ST5-IVA genotype: as a major cause of invasive infections by CA-MRSA at a Pediatric Hospital in Córdoba, Argentina

SOLA C; ANALÍA GARNERO; CATALINA CULASSO; LYDIA CARVAJAL; PATRICIA MONTANARO; ANA L. EGEA; EDUARDO GLATSTEIN; JOSE LUIS BOCCO

Villa Carlos Paz

Congreso; VI Congreso Argentino de Microbiología General; 2009

Sociedad Argentina de Microbiología General

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 Córdoba2008) 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