Community-Associated Methicillin Resistant Staphylococcus aureus (CA-MRSA) infections are increasing worldwide.
In Argentina, the emergence and dissemination of the ST5 lineage among CA-MRSA strains has been reported. The
aim of this work was the study of the evolution of the clinical and molecular epidemiology of CA-MRSA infections
from a pediatric tertiary care public hospital in Córdoba, during 2003-2008.Prospectively, 64 consecutive single patient
CA-MRSA isolates were collected and the corresponding clinical and demographic information was associated during
six years (2003-2008) at the ?Hospital de Niños de la Santísima Trinidad? from Córdoba. Molecular typing studies were
performed. The proportion of CA-MRSA increased significantly between 2003(4%) and 2008(47%)-p=0.0001(CI95%:- 0.666 to -0.194) as well as the frequency of invasive infections [0%-2003 vs 36%(9/25)-2008] with higher levels during 2007 [59%(10/17)]. The average age of patients was 4 years old. Twenty-six of them had invasive infections, of which 11(42%) had bone and joint infections with torpid evolution associated. One of these was complicated with sepsis and pulmonary involvement, other with endocarditis and another one with brain abscesses. The remaining patients had: necrotizing pneumonia(4), primary bacteremy(4), necrotizing fasciitis(2) and adenitis(3). No patients died. Molecular analysis of the strains showed that 98% of them belong to the genotype: PulsotypeI-ST5-SCCmecIVa-spat311 that harbor Panton-Valentine-leukocidin and the enterotoxin A genes, which was previously reported as the predominant clone in Argentina during 2005-2006. Only two isolates were characterized as PulsotypeN-ST30-SCCmecIVc, which carried adhesin for bone sialoprotein-(bpp) and pvl genes.The results demonstrate that the dissemination of the clone ST5-IVa, PVL and EntA (+), which caused originally and preferentially mild skin and soft tissue infections, is now the main cause of the significant increase of invasive CA-MRSA infections during 2005-2008 in this hospital in Córdoba
performed. The proportion of CA-MRSA increased significantly between 2003(4%) and 2008(47%)-p=0.0001(CI95%:-
0.666 to -0.194) as well as the frequency of invasive infections [0%-2003 vs 36%(9/25)-2008] with higher levels during
2007 [59%(10/17)]. The average age of patients was 4 years old. Twenty-six of them had invasive infections, of which
11(42%) had bone and joint infections with torpid evolution associated. One of these was complicated with sepsis and
pulmonary involvement, other with endocarditis and another one with brain abscesses. The remaining patients had:
necrotizing pneumonia(4), primary bacteremy(4), necrotizing fasciitis(2) and adenitis(3). No patients died. Molecular
analysis of the strains showed that 98% of them belong to the genotype: PulsotypeI-ST5-SCCmecIVa-spat311 that
harbor Panton-Valentine-leukocidin and the enterotoxin A genes, which was previously reported as the predominant
clone in Argentina during 2005-2006. Only two isolates were characterized as PulsotypeN-ST30-SCCmecIVc, which
carried adhesin for bone sialoprotein-(bpp) and pvl genes.The results demonstrate that the dissemination of the clone
ST5-IVa, PVL and EntA (+), which caused originally and preferentially mild skin and soft tissue infections, is now the
main cause of the significant increase of invasive CA-MRSA infections during 2005-2008 in this hospital in Córdoba
