Group A Streptococcus (GAS) as a spectrum of disease that includes non-invasive processes such as pharyngitis and impetigo to invasive infections with high mortality, such as sepsis, necrotizing fasciitis, and streptococcal toxic shock syndrome.
GAS infections are caused by the bacterium Streptococcus pyogenes.
US healthcare cost from invasive GIS are estimated to exceed $3.8 billion annually.
Group A Streptococcal (GAS) pharyngitis, commonly known as strep throat, typically presents with a sudden onset of sore throat, pain on swallowing, and fever.
Other symptoms may include headache, nausea, vomiting, and abdominal pain, particularly in children.
Physical examination often reveals tonsillopharyngeal erythema, with or without exudates, and tender, enlarged anterior cervical lymph nodes, but may include a red, swollen uvula, petechiae on the palate, and a scarlatiniform rash.
GAS pharyngitis is caused by the bacterium Streptococcus pyogenes.
GAS pharyngitis Is most prevalent in children aged 5-15 years and is more common in late winter and early spring.
Its transmission occurs through respiratory droplets from an infected person.
A 10-day course of penicillin or amoxicillin is recommended as the first-line treatment for GAS pharyngitis due to their efficacy, narrow spectrum of activity, and low cost.
For patients with a penicillin allergy, first-generation cephalosporins, clindamycin, or macrolides are recommended alternatives.
Adjunctive therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen can help manage fever and pain, but corticosteroids are not routinely recommended due to their limited benefit in symptom duration reduction.
For diagnostic purposes, a rapid antigen detection test (RADT) is recommended.
Invasive GAS disproportionally affects individuals 65 years and older and residents of long-term facilities.
GAS outbreaks have been reported among homelessness and people who inject drugs.
GAS incidence among indigenous populations is several times higher than among non-indigenous individuals.
Invasive GAS infections can present with a variety of clinical manifestations, including necrotizing fasciitis, streptococcal toxic shock syndrome (STSS), bacteremia, and pneumonia.
Early symptoms may include fever, severe pain at the site of infection, and signs of systemic toxicity such as hypotension and multi-organ failure.
Necrotizing fasciitis often begins with erythema and swelling, progressing rapidly to dusky skin discoloration, bullae formation, and gangrene.
STSS is characterized by sudden onset of shock and multi-organ failure, often accompanied by a diffuse erythematous rash.
The bacteria can enter the body through breaks in the skin, such as cuts, surgical wounds, or even minor trauma.
In some cases, the infection can arise without an obvious portal of entry, often following non-penetrating trauma like muscle strain or bruising.
Prompt initiation of antibiotic therapy and surgical intervention for invasive GAS infections.
The first-line treatment includes a combination of penicillin and clindamycin.
Clindamycin is particularly important due to its ability to inhibit toxin production and its excellent tissue penetration.
In cases of STSS or severe invasive infections, intravenous immunoglobulin (IVIG) may be considered as an adjunctive therapy to neutralize streptococcal toxins.
Early and aggressive surgical debridement is crucial in cases of necrotizing fasciitis to remove necrotic tissue and control the spread of infection.
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