Objective To assess the effects of Bifidobacterium longum subsp. infantis EVC001 (B infantis EVC001) administrationon the incidence of necrotizing enterocolitis (NEC) in
preterm infants in a single level IV neonatal intensive care unit (NICU).
Study design Nonconcurrent retrospective analysis of 2 cohorts of very low birth weight (VLBW) infants not exposed and exposed to B infantis EVC001 probiotic at Oregon Health
& Science University from 2014 to 2020. Outcomes included NEC incidence and NECassociated mortality, including subgroup analysis of extremely low birth weight (ELBW)
infants. Log-binomial regression models were used to compare the incidence and risk of NECassociated outcomes between the unexposed and exposed cohorts.
Results The cumulative incidence of NEC diagnoses decreased from 11.0% (n = 301) in the no EVC001 (unexposed) cohort to 2.7% (n = 182) in the EVC001 (exposed) cohort (P
< .01). The EVC001 cohort had a 73% risk reduction of NEC compared with the no EVC001 cohort (adjusted risk ratio, 0.27; 95% CI, 0.094-0.614; P < .01) resulting in
an adjusted number needed to treat of 13 (95% CI, 10.0-23.5) for B infantis EVC001. NEC-associated mortality decreased from 2.7% in the no EVC001 cohort to 0% in the
EVC001 cohort (P = .03). There were similar reductions in NEC incidence and risk for ELBWinfants (19.2% vs 5.3% [P < .01]; adjusted risk ratio, 0.28; 95% CI, 0.085-0.698
[P = .02]) and mortality (5.6% vs 0%; P < .05) in the 2 cohorts.
Conclusions In this observational study of 483 VLBW infants, B infantis EVC001 administration was associated with significant reductions in the risk of NEC and NECrelated mortality. B infantis EVC001 supplementation may be considered safe and
effective for reducing morbidity and mortality in the NICU.