Background: Group B streptococcus (GBS)-induced invasive disease is a major cause of illness and death among infants aged under 90 days in China; however, invasive GBS infection remains unknown in China. We aimed to describe the serotype and genotype distributions of early-onset disease (EOD) and late-onset disease (LOD), and to show the clinical correlations among various GBS serotypes and genotypes obtained from infants with invasive GBS infections. Methods: Between June 1, 2016 and June 1, 2018, 84 GBS strains were collected from patients younger than 90 days at seven Chinese hospitals. Clinical data were retrospectively reviewed. GBS serotyping was conducted and multi-locus sequence typing was performed. Results: Serotypes Ia, Ib, II, III, and V were detected. Serotype III (60.71%) was the most common, followed by Ia (16.67%) and Ib (14.29%). Intrapartum temperature ≥ 37.5 °C, chorioamnionitis, and mortality were noted in 28.57, 42.86, and 28.57% of patients with serotype Ia, respectively, and these rates were higher than those in patients with serotypes Ib and III (P = 0.041, P = 0.031, and P = 0.023, respectively). The incidence of respiratory distress was lower (P = 0.039) while that of purulent meningitis was higher (P = 0.026) in the serotype III group. Eighteen sequence types were detected among isolates, and ST17 [42.86% (36/84)] was the most prevalent. Conclusions: GBS isolates belonging to serotypes Ia, Ib, and III are common in southern mainland China, and ST17 is highly prevalent. Differences were found in the clinical manifestations of invasive GBS disease induced by serotypes Ia and III.

Objective: To analyse early risk factors for mortality in preterm infants treated with inhaled nitric oxide (iNO) in China. Design: A retrospective observational case-control study. Setting: 8 tertiary hospitals in 5 regions of China. Patients: 726 preterm infants treated with iNO for hypoxic respiratory failure or persistent pulmonary hypertension of newborns. Interventions: None. Measurements: The primary outcome was survival status at discharge. Main results: (1) The mortality rate was 27.1% (197/726), and which significantly reduced with increasing gestational age (GA) and birth weight. (2) Compared with the survival group, the death group had significantly greater use of assisted reproductive technology, higher multiple pregnancy rates and lower caesarean section rates. Infants in the death group had a significantly higher incidence of small for GA (SGA), Apgar score ≤3 at 1 min after birth, pneumorrhagia, sepsis and shock. In the death group, the utilisation rate of a pulmonary surfactant (PS) was significantly lower, whereas the oxygenation index (OI) before iNO treatment was significantly higher. The maximum dose of iNO in the death group was significantly higher than that in the survival group. (3) The Cox proportional hazard model showed that SGA (HR 1.800, 95% CI (1.113 to 2.911)), sepsis (HR 1.488, 95% CI (1.093 to 2.027)), shock (HR 1.473, 95% CI (1.033 to 2.100)), OI before iNO treatment (HR 1.016, 95% CI (1.006 to 1.026)) and the maximum dose of iNO treatment (HR 1.070, 95% CI (1.035 to 1.105)) were risk factors for death in preterm infants treated with iNO. Furthermore, GA (HR 0.876, 95% CI (0.831 to 0.924)), PS (HR 0.433, 95% CI (0.296 to 0.633)) and a higher initial dose of iNO (HR 0.926, 95% CI (0.891 to 0.962)) were identified as protective factors. (4) Stratified analysis and sensitivity analysis determined the stability of the core results in preterm infants with GA between 28 and 36 ⁺⁶ weeks. Conclusion: Premature infants treated with iNO had a high mortality rate. SGA, sepsis, shock and higher OI before iNO treatment increased the mortality risk in infants with GA between 28 and 36 ⁺⁶ weeks. A higher GA the use of PS, and a higher initial iNO dose could improve the survival outcome of these babies. Trial registration number: The study was registered in the Chinese Clinical Trials Registry ( http://www.chictr.org.cn ; registration number: ChiCTR2200066935).

Background: Bronchopulmonary Dysplasia (BPD) is a chronic lung disease affecting preterm infants, with limited prevention and treatment options. Inhaled Nitric Oxide (iNO) is sometimes used to treat Persistent Pulmonary Hypertension of the Newborn (PPHN) and Hypoxemic Respiratory Failure (HRF), and its impact on BPD development remains debated.Objective: To assess whether iNO-related factors are potential contributors to the development of BPD Grade Ⅱ-Ⅲ in very premature infants (VPI) diagnosed with PPHN or HRF at birth using Propensity Score Matching (PSM).Methods: We conducted a retrospective cohort study of infants born at 22–32 weeks gestation with PPHN or HRF, treated with iNO for over 3 h. PSM matched groups by gestational age, birth weight, and gender, etc. Multivariate logistic regression evaluated the association between iNO treatment and BPD outcomes to identify influencing factors, while Restricted Cubic Spline (RCS) and mediation analysis examined iNO dose effects and potential mediators like mechanical ventilation time and oxygenation index (OI).Results: A higher initial iNO dose was significantly associated with a reduced risk of BPD Grade Ⅱ-Ⅲ (adjusted OR = 0.68, 95% CI: 0.52–0.89, p < 0.01). Additionally, administration of iNO within the first 7 days of life was identified as an important influencing factor No significant mediation effects were observed for factors such as mechanical ventilation time and OI.Conclusion: A higher initial iNO dose within the first 7 days was associated with a reduced risk of BPD Grade Ⅱ-Ⅲ in VPI with PPHN or HRF.