Lack of evidence of efficacy of cohorting nursing personnel in a neonatal intensive care unit to prevent contact spread of bacteria: an experimental study.

Nurse cohorting was investigated in a modern neonatal intensive care unit (NICU). During 99 days bacterial infection and colonization rates were determined in 100 infants experimentally assigned cohort or noncohorted care. Colonizing isolate identity was determined by plasmid profile analyses and biotyping in weekly surveillance cultures. Between Days 2 and 7, 3 infections occurred in cohorted infants but none in noncohorted ones. No secondary spread of infection or definitive colonization cluster occurred. The first colonization rate, at any site, was 0.53/patient-week in the noncohorted and 0.3 to 0.4 in the cohorted units (P greater than 0.05). Colonization ratios with species other than usual skin bacteria in the respiratory tract and with species other than Escherichia coli in the rectum were lower for noncohorted infants. Effective infection control practices in a modern NICU, including alcohol hand antisepsis, should obviate a need for cohorting.