A retrospective review of group B streptococcus bacteraemia in Western Sydney, Australia from 2011-2023.

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.