An epidemic without illness: Using dna markers to model infection

PURPOSE: Combining molecular biology with infection control interventions can increase compliance and allow objective measurement of effectiveness. We developed a group of PCR detectable non-infectious DNA markers that can be used to model infection and provide immediate feedback on hygiene practices in institutional settings. In previous studies, we illustrated that the markers were spread in the environment in the same manner as infectious particles. METHODS: We are conducting a prospective study in 10 child care centers in order to 1) confirm that the DNA markers are valid surrogates for bacteria and viruses; 2) identify specific foci of contamination and modes of transmission; 3) illustrate the effectiveness of infection control programs utilizing the DNA markers. Centers are randomized to receive an interactive educational infection control intervention or a standard immunization intervention. The DNA markers are introduced into the center and the rate of dispersion of the DNA markers is compared with directly observed changes in hygiene behavior among the staff. RESULTS: Initial results indicate that the markers can be removed mechanically by hand washing and that common over-the-counter cleaners are effective in inactivating the markers. Toys, countertops and doorknobs appear to be more important as infectious reservoirs than brief casual contact. Data from the prospective study will be available prior to September, 2000. CONCLUSIONS: This novel approach utilizing an objective measurement will be used to identify the interaction between behavior and environmental reservoirs of infection and drive future strategies for infection control.