Abstract: Objective：To investigate the distribution of different serotypes of Group B Streptococcus (GBS) in late pregnant women in Shenyang area and the difference of drug resistance among different serotypes. Methods: 19 122 cases of late pregnant women visited to obstetrics department of Shenyang Materal and Infant Hosipital from May 2016 to August 2017 and were identified as GBS positive. The pure culture strain of GBS colleted from the pregnant women who had lived in Shenyang for more than 3 years will be selected as specimens. The serum types of GBS were determined by polymerase chain reaction (PCR) and gene sequencing. The rates of drug resistance and premature rupture of membranes were compared among different serotypes of GBS. Results: Among the 19 122 cases of late pregnant women, 572 cases were GBS positive, with a GBS carrier rate of 3.0%. Among 251 cases of pure culture strains from Shenyang area, GBS serotypes mainly were Ⅰa (44.22%) ,Ⅴ (38.65%) , Ⅲ (13.94%) , and serum NT with high homology to serotype Ⅴ was found. No resistance to Penicillin, Ampicillin, Vancomycin, Meropenem, Linezolid was found in serotypes Ⅰa, Ⅲ, Ⅴand NT. There was no significant difference in the resistance rates of Erythromycin, Clindamycin, Levofloxacin and Tetracycline to the four serotypes (All P＞0.05). There were significant differences in the resistance rates of Erythromycin, Clindamycin, Levofloxacin and Tetracycline among serotypes Ⅰa, Ⅲ, Ⅴ(P＜0.05). However, there was no statistical significant difference in drug resistance rate of serotype NT to four drugs (P＞0.05). The incidences of premature rupture of membranes in late pregnant women with serotype Ⅰa, Ⅲ, Ⅴ and NT respectively were 23.42%, 34.28%, 10.31% and 25.00%. There was significant difference ( χ2=11.128, P=0.011). Conclusions: The carrying rate of GBS was 3.0% in Shenyang area, and the main serotypes were Ⅰa, Ⅴ and Ⅲ. There was no difference in drug resistance among different serotypes. Attention should be paid to the screening of GBS in the third trimester of pregnancy, and anti-infection therapy should be given according to the screening results to reduce the occurrence of adverse pregnancy outcomes.

Key words: Streptococcus, Agalactiae, Infection, Serotype, Drug tolerance, Fetal membranes, premature rupture