Streptococcal Invasive Disease Group A 
Annual Summary of Reportable Diseases

• According to the Centers for Disease Control and Prevention (CDC), the number of serious group A strep infections in the United States have been increasing over the past decade. In 2023, the number of serious infections reached a 20-year high. This is consistent with Minnesota’s data. The increase can be seen across all age levels, including among pediatric cases.
• In 2023, long-term care facilities and their residents were impacted by the increase in group A strep transmission in Minnesota. The majority of long-term care facilities outbreaks are associated with lapses in infection prevention, staff turnover, and wound care. CDC released a decision tool for investigating and controlling GAS infections in long-term care to better guide those involved in the response.
• While group A strep bacteria circulate year-round, infection is more common in December through April (“high season”). In Minnesota, an increase was first noticed in the fall of 2022 and was sustained through August 2023 demonstrating a departure from typical seasonality.

There were 625 cases (11.0 cases per 100,000 population), including 55 deaths, reported in 2023, compared to 310 cases and 29 deaths in 2022. The median age of cases was 58 years (range, 25 days to 97 years). Sixty-one percent of cases were residents of the metropolitan area. Allowing for multiple presentations per patient, 300 (48%) had cellulitis, 169 (27%) septic shock, 93 (15%) septic arthritis and/or osteomyelitis, 89 (14%) bacteremia without another focus of infection, 84 (13%) pneumonia, 53 (8%) abscess (not skin), 44 (7%) necrotizing fasciitis, and 40 (6%) STSS. Twenty-seven (4%) cases were injection drug users in 2023 compared to 27 cases (9%) in 2022. There were two deaths in 2023 compared to no deaths in 2022. Forty-two (7%) cases were residents of long-term care facilities (LTCFs). Among 2023 LTCF-associated invasive GAS cases only, twelve facilities had a single case, four facilities had two cases, and six facilities had more than two cases.

Allowing for multiple infection types per patient, the 55 deaths included 43 that were diagnosed with septic shock, 18 with cellulitis, 12 with STSS, 11 with pneumonia, 7 with necrotizing fasciitis, and 6 with septic arthritis and/or osteomyelitis. Of the 55 deaths, the most frequently reported underlying conditions were obesity (21), diabetes (17), chronic kidney disease (13), chronic skin breakdown (13) (e.g. psoriasis, chronic ulcers), heart failure (13), current tobacco smoker (12), atherosclerotic cardiovascular disease (9), solid organ malignancy (8), and seizure disorder (7). Thirty-four fatal cases had two or more underlying conditions, and eight had none reported.

• For up to date information see: Group A Streptococcus (GAS)
• Download: 2023 Cases of Invasive Group A Streptococcal Disease by Outcome (CSV)
• Download: 2023 Cases of Invasive Group A Streptococcal Disease by Year (CSV)
• Download: 2023 Incidence of Invasive Group A Streptococcal Disease (CSV)
• Download: 2023 Incidence of Invasive Group A Streptococcal Disease by Age and Gender (CSV)
• Download: 2023 Incidence of Invasive Group A Streptococcal Disease Cases and Deaths by Age Group (CSV)

Invasive Group A Streptococcus disease (GAS) is defined as GAS isolated from a usually sterile site such as blood, cerebrospinal fluid, or a wound when accompanied with necrotizing fasciitis or streptococcal toxic shock syndrome (STSS). There were 310 cases (5.2 cases per 100,000 population), including 29 deaths, reported in 2022, compared to 214 cases and 19 deaths in 2021. The median age of cases was 56 years (range, 5 months to 101 years). Fifty-seven percent of cases were residents of the metropolitan area. Allowing for multiple presentations per patient, 114 (37%) had cellulitis, 70 (23%) septic shock, 54 (17%) bacteremia without another focus of infection, 36 (12%) pneumonia, 31 (10%) had septic arthritis and/or osteomyelitis, 27 (9%) abscess (not skin), 13 (4%) necrotizing fasciitis, and 10 (3%) STSS. Twenty-seven (9%) cases were injection drug users in 2022 compared to 43 cases (20%) in 2021. There were no deaths in 2022 compared to one death in 2021. Twenty-nine (9%) cases were residents of long-term care facilities (LTCFs). Among 2022 LTCF-associated iGAS cases only, twelve facilities had a single case, two facilities had 2 cases, and 4 facilities had more than 2 cases. 

Allowing for multiple infection types per patient, the 29 deaths included 22 that were diagnosed with septic shock, 7 with cellulitis, 5 with pneumonia, 5 with necrotizing fasciitis, three with bacteremia without another focus of infection, and one with STSS. Of the 29 deaths, the most frequently reported underlying conditions were chronic kidney disease (12), heart failure (12), atherosclerotic cardiovascular disease (8), chronic obstructive pulmonary disease (8), obesity (8), diabetes (6), current tobacco smoker (5), and solid organ malignancy (5). Twenty fatal cases had two or more underlying conditions, three had none reported, and two had unknown underlying conditions.

• For up to date information see: Group A Streptococcus (GAS)

Invasive Group A Streptococcus disease (GAS) is defined as GAS isolated from a usually sterile site such as blood, cerebrospinal fluid, or a wound when accompanied with necrotizing fasciitis or streptococcal toxic shock syndrome (STSS). Two-hundred and fourteen cases (3.8 cases per 100,000 population), including 19 deaths, were reported in 2021, compared to 271 cases and 20 deaths in 2020. The median age of cases was 55 years (range, 6 months to 93 years). Fifty-five percent of cases were residents of the metropolitan area. Allowing for multiple presentations per patient, 105 (49%) had cellulitis, 42 (20%) bacteremia without another focus of infection, 30 (14%) septic shock, 29 (13.5%) had septic arthritis and/ or osteomyelitis, 16 (7.5%) abscess (not skin), 16 (7.5%) pneumonia, and 11 (5%) necrotizing fasciitis. Forty-three (20%) cases were injection drug users in 2021, including one death, compared to 48 cases (18%) and 0 deaths in 2020. Twelve (5.6%) cases were residents of long-term care facilities. Ten facilities had a single case, one facility had 2 cases. 

Allowing for multiple infection types per patient, the 19 deaths included 11 that were diagnosed with septic shock, 11 cellulitis, 2 bacteremia without another focus of infection, 1 abscess (not skin), 1 necrotizing fasciitis, 1 pneumonia, and 1 with STSS. Of the 19 deaths, the most frequently reported underlying conditions were diabetes (11), chronic kidney disease (7), atherosclerotic cardiovascular disease (6), current tobacco smoker (6), heart failure (5), chronic obstructive pulmonary disease (4), solid organ malignancy (3), and obesity (3). Sixteen fatal cases had two or more underlying conditions, and 1 had none reported.

• For up to date information see: Group A Streptococcus (GAS)

Invasive Group A Streptococcus disease (GAS) is defined as GAS isolated from a usually sterile site such as blood, cerebrospinal fluid, or a wound when accompanied with necrotizing fasciitis or streptococcal toxic shock syndrome (STSS). Two hundred seventy-one cases (4.8 cases per 100,000 population), including 20 deaths, were reported in 2020, compared to 326 cases and 21 deaths in 2019. The median age of cases was 52 years (range, newborn to 99 years). Fifty-two percent of cases were residents of the metropolitan area. Allowing for multiple presentations per patient, 122 (45%) had cellulitis, 62 (23%) bacteremia without another focus of infection, 36 (13%) abscess (not skin), 34 (13%) septic shock, 26 (10%) necrotizing fasciitis, 21 (8%) pneumonia, and 15 (6%) had septic arthritis and/or osteomyelitis. Twenty-five (8%) cases were injection drug users in 2019, including one death, compared to 48 cases (18%) in 2020. Thirteen (5%) cases were residents of long-term care facilities. Eleven facilities had a single case, one facility had 2 cases. 

Allowing for multiple infection types per patient, the 20 deaths included 8 that presented with septic shock, 6 bacteremia without another focus of infection, 5 cellulitis, 4 pneumonia, and 3 with necrotizing fasciitis. Of the 20 deaths, the most frequently reported underlying conditions were diabetes (13), chronic kidney disease (11), current tobacco smoker (5), dementia (5), atherosclerotic cardiovascular disease (4), obesity (4), chronic dialysis (4), and heart failure (3). Fifteen fatal cases had two or more underlying conditions, and 1 had none reported.

• For up to date information see: Group A Streptococcus (GAS)

Invasive Group A Streptococcus disease (GAS) is defined as GAS isolated from a usually sterile site such as blood, cerebrospinal fluid, or a wound when accompanied with necrotizing fasciitis or streptococcal toxic shock syndrome (STSS). Three hundred twenty-six cases (5.8 cases per 100,000 population), including 21 deaths, were reported in 2019, compared to 367 cases and 37 deaths in 2018. The median age of cases was 56 years (range, newborn to 96 years). Forty-six percent of cases were residents of the metropolitan area. Allowing for multiple presentations per patient, 129 (40%) had cellulitis, 62 (19%) septic shock, 55 (17%) bacteremia without another focus of infection, 44 (14%) pneumonia, 34 (10%) septic arthritis and/or osteomyelitis, 27 (8%) necrotizing fasciitis, 25 (8%) abscess, and 13 (4%) had STSS. Twenty-five cases (8%) were injection drug users in 2018, including one death, compared to 23 cases (6%) in 2019. Nineteen (6%) cases were residents of long-term care facilities. Seventeen facilities had a single case, one facility had 2 cases.

The 21 deaths included 14 that presented with septic shock, 4 pneumonia, 3 bacteremia without another focus of infection, and 3 cellulitis (individuals could have more than one infection type). Of the 21 deaths, the most frequently reported underlying conditions were diabetes (8), current tobacco smoker (5), chronic kidney disease (4), solid organ malignancy (3), obesity (2), heart failure (2), atherosclerotic cardiovascular disease (2), asthma (2), dementia (2), cirrhosis (2), and chronic skin breakdown (2). Eighteen fatal cases had two or more underlying conditions, and 3 had none reported.

• Find up to date information at>> Group A Streptococcus (GAS)

Invasive Group A streptococcal disease (GAS) is defined as GAS isolated from a usually sterile site such as blood, cerebrospinal fluid, or a wound when accompanied with necrotizing fasciitis or streptococcal toxic shock syndrome (STSS). Three hundred sixty-seven cases (6.6 cases per 100,000 population), including 37 deaths, were reported in 2018, compared to 359 cases and 34 deaths in 2017. The median age of cases was 60 years (range, newborn to 99 years). Fifty-five percent of cases were residents of the metropolitan area. Allowing for multiple presentations per patient, 140 (38%) had cellulitis, 71 (19%) bacteremia without another focus of infection, 83 (23%) septic shock, 51 (14%) pneumonia, 25 (7%) abscess, 33 (9%) septic arthritis and/or osteomyelitis, 25 (7%) necrotizing fasciitis, and 11 (3%) had STSS. Twenty-three cases (6%) were injection drug users in 2018, compared to 10 (3%) in 2017. Forty-four (12%) cases were residents of long-term care facilities. Eighteen facilities had a single case, nine facilities had 2 or more cases including one facility that had 5 cases. A cluster of isolates from 53 cases from the west metropolitan area were determined to be indistinguishable from one another using whole genome sequencing. A review of the cases revealed that these cases were primarily residents of 19 different long term care facilities and had underlying wounds. An investigation of shared services between these facilities revealed that this cluster was associated with a single wound care provider who was contracted by these facilities.

The 37 deaths included 25 that presented with just septic shock, 7 bacteremia without another focus of infection, 8 cellulitis, and 12 pneumonia (individuals could have more than one infection type). Of the 34 deaths, the most frequently reported underlying conditions were obesity (10), current tobacco smoker (8), diabetes (7), chronic kidney disease (7), heart failure (7), atherosclerotic cardiovascular disease (7), chronic obstructive pulmonary disease (4), asthma (4), current alcohol abuse (3), dementia (3), peripheral vascular disease (3), cirrhosis (2), and chronic skin breakdown (2). Twenty-one fatal cases had two or more underlying conditions, and 5 had none reported.

• For up to date information see>> Group A Streptococcus (GAS)

• Archive of Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health
  Archive of past summaries (years prior to 2023 are available as PDFs).