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NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

Clinical Description

Invasive group A streptococcal infections may manifest as any of several clinical syndromes, including pneumonia, bacteremia in association with cutaneous infection (e.g., cellulitis, erysipelas, or infection of a surgical or nonsurgical wound), deep soft-tissue infection (e.g., myositis or necrotizing fasciitis), meningitis, peritonitis, osteomyelitis, septic arthritis, postpartum sepsis (i.e., puerperal fever), neonatal sepsis, and nonfocal bacteremia.

Laboratory Criteria For Diagnosis

Isolation of group A Streptococcus (Streptococcus pyogenes) by culture from a normally sterile site (e.g., blood or cerebrospinal fluid, or, less commonly, joint, pleural, or pericardial fluid)

Case Classification


A case that is laboratory confirmed


The 1995 case definition appearing on this page was later re-published in the 1997 MMWR Recommendations and Reports titled Case Definitions for Infectious Conditions Under Public Health Surveillance.1 Thus, the 1995 and 1997 versions of this case definition are identical.


  1. CDC. (1997). Case Definitions for Infectious Conditions Under Public Health Surveillance. MMWR, 46(RR-10), 1-55.