Association of virulence plasmid and antibiotic resistance determinants with chromosomal multilocus genotypes in Mexican Salmonella enterica serovar Typhimurium strains

<p>Abstract</p> <p>Background</p> <p>Bacterial genomes are mosaic structures composed of genes present in every strain of the same species (core genome), and genes present in some but not all strains of a species (accessory genome). The aim of this study was to compare the genetic diversity of core and accessory genes of a <it>Salmonella enterica </it>subspecies <it>enterica </it>serovar Typhimurium (Typhimurium) population isolated from food-animal and human sources in four regions of Mexico. Multilocus sequence typing (MLST) and macrorestriction fingerprints by pulsed-field gel electrophoresis (PFGE) were used to address the core genetic variation, and genes involved in pathogenesis and antibiotic resistance were selected to evaluate the accessory genome.</p> <p>Results</p> <p>We found a low genetic diversity for both housekeeping and accessory genes. Sequence type 19 (ST19) was supported as the founder genotype of STs 213, 302 and 429. We found a temporal pattern in which the derived ST213 is replacing the founder ST19 in the four geographic regions analyzed and a geographic trend in the number of resistance determinants. The distribution of the accessory genes was not random among chromosomal genotypes. We detected strong associations among the different accessory genes and the multilocus chromosomal genotypes (STs). First, the <it>Salmonella </it>virulence plasmid (pSTV) was found mostly in ST19 isolates. Second, the plasmid-borne betalactamase <it>cmy-2 </it>was found only in ST213 isolates. Third, the most abundant integron, IP-1 (<it>dfrA12</it>, <it>orfF </it>and <it>aadA2</it>), was found only in ST213 isolates. Fourth, the <it>Salmonella </it>genomic island (SGI1) was found mainly in a subgroup of ST19 isolates carrying pSTV. The mapping of accessory genes and multilocus genotypes on the dendrogram derived from macrorestiction fingerprints allowed the establishment of genetic subgroups within the population.</p> <p>Conclusion</p> <p>Despite the low levels of genetic diversity of core and accessory genes, the non-random distribution of the accessory genes across chromosomal backgrounds allowed us to discover genetic subgroups within the population. This study provides information about the importance of the accessory genome in generating genetic variability within a bacterial population.</p

Evaluación de la salud forestal de una plantación de Eucalyptus globulus Labill con fines de manejo en la Estación Experimental Tunshi, Riobamba, Ecuador

Frente a la necesidad de indagar sobre la salud forestal de una plantación de Eucalyptus globulus Labill con el propósito de disponer de información complementaria, que oriente la planificación de actividades silvícolas para su conservación y aprovechamiento, es la razón que motivó evaluar la condición de salud de los árboles en pie por rodal. Mediante el muestreo sistemático no alineado a una intensidad del 5-6% ha-1, en base a la instalación de parcelas circulares, dentro de cada parcela se registró seis rasgos que reflejan el estado de vigorosidad, saludable, enfermedad, debilidad, moribundo y árbol muerto en pie, mismos que indican el nivel de pérdida de hojas en los árboles. La aplicación de tablas de contingencia para el análisis de los residuos corregidos, siendo significativo al 5%, si el valor absoluto es &gt;1,96. Los resultados obtenidos mostraron cinco asociaciones significativas a excepción del rasgo árbol muerto en pie. Finalmente, con la formación de dos conglomerados jerárquicos que agrupa el nivel de salud, la decisión para la gestión del bosque plantado de eucalipto comprende el aprovechamiento de los rodales 2, 5, 6 y 7, más el manejo posterior de los rebrotes resultantes y de carácter conservacionista a los rodales 1, 3 y 4. La decisión se enmarca bajo criterios de manejo sostenible de los recursos forestales en base a los indicadores de salud que presentó el bosque plantado. Faced with the need to inquire on the forest health of an Eucalyptus globulus Labill plantation with the purpose of providing complementary information, which guides the planning of silvicultural activities for its conservation and use, is the reason that motivated to evaluate the health of the trees standing by stand. Through the systematic sampling not aligned at an intensity of 5-6% ha-1, based on the installation of circular plots, within each plot, six features were recorded that reflect the state of vigor, health, disease, weakness, dying and standing dead tree, which indicate the level of loss leaves in trees. The application of contingency tables for the analysis of corrected waste, being 5%, so the absolute value is &gt; 1,96. The results obtained showed five significant associations except for the dead tree feature. Finally, with the formation of two hierarchical clusters by grouping the state of forest health of the eucalyptus plantation, reinforces the decision form for the management on the planted forest considering the execution use of 2, 5, 6 and 7 stands, also the subsequent management of the resulting and conservationist sprouts to stands 1, 3 and 4. The decision was taken under the criteria of sustainable management of forest resources, which is based on the productive and health indicators presented by the planted forest

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. [Int Microbiol 2015; 18(2):99-104]Keywords: Salmonella Typhi &middot; bacterial molecular typing &middot; multilocus sequence typing (MLST) &middot; clonal complex &middot; insertion sequence IS20

Mining potential of two apiaries located in the Cevallos and Riobamba cantons, Inter-Andean Zone 3, Ecuador

Uno de los pilares para asegurar la producción apícola, es disponer de información confiable de la flora circundante y de los elementos que esta aporta al colmenar. Con ello, se puede planificar esquemas de manejo que incrementen la productividad. Frente a la necesidad de datos, se realizó el estudio de dos apiarios para contribuir al desarrollo apícola en la región interandina Zona 3, con el propósito de sustentar su gestión. Se priorizó identificar las especies vegetales de importancia melífera, y estimar su abundancia más la duración de la floración. Con la aplicación de los métodos: documental, y de campo, para el reconocimiento taxonómico de plantas melíferas, su cantidad, más el tiempo que persiste en fase de florecimiento de cada especie apícola evaluada, y la sistematización de los datos recopilados. Para el área del apiario A, se reporta 38 especies vegetales pertenecientes a 22 familias botánicas, siendo las más representativas: Asteraceae con 7 especies, y Rosaceae con 5. Por su parte, en el área del colmenar B, se registró 64 especies vegetales, correspondientes a 30 familias botánicas en las que se distingue la familia Fabaceae con 15 especies, y Asteraceae con 6. En abundancia para el apiario domina la especie Raphanus spp., en la subárea de rastrojos con más de 10000 individuos con flores, seguida por Prunus persica con 1000 a 10000 individuos con flores formando parte de la subárea de cultivos frutícolas y en el caso del apiario B, se destaca Raphanus spp con más de 10000 individuos con flores que predominan en la subárea de cultivos, y con menos de 1000 individuos en floridez para el resto de los especímenes. Cuya duración del florecimiento brinda una oferta parcialmente continua de recursos florales entre tres a seis meses, a excepción del área de pastos.One of the pillars to ensure beekeeping production is to have reliable information on the surrounding flora and the elements that it contributes to the apiary. With this, it is possible to plan management schemes that increase productivity. Faced with the need for data, a study of two apiaries was carried out to contribute to the development of beekeeping in the inter-Andean region Zone 3, in order to support their management. It was prioritized to identify the plant species of melliferous importance, and to estimate their abundance plus the duration of flowering. With the application of methods: documentary, and field, for the taxonomic recognition of honey plants, their quantity, plus the time that each bee species persists in the flowering phase, test, and the systematization of the collected data. For the area of ​​apiary A, 38 plant species belonging to 22 botanical families are reported, the most representative being: Asteraceae with 7 species, and Rosaceae with 5. On the other hand, in the area of ​​apiary B, 64 plant species were recorded, corresponding to 30 botanical families in which the Fabaceae family is distinguished with 15 species, and Asteraceae with 6. In abundance for the apiary the species Raphanus spp. dominates, in the stubble subarea with more than 10,000 individuals with flowers, followed by Prunus persica with 1000 to 10000 individuals with flowers forming part of the sub-area of ​​fruit crops and in the case of apiary B, Raphanus spp stands out with more than 10,000 individuals with flowers that predominate in the subarea of ​​crops, and with less than 1000 individuals in floridity for the rest of the specimens. Whose duration of flowering provides a partially continuous supply of floral resources between three to six months, an exception of the pasture area

OmpR and LeuO Positively Regulate the Salmonella enterica Serovar Typhi ompS2 Porin Gene

The Salmonella enterica serovar Typhi ompS2 gene codes for a 362-amino-acid outer membrane protein that contains motifs common to the porin superfamily. It is expressed at very low levels compared to the major OmpC and OmpF porins, as observed for S. enterica serovar Typhi OmpS1, Escherichia coli OmpN, and Klebsiella pneumoniae OmpK37 quiescent porins. A region of 316 bp, between nucleotides −413 and −97 upstream of the transcriptional start point, is involved in negative regulation, as its removal resulted in a 10-fold increase in ompS2 expression in an S. enterica serovar Typhi wild-type strain. This enhancement in expression was not observed in isogenic mutant strains, which had specific deletions of the regulatory ompB (ompR envZ) operon. Furthermore, ompS2 expression was substantially reduced in the presence of the OmpR D55A mutant, altered in the major phosphorylation site. Upon random mutagenesis, a mutant where the transposon had inserted into the upstream regulatory region of the gene coding for the LeuO regulator, showed an increased level of ompS2 expression. Augmented expression of ompS2 was also obtained upon addition of cloned leuO to the wild-type strain, but not in an ompR isogenic derivative, consistent with the notion that the transposon insertion had increased the cellular levels of LeuO and with the observed dependence on OmpR. Moreover, LeuO and OmpR bound in close proximity, but independently, to the 5′ upstream regulatory region. Thus, the OmpR and LeuO regulators positively regulate ompS2