Format

Send to

Choose Destination
J Infect Dis. 2008 Jan 15;197(2):187-94. doi: 10.1086/524684.

A geographic variant of the Staphylococcus aureus Panton-Valentine leukocidin toxin and the origin of community-associated methicillin-resistant S. aureus USA300.

Author information

1
Evolutionary and Structural Bioinformatics, Collegeville, Pennsylvania, USA.

Abstract

BACKGROUND:

The majority of recent community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections in the United States have been caused by a single clone, USA300. USA300 secretes Panton-Valentine leukocidin (PVL) toxin, which is associated with highly virulent infections.

METHODS:

We sequenced the PVL genes of 174 S. aureus isolates from a global clinical sample. We combined phylogenetic reconstruction and protein modeling methods to analyze genetic variation in PVL.

RESULTS:

Nucleotide variation was detected at 12 of 1726 sites. Two PVL sequence variants, the R variant and the H variant, were identified on the basis of a substitution at nt 527. Of sequences obtained in the United States, 96.7% harbor the R variant, whereas 95.6% of sequences obtained outside the United States harbor the H variant; 91.3% of MRSA isolates harbor the R variant, and 91.3% of methicillin-susceptible strains harbor the H variant. A molecular model of PVL shows 3 mechanisms by which the amino acid substitution may affect PVL function.

CONCLUSIONS:

All sampled PVL genes appear to share a recent common ancestor and spread via a combination of clonal expansion and horizontal transfer. US isolates harbor a variant of PVL that is strongly associated with MRSA infections. Protein modeling reveals that this variant may have functional significance. We propose a hypothesis for the origin of USA300.

PMID:
18177252
DOI:
10.1086/524684
[Indexed for MEDLINE]

Publication type, MeSH terms, Substances, Secondary source ID

Publication type

MeSH terms

Substances

Secondary source ID

Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center