Supplementary Material for: Decreasing Trend in Incidence of Late Onset Culture Positive Bloodstream Infections but Not Late Onset Meningitis in Preterm Infants <33 Weeks Gestation in Canadian Neonatal Intensive Care Unit

<b><i>Introduction:</i></b> Recent studies reported decreased incidence of late onset sepsis in the neonatal intensive care unit (NICU), but it is unclear whether this is also true for late onset meningitis. Recent reports that both meningitis and intraventricular hemorrhage (IVH) are associated with systemic inflammation also raise questions about an association between the 2. <b><i>Methods:</i></b> All preterm infants &lt;33 weeks gestational age admitted to CNN NICUs from 2010 to 2018 were included. We compared incidence trends of late onset culture positive bloodstream infection (CPBSI) and late onset meningitis, and examined the association of meningitis and IVH (exposure), after adjustment for potential confounders. <b><i>Results:</i></b> Of 36,573 infants included, 32,198 had no infection, 3,977 had only late onset CPBSI and 398 had late onset meningitis. There was significant decrease in incidence of late onset CPBSI (14%–10%; adjusted odds ratio (AOR) = 0.93; 95% confidence interval [CI] 0.92, 0.95) but not late onset meningitis (1.6%–1.2%; AOR = 0.98; 95% CI 0.94, 1.01). Compared to infants with no IVH grade 3 or above, infants with IVH grade 3, or above had higher odds of late onset meningitis versus no infection (AOR 4.16; 95% CI 3.17, 5.44), and higher odds of late onset meningitis versus late onset CPBSI (AOR 4.11; 95% CI 3.08, 5.50). <b><i>Conclusions:</i></b> There was a decreasing trend of late onset CPBSI but not late onset meningitis. An association between late onset meningitis and IVH grade 3 or above was observed. Late onset CPBSI and meningitis may have different risk factors and require different prevention strategies.