[Analysis of screening strategy of group B streptococcus in the third trimester and its influence on pregnancy...

Objective: To investigate the screening strategy of group B streptococcus (GBS) in the reproductive tract of women in the third trimester and analyze its impact on pregnancy outcome. Methods: A total of 85 461 pregnant women in 35-37 weeks of gestation from Bao'an Maternity and Child Health Hospital, Jinan University from January 2011 to June 2018 were enrolled. They were divided into 3 periods according to different GBS screening strategies, the unscreened period included 31 384 cases (36.72%), 33 267 cases (38.93%) were included in partial screening period, 20 810 cases (24.35%) were included in screening period. All GBS screening positive pregnant women were given intrapartum antibiotic prophylaxis (IAP). The impact on pregnancy outcomes, and the impact of different GBS collection transport and culture methods on the positive rate of GBS screening were analyzed. Results: (1) The incidence of neonatal early onset GBS disease (EOGBSD) in unscreened period was 0.03% (11/31 773), in partial screening period was 0.02%(6/33 887), and in screening period, the incidence of neonatal EOGBSD decreased to 0, the difference was statistically significant (χ(2)=7.86, P=0.02).(2) The incidence of hematogenous infection of GBS in pregnant women was 0.02%(6/33 887) in partial screening period, and there was none in screening period, there was no significant difference (adjusted χ(2)=3.75, P=0.05). (3) In the screening period, the positive rate of GBS was 14.08%(2 719/19 306), which was significantly higher than the positive rate of GBS in the partial screening period (11.48%, 2 058/17 920; χ(2)=56.12, P=0.00). (4) Antibiotic sensitivity tests of 4 777 GBS strains showed that the antibiotics with higher resistance rate were tetracycline (81.52%, 3 896/4 777), erythromycin (66.59%, 3 181/4 777), and clindamycin (64.31%, 3 072/4 777). The combination of erythromycin, clindamycin and tetracycline was the most common resistant pattern, accounting for 48.80% (2 331/4 777). No penicillin, ceftriaxone or vancomycin resistant strains was found. Conclusions: GBS screening strategy in different regions could combine the local neonatal EOGBSD incidence rate, maternal GBS colonization rate, and the socioeconomic factors to determine whether universal GBS screening or screening for high-risk maternal women. GBS screening positive rate is related to the population, scope of the investigation, the sample collection, delivery and culture methods. The multi-drug resistance rate of GBS is high.