An increasing resistance to vancomycin among clinically relevant enterococci, such as Enterococcus faecalis and Enterococcus faecium is a cause of a great concern, as it seriously limits treatment options. The vanB operon is one of most common determinants of this type of resistance. Genes constituting the operon are located in conjugative transposons, such as Tn1549-type transposons or, more rarely, in ICEEfaV583-type structures. Such elements show differences in structure and size, and reside in various sites of bacterial chromosome or, in the case of Tn1549-type transposons, are also occasionally associated with plasmids of divergent replicon types. While conjugative transposition contributes to the acquisition of Tn1549-type transposons from anaerobic gut commensals by enterococci, chromosomal recombination and conjugal transfer of plasmids appear to represent main mechanisms responsible for horizontal dissemination of vanB determinants among hospital E. faecalis and E. faecium.

This review focuses on diversity of genetic elements harbouring vanB determinants in hospital-associated strains of E. faecium and E. faecalis, the mechanisms beyond vanB spread in populations of these bacteria, and provides an overview of the vanB-MGE distribution among other enterococci and Gram-positive bacteria as potential reservoirs of vanB genes.

临床相关肠球菌（如粪肠球菌和屎肠球菌）对万古霉素的耐药性日益增加，这是一个令人非常担忧的原因，因为它严重限制了治疗选择。所述vanB操纵子是这种类型的抗性的最常见因素之一。构成操纵子的基因位于接合转座子中，例如 Tn 1549型转座子，或者更罕见地位于 ICE Efa V583 型结构中。这些元件在结构和大小上表现出差异，并且存在于细菌染色体的不同位点，或者在 Tn 1549的情况下型转座子，偶尔也与不同复制子类型的质粒相关。虽然共轭转置有助于采集Tn的1549从由肠球菌，染色体重组和质粒的接合转移厌氧肠道共生型转座子似乎代表负责的水平传播主要机制vanB医院中的决定因素粪肠球菌和屎肠球菌。

本综述的重点是在医院相关的粪肠球菌和粪肠球菌菌株中含有vanB决定因素的遗传元件的多样性，vanB在这些细菌种群中的传播机制，并概述了vanB- MGE 在其他肠球菌和革兰氏阳性菌作为vanB基因的潜在储存库。