Staphylococcus aureus carrying Panton-Valentine leukocidin genes nasal colonization and skin infection: screening in case of outbreak in a school environment

Objectives

An outbreak of Staphylococcus aureus (SA) carrying the gene coding for Panton-Valentine leukocidin (PVL) skin infections in a primary school was investigated and monitored in the Val-d’Oise region (Greater Paris) in 2006.

Patients and methods

Skin infections reported after the beginning of the school year in primary-school teachers, students and their relatives were diagnosed and treated at the local hospital and screening for nasal colonization was implemented. A patient presenting with folliculitis, an abscess or furuncle with a positive-skin test or nasal swab for SA-PV was considered to be a case of infection. Colonization was defined as identification of SA-PVL in a nasal swab in the absence of skin lesions. In addition to recommended control measures, treatment by topical intranasal mupirocin was prescribed to all colonized patients and relatives of infected patients.

Results

Over five months, 22 cases of PVL-positive SA skin infections, including a case of simple folliculitis, were confirmed in 15 primary-school students (attack rate = 18.5%) and seven relatives. The occurrence of nasal colonization in relatives not attending the same school ranged from 0 to 30% according to the number of cases of skin infection in the family (p < 0,01). Two-thirds of patients treated with mupirocin were decolonized.

Conclusion

Transmission of this SA strain in school and family environments confirms the epidemic potential of PVL-positive isolates; however, screening for nasal colonization should be restricted to cases of skin infection and people in their immediate environment.