Invasive group B Streptococcus among non-pregnant adults in Brussels-Capital Region, 2005-2019

To assess the incidence, clinical, microbiological features and outcome of invasiveStreptococcus agalactiae(GBS) infections in non-pregnant adults in three tertiary hospitals of the Brussels-Capital Region. All bacterial cultures positive for GBS, from 2005 to 2019 from 3 hospitals of the Brussels-Capital Region, were extracted, and only cases of invasive diseases were included. Medical files were retrospectively retrieved for risk factors, clinical manifestations and outcome and also antibiotic-susceptibility testing and GBS serotypes. Incidence rates were calculated based on the hospitals catchment populations. A total of 337 cases of GBS-invasive infections were included. The incidence of invasive GBS for the 3 hospitals increased from 3.7 to 8.2 cases per 100.000 inhabitants between 2009 and 2018 (p= 0.04). The most frequently identified risk factors were diabetes (36.8%), obesity (35.0%), cancer (21.7%), renal disease (20.8%), and advanced age (>= 65 years; 47.2%). Isolated bacteremia (22%), osteoarticular infection (21.4%), abscesses (13.9%), and skin and soft tissue infections (18.4%) were the most frequent manifestations. Intensive care unit admission was required in 21.7% and overall mortality was 9.4%. All strains remained susceptible to penicillin over the years. Up to 20% of strains were resistant to clindamycin. Serotypes Ia, Ib, II, III, IV, and V represented 96.8% of the available serotypes (60/62). As reported in several countries, invasive GBS disease in non-pregnant adults represents an increasing burden, particularly among diabetic, obese, and elderly patients. Almost all serotypes identified are included in the upcoming hexavalent GBS conjugate vaccine.

Automated summary

Invasive Streptococcus agalactiae infections in non-pregnant adults in three tertiary hospitals of the Brussels-Capital Region have increased from 3.7 to 8.2 cases per 100,000 inhabitants between 2009 and 2018. The most common risk factors include diabetes, obesity, cancer, renal disease, and advanced age. The main manifestations are bacteremia, osteoarticular infection, abscesses, and skin and soft tissue infections, with a mortality rate of 9.4%.