Assessing Risks for a Pre-emergent Pathogen: Virginiamycin Use and the Emergence of Streptogramin Resistance in Enterococcus faecium

The Question

What are the major factors contributing to streptogramin-resistant E faecium (SREF) emergence?

What we found

SREF emergence is likely a result of an interaction between quinupristin/dalfopristin (QD) use in medicine and long term use of virginiamycin for animal growth promotion. Virginiamycin increases the mobility and frequency of high-level resistance genes.

Why it matters

Vancomycin-resistant enterococci (VRE) are an important cause of hospital-acquired infections and an emerging infectious disease. QD was approved in 1999 to treat vancomycin-resistant Enterococcus faecium. Virginiamycin, used for animal growth promotion, threatens the efficacy of QD.