A Small Multihost Plasmid Carrying (T) Identified in .

The aim of this study was to determine the mobile genetic elements involved in the horizontal transfer of (T) in , and its transmission ability in heterologous hosts. A total of 159 erythromycin-resistant enterococci isolates were screened for the presence of macrolide resistance genes by PCR. Whole genome sequencing for (T)-carrying E165 was performed. The transmission ability in heterologous hosts was explored by conjugation, transformation, and fitness cost. The (T) gene was detected only in an isolate E165 (1/159), which was located on a 4,244-bp small plasmid, designed pE165. Using OG1RF as the recipient strain, pE165 is transferable. Natural transformation experiments using P1/7 and UA159 as the recipients indicated it is transmissible, which was also observed by electrotransformation using RN4220 as a recipient. The (T)-carrying pE165 can replicate in the heterologous host including OG1RF, P1/7, UA159, and RN4220 and conferred resistance to erythromycin and clindamycin to all hosts. Although there is no disadvantage of pE165 in the recipient strains in growth curve experiments, all the pE165-carrying recipients had a fitness cost compared to the corresponding original recipients in growth competition experiments. In brief, an (T)-carrying plasmid was for the first time described in and as transmissible to heterologous hosts.