Genomic Epidemiology of Methicillin-Resistant Staphylococcus aureus in a Neonatal Intensive Care Unit
Genomic Epidemiology of Methicillin-Resistant Staphylococcus aureus in a Neonatal Intensive Care Unit
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DOI：
10.1371/journal.pone.0164397
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发表时间：
2016-10-12
期刊：
影响因子：
3.7
通讯作者：
Salemi, Marco
中科院分区：
文献类型：
--
作者：
Azarian, Taj;Maraqa, Nizar F.;Salemi, Marco
尽管采取了预防感染的措施，但新生儿重症监护病房（NICU）患者仍存在耐甲氧西林金黄色葡萄球菌（MRSA）感染的风险。卫生保健相关（HA）和社区相关（CA）MRSA的传播模式仍然知之甚少，可能因基因型而异，阻碍了有效预防和控制策略的制定。从2008年至2010年，所有入住III级NICU的患者均接受了MRSA定植筛查，所有可用的分离株均为SPA分型。对美国最流行的CA基因型spa型t008、HA相关基因型spa型t045和2003-2011年分离的菌株的便利样品进行全基因组测序和PCR动态分析。比较了定植和非定植婴儿的患者危险因素，比较了spa型t008和非t008菌株的毒力和耐药基因。流行病学和基因组数据被用来估计MRSA输入和收购通过传输重建。在9.1%（177/1940）的住院婴儿中发现了MRSA定植，并与低胎龄和出生体重相关。在定植的婴儿中，低胎龄在t008菌株定植的婴儿中更为常见。我们的数据表明，大约70%的定植是NICU内传播事件的结果，其余的可能反映了“外部”菌株的输入。虽然在新生儿重症监护病房内的传播风险不受SPA型的影响，但t008和t045菌株之间的获得和输入模式不同。系统动力学分析表明，spa型t008菌株在社区和医院的有效种群数量呈指数增长，spa型t008菌株具有t045菌株中未发现的毒力基因;相比之下，t045菌株似乎起源较近，可能有医院来源。我们的数据强调了NICU内传播和NICU环境内MRSA定植维持的反复引入的重要性，以及流行病学中的SPA类型特异性差异。
Despite infection prevention efforts, neonatal intensive care unit (NICU) patients remain at risk of Methicillin-resistant Staphylococcus aureus (MRSA) infection. Modes of transmission for healthcare-associated (HA) and community-associated (CA) MRSA remain poorly understood and may vary by genotype, hindering the development of effective prevention and control strategies. From 2008-2010, all patients admitted to a level III NICU were screened for MRSA colonization, and all available isolates were spa-typed. Spa-type t008, the most prevalent CA- genotype in the United States, spa-type t045, a HA- related genotype, and a convenience sample of strains isolated from 2003-2011, underwent whole-genome sequencing and phylodynamic analysis. Patient risk factors were compared between colonized and noncolonized infants, and virulence and resistance genes compared between spa-type t008 and non-t008 strains. Epidemiological and genomic data were used to estimate MRSA importations and acquisitions through transmission reconstruction. MRSA colonization was identified in 9.1% (177/1940) of hospitalized infants and associated with low gestational age and birth weight. Among colonized infants, low gestational age was more common among those colonized with t008 strains. Our data suggest that approximately 70% of colonizations were the result of transmission events within the NICU, with the remainder likely to reflect importations of "outside" strains. While risk of transmission within the NICU was not affected by spa-type, patterns of acquisition and importation differed between t008 and t045 strains. Phylodynamic analysis showed the effective population size of spa-type t008 has been exponentially increasing in both community and hospital, with spa-type t008 strains possessed virulence genes not found among t045 strains; t045 strains, in contrast, appeared to be of more recent origin, with a possible hospital source. Our data highlight the importance of both intra-NICU transmission and recurrent introductions in maintenance of MRSA colonization within the NICU environment, as well as spa-type-specific differences in epidemiology.