The serotype distribution of Streptococcus agalactiae (GBS) carriage isolates among pregnant women having risk factors for early-onset GBS disease: a comparative study with GBS causing invasive infections during the same period in Denmark

Hans-Christian Slotved,Jens Kjølseth Møller,Stine Yde Nielsen,Mohammad Rohi Khalil

doi:10.1186/s12879-021-06820-2

Hans-Christian Slotved, Jens Kjølseth Møller + Show 2 more

Open Access

https://doi.org/10.1186/s12879-021-06820-2

Copy DOI

Abstract

BackgroundWe describe the serotype distribution of Streptococcus agalactiae (GBS) carriage isolates from women in labor and among GBS isolates causing invasive infections during the same period to see if the distribution of carriage serotypes reflects the GBS serotypes causing invasive diseases including early-onset disease (EOGBS).MethodsData on invasive isolates from 2019 including serotype, erythromycin and clindamycin susceptibility was retrieved from the Danish national reference laboratory, Statens Serum Institut. Carriage isolates were collected from women with risk factors for EOGBS enrolled at delivery at the maternity ward at a Danish University Hospital, first half of 2019.ResultsAmong carriage isolates, the dominant serotype was IX (21 %) followed by serotype III (19 %). The resistance to erythromycin and clindamycin was 21 and 26 %, respectively. Among invasive GBS isolates, no case of EOGBS with serotype IX was detected but the distribution of serotypes were otherwise similar to the GBS carrier strains. The corresponding resistance to erythromycin and clindamycin was 23 and 15 %, respectively. Penicillin resistance was not detected among carriage nor invasive isolates.ConclusionsThe distribution of serotypes among carriage and invasive GBS reflects the assumption that EOGBS occur following transmission of GBS from mother to newborn, with the exception of serotype IX.

Highlights

We describe the serotype distribution of Streptococcus agalactiae (GBS) carriage isolates from women in labor and among GBS isolates causing invasive infections during the same period to see if the distribution of car‐ riage serotypes reflects the GBS serotypes causing invasive diseases including early-onset disease (EOGBS)
No children of the participating women in labor were diagnosed with Early-onset disease (EOGBS) nor Late-onset disease (LOGBS)
In conclusion, we found that serotype IX dominated as carriage isolate, followed by serotype III

Summary

Introduction

We describe the serotype distribution of Streptococcus agalactiae (GBS) carriage isolates from women in labor and among GBS isolates causing invasive infections during the same period to see if the distribution of car‐ riage serotypes reflects the GBS serotypes causing invasive diseases including early-onset disease (EOGBS). Invasive infection is generally presented as an early-onset disease (EOGBS) during the first week of life. Slotved et al BMC Infect Dis (2021) 21:1129 have shown that carriage rates with GBS in pregnant women can vary from 10 to 35 % cultured at gestational week 35–37, this can only be considered as a qualified guess for the rate at birth since GBS colonization may be transient and vary during pregnancy. Invasive GBS disease occurring from seven days of life and up to three months of age is defined as a late-onset disease (LOGBS) and is generally due to transmission from the infant’s surroundings [2]. The incidence of EOGBS among Danish newborns increased from 2018 (0.15 per 1.000) to 2019 (0.29 per 1.000) [1]

Objectives

Methods

Results

Discussion

Conclusion