Recurrent Outbreak of Vancomycin – resistant Enterococcus faecium (VRE) in Hematology/ Oncology Patients at a Comprehensive Cancer Center

Recurrent Outbreak of Vancomycin – resistant Enterococcus faecium (VRE) in Hematology/ Oncology Patients at a Comprehensive Cancer Center

Background:   VRE colonization and infection in immunocompromised patients is associated with increased mortality.  Guidelines for the control of transmission of VRE exist but many studies report difficulty in controlling its spread.  This is a report of a recurring outbreak of VRE in hematology/oncology patients at a Comprehensive Cancer Center.  The initial outbreak was identified in March 2009 - 9 cases of VRE bacteremia and 7 cases of colonization.  No active surveillance screening was in place. However, this was the largest number of VRE bacteremias identified in a single month.  Immediate control measures halted the outbreak until March 2010 when 14 cases of HA-VRE colonization were identified.  Further analysis of the new isolates revealed a daptomycin resistant strain.  Additional measures were implemented to control the recurrent outbreak. 

Objective:   This report describes the multi-faceted infection control interventions implemented to control the transmission of VRE.  The identification and subsequent control of the recurrence, which included development of a daptomycin resistant strain of VRE, is also described. 

Methods:   Once the initial outbreak was confirmed and a review of current guidelines and literature was performed, concurrent interventions were implemented.  These included PFGE molecular fingerprinting of isolates, enhanced isolation measures, environmental cleaning, active surveillance cultures, staff education, adjusting anti-VRE prophylaxis and closure of the unit for terminal cleaning.  Additional measures added in the subsequent outbreak included intensive isolation compliance monitoring, quality control for environmental services and cohorting of nursing and environmental services staff.

Results:   A single, primary cause of the outbreak has not been identified. Persistence with additional control measures during the initial and subsequent outbreak period eventually led to control.   An endemic rate for colonization has been established and no additional bacteremias have been identified since 2/2010.

Conclusions: Once VRE has become endemic in a unit, prevention of transmission and eradication is very challenging.  Active screening for VRE in high risk patients is important to detect early outbreaks and to implement aggressive control measures.   We believe cohorting patient care and anti-VRE therapy were invaluable in controlling the outbreak.   At our Center many of these prevention measures have been implemented on the Blood and Marrow Transplant Unit as many of the affected hematology/oncology patients have now progressed to the transplant stage.