Egea Ana L, Gagetti Paula, Lamberghini Ricardo, Faccone Diego, Lucero Celeste, Vindel Ana, Tosoroni Dario, Garnero Analía, Saka Hector A, Galas Marcelo, Bocco José L, Corso Alejandra, Sola Claudia
Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI) CONICET and Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
Servicio Antimicrobianos, Instituto Nacional de Enfermedades Infecciosas (INEI)-ANLIS "Dr. Carlos G. Malbrán", Ciudad Autónoma de Buenos Aires, Argentina.
Int J Med Microbiol. 2014 Nov;304(8):1086-99. doi: 10.1016/j.ijmm.2014.08.002. Epub 2014 Aug 12.
Methicillin-resistant Staphylococcus aureus (MRSA) burden is increasing 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 countrywide 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 work 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 (CACO) in those without HRFs]. MRSA strains were genetically typed as CA-MRSA and HA-MRSA genotypes (CA-MRSAG and HA-MRSAG) 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]. A significantly higher MRSA proportion among CO- than HAHO-S. aureus infections was detected (58% vs 49%); mainly in children (62% vs 43%). 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 were the highest risk group for healthcare-onset CA-MRSAG infections. Most CA-MRSAG 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, an isolate belonging to USA300-0114-(ST8-SCCmecIVa-spat008-PVL(+)-ACME(+)) was detected for the first time in Argentina. Most of HA-MRSAG (66%) were related to the Cordobes/Chilean clone-(PFGE-type A-ST5-SCCmecI-t149) causing 18% of all infections (47% of HAHO- and 13% of HACO-infections). Results strongly suggest that the CA-MRSA clone ST5-IV-PVL(+) has begun to spread within hospitals, replacing the traditional Cordobes/Chilean-HA-MRSA clone ST5-I-PVL(-), mainly in children. Importantly, a growing MRSA reservoir in the community was associated with spreading of two CA-MRSA clones: ST5-IV-PVL(+), mainly in children with HRFs, and ST30-IV-PVL(+) in adults without HRFs. This is the first nationwide study in Argentina providing information about the molecular and clinical epidemiology of CA-MRSA, particularly within hospitals, which is essential for designing effective control measures in this country and worldwide.
耐甲氧西林金黄色葡萄球菌（MRSA）在全球医院（医疗保健相关的（HA）-MRSA）和社区（社区相关的（CA）-MRSA）中的感染负担正在增加。然而，CA-MRSA在医院内的影响仍然有限，尤其是在拉丁美洲。通过对来自66家医院的591株临床分离株进行前瞻性横断面多中心研究（2009年11月），在阿根廷进行了一项全国代表性的金黄色葡萄球菌感染调查。这项工作涉及医疗保健起始感染（HAHO，住院超过48小时）和社区起始（CO）感染[包括有医疗保健相关风险因素（HRF）的患者中的感染（HACO）和无HRF的患者中的感染（CACO）]。通过SCCmec和spa分型、PFGE、MLST以及PCR检测毒力基因谱，将MRSA菌株基因分型为CA-MRSA和HA-MRSA基因型（CA-MRSAG和HA-MRSAG）。考虑所有分离株，63%来自CO感染，55%是MRSA[39%为CA-MRSAG，16%为HA-MRSAG]。在CO感染的金黄色葡萄球菌中检测到的MRSA比例显著高于HAHO感染（58%对49%）；主要在儿童中（62%对43%）。CA-MRSAG/HA-MRSAG在HAHO感染中占16%/33%，在HACO感染中占39%/13%，在CACO感染中占60.5%/0%。关于医疗保健起始CA-MRSAG感染患者多变量模型中确定的流行病学关联，CA-MRSAG在医院内的表现与HA-MRSAG相似，但儿童是医疗保健起始CA-MRSAG感染的最高风险群体。大多数CA-MRSAG属于两个主要克隆：PFGE型N-ST30-SCCmecIVc-t019-PVL（+）和PFGE型I-ST5-IV-SCCmecIVa-t311-PVL（+）（各占45%）。ST5-IV-PVL（+）/ST30-IV-PVL（+）克隆分别导致了所有感染的31%/33%、HAHO感染的20%/4%、HACO感染的43%/23%和CACO感染的35%/60%，在不同年龄组（儿童/成人）和地理区域存在显著差异。重要的是，在阿根廷首次检测到一株属于USA300-0114-（ST8-SCCmecIVa-spat008-PVL（+）-ACME（+））的分离株。大多数HA-MRSAG（66%）与科尔多瓦/智利克隆相关-（PFGE型A-ST5-SCCmecI-t149），导致所有感染的18%（HAHO感染的47%和HACO感染的13%）。结果强烈表明，CA-MRSA克隆ST5-IV-PVL（+）已开始在医院内传播，取代了传统的科尔多瓦/智利-HA-MRSA克隆ST5-I-PVL（-），主要在儿童中。重要的是，社区中不断增加的MRSA储存库与两个CA-MRSA克隆的传播有关：ST5-IV-PVL（+），主要在有HRF的儿童中，以及ST30-IV-PVL（+）在无HRF的成人中。这是阿根廷第一项全国性研究，提供了关于CA-MRSA分子和临床流行病学的信息，特别是在医院内，这对于在该国和全球设计有效的控制措施至关重要。
