Streptococcus agalactiae
Serotypes
The dominant serotypes causing disease varies regionally. There is also a difference in serotype distribution between invasive and asymptomatic infections of GBS.
A systematic review by Bianchi-Jassir et.al (2020) showed that serotype III was the most frequent serotype in infant disease (60%). Two additional serotypes (Ia, II) accounted for more than 15% of infant disease in the Americas, Europe, and East Asia, whereas in Sub-Saharan Africa and Australia. serotypes Ia and V accounted for more than 20% of infant GBS disease. For maternal colonisation and disease, the top three serotypes (Ia, III and V) were similar across all regions but with some regional differences in serotype frequency.
