Different VanA Elements in E. faecalis and in E. faecium Suggest at Least Two Origins of Tn1546 Among VRE in a Brazilian Hospital.

In 2009 during surveillance in a Brazilian hospital, many patients were confirmed to be colonized by vancomycin-resistant enterococci (VRE) and a few infection cases occurred. Among 14 isolates of Enterococcus faecalis, most had the same pulsotype, virulence profile (agg(+)elrA(+)gelE(+)), and were sequence type (ST)103, indicating dissemination of a clone. The 47 Enterococcus faecium were separated into four pulsotypes, the predominant virulence profile being esp(+)acm(+). All of them harbored the hospital marker IS16, and three randomly chosen isolates were ST412, belonging to the Clonal Complex 17. E. faecalis were all susceptible to penicillin and ampicillin, while all E. faecium were resistant to them. All isolates were susceptible to daptomycin and tigecycline. There were no rep-family genes common to all VRE. The VanA element of all E. faecium lost its left-side inverted repeat (IRL) region and had a specific IS insertion. On the other hand, all E. faecalis presented intact Tn1546. The size of plasmids containing the vanA gene as well as its rep-families varied between and within species. The lack of a vanA plasmid common to all VRE, together with the differences among VanA elements, despite the fact that some patients were colonized by both species during their hospitalization, leads us to suggest at least two different Tn1546 origins.