Group A Streptococcus Infections
Charles Patrick Davis, MD, PhD
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
- Group A streptococcal infections facts
- What is group A Streptococcus (GAS)?
- How are group A streptococcal (GAS) infections contracted?
- What diseases are caused by group A streptococcal infection?
- Are group A strep infections contagious?
- What is the contagious period for group A strep infections?
- What is the incubation period for group A strep infections?
- What are the symptoms and signs of GAS infections?
- What is invasive group A streptococcal disease? Who is most at risk for getting invasive GAS disease?
- What are the symptoms and signs of necrotizing fasciitis?
- What are the signs and symptoms of toxic shock syndrome (TSS)?
- How are group A streptococcal (GAS) infections diagnosed?
- What is the treatment for invasive group A streptococcal disease?
- What specialists treat group A streptococcal infections?
- What complications are seen with group A streptococcal infections?
- Is it possible to prevent group A streptococcal infections?
- What is the prognosis for group A streptococcal infections?
- Where can people find more information about group A streptococcal infections?
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.
- Some GAS infections are contagious, and others are not.
- GAS infections that are contagious can be contagious during the incubation period (the time between infection and development of symptoms) until symptoms stop.
- The incubation period varies according to the specific GAS-caused infection, but most have a range of about one to five days while others take over a week to cause symptoms.
- Symptoms and signs of GAS disease are variable and are related to the body area that is affected by 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.
- Infectious-disease specialists, pediatricians, OB/GYN specialists, critical-care specialists, dermatologists, internal-medicine specialists, family practitioners, and surgeons may be involved in the team caring for a GAS patient.
- 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.
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