Import and spread of Panton-Valentine Leukocidin-positive Staphylococcus aureus through nasal carriage and skin infections in travelers returning from the tropics and subtropics.

ABSTRACT

BACKGROUND: Antibiotic-resistant Staphylococcus aureus is a globally emerging pathogen. Exchangeable virulence factors, such as Panton-Valentine leukocidin (PVL), have been proposed to drive this epidemic. We investigated whether skin infections and nasal colonization in travelers contribute to the global spread of such strains. METHODS: We conducted a case-control study of 38 returnees from the tropics and subtropics with S. aureus-positive skin and soft tissue infections (SSTIs) and 124 control patients with other travel-associated disorders. We collected information on travel characteristics, clinical outcomes of SSTIs, antibiotic sensitivity patterns, and genotypes of S. aureus strains isolated from skin lesions and the nares. RESULTS: S. aureus-positive SSTIs were associated with travel duration and purpose and were most common in returnees from Africa (odds ratio, 4.2; P = .005). PVL-positive (PVL(+)) S. aureus was frequent in the lesional and nasal isolates from travelers with SSTIs but could not be found in the nares of the control patients. The presence of PVL in S. aureus in travelers was associated with complicated disease, reduced antibiotic susceptibility, and secondary spread. The genotypes of PVL(+) S. aureus in returnees were reported to be endemic to the visited destination but rarely observed in Europe. CONCLUSIONS: Geographic variation in the risk of SSTIs in travelers supports a globally heterogeneous distribution of virulent S. aureus. Complicated SSTIs in returnees from nontemperate climates are associated with PVL(+) S. aureus and promote the emergence and spread of virulent and antibiotic-resistant strains. We propose a network for the surveillance of imported S. aureus (www.staphtrav.eu).