Background: Due to increases in the number of infants born with younger gestational age (GA) and lower birth weight, the incidence of neonatal sepsis is increasing. We investigated the changes in the prevalence of bacterial pathogens, their antimicrobial susceptibility, and sepsis-related mortality during 20 years at a neonatal intensive care unit.Purpose: We investigated the changes in the prevalence of bacterial pathogens, their antimicrobial susceptibility, and sepsis-related mortality during 20 years at a neonatal intensive care unit.Methods: The study period was divided into two 10-year phases (1998–2007 vs. 2008–2017). Medical records were reviewed to gather data on demographics, causative microbial pathogens, incidence of multidrug-resistant organisms, antimicrobial susceptibility, and rates of sepsis-related mortality.Results: In both study phases, the most common pathogens for neonatal sepsis were coagulase-negative Staphylococcus (CoNS) (28.6%) and Enterobacter cloacae (16.1%) for early-onset sepsis (EOS, ≤72 hours after birth) and CoNS (54.7%) and Staphylococcus aureus (12.9%) for late-onset sepsis (LOS, >72 hours after birth). CoNS and S. aureus showed 100% sensitivity to vancomycin in both phases. The susceptibility of S. aureus to oxacillin increased from 19.2% to 57.9% in phase II than phase I. K. pneumonia and E. cloacae showed increases in its susceptibility to gentamicin, cefotaxime and ceftriaxone in phase II than phase I. In both phases, the most common pathogens that caused sepsis-related death were K. pneumoniae (18.2%) and Pseudomonas aeruginosa (13.6%). Sepsis-related mortality rate was higher in infants with GA <37 weeks than those with GA over 37 weeks (P=0.016). In addition, the mortality rate of neonatal sepsis caused by gram-negative bacteria was significantly higher than that caused by gram-positive bacteria (P<0.001).Conclusions: CoNS was the most common pathogen for EOS and LOS. While we found significant changes in antimicrobial sensitivities over time. GA below 37 weeks and gram-negative organisms are associated with mortality rate.

The primary aim of this study was to investigate the compositional differences of the first passed meconium microbiome in preterm and term infants, and the secondary aim was to compare the meconium microbiomes of preterm and term infants that later developed necrotizing enterocolitis (NEC)/Feeding intolerance (FI) compared to those that did not develop NEC/FI. During the study period, a total of 108 preterm and term newborns' first passed meconium occurring within 72 hours of birth were collected and microbiome analyzed. Meconium microbiomes showed a disruption in the percentages of the core microbiome constituents in both the phylum and genus levels in infants born < 30 weeks of gestational age (GA) compared to those born ≥ 30 weeks of GA. In the phylum level, Bacteroidetes and Firmicutes, and in the genus level, Prevotella and Bacteroides, were predominant, with Prevotella accounting for 20–30% of the relative abundance. As GA increased, a significant increase in the relative abundance of Bacteroidetes (P for trend < 0.001) and decrease in Proteobacteria (P for trend = 0.049) was observed in the phylum level. In the genus level, as GA increased, Prevotella (P for trend < 0.001) and Bacteroides (P for trend = 0.002) increased significantly, whereas Enterococcus (P for trend = 0.020) decreased. Compared to the control group, the meconium of infants that later developed NEC/FI had significantly lower alpha diversities but similar beta-diversities. Furthermore, the NEC/FI group showed a significantly lower abundance of Bacteroidetes (P < 0.001), and higher abundance of Firmicutes (P = 0.034). To conclude, differences were observed in the composition of the first passed meconium in preterm and term infants that later develop NEC/FI compared to those that did not.

Unlike in adult and pediatric patients, the usefulness of lactate in preterm infants has not been thoroughly discussed. This study aimed to evaluate whether the lactate level in the first hours of life is an important factor associated with neonatal death in very-low-birth-weight (VLBW) preterm infants. Electronic medical records from a level 4 neonatal intensive care unit in South Korea were reviewed to obtain perinatal and neonatal outcomes. Data on lactate levels of preterm infants in the first 12 h of life were collected. Neonatal mortality and morbidities were compared based on lactate levels. Subsequently, machine-learning models incorporating 20 independent variables, both with and without lactate, were compared for model performances and feature importance of lactate for predicting in-hospital mortality in the applicable models. One hundred and sixty-eight preterm infants were included. Death rates on days 7 and 30 of life (D30-mortality) were significantly higher in infants with high lactate levels (≥3rd interquartile range) than in those with lower levels (<3rd interquartile range). Though statistically insignificant, the overall in-hospital mortality was more than twice as high in the high lactate level group than in the lower lactate level group. Based on the machine learning results, Random Forest, Gradient Boosting, and LightGBM models all showed greater area under the curves when lactate was included. Lactate consistently ranked in the variables of top five feature importance, particularly showing the greatest value in the Gradient Boosting model. Lactate levels during the early hours of life may be an important factor associated with in-hospital death of preterm VLBW infants. Based on the enhanced performance of the above-mentioned machine learning models, lactate levels in the early postnatal period may add to assessing the clinical status and predicting the hospital course in this population.

Background/Objectives: Systemic hydrocortisone (HCS) in very low birth weight (VLBW) infants is commonly used to treat early hypotension or prevent bronchopulmonary dysplasia. This study evaluated the associations between postnatal HCS exposure and neurodevelopment in VLBW infants by comparing regional brain volume at term-equivalent age (TEA) with neurodevelopmental outcomes in early infancy. Methods: This retrospective cohort study included VLBW infants admitted to a neonatal intensive care unit (NICU) between 2013 and 2019. The cumulative HCS dose during hospitalization was recorded, and regional brain volumes were analyzed using magnetic resonance imaging at TEA. Neurodevelopmental outcomes were assessed at a corrected age for prematurity of 18–24 months. Results: Among 146 infants, 57 were classified in the high HCS group (>90 mg/kg) and 89 in the low HCS group (≤90 mg/kg HCS). Bronchopulmonary dysplasia, periventricular leukomalacia, and sepsis were more frequent in the high HCS group. Ninety-five infants underwent magnetic resonance imaging, which revealed reduced brain volumes in the high HCS group. At follow-up, cerebral palsy (35.9% vs. 9.1%, p = 0.003), neurodevelopmental impairment (54.0% vs. 23.6%, p = 0.002), and head circumference <10th percentile (64.3% vs. 19.5%, p < 0.001) were more common in the high HCS group. After adjustment, HCS > 90 mg/kg remained independently associated with cerebral palsy (adjusted odds ratio [aOR] 5.44, p = 0.016) and reduced head circumference (aOR 4.45, p = 0.016). Conclusions: High cumulative HC exposure correlated with reduced brain volume at TEA and adverse neurodevelopmental outcomes at 24 months of age. Careful monitoring of dose and treatment duration is essential to balance therapeutic benefits against potential risks.

To determine the incidence, time course, and reversibility of metabolic acidosis associated with anti-reflux (AR) formula in NICU infants, and to identify