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.