility of platforms Viteks MS and Microflex LT for the identification of complex clinical isolates that require molecular methods for their taxonomic classification
No full textFil: Rocca, María Florencia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Fil: Barrios, Rubén. Laboratorio de Bacteriología, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Zintgraff, Jonathan. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Clínica; Argentina.Fil: Martínez, Claudia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Fil: Irazu, Lucía. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Vay, Carlos. Instituto de Fisiopatología y Bioquímica Clínica, Hospital de Clínicas José de San Martín, Facultad de Farmacia y Bioquímica, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Prieto, Mónica A. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Mass spectrometry has revolutionized the clinical microbiology field in America's and Europe's industrialized countries, for being a fast, reliable and inexpensive technique. Our study is based on the comparison of the performance of two commercial platforms, Microflex LT (Bruker Daltonics, Bremen, Germany) and Vitek MS (bioMérieux, Marcy l´Etoile, France) for the identification of unusual and hard-to-diagnose microorganisms in a Reference Laboratory in Argentina. During a four-month period (February-May 2018) the diagnostic efficiency and the concordance between both systems were assessed, and the results were compared with the polyphasic taxonomic identification of all isolates. The study included 265 isolates: 77 Gram-Negative Bacilli, 33 Gram-Positive Cocci, 40 Anaerobes, 35 Actinomycetales, 19 Fastidious Microorganisms and 61 Gram-Positive Bacilli. All procedures were practiced according to the manufacturer's recommendations in each case by duplicate, and strictly in parallel. Other relevant factors, such as the utility of the recommended extraction protocols, reagent stability and connectivity were also evaluated. Both systems correctly identified the majority of the isolates to species and complex level (82%, 217/265). Vitex MS achieved a higher number of correct species-level identifications between the gram-positive microorganisms; however, it presented greater difficulty in the identification of non-fermenting bacilli and a higher number of incorrect identifications when the profile of the microorganism was not represented in the commercial database. Both platforms showed an excellent performance on the identification of anaerobic bacteria and fastidious species. Both systems enabled the fast and reliable identification of most of the tested isolates and were shown to be very practical for the user
Determination of Benznidazole in Human Dried Blood Spots by Liquid Chromatography-Mass Spectrometry to Monitor Adherence to Trypanosoma cruzi Infection Treatment in Infants and Children
No full textMedication adherence is critical to the effectiveness of benznidazole (BZ) therapy for the treatment of Chagas disease. Assessing BZ adherence using traditional plasma sampling methods presents numerous challenges in resource-limited settings. Dried blood spot (DBS) sampling of BZ can be used to overcome logistical barriers and provides a less invasive method for assessing BZ levels. A BZ DBS assay using liquid chromatography-tandem mass spectrometry was developed and applied to a clinical study of infants and children being treated with BZ for Trypanosoma cruzi infection in Argentina. The assay was validated over a concentration range of 9.8-5,000 ng/mL. Inter-assay and intra-assay measures ranged from -2.9% to 2.7% and 0.5% to 8.3% for accuracy and from 3.5% to 12% and 1.6% to 13.6% for precision, respectively. The mean recovery of BZ was greater than 91%. Partitioning ratios for DBSs/plasma ranged from 0.95 to 1.02. A cohort of 10 infants and six children with T. cruzi infection being treated with BZ had median BZ concentrations of 1.2 (IQR 0.29, 2.14) µg/mL with seven of 65 (11%) samples above the BZ treatment goal of 3 μg/mL for adults. The reported DBS assay is a simple and accurate method for the quantitative measurement of BZ that can be applied to facilitate urgently needed clinical studies of BZ for the treatment of Chagas disease and assess BZ adherence in resource-limited settings
Assessing cross-reactivity of Junín virus-directed neutralizing antibodies
No full textFil: Leske, Anne. Friedrich Loeffler Institute. Junior Research Group Arenavirus Biology; Alemania.Fil: Waßmann, Irke. Friedrich Loeffler Institute. Junior Research Group Arenavirus Biology; Alemania.Fil: Schnepel, Kevin. Friedrich Loeffler Institute. Junior Research Group Arenavirus Biology; Alemania.Fil: Shifflett, Kyle. National Institutes of Health. National Institute of Allergy and Infectious Diseases. Division of Intramural Research. Laboratory of Virology; Estados Unidos.Fil: Holzerland, Julia. Friedrich Loeffler Institute. Junior Research Group Arenavirus Biology; Alemania.Fil: Bostedt, Linus. Friedrich Loeffler Institute. Junior Research Group Arenavirus Biology; Alemania.Fil: Bohn, Patrick. Friedrich Loeffler Institute. Junior Research Group Arenavirus Biology; Alemania.Fil: Mettenleiter, Thomas C. Friedrich Loeffler Institute. Institute of Molecular Virology and Cell Biology; Alemania.Fil: Briggiler, Ana M. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Brignone, Julia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Enria, Delia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Virales Humanas; Argentina.Fil: Cordo, Sandra M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Bioquímica. Laboratorio de Virología; Argentina.Fil: Hoenen, Thomas. National Institutes of Health. National Institute of Allergy and Infectious Diseases. Division of Intramural Research. Laboratory of Virology; Estados Unidos.Fil: Groseth, Allison. Friedrich Loeffler Institute. Junior Research Group Arenavirus Biology; Alemania.Arenaviruses cause several viral hemorrhagic fevers endemic to Africa and South America. The respective causative agents are classified as biosafety level (BSL) 4 pathogens. Unlike for most other BSL4 agents, for the New World arenavirus Junín virus (JUNV) both a highly effective vaccination (Candid#1) and a post-exposure treatment, based on convalescent plasma transfer, are available. In particular, neutralizing antibodies (nAbs) represent a key protective determinant in JUNV infection, which is supported by the correlation between successful passive antibody therapy and the levels of nAbs administered. Unfortunately, comparable resources for the management of other closely related arenavirus infections are not available. Given the significant challenges inherent in studying BSL4 pathogens, our goal was to first assess the suitability of a JUNV transcription and replication-competent virus-like particle (trVLP) system for measuring virus neutralization under BSL1/2 conditions. Indeed, we could show that infection with JUNV trVLPs is glycoprotein (GP) dependent, that trVLP input has a direct correlation to reporter readout, and that these trVLPs can be neutralized by human serum with kinetics similar to those obtained using authentic virus. These properties make trVLPs suitable for use as a proxy for virus in neutralization assays. Using this platform we then evaluated the potential of JUNV nAbs to cross-neutralize entry mediated by GPs from other arenaviruses using JUNV (strain Romero)-based trVLPs bearing GPs either from other JUNV strains, other closely related New World arenaviruses (e.g. Tacaribe, Machupo, Sabiá), or the distantly related Lassa virus. While nAbs against the JUNV vaccine strain are also active against a range of other JUNV strains, they appear to have little or no capacity to neutralize other arenavirus species, suggesting that therapy with whole plasma directed against another species is unlikely to be successful and that the targeted development of cross-specific monoclonal antibody-based resources is likely needed. Such efforts will be supported by the availability of this BSL1/2 screening platform which provides a rapid and easy means to characterize the potency and reactivity of anti-arenavirus neutralizing antibodies against a range of arenavirus species
Stable force control and contact transition of a single link flexible robot using a fractional-order controller
No full textThe control of robots that interact with the environment is an open area of research. Two applications that benefit from this study are: the control of the force exerted by a robot on an object, which allows the robot to perform complex tasks like assembly operations, and the control of collisions, which allows the robot safely collaborate with humans. Robot control is difficult in these cases because: (1) bouncing between free and constrained motion appears that may cause instability, (2) switching between free motion (position) controller and constrained motion (force) controller is required being the switching instants difficult to know and (3) robot control must be robust since the mechanical impedance of the environment is unknown. Robots with flexible links may alleviate these drawbacks. Previous research on flexible robots proved stability of a PD controller that fed back the motor position when contacting an unknown environment, but force control was not achieved. This paper proposes a control system that combines a fractional-order D tip position controller with a feedforward force control. It attains higher stability robustness and higher phase margin than a PD controller, which is the integer-order controller of similar complexity. This controller outperforms previous controllers: (1) it achieves force control with nearly zero steady state error, (2) this control is robust to uncertainties in the environment and motor friction, (3) it guarantees stability (like others) but it also guarantees a higher value of the phase margin, i.e., a higher damping, and a more efficient vibration cancellation, and (4) it effectively removes bouncing. Experimental results prove the effectiveness of this new controller