In recent decades, there have been major advances in perinatal and neonatal intensive care in China.^1,2 Neonatal mortality has been reduced substantially, but preterm birth has become the leading cause of neonatal death.³ There are approximately 0.2 million very preterm infants (VPIs) (<32 weeks’ gestational age [GA]) born every year in China.^4,5 Although steady improvements in outcomes have been reported, VPIs in China continue to contribute disproportionately to the burden of neonatal death and long-term developmental disability. Currently, national-level data on outcomes and care practices for VPIs in China are lacking. Information on care practices, morbidity, and mortality of VPIs is essential to benchmark outcomes for institutions to evaluate their performance, identify deficiencies in care, facilitate quality improvement, improve health services delivery, and support parental counseling and clinical decision-making.

To describe the incidence, case-fatality rate and pathogen distribution of late-onset sepsis (LOS) among preterm infants in China and to investigate risk factors and short-term outcomes associated with LOS caused by Gram-positive bacteria, Gram-negative bacteria and fungi. This cohort study included all infants born at <34 weeks' gestation and admitted to 25 tertiary hospitals from 19 provinces in China from May, 2015 to April, 2018, excluding infants who died or were discharged within 3 days of life. Totally 1199 episodes of culture-positive LOS were identified in 1133 infants, with an incidence of 4.4% (1133/25725). Overall, 15.4% (175/1133) of infants with LOS died and 10.0% (113/1133) of infants died within 7 days after LOS onset. Among 1214 pathogens isolated, Gram-negative bacteria were the most common pathogens (51.8%, 629/1214). Fungi accounted for 17.1% (207/1214) of pathogens. Use of central lines, longer duration of antibiotics and previous carbapenem exposure were related with increased risk of fungal LOS compared with Gram-positive bacteria. Gram-negative bacteria LOS was independently associated with increased risk of death, periventricular leukomalacia, bronchopulmonary dysplasia and necrotizing enterocolitis. Fungal LOS was independently associated with increased risk of periventricular leukomalacia, bronchopulmonary dysplasia and necrotizing enterocolitis. LOS was a significant cause of morbidity and mortality in Chinese NICUs with a distinct pathogen distribution from industrial countries. Clinical guidelines on the prevention and treatment of LOS should be developed and tailored to these LOS characteristics in Chinese NICUs.

Early-onset sepsis (EOS) poses a substantial risk to very preterm infants, necessitating the prevalent administration of empirical antibiotics in the neonatal intensive care unit (NICU). Puopolo et al¹ reported that more than one-third of the extremely preterm infants in their study were categorized as low risk for EOS, with an incidence of 0.5%. In these low-risk groups, prolonged empirical antibiotic treatment (≥5 days) was observed in approximately 35% of cases.¹ Recent studies^1-3 have suggested a potential association of prolonged antibiotic therapy with both increased mortality and a higher incidence of adverse neonatal outcomes, including bronchopulmonary dysplasia (BPD), within this vulnerable population. However, these studies often relegated BPD as a secondary outcome, lacking comprehensive consideration of relevant confounding factors. Moreover, the literature has reported inconsistent results in this domain.^4-6 The reported association may be influenced by factors such as culture-proven sepsis bacteremia, illness severity, and early respiratory disease.