IS200 and multilocus sequence typing for the identification of Salmonella enterica serovar Typhi strains from Indonesia

In this work, IS200 and multi-locus sequence typing (MLST) were used to analyze 19 strains previously serotyped as Salmonella enterica serovar Typhi and isolated in Indonesia (16 strains), Mexico (2 strains), and Switzerland (1 strain). Most of the strains showed the most common Typhi sequence types, ST1 and ST2, and a new Typhi genotype (ST1856) was described. However, one isolate from Mexico and another from Indonesia were of the ST365 and ST426 sequence types, indicating that they belonged to serovars Weltevreden and Aberdeen, respectively. These results were supported by the amplification of IS200 fragments, which rapidly distinguish Typhi from other serovars. Our results demonstrate the utility of IS200 and MLST in the classification of Salmonella strains into serovars. These methods provide information on the clonal relatedness of strains isolated worldwide (AU)

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Angiotensin-converting enzyme gene insertion/deletion polymorphisms and the susceptibility to allergic rhinitis

BACKGROUND: Angiotensin-converting enzyme (ACE) gene I/D polymorphism might be linked to the risk of the allergic rhinitis (AR). OBJECTIVE: In the present study, we assessed the association of ACE gene I/D polymorphisms with AR susceptibility using a meta-analysis. MATERIALS AND METHODS: We carried out a retrieval of studies and included the eligible studies if they met the criteria. After the data extraction, the Stata software was used to analyse the genotype frequencies. RESULTS: In total, five studies with 561 patients and 603 controls were included. However, the genotype distribution among the control of one study was not consistent with the Hardy-Weinberg equilibrium. After pooling all studies, the results indicated an association between ACE gene I/D polymorphism and AR risk in the overall analysis (II vs. others: OR = 0.70, 95% CI = 0.54-0.92, P = 0.010; D vs. I: OR = 1.29, 95% CI = 1.08-1.54, P = 0.005). In the further analysis of the East Asians, no association between ACE gene I/D polymorphism and AR risk was observed. CONCLUSION: ACE gene I/D polymorphisms were not associated with the risk of AR in East Asians. These results need to be confirmed in the following studies

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Localización cromosómica de duplicaciones submicroscópicas en pacientes con trastornos del neurodesarrollo para identificar casos con alto riesgo de recurrencia familiar / Chromosomal location of submicroscopic duplications in patients with neurodevelopmental disorders to identify cases with high risk of familial recurrence

Fundamento y objetivo: Las alteraciones genómicas desequilibradas (duplicaciones o deleciones) causantes de trastornos del neurodesarrollo (TND) son en su mayoría episodios de novo. Sin embargo, también pueden surgir como consecuencia de reordenamientos equilibrados no detectados en uno de los progenitores, cambiando radicalmente el riesgo de recurrencia y el consejo genético de estos casos. La técnica de fluorescence in situ hybridization (FISH, «hibridación in situ fluorescente») permite la identificación y localización de reordenamientos cromosómicos tanto equilibrados como desequilibrados, identificando la ubicación de los segmentos duplicados. En este trabajo se pretende localizar en el genoma los segmentos duplicados detectados en pacientes con TND, e identificar aquellos casos debidos a reordenamientos heredados. Pacientes y método: El estudio se llevó a cabo en 13 pacientes con TND y portadores de duplicaciones génicas detectadas por compared genomic hybridization-array (CGH-array, «hibridación genómica comparada sobre arrays»). Se utilizaron 2 aproximaciones de la técnica FISH: hibridación con sondas de pintado cromosómico y con sondas específicas de cada duplicación. Resultados: En la serie de 13 pacientes con duplicación estudiados, se han encontrado 11 con duplicaciones en tándem, un caso con una traslocación insercional intracromosómica, y otro con una traslocación insercional intercromosómica. Por tanto, 2 de las duplicaciones que se habían considerado de novo habían sido, en realidad, heredadas de forma desequilibrada de un progenitor que era portador equilibrado del reordenamiento. Conclusión: Los resultados ponen de manifiesto la necesidad de caracterizar, mediante la técnica de FISH, los reordenamientos que se detectan por CGH-array, para identificar los casos con un elevado riesgo de recurrencia y realizar un correcto asesoramiento genético (AU)

Background and objective: An important proportion of neurodevelopmental disorders (NDDs) results from unbalanced genomic alterations (duplication or deletion). These chromosomal rearrangements may be considered as de novo, despite they arise as a result of a balanced rearrangement not detected in a phenotypically normal parent. Therefore, if the rearrangements are inherited, the recurrence risk and the genetic counseling of these cases change radically. Fluorescence in situ hybridization (FISH) is a technique that allows detecting both balanced and unbalanced rearrangements, identifying also the location of duplicated segments. We tried to locate in the genome the duplicated segments detected in patients with NDDs in order to identify those cases due to inherited rearrangements. Patients and method: The study was conducted in 13 patients with NDDs and genomic duplications detected by compared genomic hybridization-array (CGH-array). Two approaches of FISH technique were taken: hybridization with painting chromosome probes and with specific probes for each duplication. Results: In the studied series of 13 patients with duplication, 11 patients were found to carry tandemduplications, one with an intrachromosomal insertional translocation, and another with an interchromosomal insertional translocation. Therefore, 2 of the duplications considered de novo were actually an unbalanced rearrangement inherited from a parent who is a balanced carrier. Conclusion: The results illustrate the need to characterize by FISH technique the rearrangements that are detected by CGH-array to identify those cases with a high risk of recurrence (AU)

Prevalence of mobile genetic elements and transposase genes in Vibrio alginolyticus from the southern coastal region of China and theirrole in horizontal gene transfer

Vibrio alginolyticus has high genetic diversity, but little is known about the means by which it has been acquired. In this study, the distributions of mobile genetic elements (MGEs), including integrating conjugative elements (ICEs), superintegron-like cassettes (SICs), insertion sequences (ISs), and two types of transposase genes (valT1 and valT2), in 192 strains of V. alginolyticus were investigated. ICE, SIC, and IS elements, valT1, and valT2 were detected in 8.9%, 13.0%, 4.7%, 9.4%, and 2.6% of the strains, respectively. Blast searches and phylogenetic analysis of the acquired sequences of the ICE, SIC, IS elements and transposase genes showed that the corresponding homologues were bacterial and derived from extensive sources. The high prevalences of these MGEs in V. alginolyticus implied the extensive and frequent exchange of genes with environmental bacteria and that these elements strongly contribute to the genetic and phenotypic diversity of the bacterium. To our knowledge, this is the first report of V. alginolyticus harboring ICE and SIC elements (AU)

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Selection of a biocontrol agent based on apotential mechanism of action: degradation of nicotinic acid, a growth factor essential for Erwinia amylovora

This work describes a medium-based screening method for selecting microbial biocontrol agents against Erwinia amylovora based on the degradation of a specific growth factor. Erwinia amylovora, the causal agent of the devastating fire blight disease, requires nicotinic acid or nicotinamide as an essential growth factor. Potential biocontrol agents are either selected for antimicrobial production in plate or directly on immature pears or apple blossoms. In this work, we have attempted to streamline the selection of a new potential biocontrol agent with a lower risk of non-target effects by isolation based on the ability to degrade nicotinic acid in vitro, using therefore few plant materials. A total of 735 bacteria and 1237 yeast were isolated from apple blossoms and pre-screened for nicotinic acid-degradation. Pseudomonas rhizosphaerae strain JAN was able to degrade both nicotinic acid and nicotinamide. Mutants deficient in this ability were constructed. JAN, but not the mutants, controlled E. amylovora on pear slices. On detached apple blossoms, JAN colonized apple hypanthia and strongly suppressed E. amylovora growth. Under greenhouse conditions, JAN was more effective in controlling blossom blight than P. fluorescens A506, a commercial biocontrol agent of fire blight unable to degrade nicotinic acid and nicotinamide (AU)

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Aminoglycoside resistanceof Pseudomonas aeruginosa biofilmsmodulated by extracellular polysaccharide

Pseudomonas aeruginosa is an opportunistic pathogen that produces sessile communities known as biofilms that are highly resistant to antibiotic treatment. Limited information is available on the exact role of various components of the matrix in biofilm-associated antibiotic resistance. Here we show that the presence of extracellular polysaccharide reduced the extent of biofilm-associated antibiotic resistance for one class of antibiotics. Minimal bactericidal concentration (MBC) for planktonic and biofilm cells of P. aeruginosa PA14 was measured using a 96 well microtiter plate assay. The MBC of biofilm-grown ΔpelA mutant, which does not produce the Pel polysaccharide, was 4-fold higher for tobramycin and gentamicin, and unchanged for ΔbifA mutant, which overproduces Pel, when compared to the wild type. Biofilms of pelA mutants in two clinical isolates of P. aeruginosa showed 4- and 8-fold higher MBC for tobramycin as compared to wild type. There was no difference in the biofilm resistance of any of these strains when tested with fluoroquinolones. This work forms a basis for future studies revealing the mechanisms of biofilm-associated antibiotic resistance to aminoglycoside antibiotics by P. aeruginosa (AU)

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Conceptos generales y métodos de estudio en farmacogenética / General concepts and study methods in pharmacogenetics

La farmacogenética, la ciencia que permite identificar lasbases genéticas de las diferencias interindividuales en larespuesta a los fármacos, es un tema de gran interés. Losresultados de los diferentes tipos de estudiosfarmacogenéticos en diferentes campos de la medicinapueden servir para que en un futuro se pueda ofrecer unaverdadera medicina personalizada. En este capítulodefinimos los conceptos más relevantes de esta disciplina,así como los métodos de estudio utilizados actualmente(AU)

Pharmacogenetics, the study of how individual geneticprofiles influence the response to drugs, is an importanttopic. Results from pharmacogenetics studies in variousclinical settings may lead to personalized medicine. Herein,we present the most important concepts of this discipline,as well as currently-used study methods(AU)

Massive presence of insertion sequences in the genome of SOPE, the primary endosymbiont of the rice weevil Sitophilus oryzae

Bacteria that establish an obligate intracellular relationship with eukaryotic hosts undergo an evolutionary genomic reductive process. Recent studies have shown an increase in the number of mobile elements in the first stage of the adaptive process towards intracellular life, although these elements are absent in ancient endosymbionts. Here, the genome of SOPE, the obligate mutualistic endosymbiont of rice weevils, was used as a model to analyze the initial events that occur after symbiotic integration. During the first phases of the SOPE genome project, four different types of insertion sequence (IS) elements, belonging to well-characterized IS families from gamma-proteobacteria, were identified. In the present study, these elements, which may represent more than 20% of the complete genome, were completely characterized; their relevance as a source of gene inactivation, chromosomal rearrangements, and as participants in the genome reductive process are discussed herein (AU)

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Molecular characterization of InJR06, a class 1 integron located in a conjugative plasmid of Salmonella enterica ser. Typhimurium / Caracterización molecular de InJR06, un integron de clase 1 situado en un plásmido conjugativo de Salmonella enterica ser. Typhimurium

The presence of class 1, 2, and 3 integrons was investigated in four pediatric isolates of Salmonella enterica ser. Typhimurium (S. Typhimurium). A class 1 integron was detected in one S. Typhimurium strain, the only one that also showed resistance to various aminoglycoside antibiotics. This integron, called InJR06, and the aminoglycoside resistance determinants were located in pS06, a large (≥ 55 kb) conjugative plasmid. A single mobile cassette (encoding the aminoglycoside adenylyltransferase ANT(3’’)-Ia) was detected in the variable region of InJR06, while the architecture of the attI1 and attC sites was conserved (AU)

Se investigó la presencia de integrones de clase 1, 2 y 3 en cuatro aislamientos pediátricos de Salmonella enterica ser. Typhimurium (S. Typhimurium). Un integrón de clase 1 se detectó en una cepa de S. Typhimurium, la única que además presentaba resistencia a varios antibióticos aminoglucósidos. Este integrón, llamado InJR06, y los determinantes de resistencia a aminoglucósidos se localizaron en pS06, un plásmido conjugativo de tamaño grande (≥ 55 kb). El análisis de la región variable de InJR06 mostró que un casete génico codifica la aminoglucósido adeniltransferasa ANT(3’’)-Ia y que la arquitectura de los sitios attI1 y attC está conservada (AU)