[Outbreak of skin infections due to Staphylococcus aureus carrying Panton-Valentine leukocidin genes in pupils and their relatives]. / Épidémie d'infections cutanées àStaphylococcus aureus porteur des gènes codant la leucocidine de Panton-Valentine en milieu scolaire et familial.

OBJECTIVES: The study objectives were to describe an outbreak of skin infections in school settings, caused by Staphylococcus aureus carrying Panton-Valentine leukocidin genes (Sa PVL(+)), over a 2-year period. Nasal colonization prevalence was assessed in families where new skin infections occurred, despite a prevention and control strategy. PATIENTS AND METHODS: A retrospective investigation of skin infections likely to be related to Sa and prospective monitoring and treatment of new infections occurring in pupils and their family members were implemented in October 2006, following the reporting of Sa PVL(+) abscesses and furuncles in a primary school. Additional nasal screening was performed in families where new skin infections occurred, after an initial systematic screening of Sa PVL(+) nasal carriers. RESULTS: On October 31, 2008, 53 patients, accounting for 30 households, had developed 69 skin infections, in four decreasing outbreaks. The cumulative incidence of a first skin infection was 34.6% in primary classes, 21.3% in nursery schools, and 6.5% in the pupils' family households. Several skin infections were reported in 13 households, and in one of them, all of the seven family members had developed at least one skin infection during follow-up. The estimated frequency of nasal colonization ranged from 14.1% to 19.5% according to successive nasal screenings. CONCLUSION: Early reporting of skin infection clusters is necessary to reinforce the effectiveness of hygiene and prevention measures, and thus limit the risk of a long-lasting outbreak.

[Staphylococcus aureus carrying Panton-Valentine leukocidin genes nasal colonization and skin infection: screening in case of outbreak in a school environment]. / Colonisation nasale et infections cutanées à Staphylococcus aureus porteur du gène codant la leucocidine de Panton-Valentine: dépistage lors d'une épidémie en milieu scolaire.

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.