ObjectiveTo understand the infection and antimicrobial resistance of Streptococcus agalactiae(S. agalactiae) isolated from genital tract of pregnant women in an area, and provide basis for clinical diagnosis and treatment.MethodsGenital tract secretion culture results of pregnant women in the obstetric wards and outpatient department of Guangdong General Hospital from January 2011 to December 2017 were collected, prevalence and changing trend of antimicrobial resistance of S. agalactiae in different years were compared and analyzed.ResultsA total of 31 569 genital tract specimens were detected, 1 940 strains of pathogens were isolated, 591 of which were S. agalactiae, accounting for 30.46%. Isolation rate of S. agalactiae in genital tract specimens was 1.87%; antimicrobial susceptibility testing results of S. agalactiae from 2011 to 2017 showed that no strains were resistant to penicillin, ampicillin, quinupristin/dalfopristin, linezolid, teicoplanin, and vancomycin; resistance rates of S. agalactiae to ciprofloxacin, levofloxacin, clindamycin, and erythromycin were 19.80%-28.97%, 19.80%-28.95%, 26.73%-39.29%, and 44.05%-66.34% respectively; resistance rate of S. agalactiae to tetracycline was the highest (80.37%-94.29%), but with a decreasing trend year by year (P<0.05).ConclusionS. agalactiae is the main pathogen of genital tract infection in pregnant women, analysis of antimicrobial resistance and rational use of antimicrobial agents can reduce the occurrence of S. agalactiae infection in pregnant women and newborns