Failure of daptomycin monotherapy for endocarditis caused by an Enterococcus faecium strain with vancomycin-resistant and vancomycin-susceptible subpopulations and evidence of in vivo loss of the vanA gene cluster.

Author(s): Arias CA, Torres HA, Singh KV, Panesso D, Moore J, Wanger A, Murray BE

Affiliation(s): Center for the Study of Emerging and Reemerging Pathogens, Division of Infectious Diseases, The University of Texas Medical School, Houston, TX 77030, USA.

Publication date & source: 2007-11-15, Clin Infect Dis., 45(10):1343-6. Epub 2007 Oct 5.

Publication type: Case Reports; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't

A patient with native valve endocarditis caused by a vancomycin "heteroresistant" strain of Enterococcus faecium experienced failure of daptomycin monotherapy without evidence of daptomycin resistance. The infecting organism exhibited in vivo emergence of a vancomycin-susceptible subpopulation lacking vanA. Treatment with a combination of high-dose daptomycin, gentamicin, and high-dose ampicillin cleared the infection.