Group A Streptococcus Infections

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Group A streptococcal infections facts

  • Group A streptococci (GAS) are defined gram-positive spherical-shaped bacteria that produce beta-hemolysis (lysis of red blood cells producing clear or transparent areas in special growth media) and appear usually as a chain of two or more bacteria and have molecules on their surface known as Lancefield group A antigens.
  • Group A Streptococcus (GAS) organisms are usually spread by direct human-to-human transfer. Occasionally, they can be spread by droplets or by a person touching items recently handled by an infected individual (also termed fomites).
  • GAS can cause a wide range of diseases, but most notably, strep throat; other diseases (or complications) include fever, rheumatic fever, kidney damage, skin and wound infections and occasionally, necrotizing fasciitis and shock.
  • Symptoms and signs of GAS disease are variable and are related to the body area that is undergoing the infection; for example, sore throat, throat erythema, and swollen lymph nodes in strep throat to low blood pressure and organ failure in toxic shock syndrome.
  • Early signs and symptoms of necrotizing fasciitis include fever, severe pain and swelling, and erythema (redness) at the wound site or site where GAS organisms entered the body; later signs and symptoms include fluid discharge from the infected tissue, skin loss, and low blood pressure
  • Early symptoms of toxic shock syndrome are nonspecific, often begin with flu-like symptoms of mild fever and malaise, then the condition often suddenly advances with symptoms of high fever, nausea, vomiting, diarrhea, skin rash, and a low blood pressure with possible progression to include confusion, headaches, seizures, and skin loss from the palms of the hands and from the soles of the feet.
  • Diagnosis of GAS is made by culturing the bacteria and having the laboratory identify the bacteria by metabolic functions and immunologic tests; rapid tests are based on immunological recognition of GAS antigens taken from the patient by swabbing the throat.
  • Although oral antibiotics (many types) are effective in treating milder forms of GAS infections, more serious forms of GAS such as invasive GAS disease usually require multiple antibiotics administered IV; in addition, some patients may require surgery to remove dead and dying tissue.
  • The prognosis (outcome) of GAS infections, especially mild infections, is usually good to excellent. However, as the disease progresses from moderate to severe, the prognosis decreases from good to poor; early effective treatment may improve the prognosis.
  • Prevention of GAS infections is possible by attention to good hygiene such as hand washing and avoiding eating or drinking from the same containers used by other people and avoiding direct and indirect (for example, droplet or particle contamination of clothing) contact with a infected individual; early treatment of GAS infections can reduce or prevent the progression to more severe disease.
  • Although research is ongoing, there is no commercially available vaccine to prevent GAS infections.
Medically Reviewed by a Doctor on 10/16/2014

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Discover the causes, symptoms, and treatment of a flesh-eating bacterial infection (necrotizing fasciitis).

What Is a "Flesh-Eating" Bacterial Infection?

Media reports have popularized the term "flesh-eating bacteria" to refer to a very rare but serious bacterial infection known as necrotizing fasciitis. Necrotizing fasciitis is an infection that starts in the tissues just below the skin and spreads along the flat layers of tissue (known as fascia) that separate different layers of soft tissue, such as muscle and fat. This dangerous infection is most common in the arms, legs, and abdominal wall and is fatal in 30%-40% of cases.