Genome Sequence of a Highly Virulent pvl-positive Vancomycin-intermediate-resistant Staphylococcus aureus Sequence Type 30.

BACKGROUND

Staphylococcus aureus isolates expressing the Panton-Valentine Leukocidin (PVL) have been related to a wide range of diseases. Recently, pvl-positive community-associated methicillin-resistant S. aureus belonging to USA1100 (ST30/CC30/SCCmec IV) lineage has emerged in Brazilian hospitals.

OBJECTIVE

The aim of this work was to sequence the genome of a pvl-positive USA1100 Vancomycin-Intermediate-Resistant S. aureus (VISA) isolate from Rio de Janeiro, Brazil.

METHODS

The 13420 genome was sequenced using the HiSeq 2500 platform. The draft genome, plasmids annotation, and genome analysis were performed using RAST. Comparison of the relative pvl gene expression of six S. aureus isolates was performed by qRT-PCR.

RESULTS

The isolate presented the ϕPVL phage codifying for the H2b PVL protein isoform, and another prophage carrying a PVL variant named lukF and lukS-PV.2. The 13420 genome presented a high number of virulence determinants, such as genes codifying for serine-protease proteins, enterotoxins (egc), the immune evasion cluster (IEC), adhesion proteins, spermine/spermidine acetyltransferase gene (blt), superantigen-like proteins, as well as the ica operon. Point mutations at vraS, tcaA, and tcaB genes were detected. Moreover, the PVL mRNA relative expression of the 13420 isolate was five times higher than mRNA PVL levels of the USA300/ST8 reference strain.

CONCLUSION

We described for the first time the genome sequence of a VISA isolate harboring two pvl-associated genes and other virulence factors that may improve the USA1100/ST30 lineage fitness and impact its pathogenicity and spreading at Brazilian hospitals.