Staphylococcus aureus (S. aureus) is a common cause of neonatal infections. Our aim was to determine sustainability of a program of active surveillance cultures and decolonization on the incidence of positive S. aureus clinical cultures.
We performed a retrospective cohort study of neonates admitted to a tertiary NICU from April 1, 2011 to June 30, 2016. We compared the incidence of S. aureus-positive clinical cultures before and after implementation of the program. S. aureus-positive cultures were defined as non-surveillance cultures that grew S. aureus. Cultures of specimens were considered unique events if collected from the same body site at least 30 days apart or from different body sites at least 14 days apart. Hospital-onset was defined as clinical culture growth obtained more than two days after admission. Hospital-onset cultures were used as comparison, as cultures obtained in the first 48 hours should not be affected by the program and the effect may be more pronounced. We used 2-sided Poisson tests for comparing independent incidence rates and interrupted time series analysis.
There were 70 and 72 positive cultures in the pre (29,220 patient-days) and post (47,135 patient-days) intervention periods, respectively. Overall, there was a 36% reduction in the incident rate of S. aureus-positive cultures (IRR= 0.64, 95% CI 0.460-.884). Prior to the intervention, the quarterly rate of positive cultures did not change over time (Figure 1a). After implementation, there was a non-significant immediate 24.1% reduction in S. aureus cultures (IRR=0.76, 95% CI 0.35-1.65), after which positive cultures decrease by 4.1% per quarter (IRR=0.959, 95% CI 0.93-0.99). When examining the hospital-onset cultures, there was a 43% decrease, when comparing the two periods (IRR=0.57 95% CI 0.411- 0.801). After implementation of the program, there was a similar immediate non-significant decrease of hospital-onset S. aureus cultures of 37.9% (IRR=0.621, CI 0.24-1.58), and a non-significant 3.0% per quarter decrease in hospital-onset positive cultures (Figure 1b) (IRR=0.97, CI 0.92-1.023).
Active surveillance and decolonization may effectively and sustainably decrease S. aureus-positive clinical cultures in the NICU.
A. Sick, None
S. W. Aucott, None
A. M. Milstone, None