Paediatric musculoskeletal infections with Panton-Valentine leucocidin.

Paediatric musculoskeletal infections by Panton-Valentine leucocidin (PVL)-producing Staphylococcus aureus constitute a rare, but highly critical event. They are characterised by a rapid course of marked inflammation, worsening under conservative therapy and a high rate of recurrence. This study aimed to illustrate the importance of paediatric PVL-producing S. aureus musculoskeletal infections in western Switzerland. Case records, clinical parameters and biological assessments of children with musculoskeletal infections due to PVL-producing S. aureus who attended the University Hospitals of Lausanne and Geneva from 2008 to 2016 were studied retrospectively. Of the nine cases (seven male), four presented with haematogenous acute osteomyelitis, two with septic arthritis, and three with skin and soft tissue infections. Laboratory analysis revealed mean values for white blood cell count of 12,700/mm3, C-reactive protein (CRP) 171mg/l, erythrocyte sedimentation rate (ESR) 62 mm/h and platelet count 241,000/mm3. Notably, fever and laboratory values were higher for osteoarticular infections. PVL was produced by methicillin-sensitive S. aureus (MSSA) in eight cases and by community-acquired methicillin-resistant S. aureus (CA-MRSA) in one case. PVL was identified in blood cultures (six cases), operative samples (seven cases) and an oral swab (one case). Treatment relied on surgical procedures, endorsed by two-agent antimicrobial therapy for up to 9 weeks. Complications included recurrent infections (five cases), pathological fracture (one case) and growth arrest (two cases), as well as an important psychological impact (one case). The results of this study highlight the low prevalence of PVL-producing S. aureus musculoskeletal infections in the paediatric population in our region. Nevertheless, given the importance of complications, the recurrence rate and the duration of treatment, clinicians caring for children need to be especially well versed with the peculiarity of this entity. Retrospective case series. IV