Case Definition for Invasive Group A Streptococcal Infection (iGAS)
Clinical criteria
Severe clinical presentation consistent with iGAS or severe GAS infection such as;
- streptococcal toxic shock syndrome (STSS)
- necrotising fasciitis
- pneumonia
- septic arthritis
- meningitis
- peritonitis
- osteomyelitis
- myositis
- puerperal sepsis
- cellulitis
accompanied by a systemic presentation necessitating hospitalisation.
Laboratory criteria
- Laboratory criteria
- Isolation of group A streptococcus (GAS), by culture or molecular methods (such as PCR), from a normally sterile body site (blood, cerebrospinal fluid, pleural-peritoneal-pericardial fluids, joint aspirate, bone, or deep tissue or abscess at operation or post-mortem)
- Isolation of GAS from a non-sterile site (e.g. throat, sputum, vagina)
Epidemiological criteria
Suspected case has an epidemiological link to a confirmed case of iGAS
Case classification
- Confirmed case
- Any person meeting the laboratory criteria of (1) above
OR - Any person meeting the laboratory criteria of (2) above PLUS the clinical criteria described above
- Any person meeting the laboratory criteria of (1) above
- Probable case
- Any person meeting the clinical criteria above
PLUS
- the epidemiological criteria above
OR - the clinician considers that GAS is the most likely cause
- the epidemiological criteria above
- Any person meeting the clinical criteria above
Current as of: 22 December 2022