A single-center investigation on serotypes, drug resistance and clinical significance of GBS isolates from pregnant and non-pregnant adults in Baoji, China

ObjectivesTo assess the epidemiology, serotype distribution, and antimicrobial resistance of GBS among both pregnant and non-pregnant adults in Baoji, China, addressing an existing gap in current research.MethodsBased on the GBS strains identified in the clinical laboratory from 2016 to 2024, inform...

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Main Authors: Siyu Chen, Haiying Li, Mengyang Guo, Hua Wang, Wei Gao, Yating Cui, Yani Zhang, Lin Yuan, Wei Shi, Kaihu Yao
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-07-01
Series:Frontiers in Cellular and Infection Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fcimb.2025.1556603/full
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author Siyu Chen
Haiying Li
Mengyang Guo
Hua Wang
Wei Gao
Yating Cui
Yani Zhang
Lin Yuan
Wei Shi
Kaihu Yao
author_facet Siyu Chen
Haiying Li
Mengyang Guo
Hua Wang
Wei Gao
Yating Cui
Yani Zhang
Lin Yuan
Wei Shi
Kaihu Yao
author_sort Siyu Chen
collection DOAJ
description ObjectivesTo assess the epidemiology, serotype distribution, and antimicrobial resistance of GBS among both pregnant and non-pregnant adults in Baoji, China, addressing an existing gap in current research.MethodsBased on the GBS strains identified in the clinical laboratory from 2016 to 2024, information on age, gender, specimen type, and diagnosis was collected for the corresponding adult cases, including both colonization and infection cases. GBS was identified using three methods: mass spectrometry, CAMP test and latex agglutination kit for streptococcal serotyping. Serotypes were determined by latex agglutination, and antimicrobial susceptibility was tested against 20 antimicrobials using an automated drug susceptibility system.ResultsA total of 200 GBS strains were collected, in which 107 were from pregnant women, and 93 from non-pregnant adults including 34 males. Clinical pathogenic isolates were defined for 86 cases, in which the urinary tract infections were predominant (61.6%), and invasive infections were confirmed for 16 cases (18.6%). A total of 5 serotypes were identified in the present 200 strains, including serotype Ib (34.5%), V (26.0%), III (21.5%), Ia (2.0%) and VIII (1.0%). In addition, 30 strains (15.0%) were non-typeable (NT). The coverage rate of the hexavalent vaccine currently in development is 84.5%. Significant differences are observed in the proportions of serotypes Ib, III, and/or V across various age groups, pregnancy statuses, and between colonized and infectious strains. Notably, the proportion of serotype V varies markedly, with 32.3% in the 18–39 age group versus 18.9% in the 40–64 age group and 10% in the >64 age group, 36.4% in pregnant women compared to 14.0% in non-pregnant women, and 34.2% in colonized strains as opposed to 15.1% in infectious ones. All 200 GBS strains were sensitive to penicillin, and the resistance rates to erythromycin, azithromycin, levofloxacin, clindamycin, tetracycline, and chloramphenicol were 93.5%, 93.5%, 70.5%, 70.0%, 53.5%, and 13.0%, respectively.ConclusionThe present findings suggest that GBS may potentially infect and colonize adults, regardless of gender or age, in Baoji, China. Serotypes Ib, III, and V are common serotypes, but their frequency is related to the host’s age group, pregnancy status, and clinical relevance. GBS isolates are still generally susceptible to penicillin.
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spelling doaj-art-b281f1a7d4e84d278653ddcd5fa91b1c2025-08-20T03:28:22ZengFrontiers Media S.A.Frontiers in Cellular and Infection Microbiology2235-29882025-07-011510.3389/fcimb.2025.15566031556603A single-center investigation on serotypes, drug resistance and clinical significance of GBS isolates from pregnant and non-pregnant adults in Baoji, ChinaSiyu Chen0Haiying Li1Mengyang Guo2Hua Wang3Wei Gao4Yating Cui5Yani Zhang6Lin Yuan7Wei Shi8Kaihu Yao9Ministry of Education Key Laboratory of Major Diseases in Children, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, ChinaDepartment of Laboratory Medicine, Baoji People’s Hospital, Baoji, Shannxi, ChinaMinistry of Education Key Laboratory of Major Diseases in Children, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, ChinaDepartment of Laboratory Medicine, Baoji People’s Hospital, Baoji, Shannxi, ChinaMinistry of Education Key Laboratory of Major Diseases in Children, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, ChinaDepartment of Laboratory Medicine, Baoji People’s Hospital, Baoji, Shannxi, ChinaDepartment of Laboratory Medicine, Baoji People’s Hospital, Baoji, Shannxi, ChinaMinistry of Education Key Laboratory of Major Diseases in Children, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, ChinaMinistry of Education Key Laboratory of Major Diseases in Children, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, ChinaMinistry of Education Key Laboratory of Major Diseases in Children, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, ChinaObjectivesTo assess the epidemiology, serotype distribution, and antimicrobial resistance of GBS among both pregnant and non-pregnant adults in Baoji, China, addressing an existing gap in current research.MethodsBased on the GBS strains identified in the clinical laboratory from 2016 to 2024, information on age, gender, specimen type, and diagnosis was collected for the corresponding adult cases, including both colonization and infection cases. GBS was identified using three methods: mass spectrometry, CAMP test and latex agglutination kit for streptococcal serotyping. Serotypes were determined by latex agglutination, and antimicrobial susceptibility was tested against 20 antimicrobials using an automated drug susceptibility system.ResultsA total of 200 GBS strains were collected, in which 107 were from pregnant women, and 93 from non-pregnant adults including 34 males. Clinical pathogenic isolates were defined for 86 cases, in which the urinary tract infections were predominant (61.6%), and invasive infections were confirmed for 16 cases (18.6%). A total of 5 serotypes were identified in the present 200 strains, including serotype Ib (34.5%), V (26.0%), III (21.5%), Ia (2.0%) and VIII (1.0%). In addition, 30 strains (15.0%) were non-typeable (NT). The coverage rate of the hexavalent vaccine currently in development is 84.5%. Significant differences are observed in the proportions of serotypes Ib, III, and/or V across various age groups, pregnancy statuses, and between colonized and infectious strains. Notably, the proportion of serotype V varies markedly, with 32.3% in the 18–39 age group versus 18.9% in the 40–64 age group and 10% in the >64 age group, 36.4% in pregnant women compared to 14.0% in non-pregnant women, and 34.2% in colonized strains as opposed to 15.1% in infectious ones. All 200 GBS strains were sensitive to penicillin, and the resistance rates to erythromycin, azithromycin, levofloxacin, clindamycin, tetracycline, and chloramphenicol were 93.5%, 93.5%, 70.5%, 70.0%, 53.5%, and 13.0%, respectively.ConclusionThe present findings suggest that GBS may potentially infect and colonize adults, regardless of gender or age, in Baoji, China. Serotypes Ib, III, and V are common serotypes, but their frequency is related to the host’s age group, pregnancy status, and clinical relevance. GBS isolates are still generally susceptible to penicillin.https://www.frontiersin.org/articles/10.3389/fcimb.2025.1556603/fullgroup B streptococcusadultsinfectionserotypeantimicrobial resistance
spellingShingle Siyu Chen
Haiying Li
Mengyang Guo
Hua Wang
Wei Gao
Yating Cui
Yani Zhang
Lin Yuan
Wei Shi
Kaihu Yao
A single-center investigation on serotypes, drug resistance and clinical significance of GBS isolates from pregnant and non-pregnant adults in Baoji, China
Frontiers in Cellular and Infection Microbiology
group B streptococcus
adults
infection
serotype
antimicrobial resistance
title A single-center investigation on serotypes, drug resistance and clinical significance of GBS isolates from pregnant and non-pregnant adults in Baoji, China
title_full A single-center investigation on serotypes, drug resistance and clinical significance of GBS isolates from pregnant and non-pregnant adults in Baoji, China
title_fullStr A single-center investigation on serotypes, drug resistance and clinical significance of GBS isolates from pregnant and non-pregnant adults in Baoji, China
title_full_unstemmed A single-center investigation on serotypes, drug resistance and clinical significance of GBS isolates from pregnant and non-pregnant adults in Baoji, China
title_short A single-center investigation on serotypes, drug resistance and clinical significance of GBS isolates from pregnant and non-pregnant adults in Baoji, China
title_sort single center investigation on serotypes drug resistance and clinical significance of gbs isolates from pregnant and non pregnant adults in baoji china
topic group B streptococcus
adults
infection
serotype
antimicrobial resistance
url https://www.frontiersin.org/articles/10.3389/fcimb.2025.1556603/full
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