Staphylococcus aureus is a major cause of skin and
soft tissue infections, such as
furuncles,
carbuncles, and
abscesses, but it also frequently colonizes the human skin and mucosa without causing clinical symptoms.
Panton-Valentine leukocidin (PVL) is a pore-forming toxin that has been associated with
soft tissue infections and
necrotizing pneumonia. We have compared the genotypes, virulence gene repertoires, and phage patterns of 74
furunculosis isolates with those of 108 control strains from healthy nasal carriers. The large majority of
furunculosis strains were
methicillin sensitive. Clonal cluster (CC) 121 (CC121) and CC22 accounted for 70% of the
furunculosis strains but for only 8% of the nasal isolates. The PVL-encoding genes
luk-PV were detected in 85% of
furunculosis strains, while their prevalence among colonizing S. aureus strains was below 1%.
luk-PV genes were distributed over several lineages (CCs 5, 8, 22, 30, and 121 and sequence type 59). Even within the same lineages,
luk-PV-positive phages characterized
furunculosis strains, while their
luk-PV-negative variants were frequent among nasal strains. The very tight epidemiological linkage between
luk-PV and
furunculosis, which could be separated from the genetic background of the S. aureus strain as well as from the gene makeup of the
luk-PV-transducing phage, lends support to the notion of an important role for PVL in human
furunculosis. These results make a case for the determination of
luk-PV in recurrent
soft tissue infections with
methicillin-sensitive as well as methicillin-resistant S. aureus.