Vancomycin-Resistant enterococcus Outbreak and Containment in a Neonatal ICU
Tricia Thomson, MD, Julie Venci, MD, Jorge P. Parada, MD, MPH, Paul Schreckenberger, PhD, Marc Weiss, MD, Alexander Tomich, MSN, RN, Patricia Hester-Lund, RN, Violeta Rekasius, MT(ASCP), Malliswari Challapalli, MD
Loyola University Medical Center, Maywood, IL, USA
Background: Vancomycin-resistant enterococcus (VRE) is an uncommon cause of infection in neonates. In our neonatal ICU (NICU) we only had 1 case annually from 2005-2007. However, starting in May of 2009 we encountered 2 infants with VRE infections within 7 weeks of each other. This prompted surveillance cultures (SC) on all neonates in the NICU to determine the possibility, magnitude, and scope of an outbreak.
Objective: To determine the extent and scope of a VRE outbreak in our NICU and to prevent further spread.
Methods: After the second case of VRE, we began SC of all neonates in our NICU at an approximately 1 month interval (7/9/09, 9/1/09, 9/30/09, 11/10/09). SC were obtained via rectal swabs which were plated on selective agar containing vancomycin (Campy blood agar) and then incubated at 35-37ūC. Positive isolates were run through repetitive sequence-based PCR (rep-PCR) to determine strain type. Colonized neonates were placed on contact isolation and cohorted in a separate room of the NICU. In addition, we obtained environmental swabs from frequently touched surfaces around the neonates (including monitors, isolettes, oxygen blenders, IV pumps) to look for possible sources of spread. All staff was re-educated on the importance of strict hand-washing and strict implementation of barrier precautions was emphasized. Efforts at environmental cleaning were redoubled with use of bleach-containing solutions.
Results: Initial SC obtained on 7/9/09 detected VRE in 9 of 31 infants. On subsequent cultures, 3 of 33 infants on 9/1/09 and 4 of 29 on 9/30/09 were colonized with VRE. The most recent cultures, on 11/10/09, revealed no VRE in any of the 23 infants. Of those colonized infants 8 of 9 from the first screen, 2 of 3 from the second, and 1 of 4 on the third screen had the outbreak strain. In total, there were 4 different strains of VRE isolated through SC (1 of which was the outbreak strain). Of the 37 environmental cultures 1 was positive for VRE (an isolette). Most of the affected infants seem to have been located next to each other or in the same aisle as each other.
Conclusions: Through strict adherence to hand-washing protocols, implementation of barrier precautions, segregation of colonized infants to a separate room, assignment of separate personnel to care for these infants, and thorough environmental cleaning, VRE clinical infection and widespread colonization in the NICU appeared to be contained 4 months after the initial outbreak. The presence of 4 distinct strains of VRE in our NICU suggests that vertical transmission may be a possible source of VRE introduction into the NICU.