Genomic profile of Brazilian methicillin-resistant Staphylococcus aureus resembles clones dispersed worldwide.

PURPOSE: Comparative genomic analysis of strains may help us to better understand the wide diversity of their genetic profiles. The aim of this study was to analyse the genomic features of the resistome and virulome of Brazilian first methicillin-resistant Staphylococcus aureus (MRSA) isolates and their relationship to other Brazilian and international MRSA strains. METHODOLOGY: The whole genomes of three MRSA strains previously isolated in Vitória da Conquista were sequenced, assembled, annotated and compared with other MRSA genomes. A phylogenetic tree was constructed and the pan-genome and accessory and core genomes were constructed. The resistomes and virulomes of all strains were identified.Results/Key findings. Phylogenetic analysis of all 49 strains indicated different clones showing high similarity. The pan-genome of the analysed strains consisted of 4484 genes, with 31 % comprising the gene portion of the core genome, 47 % comprising the accessory genome and 22 % being singletons. Most strains showed at least one gene related to virulence factors associated with immune system evasion, followed by enterotoxins. The strains showed multiresistance, with the most recurrent genes conferring resistance to beta-lactams, fluoroquinolones, aminoglycosides and macrolides. CONCLUSIONS: Our comparative genomic analysis showed that there is no pattern of virulence gene distribution among the clones analysed in the different regions. The Brazilian strains showed similarity with clones from several continents.

Modeling Immune Response to Leishmania Species Indicates Adenosine As an Important Inhibitor of Th-Cell Activation.

Infection by Leishmania protozoan parasites can cause a variety of disease outcomes in humans and other mammals, from single self-healing cutaneous lesions to a visceral dissemination of the parasite. The correlation between chronic lesions and ecto-nucleotidase enzymes activity on the surface of the parasite is addressed here using damage caused in epithelial cells by nitric oxide. In order to explore the role of purinergic metabolism in lesion formation and the outcome of the infection, we implemented a cellular automata/lattice gas model involving major immune characters (Th1 and Th2 cells, IFN-γ, IL-4, IL-12, adenosine-Ado-, NO) and parasite players for the dynamic analysis of the disease progress. The model were analyzed using partial ranking correlation coefficient (PRCC) to indicate the components that most influence the disease progression. Results show that low Ado inhibition rate over Th-cells is shared by L. major and L. braziliensis, while in L. amazonensis infection the Ado inhibition rate over Th-cells reaches 30%. IL-4 inhibition rate over Th-cell priming to Th1 independent of IL-12 are exclusive of L. major. The lesion size and progression showed agreement with published biological data and the model was able to simulate cutaneous leishmaniasis outcomes. The sensitivity analysis suggested that Ado inhibition rate over Th-cells followed by Leishmania survival probability were the most important characteristics of the process, with PRCC of 0.89 and 0.77 respectively. The simulations also showed a non-linear relationship between Ado inhibition rate over Th-cells and lesion size measured as number of dead epithelial cells. In conclusion, this model can be a useful tool for the quantitative understanding of the immune response in leishmaniasis.

Draft Genome Sequence of Methicillin-Resistant Staphylococcus aureus Strain LC33 Isolated from Human Breast Milk.

Here, we report the draft genome sequence of Staphylococcus aureus strain LC33, isolated from human breast milk in Brazil. This microorganism has been typed as ST1/t127/sccmecV. To our knowledge, this is the first draft genome sequence of a methicillin-resistant S. aureus strain isolated from human breast milk.

Draft Genome Sequences of Two Clinical Methicillin-Resistant Staphylococcus aureus Strains Isolated from Healthy Children in Brazil.

We report here the draft genome sequences of two community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains, C18 and C80, isolated from healthy children from day care centers. To our knowledge, these are the first draft genome sequences of CA-MRSA ST398/CC398/SccmecV and CA-MRSA ST5/CC5/SccmecIVa isolated from healthy children in Brazil.

Correlation between infection rate of triatominies and Chagas Disease in Southwest of Bahia, Brazil: a warning sign?

Chagas disease, caused by the Trypanosoma cruzi, has a wide distribution in South America, and its main method of control is the elimination of triatomines. It is presented here the geographic distribution and the rate of natural infection by T. cruzi of triatomines collected and evaluated from 2008 to 2013 in southwest of Bahia. Triatomines were captured in the intradomiciliary and peridomiciliary areas of five cities located in the southwest of Bahia state, identified, and analyzed for the presence of trypanosomatids in their feces. During the study period the number of patients suspected for acute Chagas disease was recovered from the Notifiable Diseases Information System (SINAN). 8966 triatomines were captured and identified as belonging to eight species. Twenty-six presented themselves infected, being Triatoma sordida the most abundant and with the highest percentage of infection by T. cruzi. Tremedal was the city with the highest number of cases of acute Chagas' disease reported to SINAN. All cities showed triatomines infected with T. cruzi, so there is considerable risk of vectorial transmission of Chagas disease in the southwestern Bahia state, evidencing the need for vector transmission control programs and preventive surveillance measures.

Nuclear organization of the serotonergic system in the brain of the rock cavy (Kerodon rupestris).

Serotonin, or 5-hydroxytryptamine (5-HT), is a substance found in many tissues of the body, including as a neurotransmitter in the nervous system, where it can exert different post-synaptic actions. Inside the neuro-axis, 5-HT neurons are almost entirely restricted to the raphe nuclei of the brainstem. As such, 5-HT-immunoreactivity has been considered a marker of the raphe nuclei, which are located in the brainstem, at or near the midline. The present study investigated distribution of serotonergic neurons in the brain of the rock cavy (Kerodon rupestris), a rodent species inhabiting the Brazilian Northeast. The cytoarchitectonic location of serotonergic neurons was established through a series of 5-HT immunostained sections, compared with diagrams obtained from adjacent coronal and sagittal sections stained by the Nissl method. The following nuclei were defined: the rostral group, consisting of rostral linear raphe, caudal linear raphe, median and paramedian raphe, dorsal raphe, and pontine raphe nuclei, and the caudal group composed of raphe magnus, raphe pallidus and raphe obscurus nuclei. Other serotonergic neuronal clusters, such as the supralemniscal group and the rostral and caudal ventrolateral medulla oblongata clusters, were found outside the midline. Rare 5-HT-producing neurons were identified in the lateral parabrachial nucleus and in the pontine reticular formation, mostly along fibers of the lateral lemniscus. Despite exhibiting some specializations, the picture outlined for serotonergic groups in the rock cavy brain is comparable to that described for other mammalian species.

Genomic analyses, gene expression and antigenic profile of the trans-sialidase superfamily of Trypanosoma cruzi reveal an undetected level of complexity.

The protozoan parasite Trypanosoma cruzi is the etiologic agent of Chagas disease, a highly debilitating human pathology that affects millions of people in the Americas. The sequencing of this parasite's genome reveals that trans-sialidase/trans-sialidase-like (TcS), a polymorphic protein family known to be involved in several aspects of T. cruzi biology, is the largest T. cruzi gene family, encoding more than 1,400 genes. Despite the fact that four TcS groups are well characterized and only one of the groups contains active trans-sialidases, all members of the family are annotated in the T. cruzi genome database as trans-sialidase. After performing sequence clustering analysis with all TcS complete genes, we identified four additional groups, demonstrating that the TcS family is even more heterogeneous than previously thought. Interestingly, members of distinct TcS groups show distinctive patterns of chromosome localization. Members of the TcSgroupII, which harbor proteins involved in host cell attachment/invasion, are preferentially located in subtelomeric regions, whereas members of the largest and new TcSgroupV have internal chromosomal locations. Real-time RT-PCR confirms the expression of genes derived from new groups and shows that the pattern of expression is not similar within and between groups. We also performed B-cell epitope prediction on the family and constructed a TcS specific peptide array, which was screened with sera from T. cruzi-infected mice. We demonstrated that all seven groups represented in the array are antigenic. A highly reactive peptide occurs in sixty TcS proteins including members of two new groups and may contribute to the known cross-reactivity of T. cruzi epitopes during infection. Taken together, our results contribute to a better understanding of the real complexity of the TcS family and open new avenues for investigating novel roles of this family during T. cruzi infection.

Analysis of Leishmania chagasi by 2-D difference gel electrophoresis (2-D DIGE) and immunoproteomic: identification of novel candidate antigens for diagnostic tests and vaccine.

Identification of novel antigens is essential for developing new diagnostic tests and vaccines. We used DIGE to compare protein expression in amastigote and promastigote forms of Leishmania chagasi. Nine hundred amastigote and promastigote spots were visualized. Five amastigote-specific, 25 promastigote-specific, and 10 proteins shared by the two parasite stages were identified. Furthermore, 41 proteins were identified in the Western blot employing 2-DE and sera from infected dogs. From these proteins, 3 and 38 were reactive with IgM and total IgG, respectively. The proteins recognized by total IgG presented different patterns in terms of their recognition by IgG1 and/or IgG2 isotypes. All the proteins selected by Western blot were mapped for B-cell epitopes. One hundred and eighty peptides were submitted to SPOT synthesis and immunoassay. A total of 25 peptides were shown of interest for serodiagnosis to visceral leishmaniasis. In addition, all proteins identified in this study were mapped for T cell epitopes by using the NetCTL software, and candidates for vaccine development were selected. Therefore, a large-scale screening of L. chagasi proteome was performed to identify new B and T cell epitopes with potential use for developing diagnostic tests and vaccines.

Molecular bacterial diversity and distribution in waste from a steel plant.

We characterized the bacterial diversity of newly produced steelmaking wastes (NPSW) and steelmaking wastes deposited (SWD) in a restricted land area, generated by the siderurgic industry, using the 16S rDNA clone library approach. A total of 212 partial-length sequences were analyzed, revealing 123 distinct operational taxonomic units (OTUs) determined by the DOTUR program to 97% sequence similarity. Phylogenetic analysis of bacterial 16S rDNA sequences from the NPSW and SWD libraries demonstrated that Gammaproteobacteria, Betaproteobacteria, Alphaproteobacteria, Actinobacteria, Planctomycetes, Firmicutes, and Bacteroidetes were represented in both libraries. Deltaproteobacteria, Acidobacteria, Chloroflexi, Deinococcus-thermus, Gemmatimonadetes, and candidate divisions OP10 and OD1 were only present in the SWD library, and Nitrospira was only present in the NPSW library. The abundance of sequences affiliated with Gammaproteobacteria was high in both libraries. Six previously unclassified OTUs may represent novel taxa. Based on diversity indices (Simpson, Shannon-Weaver, Chao1, and ACE), the SWD library had a higher diversity. LIBSHUFF comparisons of the composition of the 2 libraries showed that they were significantly different. These results indicate that the bacterial communities in steelmaking wastes present high phylogenetic diversity and complexity. A possible association between the functional diversity and the bacterial communities' complexity requires further phenotypic investigation.