Study on colonization of Group B Streptococcus in pregnant women of Mongolian and Han nationality and the status of neonatal early-onset septicemia / 中华急诊医学杂志

ABSTRACT

Objective:To explore the carrier status of group B streptococci (GBS) in pregnant women of Mongolian and Han nationality and the neonatal GBS infection in order to identify the high risk factors of GBS infection in Mongolian and Han newborns in this area.Methods:Totally 7289 pregnant women and their newborns born alive were tested for GBS in the Affiliated Hospital of Inner Mongolia Medical University from June 2017 to June 2020, and their newborns were cultured for GBS, and the venous blood of newborns delivered by GBS positive women were detected for anti-GBS capsular polysaccharide antibody level, in order to determine the high risk factors of neonatal GBS infection.Results:Among the 7289 pregnant women, 3136 were Mongolian pregnant women (2599 full-term delivery and 537 premature delivery) and 4153 were Han pregnant women (3541 full-term delivery and 612 premature delivery). The results of GBS test showed that the GBS carrier rate was 8.19% in the Mongolian preterm delivery group, 4.35% in the Mongolian term group, 11.93% in the Han preterm group, and 5.76% in the Han term group, indicating that the carrier rate of GBS in the preterm group was significantly higher than that in the term group, regardless of Mongolian and Han nationality ( P < 0.05). Further comparing the GBS carrier rate of Mongolian and Han pregnant women, the GBS carrier rate of Mongolian pregnant women was significantly lower than that of Han pregnant women regardless of the premature delivery group and term group ( P < 0.05). (2) A total of 434 newborns were born by GBS positive parturients. The positive rates of GBS in Mongolian premature infants, Mongolian full-term infants, Han premature infants and Han full-term infants were 29.55%, 14.16%, 31.51% and 17.65%, respectively, suggesting that the positive rate of GBS in premature infants was significantly higher than that in full-term infants, regardless of Mongolian and Han nationality ( P<0.05). Further comparing the positive rate of GBS in Mongolian and Han newborns, there was no significant difference in the positive rate of GBS between Mongolian newborns and Han newborns, no matter the premature delivery group and the full-term group. (3) This study compared the incidence of early-onset GBS septicemia in Mongolian and Han newborns. The results showed that the incidence of early-onset GBS septicemia in Mongolian premature infants was 23.08%, and none in full-term infants. The incidence of early-onset GBS septicemia in Han premature infants was 26.09%. The incidence of early-onset GBS septicemia in term infants was 5.56%. The incidence of neonatal GBS septicemia in the preterm group was significantly higher than that in the term group, regardless of Mongolian and Han nationality. By further comparing the incidence of GBS septicemia in Mongolian and Han newborns, there was no significant difference in the positive rate of GBS between Mongolian newborns and Han newborns regardless of the premature delivery group and the term group. (4) In both Mongolian and Han nationality, the level of anti-GBS capsular polysaccharide antibody in premature infants was significantly lower than that in term infants ( P < 0.05). (5) Regardless of the Mongolian and Han nationality, compared with GBS negative group, GBS positive rate was higher in pregnant women aged≥35 years old, with history of menstruation, miscarriage, vaginitis, floating population, and those who had not undergone pre-pregnancy examination,,which were the high risk factors for GBS-positive pregnant women during pregnancy. (6) In both Mongolian and Han nationality, the incidence of chorioamnionitis, puerperal infection, premature delivery and premature rupture of membranes in the GBS positive group was higher than that in the GBS negative group, and the incidence of fetal distress and neonatal asphyxia in the GBS positive group was also higher than that in the GBS negative group. Conclusions:The carrier rate of GBS in Mongolian pregnant women is lower than that in Han pregnant women, and positive GBS during pregnancy will increase the incidence of adverse maternal and fetal outcomes such as chorioamnionitis, puerperal infection, premature delivery, premature rupture of membranes, fetal distress, neonatal asphyxia and neonatal early-onset GBS septicemia. The high risk factors are maternal age ≥ 35 years old, history of menstruation, abortion, vaginitis, floating population, and infection without pre-pregnancy examination. We should attach great importance to the perinatal high risk factors and formulate corresponding intervention measures accordingly, and make rational use of antibiotics for prenatal prevention, so as to further reduce the incidence of early-onset GBS septicemia in newborns.