Background
Following anecdotal domestic and international reports of post-pandemic increases streptococcal brain abscess incidence,[1] we investigated trends, patient demographics and microbial aetiology of hospital admissions for brain abscesses in England.
Methods
National patient admission data were extracted from England’s hospital admission database[2] for 2014-2023 records with a brain abscess ICD10-code (G06.0/G06.2). Positive microbiological specimens were identified via linkage to the UKHSA national laboratory surveillance database.[3] Preliminary descriptive statistics were performed to investigate factors associated with streptococcal brain abscess.
Results
Between 2014-2023, 11,011 brain abscess admissions were identified from 8,553 (77.7%) adults (≥18yrs), 1,482 (13.5%) children (1-17yrs), and 296 (2.7%) infants (<1yr; missing age=680).
Where microbiology was available (n=7,324), 30% were streptococcal species (26% adults, 51% children, 38% infants), increasing from 23% (n=146) in 2014 to 35% (n=383) in 2023.
The age-adjusted odds of having a streptococcal species brain abscess in patients of white ethnicity was 1.6 times higher (p<0.001), compared to Asian patients where non-streptococcal species were more likely.
Streptococcus intermedius was the most frequently identified streptococcal species in adults (54%, n=1,179) and children (63%, n=458), whereas Streptococcus pneumoniae was the most common for infants (55%, n=45)
The overall 90-day all-cause case fatality rate for streptococcal brain abscess cases was 8.5% (95% CI 7.5-9.5%); adults: 10.9%, children: 1.8%, infants: 2.4%.
Conclusions
Our study showed a marked increase in streptococcal brain abscess incidence in England since 2014 The microbial aetiology differed by age and ethnicity. Differences between surgical and community-acquisition and predisposing conditions need to be assessed to identify prevention opportunities.