County of Los Angeles
Department of Public Health
Acute Communicable Disease Control
313 N. Figueroa Street, Room 212
Los Angeles, CA 90012
Phone: (213) 240-7941
Fax: (213) 482-4856
E-Mail:acdc2@ph.lacounty.gov

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Streptococcal Infections, Group A (IGAS) and
Toxic Shock Syndrome (STSS)

Invasive Group A Streptococcal (IGAS) disease is caused by the group A beta-hemolytic Streptococcus pyogenes bacterium. Transmission is by direct or, rarely, indirect contact. Illness manifests as various overlapping clinical syndromes including bacteremia without focus, sepsis, cutaneous wound or deep soft-tissue infection, septic arthritis, and pneumonia. It is the most common cause of necrotizing fasciitis, commonly known as “flesh eating bacteria.” IGAS occurs in all age groups but more frequently among the very old. Infection can result in severe illness, including death.

Streptococcal toxic shock syndrome (STSS) is a rare but extremely severe illness characterized by rapid onset of hypotension (low blood pressure) and shock. Other symptoms can include renal (kidney) impairment, coagulopathy (abnormality in the blood's ability to clot), adult acute respiratory distress syndrome, rash and local tissue destruction. Death occurs in up to 70% of people who develop streptococcal toxic shock syndrome.

For surveillance purposes in LAC, IGAS is defined as isolation of S. pyogenes from a normally sterile body site (e.g., blood, cerebrospinal fluid, synovial fluid, or from tissue collected during surgical procedures). Isolation can include a non-sterile site if associated with STSS or necrotizing fasciitis (NF). IGAS cases are characterized as STSS if the diagnosis fulfills the CDC or Council of State and Territorial Epidemiologists (CSTE) case definitions for this syndrome; and as NF if the diagnosis was made by the treating physician.

• ACDC (IGAS): A Manual of Departmental Rules, Regulations and Control Procedures
• ACDC (STSS): A Manual of Departmental Rules, Regulations and Control Procedures
  • LAC Report Form: Invasive Group A Streptococcal Disease (IGAS) Report Form

Los Angeles County Annual Reports

• Annual Reports 2001-2006

Los Angeles County Special Study Reports

• 2006: Risk Factors for Invasive Group A Streptococcal Disease, 2004-2006
• 2000: Group A Streptococcal Invasive Disease
• 1999: Group A Streptococcal Invasive Disease
• 1998: Group A Streptococcal Invasive Disease
• 1996: Group A Streptococcal Invasive Disease

Additional Resources

• CDC: Active Bacterial Core Surveillance Reports
• CDC: Streptococcus pyogenes emm sequence database
• CDC: General Information
• NIAID: Fact Sheet
• O’Brien KL, Beall B, Barret NL, et al. Epidemiology of invasive group A streptococcal disease in the United States, 1995-1999. Clin Infec Dis 2002;36:268-276
• American Academy of Pediatrics. Committee on Infectious Diseases. Severe invasive group A streptococcal infections: a subject review. Pediatrics. 1998;101:136-40
• Kaul R, McGeer A, Low D, et al. Population-based surveillance for group A streptococcal necrotizing fasciitis: clinical features, prognostic indicators, and microbiologic analysis of seventy-seven cases. Am J Med 1997;103:18-24
• Factor SH, Levine OS, Schwartz B, et al. Invasive group A streptococcal disease: risk factors for adults. Emerg Infect Dis 2003; 9(8):970-977. Available at http://www.cdc.gov/ncidod/eid/vol9no8/02-0745.htm
• Factor SH, Levine OS, Harrison LH, Farley MM, McGeer A, Skoff T, Wright T, Schwartz B, Schuchat A. Risk Factors for Pediatric Invasive Group A Streptococcal Disease. Emerg Infect Dis 2005;11(7):1062-1066. Available at http://www.cdc.gov/ncidod/eid/vol11no07/04-0900.htm
• Robinson KA, Rothrock G, Phan Q, Sayler B, Stefonek K, Van Beneden C, Levine OS. Active Bacterial Core Surveillance /Emerging Infections Program Network. Risk for severe group A streptococcal disease among patients' household contacts. Emerg Infect Dis 2003;9(4):443-447. Available at http://www.cdc.gov/ncidod/EID/vol9no4/02-0369.htm
• Manning SE, Lee E, Bambino M, et al. Invasive Group A Streptococcal Infection in High School Football Players, New York City, 2003. Emerg Infect Dis 2005; 11(1):146-149. Available at http://www.cdc.gov/ncidod/eid/vol11no01/04-0559.htm
• CDC: Use of Pulsed-Field Gel Electrophoresis for Investigation of a Cluster of Invasive Group A Streptococcal Illness -- Spokane, Washington, 1999. MMWR 1999; 48:681-683. Available at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4831a1.htm
• CDC: Outbreak of invasive group A Streptococcus associated with varicella in a childcare center -- Boston, Massachusetts, 1997. MMWR 1997:46:944-8. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/00049535.htm

STSS Resources

• Brown, EJ. The Molecular Basis of Streptococcal Toxic Shock Syndrome. NEJM 2004; 350(20): 2093-2094.
• Stevens, DL. Streptococcal Toxic-Shock Syndrome: Spectrum of Disease, Pathogenesis, and New Concepts in Treatment. Emerg Infect Dis 1995; 1(3): 69-78.