TABLE 1.

Selective media used to detect donor strain, recipient strain, and transconjugants in transfer experiments

Antimicrobial-supplemented mediuma	Day of collection of stool sample	Use
32 μg/ml vancomycin-supplemented Enterococcosel agar	0, 14, 35	As negative controls to make sure that none of the volunteers were colonized by vancomycin-resistant enterococci before and after the study
32 μg/ml vancomycin- and 32 μg/ml erythromycin-supplemented Enterococcosel agar	0 to 7, 14, 35	For detection of the donor strain and transconjugants
25 μg/ml fusidic acid- and 25 μg/ml rifampin-supplemented Enterococcosel agar	0 to 7, 14, 35	For detection of the recipient strain and transconjugants
25 μg/ml fusidic acid-, 25 μg/ml rifampin-, and 32 μg/ml vancomycin-supplemented Enterococcosel agar	0 to 7, 14, 35	For detection of transconjugants only

^aEnterococcosel agar (BD Diagnostics, Sparks, MD); fusidic acid (Leo Pharmaceuticals, Ballerup, Denmark); erythromycin, rifampin, and vancomycin (Sigma-Aldrich Corp., St. Louis, MO).