Methicillin-resistant S. aureus belonging to CC121 responsible for invasive infections

EGEA AL; GONZALES L; MOYANO AJ; BOCCO JL; SOLA C

Potrero de Los Funes. San Luis

Congreso; XLVII Reunión anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular o; 2011

SAIB

Since 1990s methicillin resistant Staphylococcus aureus (MRSA) emerged as a community associated pathogen (CAMRSA) worldwide. Most CAMRSA carry the staphylococcal cassette chromosome (SCCmec) type IV and the Panton-Valentine leukocidin (PVL) gene. Successful lineages of MSSA PVL+ would behave as a reservoir for emergence of CAMRSA PVL+ clones. Although the CC121 is one of most dominant MSSA lineages, its genetic background seems to be incompatible for stable integration of SCCmec. The aim of this work was the molecular and clinical analysis of two cases of CAMRSA infections caused by strains belonging to the lineage CC121 by molecular typing methods. These strains were isolated from children (11 and 14 years old) hospitalized in a tertiary care public hospital in Córdoba. They were affected by osteomielitis with torpid evolution; one of them was complicated with sepsis. Molecular analysis of the strains showed that both belong to CC121 characterized by: Pulsotype V-ST1210 (CC121), agr 4, SCCmec IVa-spa t645. They harbor the following genes pvl, Enterotoxin B, cluster egc, adhesins for bone sialoprotein-binding protein (bbp) and for collagen (cna). We demonstrated the emergence of two MRSA isolates PVL+ belonging to CC121, associated to SCCmecIVa. As far as we know, this genetic background has never been reported in MRSA, moreover this clone have all the genetic potential to becoming an epidemic CAMRSA