Prolonged colonization with vancomycin-resistant Enterococcus faecium in long-term care patients and the significance of "clearance".

Little is known about the persistence of colonization with vancomycin-resistant Enterococcus faecium (VRE) in the nononcologic, non-intensive care unit patient. We studied all patients who had VRE isolated on > or =2 occasions of > 1 year apart (Study A) and those who had been "cleared" of VRE colonization after 3 negative stool cultures (Study B). Twelve patients had stored VRE isolates recovered > 1 year apart (Study A), and 58% of paired isolates were genotypically related according to pulsed field gel electrophoresis patterns. In Study B, stool samples were obtained weekly from 21 "cleared" patients for 5 weeks, which revealed that 24% were VRE positive. For these culture-positive patients, 72% of the cultures failed to detect VRE. Recent antibiotic use was significantly more common in the culture-positive patients, as compared with culture-negative patients (P=.003). Colonization with VRE may persist for years, even if the results of intercurrent surveillance stool and index site cultures are negative. Cultures for detection of VRE in stool samples obtained from patients declared "cleared" are insensitive.