What it is

Group A Streptococcus are bacteria.

Types

Group A strep bacteria can cause many different types of infections that range from minor to serious. The bacteria can also cause inflammatory diseases.

The following are some, but not all, of the conditions associated with group A strep bacteria.

Minor infections

The following infections caused by group A strep bacteria are generally mild:

• Impetigo
• Scarlet fever
• Strep throat

Serious infections

Three infections caused by group A strep bacteria can be very serious and even deadly:

• Cellulitis
• Necrotizing fasciitis
• Streptococcal toxic shock syndrome

Inflammatory diseases

Long-term health issues related to group A strep bacteria include:

• Post-streptococcal glomerulonephritis
• Rheumatic fever

Both are thought to be caused by an immune response to an earlier group A strep infection. As the body’s defense system, the immune system is important in fighting off infections. But the immune system can mistakenly attack healthy parts of the body and cause damage.

Risk factors for serious infections

Who’s at increased risk of getting any specific condition listed above varies. However, some people are generally at increased risk of getting a serious group A strep infection.

Viral infections, like flu or chickenpox, can increase this risk.

Medical conditions that can increase the risk for getting a serious group A strep infection include:

• Cancer
• Chronic heart, kidney, liver, or lung disease
• Diabetes
• Immunocompromising condition (having a weakened immune system)
• Obesity
• Wounds or skin disease

Other groups at increased risk for getting a serious group A strep infection include:

• American Indian, Alaska Native, Native Hawaiian, and Pacific Island populations
• People aged 65 years or older
• People who inject drugs or who are experiencing homelessness
• Residents of long-term care facilities

How it spreads

Group A strep bacteria are very contagious. Some people infected with group A strep bacteria don’t have symptoms or seem sick. They can still spread the bacteria to others.

Generally, people spread the bacteria to others through respiratory droplets or direct contact. Rarely group A strep bacteria can spread through food that isn’t handled properly.

Respiratory droplets

Group A strep bacteria often live in the nose and throat. People who are infected spread the bacteria by talking, coughing, or sneezing. This creates respiratory droplets that contain the bacteria.

People can get sick if they:

• Breathe in respiratory droplets that contain the bacteria
• Touch their mouth or nose after touching something with those droplets on it
• Use the same plate, utensils, or glass as someone infected with the bacteria

Once washed, plates, utensils, and glasses are safe for others to use.

Direct contact

People can also spread group A strep bacteria from infected sores on the skin. Other people can get sick if they touch those sores or come into contact with fluid from the sores.

Once the sores heal, the bacteria aren’t usually able to spread to other people.

Prevention

There are things people can do to protect themselves and others from group A strep infections.

Group A strep prevention activities vary by each disease, but generally focus on three important goals:

1. Limit exposure and spread of bacteria
2. Treat group A strep infections promptly
3. Use preventive antibiotics when appropriate