Abstract I. paraguariensis St. Hil. is a south American species of agronomic interest with studies supporting its medicinal properties. As the investigation of active ingredients with antimicrobial effect from medicinal plants is a suitable approach to the current antibacterial resistance problem, the aim of the present study was to determine the antibacterial activity of yerba mate ethanolic extracts against carbapenemase-producing gram-negative bacteria (reference strains and clinical isolates). Extracts showed antibacterial activity against Klebsiella pneumoniae ATCC® BAA-2342™ (KPC producing), Providencia rettgeri (NDM producing), Pseudomonas aeruginosa (MBL producing) and P. aeruginosa (VIM producing) at the concentrations tested. The Minimal-Inhibitory-Concentration and Minimal-Bactericidal-Concentration values ranged between 1 and 32 mg.ml-1 for the reference strains, and between 0.125 and 1 mg.ml-1 for the clinical isolates. The MBC/MIC index characterized the extracts as bactericidal. The combinations of commercial antibiotics and extracts showed a synergistic action on the reference strains studied. The lethal concentration 50 obtained using the Artemia salina toxicity assay were higher than 1 mg.ml-1 for all the extracts, indicating a low toxicity. The in vitro activity and low toxicity suggest that ethanolic I. paraguariensis leaf extracts constitute an outstanding source for new antibacterial compounds, and further studies should be carried out to understand their mechanism of action. I St Hil properties problem carbapenemaseproducing carbapenemase producing gramnegative gram negative isolates . isolates) ATCC BAA2342™ BAA2342 BAA 2342™ 2342 BAA-2342 KPC producing, , NDM MBL P VIM tested MinimalInhibitoryConcentration Minimal Inhibitory Concentration MinimalBactericidalConcentration Bactericidal 3 mg.ml1 mgml1 mgml mg.ml mg ml mg.ml- 0125 0 125 0.12 MBCMIC MBC MIC bactericidal studied 5 compounds BAA234 234 BAA-234 ml1 012 12 0.1 BAA23 23 BAA-23 01 0. BAA2 2 BAA-2 BAA-

RESUMEN El filtrado de secuencias es un paso esencial sin importar el tipo de tecnología aplicada para la secuenciación de un genoma, en el cual las lecturas de baja calidad o una parte son eliminadas. En un ensamblado la construcción de un genoma se realiza a partir de la unión de lecturas cortas en cóntigos. Algunos ensambladores miden la relación que existe entre secuencias de una longitud fija (k-mer) que puede verse afectada por la presencia de secuencias de baja calidad. Un enfoque común para evaluar los ensamblados se basa en el análisis del número de cóntigos, la longitud del cóntigo más largo y el valor del N50, definido como la longitud del cóntigo que representa el 50 % de la longitud del conjunto. En este contexto, el presente estudio tuvo como objetivo evaluar el efecto del uso de lecturas crudas y filtradas en los valores de los parámetros de calidad obtenidos en el ensamblado del genoma de Bacillus altitudinis 19RS3 aislada de Ilex paraguariensis. Se realizó el análisis de calidad de ambos archivos de partida con el software FastqC y se filtraron las lecturas con el softwareTrimmomatic. Para el ensamblado se utilizó el software SPAdes y para su evaluación la herramienta QUAST. El mejor ensamblado para B. altitudinis 19RS3 se obtuvo a partir de las lecturas filtradas con el valor de k-mer 79, que generó 16 cóntigos mayores a 500 pb con un N50 de 931 914 pb y el cóntigo más largo de 966 271 pb.

ABSTRACT Sequence filtering is an essential step regardless of the type of technology applied for sequencing a genome, in which low-quality readings or a portion are eliminated. In an assembly, the construction of a genome is carried out from the union of short reads in contigs. Some assemblers measure the relationship between sequences of a fixed length (k-mer) that can be affected by the presence of low-quality sequences. A common approach to evaluating assemblies is based on the analysis of the number of contigs, the length of the longest contig, and the value of N50 defined as the length of the contig representing 50 % of the length of the assembly. In this context, the objective of this study was to evaluate the effect of the use of crude and filtered reads on the values of the quality parameters obtained from the genome assembly of Bacillus altituidinis 19RS3 isolated from Ilex paraguariensis. The quality analysis of both starting files was performed with the FastqC software and the readings were filtered with the Trimmomatic software. The SPAdes software was used for the assembly and the QUAST tool for its evaluation. The best assembly for B. altitudinis 19RS3 was obtained from the filtered readings with the value of k-mer 79, which generated 16 contigs greater than 500 bp with a N50 of 931 914 bp and the longest contig of 966 271 bp.

Introduction: Although Streptococcus agalactiae is commensal of the gastrointestinal and genitourinary tract, it is the main cause of invasive diseases and mortality in newborns. The infection can be acquired through the aspiration of infected amniotic fluid or during the passage through the birth canal. Objectives: to compare the effectiveness of various methods for the conservation of Streptococcus agalactiae strains that can be reproducible and accessible to laboratories of low and medium complexity and guarantee their phenotypic and genotypic stability through a preservation method called continuous subculture, for the maintenance of the culture in an adequate environment with fresh medium transfers at variable interval periods. Methods: 40 strains of Streptococcus agalactiae were randomly selected, which were subjected to verification of viability, purity and genotypic and phenotypic characterization before and after being subjected to conservation, using identical environments, reactive and methodologies in both circumstances. Different means of preservation of strains were tested, which allowed laboratories of low and medium complexity their transfer to specialized centers for the proper surveillance of the organism. The strains were kept for nine months with subcultures that showed original characteristics. Results: The most effective environments were ATS-TA and LD-4 % -SO-20 ºC because they guaranteed viability, purity and genotypic and phenotypic stability of the strains. It was shown that the use of this environment is an adequate alternative for the conservation of Streptococcus agalactiae in laboratories where lyophilization and dessication are not available and are low cost, fast and very easy to use in regular practice. Conclusions: The ATS-TA and LD-4 % -SO-20 ºC environments are a good alternative for short periods of preservation and transportation of Streptococcus agalactiae strains in laboratories of low and medium complexity.

Introducción: Si bien Streptococcus agalactiae es comensal del tracto gastrointestinal y genitourinario, es la principal causa de enfermedades invasivas y de mortalidad en niños recién nacidos. La infección puede adquirirse a través de la aspiración de líquido amniótico infectado o durante el paso por el canal de parto. Objetivos: comparar la utilidad de diversos métodos de conservación de cepas de Streptococcus agalactiae que resulten reproducibles, accesibles a laboratorios de baja y mediana complejidad, y asegurar su estabilidad fenotípica y genotípica mediante el método de preservación llamado subcultivo continuo, para el mantenimiento del cultivo en medio adecuado con transferencias a medio fresco a intervalos variables. Métodos: Se seleccionaron al azar 40 cepas de Streptococcus agalactiae, las que se sometieron a verificación de viabilidad, pureza y caracterización fenotípica y genotípica antes y después de ser sometidas a conservación, utilizando idénticos medios, reactivos y metodología en ambas circunstancias. Se probaron diferentes medios de preservación de las cepas, que permitieran a laboratorios de baja y mediana complejidad su traslado a centros especializados para la vigilancia adecuada del organismo. Las cepas se conservaron durante nueve meses con subcultivos que mostraron las características originales. Resultados: Los medios más efectivos fueron ATS-TA y LD 4 %-SO-20 ºC, ya que garantizaron viabilidad, pureza y estabilidad fenotípica y genotípica de las cepas. Se demostró que el uso de este medio es una alternativa adecuada para la conservación de Streptococcus agalactiae en laboratorios donde la liofilización y la desecación no están disponibles y que son de bajo costo, rápidos y muy fáciles de usar en la práctica habitual. Conclusiones: los medios ATS-TA y LD 4 %-SO-20 ºC constituyen una buena alternativa para cortos períodos de preservación y transporte de cepas de Streptococcus agalactiae en laboratorios de baja y mediana complejidad.