Modeling the spread of resistant nosocomial, pathogens in an intensive-care unit

OBJECTIVES: To show the value of mathematical modeling in simulating the spread of nosocomial pathogens in an intensive-care unit (ICU), to provide a framework for listing available knowledge; to predict the benefits of various control measures; and to supplement the epidemiological assessment of these measures. DESIGN: Simulated outbreak of a nosocomial pathogen in an ICU, based on a deterministic compartmental model describing both person-to-person spread and indirect spread between patients through staff members. INTERVENTIONS: Simulation of three typical colonization control measures: effective handwashing compliance among staff members, ICU antimicrobial policy, and curtailing ICU admission of colonized patients. RESULTS: In controlling colonization, effective handwashing compliance reduced staff member colonization, but only moderately limited patient colonization unless the ICU was isolated strictly by curtailing the admission of colonized patients. The impact of antibiotic policy was very slight. CONCLUSIONS: In the field of nosocomial infection, mathematical modeling appears to be a valuable tool that can be used to evaluate the magnitude of the expected effects of control strategies and to guide the selection of the best randomized clinical trials to pursue.