Etiological serotype and genotype distributions and clinical characteristics of group B streptococcus-inducing invasive disease among infants in South China.

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.

[Clinical effect of endotracheal lavage with porcine pulmonary surfactant in term neonates with severe meconium aspiration syndrome].

OBJECTIVE: To evaluate the clinical effect of endotracheal lavage with porcine pulmonary surfactant (PS) in term neonates with severe meconium aspiration syndrome (MAS). METHODS: A total of 136 full-term infants with severe MAS who were admitted to the neonatal intensive care unit between January 2010 and June 2013 were randomly and equally divided into PS lavage and PS injection groups. In the PS lavage group, patients were treated with endotracheal lavage using 3-5 mL of diluted PS (12 mg/mL) each time, and the PS injection group was given PS by intratracheal injection at the first dose of 200 mg/kg. Blood gas, oxygenation index (OI), and PaO2/FiO2 (P/F) of the two groups were evaluated before and 2, 12, 24, and 48 hours after the treatment, and the duration of mechanical ventilation, complication rate, and cure rate were compared between the two groups. RESULTS: Compared with the PS injection group, the PS lavage group had significantly higher PaO2 and P/F ration and significantly lower PaCO2 and OI at 12, 24, and 48 hours post-treatment (P<0.01), a significantly shorter duration of mechanical ventilation (P<0.01), a significantly smaller amount of PS (P<0.01), a significantly lower complication rate (P<0.05), and a significantly higher cure rate (97% vs 88%; P<0.05). CONCLUSIONS: Compared with the intratracheal injection of PS, endotracheal lavage with diluted PS in term neonates with severe MAS can increase ventilation and oxygenation efficiency, shorten the duration of mechanical ventilation, reduce the complication rate, and increase the cure rate, indicating that this method is a safe and effective therapeutic strategy.

[Clinical effect of combination therapy with high-frequency oscillation ventilation, pulmonary surfactant and inhaled nitric oxide in the treatment of neonatal hypoxemic respiratory failure].

OBJECTIVE: To investigate the clinical effect of combination therapy with high-frequency oscillation ventilation (HFOV), pulmonary surfactant (PS) and inhaled nitric oxide (iNO) in the treatment of neonatal hypoxemic respiratory failure (HRF). METHODS: A total of 116 neonates with HRF were studied, and they were randomly divided into two groups: triple therapy (n=58) and dual therapy (n=58). The triple therapy group received HFOV, PS, and iNO, while the dual therapy group received HFOV and iNO. Blood gas values, PaO2/FiO2 (P/F), oxygenation index (OI), and pulmonary arterial pressure (PA) were determined before treatment and after 24 and 48 hours of treatment. Among the neonates with different P/F ratios and OI values and with or without persistent pulmonary hypertension of the newborn (PPHN), the treatment outcomes of two groups were compared. RESULTS: The durations of mechanical ventilation and iNO therapy in the triple therapy group were significantly shorter than in the dual therapy group (P<0.01). After 24 and 48 hours of treatment, the triple therapy group had significantly improve PaO2 and PaCO2 compared with the dual therapy group (P<0.01). After 24 and 48 hours of treatment, the neonates with PPHN in the triple therapy group had significantly decreased PA compared with the dual therapy group (P<0.01). In the cases with a P/F ratio of ≤50, the triple group had a significantly higher cure rate than the dual therapy group (P<0.05). In both groups, the P/F ratios of the neonates who died were significantly lower than those of survivors (P<0.01). In the cases with an OI of ≥40, the triple group had a significantly higher cure rate than the dual therapy group (P<0.05). In both groups, the OI values of the neonates who died were significantly higher than those of survivors (P<0.01). In neonates with PPHN, the triple group had a significantly higher cure rate than the dual therapy group (P<0.05). The triple therapy group had a significantly shorter length of hospital stay (P<0.01) and a significantly higher cure rate (P<0.05) compared with the dual therapy group. There were no significant differences in complications between the two groups (P>0.05). No severe side effect was found during the treatment in either group. CONCLUSIONS: Triple therapy with HFOV, PS and iNO is a more effective treatment for neonatal HRF compared with the dual therapy with HFOV and iNO. The triple therapy can significantly improve oxygenation and survival rate, providing a new treatment for the neonates with HRF, especially the critical cases who suffer severe lung disease with PPHN and have a P/F ratio of ≤50 or an OI of ≥40.

[Nasal synchronized intermittent positive pressure ventilation for the treatment of apnea in preterm infants].

OBJECTIVE: To compare the efficacy of nasal synchronized intermittent positive pressure ventilation (NSIPPV) and nasal continuous positive airway pressure ventilation (NCPAP) for the treatment of apnea in preterm infants. METHODS: Eighty preterm infants with apnea from August 2010 to January 2011 were randomly administered with NSIPPV and NCPAP (n=40 each).The blood gas results before and 2 hrs after ventilation, time of using ventilator, therapeutic efficacy and complications were compared between the two groups. RESULTS: There were no significant differences in the blood gas results between the two groups before ventilation. The blood gas results (pH, PO2, PCO2) in the NSIPPV group were better than those in the NCPAP group 2 hrs after ventilation. The time of using ventilator in the NSIPPV group was shorter than that in the NCPAP group (50±9 h vs 91±11 h; P<0.01). There were no significant differences in the total effective rate between the NSIPPV and the NCPAP groups (95% vs 85%; P>0.05). The proportion of ventilator weaning within 3 days in the NSIPPV group (23/40) was higher than that in the NCPAP group (14/40) (P<0.05). The incidence of complications in the NSIPPV group was not different from that in the NCPAP group (22% vs 25%). CONCLUSIONS: NSIPPV appears to be superior to NCPAP for the treatment of apnea in preterm infants.

Ambroxol interferes with Pseudomonas aeruginosa quorum sensing.

The mucolytic agent ambroxol has been reported to interfere with the formation of Pseudomonas aeruginosa-derived biofilms in addition to reducing alginate production by undefined mechanisms. Since quorum sensing is a key regulator of virulence and biofilm formation, we examined the effects of ambroxol on P. aeruginosa PAO1 wild-type bacterial clearance rates, adhesion profiles and biofilm formation compared with the quorum sensing-deficient, double-mutant strains DeltalasR DeltarhlR and DeltalasI DeltarhlI. Data presented in this report demonstrated that ambroxol treatment reduced survival rates of the double-mutant strains compared with the wild-type strain in a dose-dependent manner even though the double-mutants had increased adhesion in the presence of ambroxol compared with the wild-type strain. The PAO1 wild-type strain produced a significantly thicker biofilm (21.64+/-0.57 microm) compared with the biofilms produced by the DeltalasR DeltarhlR (7.36+/-0.2 microm) and DeltalasI DeltarhlI (6.62+/-0.31 microm) isolates. Ambroxol treatment reduced biofilm thickness, increased areal porosity, and decreased the average diffusion distance and textual entropy of wild-type and double-mutant strains. However, compared with the double-mutant strains, the changes observed for the wild-type strain were more clearly defined. Finally, ambroxol exhibited significant antagonistic quorum-sensing properties, suggesting that it could be adapted for use clinically in the treatment of cystic fibrosis and to reduce biofilm formation and in the colonisation of indwelling devices.