Comparative Prevalence of Immune Evasion Complex Genes Associated with β-Hemolysin Converting Bacteriophages in MRSA ST5 Isolates from Swine, Swine Facilities, Humans with Swine Contact, and Humans with No Swine Contact.
Comparative Prevalence of Immune Evasion Complex Genes Associated with β-Hemolysin Converting Bacteriophages in MRSA ST5 Isolates from Swine, Swine Facilities, Humans with Swine Contact, and Humans with No Swine Contact.
复制标题
免疫逃避复合物基因的比较患病率与β-羟蛋白蛋白相关的MRSA ST5分离株中的β-蛋白酶相关的基因从猪，猪设施，具有猪接触的人类和没有猪接触的人类中的人类中转化。
DOI：
10.1371/journal.pone.0142832
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Nicholson TL
中科院分区：
文献类型：
--
作者：
Hau SJ;Sun J;Davies PR;Frana TS;Nicholson TL
家畜相关耐甲氧西林金黄色葡萄球菌（LA-MRSA）引起了公共卫生界的关注，因为在一些国家，这些微生物可能是医院环境外最大的MRSA储存库。最近的研究表明，来自猪的LA-MRSA菌株比首次报道的序列类型ST 398更具遗传多样性。在美国，发现了LA-MRSA的多样化群体，包括ST 398、ST 9和ST 5谱系的生物体。猪中ST 5 MRSA的发生特别令人担忧，因为ST 5是引起人类临床感染的最流行谱系之一。ST 5在临床疾病中的突出被认为是由于获得含有毒力或宿主适应性基因的噬菌体，包括由β-溶血素转化噬菌体携带的免疫逃避簇（IEC）基因，其在LA-MRSA ST 398中的缺失被认为有助于降低与该谱系相关的人类感染和传播的速率。本研究的目的是研究从农业来源（包括猪、养猪设施和短期或长期暴露于猪的人）获得的MRSA ST 5分离株中与β-溶血素转化噬菌体相关的IEC基因的流行率。为了获得更广泛的视角，将这些基因在LA-MRSA ST 5菌株中的流行率与来自人类的临床MRSA ST 5菌株中的流行率进行了比较，这些菌株没有已知的猪暴露。IEC基因不存在于来自农业来源的任何测试的MRSA ST 5菌株中，并且β-溶血素基因在这些菌株中是完整的，表明噬菌体不存在。相比之下，来自未暴露于猪的人的MRSA ST 5菌株中β-溶血素转化噬菌体的流行率为90.4%。在LA-MRSA ST 5分离株中不存在β-溶血素转化噬菌体，这与先前评价ST 398菌株的报告一致，并提供了遗传证据，表明LA-MRSA ST 5分离株可能具有降低的在免疫活性人体中引起严重疾病的能力。
Livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) draws concern from the public health community because in some countries these organisms may represent the largest reservoir of MRSA outside hospital settings. Recent studies indicate LA-MRSA strains from swine are more genetically diverse than the first reported sequence type ST398. In the US, a diverse population of LA-MRSA is found including organisms of the ST398, ST9, and ST5 lineages. Occurrence of ST5 MRSA in swine is of particular concern since ST5 is among the most prevalent lineages causing clinical infections in humans. The prominence of ST5 in clinical disease is believed to result from acquisition of bacteriophages containing virulence or host-adapted genes including the immune-evasion cluster (IEC) genes carried by β-hemolysin converting bacteriophages, whose absence in LA-MRSA ST398 is thought to contribute to reduced rates of human infection and transmission associated with this lineage. The goal of this study was to investigate the prevalence of IEC genes associated with β-hemolysin converting bacteriophages in MRSA ST5 isolates obtained from agricultural sources, including swine, swine facilities, and humans with short- or long-term swine exposure. To gain a broader perspective, the prevalence of these genes in LA-MRSA ST5 strains was compared to the prevalence in clinical MRSA ST5 strains from humans with no known exposure to swine. IEC genes were not present in any of the tested MRSA ST5 strains from agricultural sources and the β-hemolysin gene was intact in these strains, indicating the bacteriophage’s absence. In contrast, the prevalence of the β-hemolysin converting bacteriophage in MRSA ST5 strains from humans with no exposure to swine was 90.4%. The absence of β-hemolysin converting bacteriophage in LA-MRSA ST5 isolates is consistent with previous reports evaluating ST398 strains and provides genetic evidence indicating LA-MRSA ST5 isolates may harbor a reduced capacity to cause severe disease in immunocompetent humans.