Natural history of vancomycin-resistant enterococcal colonization in liver and kidney transplant recipients

At Mayo Medical Center (Rochester, MN), surveillance rectal (and other-site) cultures have been routinely collected from liver transplant recipients as part of a selective bowel decontamination program. Beginning in 1995, vancomycin-resistant enterococcus (VRE) colonization and infection were identified in Mayo Clinic liver and kidney transplant patients through our surveillance cultures. The purpose of this study is to describe the natural history of VRE colonization in this patient population. Fifty-two patients with VRE colonization (predominantly with a single vanB clone) were identified from September 1995 through December 1997. Five hundred ninety cultures were reviewed for this study (mean, 11.3 cultures/patient). The median time from initial VRE colonization to the last surveillance culture obtained was 306 days (range, 1 to 1,393 days). VRE infection was documented in 6 patients (11.3%). Eighteen patients (35%) met the criteria for clearance of VRE colonization, defined as VRE-negative rectal culture results on at least 3 consecutive occasions greater than 1 week apart. However, VRE was detected on subsequent surveillance cultures from 2 of these patients (11% relapse rate). Of the remaining 34 patients, 16 remained colonized with VRE and 18 did not meet the definition for clearance of VRE colonization because of incomplete follow-up. This study documents that VRE colonization usually persists for months to years in liver and kidney transplant patients.