Trends in beta-hemolytic Streptococcus infections within Veterans' Affairs medical centers from 2009 to 2018

Objective: The purpose of this study was to describe the recent trends of invasive and noninvasive β-hemolytic Streptococcus cultures in the Veterans' Affairs (VA) cohort from 2009 to 2018. Design: Retrospective cohort study from January 1, 2009, to January 1, 2019. Setting: Veterans' Affairs medical centers. Patients or participants: All patients aged 18 years and older with cultures positive for β-hemolytic Streptococcus at a VA facility were included in the study. Intervention(s): Data were retrieved from the VA Corporate Data Warehouse using structure query language through the SQL Server Management Studio software. Results: Between 2009 and 2018, there were 40,625 patients with cultures with β-hemolytic Streptococcus. The median age was 64 years (interquartile range [IQR], 55-71) and the median Charlson comorbidity index was 4 (IQR, 2-7). Distributions for each type of β-hemolytic Streptococcus based on site of culture are provided. The 30-day all-cause mortality rate from all invasive β-hemolytic Streptococcus cases was 2.3%, and the 90-day all-cause mortality rate was 4.4%. The 30- and 90-day all-cause mortality rates for Streptococcus cases were higher for group A (3.9% and 6.1% respectively) and for groups C and G combined (3.2% and 6.1%, respectively) than for group B (2.0% and 4.0%, respectively). Conclusions: Trends of cultures for invasive and noninvasive β-hemolytic Streptococcus suggest an association with disease and mortality. The burden associated with β-hemolytic Streptococcus infections should not be underestimated.