BETHESDA, MD. — The presence of vancomycin-resistant enterococci in 29 (1.4%) of 2,061 stool samples collected from healthy volunteers suggests that VRE is at large outside of the hospital setting, Amie May reported at the annual conference on antimicrobial resistance sponsored by the National Foundation for Infectious Diseases.
In an ongoing study, Ms. May and her colleagues at the Centers for Disease Control and Prevention's National Center for Infectious Diseases collected 10–20 stool specimens each month between 2000 and 2002 from healthy volunteers or outpatients with diarrhea who had no hospital contact within 6 months of their sampling.
The samples came from sites in five states: Georgia, Maryland, Michigan, Minnesota, and Oregon. Two isolates were found in Maryland, 23 were found in Michigan, and 4 were found in Minnesota.
The number of samples containing VRE increased each year: 7 were found in 2000, 9 were found in 2001, and 13 were found in 2002. A total of 28 samples were Enterococcus faecium, while only 1 was E. faecalis. Fourteen (48%) of the 29 samples had minimum inhibitory concentrations greater than 256 mcg/mL.
Overall, 12 (50%) of 24 of the VRE samples had high levels of gentamicin resistance, 3 (12%) of 25 were resistant to quinupristin (Synercid), 13 (54%) of 24 were resistant to tetracycline, and 20 (83%) of 24 were resistant to penicillin.
The finding that both E. faecium and E. faecalis samples were resistant to quinupristin was of particular concern, since it is one of the few available options for treating VRE, Ms. May noted.