The NICU Antibiotics and Outcomes (NANO) trial: a randomized multicenter clinical trial assessing empiric antibiotics and clinical outcomes in newborn preterm infants

Background

Early-onset sepsis is an important cause of neonatal morbidity and mortality in the preterm population. Infants perceived to be at increased risk for early-onset sepsis are often treated empirically with broad-spectrum antibiotics while awaiting confirmatory blood cultures, despite an overall incidence of early-onset sepsis of 2–3% among extremely-low-birthweight (ELBW) infants. Recent observational studies associate perinatal antibiotic use with an increased incidence of necrotizing enterocolitis, late-onset sepsis, and mortality among ELBW infants. Given currently available data and variability in clinical practice, we designed a prospective multi-institutional randomized controlled trial to determine the safety of early antibiotic use in ELBW infants.

Methods

The NICU Antibiotics and Outcomes (NANO) trial is a multicenter, double-blinded, randomized controlled trial. A sample of 802 ELBW preterm infants will undergo web-based stratified block randomization to receive empiric antibiotics (EA; ampicillin and gentamicin) or placebo during routine evaluation for early-onset sepsis. Participating sites will use preexisting institutional protocols for antibiotic dosage and duration. Infants born at participating sites with a gestational age of 29 weeks or less are eligible for enrollment. Exclusion criteria include maternal intrauterine infection, hemodynamic or respiratory instability, delivery by caesarean section for maternal indications without labor or prolonged rupture of membranes, and prior administration of antibiotics. The primary outcome is the composite incidence of necrotizing enterocolitis, late-onset sepsis, or death during participants’ index hospitalization. Maternal and infant samples will be collected longitudinally and assessed for differences in microbiome composition and diversity.

Discussion

The NANO trial is designed to compare the rate of adverse outcomes of EA use at birth versus placebo in ELBW preterm infants. If EA at birth worsens clinical outcomes, then the results of the trial may help providers decrease antibiotic utilization in the NICU and subsequently decrease the incidence of complications associated with early antibiotic use in ELBW infants. If we instead find that EA improve outcomes, then the trial will validate a longstanding clinical practice that has not previously been supported by high-quality data. Future studies will assess long-term clinical and microbial outcomes in infants who received empiric antibiotics following delivery.

Trial registration

Trial registration data: June 25, 2019 NCT03997266.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06352-3.

The relationship between reticulated platelets, intestinal alkaline phosphatase, and necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) affects up to 10% of extremely-low-birthweight infants, with a 30% mortality rate. Currently, no biomarker reliably facilitates early diagnosis. Since thrombocytopenia and bowel ischemia are consistent findings in advanced NEC, we prospectively investigated two potential biomarkers: reticulated platelets (RP) and intestinal alkaline phosphatase (iAP).

METHODS

Infants born ≤ 32 weeks and/or ≤ 1500 g were prospectively enrolled from 2009 to 2012. Starting within 72 hours of birth, 5 weekly whole blood specimens were collected to measure RP and serum iAP. Additional specimens were obtained at NEC onset (Bell stage II or III) and 24 hours later. Dichotomous cut-points were calculated for both biomarkers. Non-parametric (Mann-Whitney) and Chi-square tests were used to test differences between groups. Differences in Kaplan-Meier curves were examined by log-rank test. The Cox proportional hazards model estimated hazard ratios.

RESULTS

A total of 177 infants were enrolled in the study, 15 (8.5%) of which developed NEC (40% required surgery and 20% died). 14 (93%) NEC infants had "low" (≤ 2.3%) reticulated platelets, and 9 (60%) had "high" iAP (>0 U/L) in at least one sample before onset. Infants with "low" RP were significantly more likely to develop NEC [HR=11.0 (1.4-83); P=0.02]. Infants with "high" iAP were at increased risk for NEC, although not significant [HR=5.2 (0.7-42); P=0.12]. Median iAP levels were significantly higher at week 4 preceding the average time to NEC onset by one week (35.7 ± 17.3 days; P=0.02).

CONCLUSION

Decreased RP serves as a sensitive marker for NEC onset, thereby enabling early preventative strategies. iAP overexpression may signal NEC development.