Objectives This study aimed to describe the epidemiology, clinical manifestations, management, and outcomes of group B streptococcus (GBS) bacteraemia in a large cohort spanning 13 years.

Methods This retrospective study included patients aged 16 years or older with positive GBS blood cultures obtained from four metropolitan hospitals in Western Sydney, Australia, from 1 January 2011 to 31 December 2023, inclusive. The case details of these positive cultures were reviewed using electronic medical records.

Results A total of 344 patients with GBS bacteraemia were included during the 13-year study period. The median age was 65 years, and 50% of the patients were aged 65 years or older. Known risk factors were identified in 83.1% of the patients with cardiac disease, and diabetes mellitus was the most prevalent. Skin and soft tissue infections were the most common primary manifestation (32.0%). Pregnancy-related infections represented a notable proportion of the cases (16.3%). The 7- and 30-day mortality rates were 2.3% and 5.2% respectively, with a higher mortality rate of 9.3% for those aged 65 years or older. Penicillins were the most common antibiotic class used to treat GBS bacteraemia and its resultant manifestations (66.1%).

Conclusions GBS bacteraemia most commonly occurs in individuals aged ≥65 years or during pregnancy. While mortality rates are generally low, they are twice as high in those aged ≥65 years.