Regional dissemination of vancomycin-resistant enterococci resulting from interfacility transfer of colonized patients.

During early 1997, the Siouxland District Health Department (SDHD; Sioux City, IA) reported an increased incidence of vancomycin-resistant enterococcal (VRE) isolates at area health care facilities. To determine the prevalence and risk factors for colonization with VRE strains at 32 health care facilities in the SDHD region, a prevalence survey and case-control study were performed. Of 2266 patients and residents, 1934 (85%) participated, and 40 (2.1%) were positive for (gastrointestinal) VRE colonization. The prevalence of VRE isolates was significantly higher in acute care facilities (ACFs) than in long-term care facilities (LTCFs) (10/152 [6.6%] vs. 30/1782 [1.7%]; odds ratio [OR], 4.1; 95% confidence interval [CI], 1.8-9.0). LTCF case patients were significantly more likely than controls to have been inpatients at any ACF (19/30 vs. 12/66; OR, 8.0; 95% CI, 2.7-23.8). Of 40 VRE isolates, 34 (85%) were a related strain. The predominant strain was present in all 12 LTCFs that had at least 1 case patient in each facility. Soon after the introduction of VRE isolates into this region, dissemination to multiple LTCFs resulted from resident transfer from ACFs to LTCFs.