Service of Hospital Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland.
PLoS One. 2012;7(6):e38969. doi: 10.1371/journal.pone.0038969. Epub 2012 Jun 18.
Staphylococcus aureus is recognized as one of the major human pathogens and is by far one of the most common nosocomial organisms. The genetic basis for the emergence of highly epidemic strains remains mysterious. Studying the microevolution of the different clones of S. aureus is essential for identifying the forces driving pathogen emergence and spread. The aim of the present study was to determine the genetic changes characterizing a lineage belonging to the South German clone (ST228) that spread over ten years in a tertiary care hospital in Switzerland. For this reason, we compared the whole genome of eight isolates recovered between 2001 and 2008 at the Lausanne hospital. The genetic comparison of these isolates revealed that their genomes are extremely closely related. Yet, a few more important genetic changes, such as the replacement of a plasmid, the loss of large fragments of DNA, or the insertion of transposases, were observed. These transfers of mobile genetic elements shaped the evolution of the ST228 lineage that spread within the Lausanne hospital. Nevertheless, although the strains analyzed differed in their dynamics, we have not been able to link a particular genetic element with spreading success. Finally, the present study showed that new sequencing technologies improve considerably the quality and quantity of information obtained for a single strain; but this information is still difficult to interpret and important investments are required for the technology to become accessible for routine investigations.
金黄色葡萄球菌被认为是主要的人类病原体之一，迄今为止也是最常见的医院病原体之一。高度流行菌株出现的遗传基础仍然神秘。研究金黄色葡萄球菌不同克隆的微进化对于确定驱动病原体出现和传播的力量至关重要。本研究的目的是确定在瑞士一家三级保健医院传播了十年的属于南德克隆（ST228）的谱系的特征性遗传变化。为此，我们比较了洛桑医院在 2001 年至 2008 年间分离的 8 株的全基因组。这些分离株的遗传比较表明，它们的基因组非常密切相关。然而，观察到了一些更重要的遗传变化，例如质粒的替换、大片段 DNA 的丢失或转座酶的插入。这些移动遗传元件的转移塑造了在洛桑医院内部传播的 ST228 谱系的进化。然而，尽管分析的菌株在动力学上有所不同，我们还无法将特定的遗传元件与传播成功联系起来。最后，本研究表明，新的测序技术极大地提高了单个菌株获得的信息量和质量；但信息仍然难以解释，需要大量投资才能使该技术可用于常规研究。
