New patterns of methicillin-resistant Staphylococcus aureus (MRSA) clones, community-associated MRSA genotypes behave like healthcare-associated MRSA genotypes within hospitals, Argentina.

EGEA A.L.; GAGETTI P.; LAMBERGHINI R.O.; FACCONE D.; LUCERO C.; GALAS M.; VINDEL A.; TOSORONI D.; MRSA CORDOBA STUDY GROUP; BOCCO J.L.; CORSO A.; SOLA C.

INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY (PRINT)

ELSEVIER GMBH

Lugar: Jena; Año: 2014

1438-4221

Methicillin-resistant Staphylococcus aureus (MRSA) burden is increasingly worldwide in hospitals [healthcare-associated (HA)-MRSA] and in communities [community-associated (CA)-MRSA]. However, the impact of CA-MRSA within hospitals remains limited, particularly in Latin America. A nationally representative survey of S. aureus infections was performed in Argentina by analyzing 591 clinical isolates from 66 hospitals in a prospective-cross-sectional-multicenter-study (Nov-2009). This study involved healthcare-onset infections-(HAHO, >48 hospitalization hours) and community-onset (CO) infections [including both, infections (HACO) in patients with healthcare-associated risk-factors (HRFs) and infections in those without HRFs, (CACO)]. MRSA strains were genetically typed as CA-MRSAG and HA-MRSAG genotypes (G) or strain type, by SCCmec- and spa-typing, PFGE, MLST and virulence genes profile by PCR. Considering all isolates, 63% were from CO- infections and 55% were MRSA [39% CA-MRSAG and 16% HA-MRSAG]. MRSA proportion differed significantly between CO- and HAHO- infections (58% vs 49%, P=0.045); mainly in children, 62% vs 43%, P=0.01). The CA-MRSAG/HA-MRSAG have accounted for 16%/33% of HAHO-, 39%/13% of HACO- and 60.5%/0% of CACO- infections. Regarding the epidemiological associations identified in multivariate models for patients with healthcare-onset CA-MRSAG infections, CA-MRSAG behave like HA-MRSAG within hospitals but children was the highest risk group for healthcare-onset CA-MRSAG infections. Most CA-MRSAG strains types belonged to two major clones: PFGE-type N-ST30-SCCmecIVc-t019-PVL+ and PFGE-type I-ST5-IV-SCCmecIVa-t311-PVL+ (45% each). The ST5-IV-PVL+ /ST30-IV-PVL+ clones have caused 31%/33% of all infections, 20%/4% of HAHO-, 43%/23% of HACO- and 35%/60% of CACO- infections, with significant differences by age groups (children/adults) and geographical regions. Importantly, the first isolate belonging to USA300-0114-(ST8-SCCmecIVa-spat008-PVL+-ACME+) was detected in Argentina. Most HA-MRSAG strains types (66%) were related to the Cordobes/Chilean clone-( PFGE-type A-ST5-SCCmecI-t149) which has caused 18% of all infections (47% of HAHO- and 13% of HACO- infections). Results suggest that the clone ST5-IV-PVL has begun to spread within hospitals, replacing the Cordobes/Chilean-HA-MRSA clone ST5-I- PVL-, mainly in children. Importantly, greater MRSA rates in CO- than HO-infections were associated with spreading of two CA-MRSA clones: ST5-IV-PVL+, mainly in children with HRFs, and ST30-IV-PVL+ in adults without HRFs mainly in northern and center regions of Argentina. This study provides information about the molecular and clinical epidemiology of CA-MRSA, particularly within hospitals, which is essential for designing effective control measures in Argentina and worldwide.