Enterococcus spp on fomites and hands indicate increased risk of respiratory illness in child care centers

Surface-mediated transmission is a potential route for respiratory disease in child care centers, but evidence of its importance relative to other routes (eg, airborne) is limited.

We tracked respiratory disease and monitored bacteria contamination on hands and fomites over 4 months during 64 visits at 2 child care centers. Staff monitored health daily by recording respiratory symptoms. We measured concentrations of Escherichia coli, Enterococcus spp, and fecal coliform in hand rinses and on select fomites.

We demonstrated that symptomatic respiratory illness was positively associated with microbial contamination on hands and fomites, as measured using Enterococcus spp. Enterococcus spp were 0.28 (95% confidence interval: 0.08-0.48)-log10 (colony-forming units per 2 hands) higher when an individual had symptomatic respiratory illness. Susceptible individuals were 1.62 (95% confidence interval: 1.06-2.46) times more likely to develop respiratory illness within 4 days with every log10 increase of Enterococcus spp on hands.

The findings imply that hand contamination as measured using Enterococcus spp is a risk factor for onset of respiratory illness and highlight the utility of fecal indicator bacteria as a metric for hand and fomite contamination.