Unit of Microbiology, Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy.
Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy.
J Antimicrob Chemother. 2017 Sep 1;72(9):2447-2453. doi: 10.1093/jac/dkx197.
To analyse the recombination events associated with conjugal mobilization of two multiresistance plasmids, pRUM17i48 and pLAG (formerly named pDO1-like), from Enterococcus faecium 17i48 to Enterococcus faecalis JH2-2.
The plasmids from two E. faecalis transconjugants (JH-4T, tetracycline resistant, and JH-8E, erythromycin resistant) and from the E. faecium donor (also carrying a pHTβ-like conjugative plasmid, named pHTβ17i48) were investigated by several methods, including PCR mapping and sequencing, S1-PFGE followed by Southern blotting and hybridization, and WGS.
Two locations of repApHTβ were detected in both transconjugants, one on a ∼50 kb plasmid (as in the donor) and the other on plasmids of larger sizes. In JH-4T, WGS disclosed an 88.6 kb plasmid resulting from the recombination of pHTβ17i48 (∼50 kb) and a new plasmid, named pLAG (35.3 kb), carrying the tet(M), tet(L), lsa(E), lnu(B), spw and aadE resistance genes. In JH-8E, a 75 kb plasmid resulting from the recombination of pHTβ17i48 and pRUM17i48 was observed. In both cases, the cointegrates were apparently derived from replicative transposition of an IS1216 present in each of the multiresistance plasmids into pHTβ17i48. The cointegrates could resolve to yield the multiresistance plasmids and a pHTβ17i48 derivative carrying an IS1216 (unlike the pHTβ17i48 of the donor).
Our results completed the characterization of the multiresistance plasmids carried by the E. faecium 17i48, confirming the role of pHT plasmids in the mobilization of non-conjugative antibiotic resistance elements among enterococci. Results also revealed that mobilization to E. faecalis was associated with the generation of cointegrate plasmids promoted by IS1216-mediated transposition.
分析与屎肠球菌 17i48 中两种多药耐药质粒 pRUM17i48 和 pLAG（以前称为 pDO1 样）的接合转移相关的重组事件，转移至屎肠球菌 JH2-2。
从两个屎肠球菌转导子（JH-4T，四环素耐药，JH-8E，红霉素耐药）和供体屎肠球菌（也携带一种命名为 pHTβ17i48 的可接合质粒 pHTβ 样质粒）中通过多种方法（包括 PCR 图谱和测序、S1-PFGE 后 Southern 印迹和杂交以及 WGS）研究质粒。
在两个转导子中均检测到 repApHTβ 的两个位置，一个位于约 50kb 质粒（与供体相同），另一个位于较大大小的质粒上。在 JH-4T 中，WGS 揭示了一个 88.6kb 的质粒，该质粒是由 pHTβ17i48（约 50kb）和一个新的质粒 pLAG（35.3kb）重组而成的，该质粒携带 tet(M)、tet(L)、lnu(B)、spw 和 aadE 耐药基因。在 JH-8E 中，观察到一个 75kb 的质粒是由 pHTβ17i48 和 pRUM17i48 重组而成的。在两种情况下，嵌合体显然是由每个多药耐药质粒中的 IS1216 复制转位到 pHTβ17i48 中产生的。嵌合体可以解析以产生多药耐药质粒和携带 IS1216 的 pHTβ17i48 衍生物（与供体的 pHTβ17i48 不同）。
我们的结果完成了屎肠球菌 17i48 携带的多药耐药质粒的特征描述，证实了 pHT 质粒在肠球菌中非接合性抗生素耐药元件的转移中的作用。结果还表明，与 IS1216 介导的转位促进的嵌合质粒的产生有关，可将其转移至屎肠球菌 JH2-2。
