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Updated: Aug 25, 2025
A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Invasive group B Streptococcus strains and clinical characteristics in Danish infants from 1999 to 2009
Mads Andersen1,2, Birgitte Smith3,4, May Murra5
1Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
Insights
Group B Streptococcus (GBS) strains vary in infant infections, with some strains like III/CC19 showing higher mortality. Understanding these GBS serotypes and clonal complexes is crucial for developing effective infant vaccines and treatments.
Area of Science:
- Pediatric Infectious Diseases
- Bacteriology
- Vaccinology
Background:
- Group B Streptococcus (GBS) infections pose significant risks to infants, causing severe illness and mortality.
- Surveillance of GBS strains and their clinical impact is vital for developing vaccines and improving infant care.
- Understanding GBS serotypes and clonal complexes (CC) in early and late-onset infections is essential.
Purpose of the Study:
- To investigate GBS serotypes and clonal complexes in Danish infants with early-onset infection (EOD) and late-onset infection (LOD).
- To analyze the association between specific GBS strains and clinical outcomes in infants.
- To inform the development of targeted GBS vaccines and treatments.
Main Methods:
- Analysis of 212 GBS isolates from Danish infants (1999-2009) using serotyping and multilocus sequence typing.
- Classification of isolates into clonal complexes (CC).
- Collection of clinical data including gestational age, symptom severity, and mortality.
Main Results:
- Dominant GBS strains identified: III/CC17 (41%), Ia/CC23 (17%), III/CC19 (15%).
- Strain III/CC19 exhibited the highest mortality rate (22%), followed by Ia/CC23 (16%).
- Strain distribution varied between EOD and LOD, with III/CC17 prevalent in both.
Conclusions:
- Observed variations in disease severity among GBS strains highlight the need for ongoing surveillance.
- Continuous monitoring of infant GBS strains and clinical characteristics is crucial for optimizing vaccine development and treatment strategies.
Background:
Group B Streptococcus (GBS) infection in infants may result in both respiratory, cardiovascular, and neurological dysfunction and ultimately death of the infant. Surveillance of GBS strains in infants and their clinical characteristics guide development of effective vaccines and other potential treatments and may have implications for future prognostics and infant care. Therefore, we aimed to study GBS serotypes and clonal complexes (CC) in Danish infants with early onset infection (EOD) (0-6 days of life) and late-onset infection (LOD) (7-89 days of life) and to estimate the association between GBS strain and different clinical outcomes.
Methods:
We included Danish infants less than 3 months of age with GBS isolates from blood or cerebrospinal fluid between 1999 and 2009. GBS isolates were analyzed by serotyping and multilocus sequence typing with classification of isolates into clonal complexes. Clinical characteristics were obtained by questionnaires completed by tending pediatrician including gestational age, Apgar scores, age at onset, meningitis, symptom severity, treatment duration, and mortality. Symptom severities were reported within neurological symptoms, need for respiratory or circulatory support, and treatment of disseminated intravascular coagulation.
Results:
A total of 212 GBS isolates were collected with 129 from EOD and 83 from LOD. The dominating GBS strains were III/CC17 (41%), Ia/CC23 (17%), III/CC19 (15%), Ib/CC8-10 (7%), and V/CC1 (6%). Strain Ia/CC23 was mostly found in EOD, while III/CC17 was widespread in LOD, though being the most common in both EOD and LOD. Strain III/CC17 and Ia/CC23 had highest percentage of samples from cerebrospinal fluid (26%), while III/CC19 had the least (8%). Strain III/CC19 had highest mortality with about one fifth of infected infants dying (22%) followed by Ia/CC23 (16%), Ib/CC8-10 (9%), and then III/CC17 (6%). The symptom severity varied between strains, but with no strain consistently resulting in more severe symptoms.
Conclusion:
Some potential differences in disease severity were observed between the different strains. These findings emphasize the continuous need for multimodal surveillance of infant GBS strains and their clinical characteristics to optimize development of GBS vaccines and other potential treatments.
