CC8 MRSA Strains Harboring SCCmec Type IVc are Predominant in Colombian Hospitals

Abstract

Background Recent reports highlight the incursion of community-associated MRSA within healthcare settings. However, knowledge of this phenomenon remains limited in Latin America. The aim of this study was to evaluate the molecular epidemiology of MRSA in three tertiary-care hospitals in Medellín, Colombia. Methods An observational cross-sectional study was conducted from 2008–2010. MRSA infections were classified as either community-associated (CA-MRSA) or healthcare-associated (HA-MRSA), with HA-MRSA further classified as hospital-onset (HAHO-MRSA) or community-onset (HACO-MRSA) according to standard epidemiological definitions established by the U.S. Centers for Disease Control and Prevention (CDC). Genotypic analysis included SCC mec typing, spa typing, PFGE and MLST. Results Out of 538 total MRSA isolates, 68 (12.6%) were defined as CA-MRSA, 243 (45.2%) as HACO-MRSA and 227 (42.2%) as HAHO-MRSA. The majority harbored SCC mec type IVc (306, 58.7%), followed by SCC mec type I (174, 33.4%). The prevalence of type IVc among CA-, HACO- and HAHO-MRSA isolates was 92.4%, 65.1% and 43.6%, respectively. From 2008 to 2010, the prevalence of type IVc-bearing strains increased significantly, from 50.0% to 68.2% ( p = 0.004). Strains harboring SCC mec IVc were mainly associated with spa types t1610, t008 and t024 (MLST clonal complex 8), while PFGE confirmed that the t008 and t1610 strains were closely related to the USA300-0114 CA-MRSA clone. Notably, strains belonging to these three spa types exhibited high levels of tetracycline resistance (45.9%). Conclusion CC8 MRSA strains harboring SCC mec type IVc are becoming predominant in Medellín hospitals, displacing previously reported CC5 HA-MRSA clones. Based on shared characteristics including SCC mec IVc, absence of the ACME element and tetracycline resistance, the USA300-related isolates in this study are most likely related to USA300-LV, the recently-described ‘Latin American variant’ of USA300.

Staphylococcus aureus resistente a meticilina causante de infecciones comunitarias y de infecciones asociadas a la atención en salud en pacientes pediátricos del Hospital Universitario de Santander

“…Both were present in all three types of infection. This result supports the previous reports of studies in our country, which have shown the predominance of the SCCmec IVc subtype among isolates, followed by a smaller proportion for SCCmec IVa (40,41).…”

“…Among the MRSA isolates tested in our study, 88% carried the lukS/F-PV genes, and these genes were detected in all SCCmec types identified (SCCmec IVc, Iva and I). In Colombia, there have been several reports of infections caused by PVL-positive MRSA strains carrying SCCmec IVc belonging to clonal complex 8 (CC8) in hospitals (13,(41)(42)(43). In a recent previous work, we reported the ST8-MRSA-IVc clone as the main strain causing HAI (13).…”

Cambios a lo largo del tiempo en la distribución de los complejos de clones dominantes de Staphylococcus aureus resistente a la meticilina en Medellín, Colombia

“…Se incluyeron aislamientos de SARM obtenidos de pacientes hospitalizados con infección, y recolectados en dos periodos diferentes: 67 aislamientos recolectados de forma prospectiva, obtenidos durante el año 1994, y 331 aislamientos recolectados de forma prospectiva y obtenidos entre febrero de 2008 y junio de 2010. Estos últimos aislamientos hacían parte de un estudio reportado previamente (14). En ambos periodos de estudio se incluyó una muestra por paciente correspondiente al primer aislamiento clínico de SARM obtenido durante el proceso infeccioso.…”

“…En Colombia se han identificado clones de SARM-AH como el pediátrico, el brasilero y el chileno/cordobés, principalmente en hospitales de tercer nivel en Bogotá (9)(10)(11). Asimismo, el clon de SARM-AC USA300 (CC8-ST8-SCCmecIV) se ha descrito como causante de infecciones hospitalarias (12)(13)(14).…”

Aislamientos de Staphylococcus aureus sensibles a meticilina relacionados genéticamente con el clon USA300, ¿origen de los aislamientos SARM de genotipo comunitario en Colombia?

“…En Colombia y en varios países de Suramérica se ha reportado la diseminación de aislamientos SARM asociados a la comunidad (SARM-AC), los cuales causan infecciones no solo en personas en la comunidad, sino también en pacientes hospitalizados (8)(9)(10)(11). La mayoría de estos aislamientos presentan características moleculares similares al clon USA300 diseminado en Estados Unidos: la ST8 y los genes lukS-PV/lukF-PV, seq, sek y bsa (8)(9)(10).…”