Background: Necrotizing soft tissue infections (NSTIs) are life-threatening conditions often caused by beta-hemolytic streptococci, Group A streptococci (GAS) in particular. Clinical knowledge on streptococcal NSTI has mainly been derived from surveillance studies and retrospective single-center studies. INFECT is a multicenter, EU-funded study of NSTIs and includes a large clinical cohort. It is the largest prospective study of NSTIs to date.
Methods: Adults admitted with NSTI to five clinical centers in Denmark, Sweden and Norway from February 2013 to June 2017 were included prospectively. Details on underlying medical conditions, findings at admission, antibiotic treatment, surgery, supportive care, hyperbaric treatment, high-dose immunoglobulin treatment and outcome were recorded. Molecular analysis of GAS and group C and G streptococci (GCS/GGS) cultured from blood or tissue was performed.
Results: In total, around 400 patients were included. Approximately 1/3 was caused by GAS and 1/10 by GCS/GGS. The GAS cases were associated with younger age and less comorbidity. Preliminary data on the streptococcal cases indicate a 90-day mortality rate of 15-20%, a clear association of toxic shock syndrome and mortality and predominance of emm1 and other emm types previously associated with invasive disease. Details on the whole cohort of streptococcal cases will be presented. These include molecular and clinical characteristics and interrelations of comorbidity, clinical presentation, treatment and outcome.
Conclusions This large prospective multicenter cohort study confirms the high severity of streptococcal NSTIs observed in previous surveillance studies and retrospective single-center studies. The diversity of disease and possible prognostic factors are described.