Sistema de Gestión del Conocimiento ANLIS MALBRÁN
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Experimental combination therapy using low doses of benznidazole and allopurinol in mouse models of Trypanosoma cruzi chronic infection
No full textThis study evaluated the effectiveness of low doses of benznidazole (BNZ) on continuous administration (BNZc), combined with allopurinol (ALO), in C57BL/6J and C3H/HeN mice infected with Trypanosoma cruzi Nicaragua strain and T. cruzi Sylvio-X10/4 clone. TcN-C57BL/6J was also treated with intermittent doses of BNZ (BNZit). The drug therapy started 3 months post infection (pi) in the chronic phase of mice with heart disease progression, followed-up at 6 months pi. TcN-C57BL/6J treated with BNZc was also monitored up to 12 months pi by serology and electrocardiogram. These mice showed severe electrical abnormalities, which were not observed after BNZc or BNZit. ALO only showed positive interaction with the lowest dose of BNZ. A clear parasitic effect, with significant reductions in antibody titres and parasitic loads, was achieved in all models with low doses of BNZ, and a 25% reduction of the conventional dose showed more efficacy to inhibit the development of the pathology. However, BNZ 75 showed partial efficacy in the TcSylvio-X10/4-C3H/HeN model. In our experimental designs, C57BL/6J allowed to clearly define a chronic phase, and through reproducible efficacy indicators, it can be considered a good preclinical model
Prevalence, antimicrobial resistance profile and comparison of methods for the isolation of salmonella in chicken liver from Argentina
No full textFil: Procura, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Laboratorio de Sanidad Aviar, Instituto Nacional de Tecnología Agropecuaria EEA Concepción del Uruguay, Ruta Provincial 39 Km 143,5, 3260 Concepción del Uruguay, Entre Ríos; Argentina.Fil: Bueno, Dante G. Instituto Nacional de Tecnología Agropecuaria EEA Concepción del Uruguay, Ruta Provincial 39 Km 143,5, 3260 Concepción del Uruguay, Entre Ríos; Argentina.Fil: Bruno, Susana B. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos. Servicio de Antígenos y Antisueros; Argentina.Fil: Rogué, Ariel D. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos. Servicio de Antígenos y Antisueros; Argentina.This study was conducted to estimate the apparent prevalence of Salmonella spp. in chicken livers obtained from markets in Entre Ríos, Argentina, using two culture methods (preenrichment and direct selective agar plating). We also determined the antimicrobial resistance of Salmonella isolated strains and evaluated the performance of the two culture methods and selective-differential plating media used for Salmonella isolation. Of 666 chicken livers studied, 32 organs (4.8%) related to 4 poultry slaughterhouse companies were positive for Salmonella sp. using one or two culture methods. Fifty Salmonella strains were isolated from the positive liver samples and were typed into 3 serovars: S. ser. Schwarzengrund (78%), S. ser. Enteritidis (18%), and S. ser. Typhimurium 4(%). More than one Salmonella serovar was found in livers belonging to two chicken slaughterhouse companies. All strains were susceptible to all antibiotics tested, with the exception of erythromycin (100% resistant) and streptomycin (22% intermediate sensitivity). Overall, 32 (4.80%) and 3 (0.45%) of the chicken liver samples were positive for Salmonella sp. in preenrichment method and direct selective agar plating method, respectively; these percentages were significantly different (P=0.0001; kappa=0.16). There was also a statistical difference in relative accuracy, sensitivity and negative predictive value between the preenrichment method and the direct selective agar plating method; the first had greater values for these parameters than the direct selective agar plating method. These parameters were statistically different between MacConkey agar (MCA) and modified lysine iron (MLIA) in the two culture methods; the second had greater values than MCA for both culture methods. This study shows that even though serovars that are important for public health were isolated, the prevalence of Salmonella sp. is low in chicken livers from Entre Rios, Argentina. The isolated strains do not have multi-resistance patterns. Furthermore, the preenrichment method and MLIA are superior to the direct selective agar plating method and MCA for Salmonella sp. isolation from chicken liver samples, respectively
Global phylodynamics of Echovirus 30 revealed differential behavior among viral lineages
No full textEchovirus 30 (E30) is an important causative agent of aseptic meningitis worldwide. Despite this, the global and regional dispersion patterns, especially in South America, are still largely unknown. We performed an in-depth analysis of global E30 population dynamics, by using the VP1 sequences of 79 strains isolated in Argentina, between 1998 and 2012, and 856 sequences from GenBank. Furthermore, the 3Dpol regions of 329 sequences were analyzed to study potential recombination events. E30 evolution was characterized by co-circulation and continuous replacement of lineages over time, where four lineages appear to circulate at present and another four lineages appear to have stopped circulating. Five lineages showed a global distribution, whereas three other lineages had a more restricted circulation pattern. Strains isolated in South America belong to lineages E and F. Analysis of the 3Dpol region of Argentinean strains indicated that recombination events occurred in both lineages
IgY-based antivenom against Bothrops alternatus: Production and neutralization efficacy
No full textAntivenom for the treatment of bothropic snakebite is a priority for public health institutions from Latin America. An alternative to the conventional antivenom production is based on the use of egg yolk antibodies - IgY-technology - by immunizing laying hens. In this study, we produced, characterized and assessed the efficacy of IgY-based antivenoms against B. alternatus venom. Immunochemical studies (reactivity, avidity and antigen recognition pattern) as well as antivenom efficacy assays were performed. After the 3rd immunization, levels of specific IgY reached a maximum that was maintained throughout the observation period, while avidity indexes of the extracts increased after the successive immunizations. Furthermore, IgY against B. alternatus recognized protein complexes of the venom with high (>40 kDa), medium (20-40 kDa) and low (<20 kDa) molecular weights. IgY antivenoms obtained after 8 immunizations neutralized 35.65 μg of B. alternatus venom per mg of antivenom, while specific activities values ranged from 0.28 to 0.42. In conclusion, we produced and characterized IgY antivenoms capable of neutralizing the lethal activity of B. alternatus venom at a preclinical level. Thus, IgY-technology may allow the production of effective and affordable antivenoms fulfilling the urgent needs of many countries where conventional manufacture is unable to provide enough availability of antivenoms
IgY-based antivenom against Bothrops alternatus: Production and neutralization efficacy
No full textAntivenom for the treatment of bothropic snakebite is a priority for public health institutions from Latin America. An alternative to the conventional antivenom production is based on the use of egg yolk antibodies - IgY-technology - by immunizing laying hens. In this study, we produced, characterized and assessed the efficacy of IgY-based antivenoms against B. alternatus venom. Immunochemical studies (reactivity, avidity and antigen recognition pattern) as well as antivenom efficacy assays were performed. After the 3rd immunization, levels of specific IgY reached a maximum that was maintained throughout the observation period, while avidity indexes of the extracts increased after the successive immunizations. Furthermore, IgY against B. alternatus recognized protein complexes of the venom with high (>40 kDa), medium (20-40 kDa) and low (<20 kDa) molecular weights. IgY antivenoms obtained after 8 immunizations neutralized 35.65 μg of B. alternatus venom per mg of antivenom, while specific activities values ranged from 0.28 to 0.42. In conclusion, we produced and characterized IgY antivenoms capable of neutralizing the lethal activity of B. alternatus venom at a preclinical level. Thus, IgY-technology may allow the production of effective and affordable antivenoms fulfilling the urgent needs of many countries where conventional manufacture is unable to provide enough availability of antivenoms
Detection of Trichinella britovi in pork sausage suspected to be implicated in a human outbreak in Mendoza, Argentina
No full textOf the three Trichinella species described in South America, T. spiralis, T. pseudospiralis and T. patagoniensis, only the former has been implicated in human infections from consumption of pork-derived products. During a presumed trichinellosis outbreak in 2012 in Mendoza, Argentina, we evaluated the serological responses of three patients who had eaten the incriminated food and had signs and symptoms compatible with trichinellosis, using ELISA. We also analyzed potentially contaminated pork sausage by artificial digestion technique and recovered Trichinella muscle larvae, which were identified to the species level using a PCR multiplex assay and by sequencing a region of the mitochondrial gene coding cytochrome oxidase subunit I. No antibodies were detected in the sera of the patients, probably because the samples were collected during the immunological window period. According to molecular identification, all larvae from the sausage corresponded to T. britovi. Trichinella britovi is reported here for the first time in the American Continent, and represents the only cold-tolerant member of the genus in the Neotropics. This species was most likely introduced from Europe to South America during Spanish colonization through pigs, wild boars and/or rats
HIV and Chagas Disease Coinfection, a Tractable Disease?
No full textWe present 2 patients born in Argentina who were newly diagnosed with advanced HIV disease and Chagas disease reactivation with central nervous system involvement. The patients received concurrent benznidazole treatment and antiretroviral therapy, showing good response. Improvement in morbidity and mortality due to early treatment makes this treatment appropriate for coinfected patients
Multiple clones of metallo-β-lactamase-producing Acinetobacter ursingii in a children hospital from Argentina
No full textAcinetobacter spp. are opportunistic pathogens being A. baumannii the most frequently identified in nosocomial settings. A. ursingii was mainly described as causing bacteremia and outbreaks in neonatal intensive care units. Ten A. ursingii isolates were recovered from rectal swab screening for carbapenemase-producing bacteria between June 2013 and December 2015 from a children hospital in Argentina. All ten isolates were metallo-β-lactamase-producing, nine were positive for blaIMP-1 and one for blaNDM-1. IMP-positive isolates were also positive for blaOXA-58 gene. All isolates were susceptible to ciprofloxacin, colistin and minocycline, and nine were susceptible to ampicillin-sulbactam and gentamicin. Two A. ursingii displayed high level of resistance to aztreonam associated with blaCTX-M-15 in one isolate, and blaVEB-1 in the other. Eight SmaI-PFGE patterns were recognized. We evaluated the usefulness of Acinetobacter MLST-Pasteur scheme, to analyse A. ursingii isolates, however the rpoB gene was not amplified. A new set of primers were designed for specific amplification and sequencing, allowing the analysis of rpoB gene for this species. New alleles and the sequence types 748, 749, 750, 751, 993, 1186, 1187, and 1189 were included at the Acinetobacter MLST-Pasteur database. Those isolates showing related PFGE patterns were assigned to the same ST. To the best of our knowledge, this is the first report of MBL-producing A. ursingii in Argentina. The inclusion of A. ursingii species to the Acinetobacter MLST-Pasteur scheme allows deeper molecular characterization and a better understanding about the epidemiology of this germen
Characterization of a multidrug resistant Citrobacter amalonaticus clinical isolate harboring blaNDM-1 and mcr-1.5 genes
No full textFil: Faccone, Diego. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Servicio Antimicrobianos; Argentina.Fil: Albornoz, Ezequiel. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Servicio Antimicrobianos; Argentina.Fil: Tijet, Nathalie. Public Health Ontario Laboratory; Canada.Fil: Biondi, Estefania. Hospital de niños Dr. Ricardo Gutierrez; Argentina.Fil: Gómez, Sonia A. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Servicio Antimicrobianos; Argentina.Fil: Pasteran, Fernando. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Servicio Antimicrobianos; Argentina.Fil: Vázquez, Miryam. Hospital de niños Dr. Ricardo Gutiérrez; Argentina.Fil: Melano, Roberto. Public Health Ontario Laboratory; Canada.Fil: Corso, Alejandra. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Servicio Antimicrobianos; Argentina.A multidrug resistant isolate, identified as Citrobacter amalonaticus using MALDI-TOF MS and confirmed by genomic analysis, was recovered from a pediatric patient in a hospital from Buenos Aires, Argentina. By whole-genome sequencing a total of 16 resistance genes were detected, including blaNDM-1 and mcr-1.5. To the best of our knowledge this is the first description of these two genes together in a clinical isolate of the Citrobacter genus