Pathogen Transmission in the Child Care Setting Using Cauliflower DNA as a Surrogate Marker • 718

Objective. This study describes use of specifically designed DNA markers as surrogate indicators of transmission of enteric pathogens in child care settings and from the settings to homes of children. Methods. Two regions of cauliflower CaMV 35S promoter DNA were designed as markers and were introduced into the environment through sensitized objects. Spread of markers in the environment was traced by detection of the markers using PCR technique. Studies of marker transmission were conducted in a child care home, in a child care center (CCC), and in homes of children attending CCC.Results. The DNA markers were stable for at least one month on a dried surface at room temperature. In the child care home, DNA markers spread rapidly in the environment following introduction. Hand touching of the contaminated areas was the major factor leading to spread of the markers. Hand washing and wiping of contaminated surfaces decreased spread of the markers. In the CCC infant room, 62% of 13 infant's hands, 70% of 10 surfaces and 100% of 10 toys were positive at 24 hours. In the toddler room, 73% of 15 toddler's hands and 100% of 10 toys and 10 surfaces were positive at 24 hours. Two weeks later <10% of toys and surfaces in the infant room were positve, while 40% of toys and 30% of surfaces in the toddler room remained positve. The markers spread minimally from room to room in the center. In children's homes the day after introduction of markers in the CCC, 7/9 (78%) car seats, 6/9 (67%) high chairs, 15/45 (33%) toys and 2/9 (22%) cribs were positive.Conclusion. DNA markers provide safe and effective surrogate indicators for studying transmission of enteric pathogens in child care settings and for evaluating methods of intervention.