Abstract

Background: Streptococcus agalactiae (Group B Streptococcus or GBS) is a natural resident of the gastrointestinal tract of healthy individuals, and is the most common cause of sepsis, meningitis, pneumonia, and severe diseases in newborns. Resistance to penicillin and macrolides, as selective antibiotics for the treatment of GBS infections, is increasing. In this study, we aimed to determine the capsule serotypes and antibiotic resistance pattern of Streptococcus agalactiae isolated from pregnant women referred to the Valiasr hospital in Borujen City, Iran. Methods: In this descriptive cross-sectional study, a total of 760 vaginal samples were collected from pregnant women in the period between 35-37 weeks of gestation. Following conventional phenotypic evaluation and GBS confirmation, GBS isolates resistance to antibiotic disc was assessed through disk diffusion test. Finally, capsular serotypes were determined using multiplex polymerase chain reaction (multiplex PCR) method. Findings: Out of 760 pregnant women participating in this study, 70 (9.2) were carriers of GBS. Our finding disclosed that the lowest and highest resistance among GBS isolates were related to penicillin (0), and tetracycline (92.85), respectively. The most common capsular serotypes were III (45.71), followed by II (17.14), VI (14.28), Ib (11.42), V (8.57), and Ia (2.85), respectively. Conclusion: In this study, we detected low prevalence of GBS, as well as low level resistance to macrolides. In addition, predominant capsular serotype was III. © 2021 Isfahan University of Medical Sciences(IUMS). All rights reserved.