Purpose: To evaluate environmental surface contamination during norovirus outbreaks at LTCFs.
Methods: Macrofoam swabs were used on hard surfaces in ill patient rooms and from common areas in 4 metro Atlanta LTCFs during norovirus outbreaks. Sampling was conducted as soon as each outbreak was reported (phase 1) and after the outbreak was concluded (phase 2). A total of 172 samples were collected. Viral RNA was extracted from swabs and further concentrated. Norovirus was detected by realtime RT-PCR and positive samples were genotyped after conventional RT-PCR and sequencing. Stool samples were collected from all outbreaks and tested as part of normal outbreak investigation.
Results: Of the 88 swabs collected during phase 1, 29 (33%) tested positive for GII norovirus while 28 (32%) of 88 swabs collected at phase 2. Positive samples included door knobs, hand rails, tables, toilets, and other surfaces in patient rooms and common areas. Toilets seats in ill resident rooms were the most frequently identified positive surfaces. Viral loads ranged from 1.35 to 5.21 log gc per sampling site. Identical GII.4 Sydney sequences were identified in 7 swab and stool samples from each outbreak.
Significance: During norovirus outbreaks at LTCFs environmental surfaces become contaminated with high levels of norovirus and these surfaces remain contaminated beyond the duration of the outbreak. Review of current surface disinfection procedures may be needed to help reduce norovirus transmission via contaminated surfaces. Similar vigilance is needed for surfaces that are used for preparation of foods.