Pathogenomic analysis of the common bovine Staphylococcus aureus clone (ET3): emergence of a virulent subtype with potential risk to public health.

A common clone (ET3) of Staphylococcus aureus is responsible for a large proportion of cases of bovine mastitis and occasionally causes zoonotic infections of humans. In the present study, we report the identification of a virulent clonal subtype (ST151) of ET3, which resulted in increased tissue damage and mortality in a mouse model of mastitis. ST151 has undergone extensive diversification in virulence and regulatory-gene content, including the acquisition of genetic elements encoding toxins not made by other ET3 strains.

Molecular correlates of host specialization in Staphylococcus aureus.

Background: The majority of Staphylococcus aureus isolates that are recovered from either serious infections in humans or from mastitis in cattle represent genetically distinct sets of clonal groups. Moreover, population genetic analyses have provided strong evidence of host specialization among S. aureus clonal groups associated with human and ruminant infection.

Sequence analysis of the Staphylococcus aureus srrAB loci reveals that truncation of srrA affects growth and virulence factor expression.

The SrrAB system regulates metabolism and virulence factors in Staphylococcus aureus. We sequenced the srrAB loci of 21 isolates and performed a phylogenetic analysis. Vaginal and bovine isolates clustered together, while skin isolates were genetically diverse.

MGView: an alignment and visualization tool to enhance gap closure of microbial genomes.

Gap closure is a challenging phase in microbial random shotgun genome sequencing projects, particularly since genome assemblies are often complicated by the presence of repeat elements, insertion sequences and other similar factors that contribute to sequence misassemblies. While it is well recognized that the conservation of genetic information between microbial genomes, combined with the exponential increase in available microbial sequences, can be exploited to increase the efficiency of gap closure, we lack the computational tools to aid in this process. We describe here a new tool, MGView, which was developed to create a graphical depiction of the alignment of a set of microbial contigs against a completed microbial genome.