Rapid control of vancomycin-resistant Enterrococcus outbreak in an adult hematology unit at a tertiary hospital in Singapore

BACKGROUND/OBJECTIVES: While vancomycin-resistant Enterrococcus (VRE) infection is endemic in U.S. hospitals, little information exists concerning the problem in Southeast Asia. The recent VRE outbreak in our hospital marked the first outbreak in Singapore and called for the need to evaluate antibiotic utilization and strict infection control measures to prevent local epidemics. METHOD: In April 2004, vancomycin-resistant Enterrococcus faecium was cultivated from blood culture samples of two patients from the hematology unit of an acute tertiary-care hospital. Surveillance cultures, including rectal swabs or stool specimens, were then performed for the 14 existing hematology patients in the unit to assess the extent of the outbreak. Four patients yielded epidemiologically identical strains of VRE compared to the two index cases. A case control study was then conducted to determine possible contributory factors and antibiotic usage was analyzed to determine any correlation with the outbreak. Infection control measures instituted then were patient isolation with emphasis on contact precautions, quarantine of patients suspected to have contact with the index patients, ward closure and intensive environmental cleaning. RESULTS: A total of two infected and four colonizer cases were identified with identical pulsed-field gel electrophoresis (PFGE) patterns. The case control study showed that these patients had longer length of stay and received longer courses of antibiotics. Using logistic regression test, the use of metronidazole (p = 0.027) as well as the combination of metronidazole and cephalosporin group (p = 0.027) were significantly associated with the presence of VRE in the patient. CONCLUSION: Our study suggests that strict infection control measures successfully prevented further nosocomial spread of VRE. Further study is needed to determine the effectiveness of specific antibiotic therapy and cost-effectiveness of routine screening of VRE in preventing future outbreaks.