Objectives: To analyse the recombination events associated with conjugal mobilization of two multiresistance plasmids, pRUM17i48and pLAG (formerly named pDO1-like), from Enterococcus faecium 17i48 to Enterococcus faecalis JH2-2. Methods: The plasmids from two E. faecalis transconjugants (JH-4T, tetracycline resistant, and JH-8E, erythromycin resistant) and from the E. faeciumdonor (also carrying a pHTb-like conjugative plasmid, named pHTÎ²17i48) were investigated by several methods, including PCR mapping and sequencing, S1-PFGE followed by Southern blotting and hybridization, and WGS. Results: Two locations of repApHTÎ²were 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 pHTÎ²17i48(50kb) 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 pHTÎ²17i48and 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 pHTÎ²17i48. The cointegrates could resolve to yield themultiresistance plasmids and a pHTÎ²17i48derivative carrying an IS1216 (unlike the pHTÎ²17i48of the donor). Conclusions: 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.
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|Titolo:||pHTbeta-promoted mobilization of non-conjugative resistance plasmids from Enterococcus faecium to Enterococcus faecalis|
|Appare nelle tipologie:||1.1 Articolo in rivista|