Effective Control of a Nosocomial Outbreak of Vancomycin-Resistant Enterococcus faecium in a Hemato-Oncology Unit in a Korean Tertiary Care Hospital

Abstract

BACKGROUND/OBJECTIVES: To determine the risk factors and cost for nosocomial vancomycin-resistant enterococci (VRE) bacteremia and to control the outbreak of nosocomial VRE bacteremia in a hemato-oncology unit. METHODS: A total of 7 cases of VRE isolated patients were detected from Nov 13 to Dec 2, 2005 in a 69-bed hemato-oncology unit in a 1250-bed tertiary care hospital in Korea. Thirty patients were selected for control among the patients without VRE infection or colonization, who were admitted to the same unit during the same period. Risk factors for VRE bacteremia were analyzed with Mann-Whitney U test and Fishers exact test. Intensive infection control strategies were implemented to control the VRE outbreak: reinforcing strict isolation and hand hygiene for VRE isolated patients, health care workers (HCWs); surveillance cultures from patients, HCWs and environment; thorough environmental cleaning and disinfection; re-education for HCWs about VRE infection control policies. RESULTS: Among the enrolled 7 patients, 4cases had VRE bacteremia and 3 cases were VRE rectal colonizer. VRE were grown from 5 out of 72 surveillance cultures of environment during the outbreak period. Before the outbreak, patients with VRE bacteremia were only 2 cases in the unit from Jan 1, 2004 to Nov 13, 2005. Risk factors for VRE bacteremia were as follows: indwelling Hickman catheter (p = 0.003), duration of hospitalization (p > 0.001), admission to a multi-bed room (p = 0.016) , <i>C. difficile</i> positivity (p = 0.027), and duration of vancomycin usage (p > 0.001). PFGE for VRE revealed 3 different PFGE patterns. VRE from 4 cases showed the same PFGE pattern as that of environmental culture isolates. Intensive infection control implementation terminated outbreak promptly and no new cases were detected up to now (for more than 1 month) after the outbreak. We spent around $900∼950 for investigation and control of the outbreak, which was cheaper than the cost for an isolation private room fee ($4760∼5460). CONCLUSIONS: Our data suggest that early intervention was very effective to control the outbreak and to save the extra cost of strict isolation for VRE patients.