Staphylococcus aureus abscesses: methicillin-resistance or Panton-Valentine leukocidin presence?

Introduction Panton-Valentine leukocidin (PVL) is a toxin associated with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) worldwide and also occurs in community-associated methicillin-susceptible S aureus (CA-MSSA) strains. The aims of the study were to determine the prevalence of PVL in community-onset S aureus skin and soft-tissue infections (SSTIs) and to analyse the influence of methicillin resistance and PVL presence on the clinical characteristics of these infections. Patients and methods We prospectively enrolled all children with S aureus community-onset SSTIs attending the emergency department of a tertiary hospital between 2007 and 2009. Results A total of 142 S aureus SSTIs were identified, 46 (32%) were PVL positive. The proportion of subjects in each group was: 89 (63%) PVL-MSSA, 33 (23%) PVL+MSSA, 13 (9%) PVL+MRSA and 7 (5%) PVL-MRSA. PVL+infections were more frequently abscesses (63% vs 39%, p<0.01), and more often required incision and drainage (p<0.01) and hospital admission (46% vs 26%, p=0.02). MRSA infections were also more frequently associated with abscesses but in a multivariable analysis only PVL remained independently related (OR 2.33; 95% CI 1.10 to 4.90). Conclusions Our study found a high prevalence of PVL presence in community-onset S aureus SSTIs in children in Spain. This toxin is associated with more abscess formation, regardless of methicillin resistance.