LAUSR

To examine the association between probiotic use and antimicrobial utilization. We retrospectively evaluated very-low-birth-weight (VLBW) infants admitted to tertiary neonatal intensive care units in Canada between 2014 and 2019. Our outcome was antimicrobial utilization rate (AUR) defined as number of days of antimicrobial exposure per 1000 patient-days. Of 16,223 eligible infants, 7279 (45%) received probiotics. Probiotic use rate increased from 10% in 2014 to 68% in 2019. The AUR was significantly lower in infants who received probiotics vs those who did not (107 vs 129 per 1000 patient-days, aRR = 0.89, 95% CI [0.81, 0.98]). Among 13,305 infants without culture-proven sepsis or necrotizing enterocolitis ≥Stage 2, 5931 (45%) received probiotics. Median AUR was significantly lower in the probiotic vs the no-probiotic group (78 vs 97 per 1000 patient-days, aRR = 0.85, 95% CI [0.74, 0.97]). Probiotic use was associated with a significant reduction in AUR among VLBW infants.