Robert Koch Institute, Infectious Diseases, Wernigerode Branch, Burgstraße 37, D-38855 Wernigerode, Germany.
Int J Med Microbiol. 2011 Feb;301(2):165-75. doi: 10.1016/j.ijmm.2010.08.015. Epub 2010 Oct 15.
Enterococcus faecium is considered to be a nosocomial pathogen with increasing medical importance. The putative virulence factor, hyl(Efm), encoding a putative hyaluronidase, is enriched among the hospital-associated polyclonal subpopulation of E. faecium.. The hyl(Efm) gene is described to be part of a genomic island and was recently identified to be plasmid-located. Here, we present a description of the structure, localization, and distribution of the putative pathogenicity factor hyl(Efm) and its putative island among 39 clinical isolates and elucidate the composition and host range of pLG1, a hyl(Efm) multiresistance plasmid of approximately 281.02kb. The hyl(Efm) gene was located within a 17,824-bp element highly similar to the putative genomic island (GI) structure that had been previously described. This genomic region was conserved among 39 hyl(Efm)-positive strains with variation in a specific region downstream of hyl(Efm) in 18 strains. The putative hyl(Efm) was located on large plasmids (150-350kb) in 37 strains. pLG1 could be horizontally transferred into four different E. faecium recipient strains (n=4) but not into E. faecalis (n=3). Sequencing of pLG1 resolved putative plasmid replication, conjugation, and maintenance determinants as well as a pilin gene cluster, carbon uptake and utilization genes, heavy metal and antibiotic resistance clusters. The hyl(Efm) transferable plasmid pLG1 bears additional putative pathogenicity factors and antibiotic resistance genes. These findings suggest horizontal gene transfer of virulence factors and antibiotic resistance gene clusters by a single genetic event (conjugative transfer) which might be triggered by heavy antibiotic use common in health care units where E. faecium is increasingly prevalent.
屎肠球菌被认为是一种具有日益重要医学意义的医院病原体。假定的毒力因子 hyl(Efm)，编码一种假定的透明质酸酶，在屎肠球菌的医院相关多克隆亚群中富集。hyl(Efm)基因被描述为基因组岛的一部分，最近被鉴定为质粒定位。在这里，我们描述了假定的致病性因子 hyl(Efm)及其假定的岛在 39 株临床分离株中的结构、定位和分布，并阐明了 hyl(Efm)多抗性质粒 pLG1 的组成和宿主范围，pLG1 约为 281.02kb。hyl(Efm)基因位于一个与先前描述的假定基因组岛 (GI)结构高度相似的 17824bp 元件内。这个基因组区域在 39 株 hyl(Efm)阳性株中是保守的，在 18 株中有 hyl(Efm)下游的特定区域发生变异。假定的 hyl(Efm)位于 37 株大质粒（150-350kb）上。pLG1 可以水平转移到 4 种不同的屎肠球菌接受株（n=4），但不能转移到屎肠球菌（n=3）。pLG1 的测序确定了假定的质粒复制、共轭和维持决定因素以及一个 pilin 基因簇、碳摄取和利用基因、重金属和抗生素抗性簇。可转移的 hyl(Efm)质粒 pLG1 还具有其他假定的致病性因子和抗生素抗性基因。这些发现表明，毒力因子和抗生素抗性基因簇的水平基因转移是由一个单一的遗传事件（共轭转移）引起的，这可能是由卫生保健单位中普遍存在的大量抗生素使用引发的。
