Background: All Staphylococcus aureus isolated during 2003-2006 at a university hospital in Thessalia, central Greece, from ulcerative upper-extremity infections were tested for the presence of PVL gene and for possible clonal relationship to validate the role of PVL toxin in the clinical features of these infections and also to establish preventive measures towards limiting the spread of such strains among close contacts.
Material and Method: Of 305 bacterial cultures obtained from consecutive patients suffering from purulent musculoskeletal infections of an upper extremity, 207 revealed the presence of S. aureus (81 methicillin-resistant and 126 methicillin-sensitive). Seventy of the 207 cultures were found to be positive for the PVL gene.
Results: The PVL gene was detected in 12.1% (2003), 46.7% (2004), 34% (2005), and 53% (2006) of upper-extremity staphylococcal infections, indicating a statistically significant increase between 2003 and 2004-2006. However, there was a significant decrease in readmissions during 2005 and 2006 and also in the number of relatives diagnosed with PVL-positive infections during the same period of time. The localization of these infections, their higher incidence during summer, and the transmission to family members indicated that contact was the means of spread of PVL-positive S. aureus. Most isolates belonged to the ST-80 clone, predominant in Europe.
Conclusions: The emergence of new MRSA and also MSSA clones carrying the PVL gene and the decreases in readmissions and number of infected "close contacts" emphasizes the need for closer systematic surveillance and the implementation of preventive measures.

Keywords: Upper Extremity - pathology, young adult, Staphylococcus aureus - pathogenicity, Staphylococcal Infections - pathology, Microbial Sensitivity Tests, Methicillin-Resistant Staphylococcus aureus - pathogenicity, Leukocidins - genetics, Greece, Exotoxins - genetics, Drug Resistance, Bacterial, Child, Preschool, Child, Bacterial Toxins - genetics, Aged, 80 and over, Adult, Adolescent