Glossary

Key points

  • Below are a number of terms and definitions used in group A Streptococcus (GAS) investigations.
  • This information is provided as part of the online version of the long-term care facility (LTCF) outbreak investigation toolkit.

Group A Streptococcus or GAS

Another name for Streptococcus pyogenes bacteria. These bacteria cause many types of infections, which can be grouped into two general categories — invasive and non-invasive.

Invasive GAS infection

An illness with isolation (by culture) or identification (by molecular test) of GAS from either:

  1. A normally sterile site (e.g., blood, cerebrospinal fluid)
  2. A wound culture in a patient with either of the following
    1. Necrotizing fasciitis
    2. Streptococcal toxic shock syndrome

Non-invasive GAS infection

GAS detection in a patient with a clinical presentation consistent with GAS infection who does not meet the invasive case definition. Sampled from a non-sterile site (e.g., throat), GAS can be detected by

  • Isolation
  • Molecular test
  • Rapid antigen detection test (aka a rapid strep test)

Clinical presentations can include pharyngitis (also called strep throat), wound infection, or skin infection.

Healthcare personnel (HCP)

Refers to people serving in healthcare settings (oaid or unpaid) with the potential for exposure to patients or infectious materials. Infectious materials include:

  • Body substances (blood, tissue, specific body fluids)
  • Contaminated medical supplies, devices, and equipment
  • Contaminated environmental surfaces
  • Contaminated air

Adapted from Terminology | HCP | Infection Control Guidelines Library | CDC.

GAS carriage

Presence of GAS in the throat or on the skin of a person who has no signs or symptoms of infection. This is also called colonization.

Outbreak

An increase in frequency of disease beyond that expected in a particular time and place.

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Content Source:
National Center for Immunization and Respiratory Diseases; Division of Bacterial Diseases