Characterization of a Multiresistance Plasmid Carrying the optrA and cfr Resistance Genes From an Enterococcus faecium Clinical Isolate

• Published in: Frontiers in microbiology Vol. 9; p. 2189
• Main Authors: Morroni, Gianluca, Brenciani, Andrea, Antonelli, Alberto, Maria D'Andrea, Marco, Di Pilato, Vincenzo, Fioriti, Simona, Mingoia, Marina, Vignaroli, Carla, Cirioni, Oscar, Biavasco, Francesca, Varaldo, Pietro E, Rossolini, Gian Maria, Giovanetti, Eleonora
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 11.09.2018
• Subjects: cfr gene; Enterococcus faecium; Microbiology; multiresistance plasmid; optrA gene; oxazolidinone resistance; Enterococcus faecium; multiresistance plasmid; oxazolidinone resistance; cfr gene; optrA gene
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2018.02189

E35048, a bloodstream isolate from Italy, was the first strain where the oxazolidinone resistance gene was detected outside China. The strain was also positive for the oxazolidinone resistance gene . WGS analysis revealed that the two genes were linked (23.1 kb apart), being co-carried by a 41,816-bp plasmid that was named pE35048-oc. This plasmid also carried the macrolide resistance gene (B) and a backbone related to that of the well-known plasmid pRE25 (identity 96%, coverage 65%). The gene context was original, being part of a composite transposon, named Tn , which was integrated into the gene encoding for the ζ toxin protein ( of pRE25). The gene was flanked by two IS insertion sequences and the element was inserted into an (E) gene. Both and contexts were excisable. pE35048-oc could not be transferred to enterococcal recipients by conjugation or transformation. A plasmid-cured derivative of E35048 was obtained following growth at 42°C, and the complete loss of pE35048-oc was confirmed by WGS. pE35048-oc exhibited some similarity but also notable differences from pEF12-0805, a recently described enterococcal plasmid from human also co-carrying and ; conversely it was completely unrelated to other - and -carrying plasmids from . The - linkage is a matter of concern since it could herald the possibility of a co-spread of the two genes, both involved in resistance to last resort agents such as the oxazolidinones.