Ana C. Ferreira

Evaluation of a Multiplex PCR Assay (Bruce-ladder) for Molecular Typing of All Brucella Species, Including the Vaccine Strains

ABSTRACT An evaluation of a multiplex PCR assay (Bruce-ladder) was performed in seven laboratories using 625 Brucella strains from different animal and geographical origins. This robust test can differentiate in a single step all of the classical Brucella species, including those found in marine mammals and the S19, RB51, and Rev.1 vaccine strains.

MLVA16 Typing of Portuguese Human and Animal Brucella melitensis and Brucella abortus Isolates

To investigate the epidemiological relationship of isolates from different Portuguese geographical regions and to assess the diversity among isolates, the MLVA16Orsay assay (panels 1, 2A and 2B) was performed with a collection of 126 Brucella melitensis (46 human and 80 animal isolates) and 157 B. abortus field isolates, seven vaccine strains and the representative reference strains of each species. The MLVA16Orsay showed a similar high discriminatory power (HGDI 0.972 and 0.902) for both species but panel 1 and 2A markers displayed higher diversity (HGDI 0.693) in B. abortus compared to B. melitensis isolates (HGDI 0.342). The B. melitensis population belong to the “Americas” (17%) and “East Mediterranean” (83%) groups. No isolate belonged to the “West Mediterranean” group. Eighty-five percent of the human isolates (39 in 46) fit in the “East-Mediterranean” group where a single lineage known as MLVA11 genotype 116 is responsible for the vast majority of Brucella infections in humans. B. abortus isolates formed a consistent group with bv1 and bv3 isolates in different clusters. Four MLVA11 genotypes were observed for the first time in isolates from S. Jorge and Terceira islands from Azores. From the collection of isolates analysed in this study we conclude that MLVA16Orsay provided a clear view of Brucella spp. population, confirming epidemiological linkage in outbreak investigations. In particular, it suggests recent and ongoing colonisation of Portugal with one B. melitensis lineage usually associated with East Mediterranean countries.

Development and evaluation of a selective medium for Brucella suis.

A new selective medium, named LNIV-M, has been developed for isolation of Brucella suis. In this work, we evaluated the growth of B. suis reference and field strains from domestic pigs in different basal media and the susceptibility to different antibiotics contained in the currently used Farrells and modified Thayer-Martin media. We also determined the efficacy of LNIV-M and its diagnostic performance for isolating B. suis from wild boar tissue samples. A total of 1649 samples from 918 hunter-harvested wild boars were cultured in LNIV-M, Farrells and modified Thayer-Martin media. One hundred and thirty-nine (8.4%) samples from 63 (6.9%) animals resulted in a positive culture. LNIV-M detected 93.6% and 62.6% of positive animals and samples, respectively, while Farrells and modified Thayer-Martin media detected, respectively, 92.1% and 79.4% of positive animals and 58.3% and 59.7% of samples. These results confirm the adequate diagnostic performance of LNIV-M in the isolation of B. suis.

Whole-genome mapping reveals a large chromosomal inversion on Iberian Brucella suis biovar 2 strains.

Optical mapping is a technology able to quickly generate high resolution ordered whole-genome restriction maps of bacteria, being a proven approach to search for diversity among bacterial isolates. In this work, optical whole-genome maps were used to compare closely-related Brucella suis biovar 2 strains. This biovar is the unique isolated in domestic pigs and wild boars in Portugal and Spain and most of the strains share specific molecular characteristics establishing an Iberian clonal lineage that can be differentiated from another lineage mainly isolated in several Central European countries. We performed the BamHI whole-genome optical maps of five B. suis biovar 2 field strains, isolated from wild boars in Portugal and Spain (three from the Iberian lineage and two from the Central European one) as well as of the reference strain B. suis biovar 2 ATCC 23445 (Central European lineage, Denmark). Each strain showed a distinct, highly individual configuration of 228-231 BamHI fragments. Nevertheless, a low divergence was globally observed in chromosome II (1.6%) relatively to chromosome I (2.4%). Optical mapping also disclosed genomic events associated with B. suis strains in chromosome I, namely one indel (3.5kb) and one large inversion (944kb). By using targeted-PCR in a set of 176 B. suis strains, including all biovars and haplotypes, the indel was found to be specific of the reference strain ATCC 23445 and the large inversion was shown to be an exclusive genomic marker of the Iberian clonal lineage of biovar 2.

Complete Genome Sequences of Three Iberian Brucella suis Biovar 2 Strains Isolated from Wild Boars

ABSTRACT Brucella suis biovar 2 is the most common biovar isolated from wild boars (Sus scrofa) associated with transmission to outdoor-reared pigs in Europe. We report here the complete and annotated genome sequences of three strains isolated from wild boars in Portugal and Spain and belonging to the Iberian clone (haplotypes 2d and 2e).

MLVA-16 typing of Brucella suis biovar 2 strains circulating in Europe

Swine brucellosis due to Brucella suis biovar 2 is an emerging disease in Europe, associated with increase of extensive swine farms and high density of infected wild boars. Since knowledge of predominant circulating strains is a prerequisite for any epidemiological study, accurate molecular typing procedures were applied to a collection of 176 B. suis isolates. By using suis-ladder multiplex PCR and PCR-RFLP analysis of omp2a, omp2b and omp31 genes, five haplotypes were identified among 160 biovar 2 isolates, with haplotypes 2d and 2e restricted to Portugal and Spain and haplotypes 2a, 2b and 2c widespread in Europe (except Portugal). MLVA based on 16 genetic markers (MLVA-16) revealed 126 genotypes, with 101 singletons, and grouped biovar 2 isolates in two clusters according to their geographic origins and haplotypes, defining the Iberian (Portugal and Spain) and the Central-European clonal lineages. In order to get insights on the evolutionary associations between B. suis lineages and their host species, an extended analysis was performed using a subset of 11 markers and publicly available data for 350 additional strains. This MLVA-11 analysis revealed a high genetic divergence amongst the 526 B. suis strains based on their hosts and highlighted the close relationship between strains from swine, wild boars and hares. Beyond corroborating the existence of Iberian and Central European biovar 2 clonal lineages and pointing to the evolution of biovar 2 Iberian clonal lineage from Central-European one by an allopatric speciation event, an ongoing colonization of Iberian Peninsula with specific MLVA-11 genotypes is also highlighted.

Complete Genome Sequences of Two Central European Brucella suis bv. 2 Haplotype 2c Strains Isolated from Wild Boars.

ABSTRACT The Brucella suis haplotype 2c is commonly isolated from wild boars and domestic pigs across Central Europe, though it is rarely described in the Iberian Peninsula. We report here the complete and annotated genome sequences of two haplotype 2c strains isolated from wild boars in the northeast region of Spain, above the Ebro River.

Os efeitos do crescimento urbano sobre a dengue

Objective: To analyze the spatial and temporal dynamics of dengue in Coronel Fabriciano, Minas Gerais State, Brazil, and to associate cases to the growth of urban areas and loss of natural areas in recent years. Methods: This is a descriptive, exploratory study, with a quantitative approach. Dengue cases of 2009 were obtained from the Health Municipal Secretariat, including the suspected and confirmed cases. Shape files were obtained, containing information about the municipal boundary, boundary of the urban area, census tracts, areas with buildings and natural areas. Based on the distribution of dengue cases, the Kernel estimator was used to measure data dispersion. Results: Dengue cases reported were georeferenced in GIS (Geographic Information System) environment. The landscape showed changes in the units of urban area and pasture, as an urban growth over the pasture matrix. No changes were observed in the areas of remaining forest and eucalyptus. There are cases spatially spread with a tendency to form clusters. Conclusion: Cases of dengue were observed spatially clustered in the northern region of the city, where new neighborhoods have emerged in recent years, following the population growth without proper structure of urbanization and urban planning. In addition, urban growth have reduced the margin of watercourses providing a bare soil, suitable for accumulation of trash and formation of breeding sites for mosquitoes. Efficient public policies and appropriate urban planning might reduce the impact of dengue in endemic regions. doi: http://dx.doi.org/10.5020/18061230.2013.p539