The Different Types of Streptococci (Strep Bacteria)

But most commonly, strep is found in children ages 3 to 14 years old, according to Robert Hagerty, MD, a pediatrician at the Children’s Hospital of New York at NewYork-Presbyterian.

Here’s what to know about how the different types of streptococcal infections are spread, treated, and prevented.

Group A strep, sometimes called GAS, tends to affect your throat and your skin. You may carry GAS in these areas yet not show any symptoms of illness.

Group A strep infections spread through direct contact with mucus from the nose or throat, or through contact with infected wounds or sores.

Illnesses caused by infection with group A strep include:

Strep Throat

• A sore throat that comes on very quickly
• Pain when swallowing
• Fever
• Red and swollen tonsils, sometimes with white patches or streaks of pus
• Small red spots on the roof of your mouth
• Swollen lymph nodes in the front of your neck

Strep throat may also happen along with headache, abdominal pain, nausea, or vomiting, especially in children. The illness tends to become noticeable two to five days after exposure to the virus.

There are several signs that doctors look for to figure out if a child might have strep throat, Dr. Hagerty says. These include:

• Swollen tonsils, sometimes with white spots
• Swollen, tender lymph nodes on the neck under the chin
• A fever over 100.4 degrees F
• No cough

But a doctor can’t tell if someone has strep throat just by looking alone. Testing is needed, too. A rapid strep test involves swabbing the throat and running a lab test to see if GAS is the cause of the illness.

While most sore throats are caused by viruses, strep throat is caused by bacteria. So, it can be treated with antibiotics, Hagerty says.

“If throat pain becomes more severe instead of improving after the first couple of days on antibiotics, it's important to seek follow-up care,” says Christian Nechyba, MD, a pediatrician with Duke Health in Wake Forest, North Carolina. “It's also important to seek care right away if you have difficulty drinking, have significant neck swelling, or have fevers that last longer than a couple of days after starting treatment.”

Strep throat can last for a long time without treatment and could spread to other parts of the body, Hagerty says.

“It's important to take all the antibiotics prescribed by your doctor, because if you only take part of them, the strep throat might not completely go away,” he says.

Strep throat is highly contagious. It spreads when someone coughs or sneezes. This sends small droplets that carry the bacteria into the air, causing illness. It also spreads from touching your nose or mouth after touching something the droplets landed on.

Scarlet Fever

• A very red, sore throat
• A rough, red rash on your skin
• A “strawberry,” or red and bumpy, tongue
• Fever
• Swollen glands in your neck
• A whitish coating on your tongue
• Bright red skin on your underarm, elbow, or groin

The illness typically begins with a fever and sore throat. The rash, caused by a toxin made by group A strep bacteria, usually appears a day or two later. But it can begin before the illness or up to seven days later. Without treatment, strep throat can turn into scarlet fever.

The availability of rapid strep–throat testing, which allows for early treatment, has made scarlet fever less common over time, says Dawn Sokol, MD, a pediatric infectious–disease specialist at Ochsner Children’s Health Center in New Orleans, Louisiana.

• Abscesses around your tonsils
• Swollen lymph nodes in your neck
• Sinus and ear infections

Symptoms of rheumatic fever include:

• Swelling and pain in joints
• Skin rashes
• Fever

In serious cases, there can be damage to your heart valves. This is known as rheumatic heart disease.

Like strep throat, scarlet fever is more common in children than adults, particularly those ages 5 to 15. Close contact with someone who has the infection is the biggest risk factor for getting the illness.

• Use a tissue to cover your mouth when sneezing or coughing.
• Wash your hands often.
• Use an alcohol–based hand sanitizer if soap and water aren’t available.
• Cough or sneeze into your upper sleeve or the crook of your elbow, rather than into your hands, if a tissue is not available.

Impetigo

Symptoms begin as itchy, red, or pimple-like sores surrounded by red skin, usually on the face, arms, or legs. The sores are filled with pus.

Post-Streptococcal Glomerulonephritis (PSGN)

This kidney disease can develop after a group A strep infection. But PSGN is not an infection of the kidneys. It’s a result of your immune system fighting off the group A strep infection.

• Dark, reddish-brown urine
• Swelling in your face, hands, and feet
• Decreased amount of urine or less need to urinate
• Fatigue

The condition is treated by managing symptoms, including limiting salt and water intake. Your doctor may prescribe medication to reduce swelling. Antibiotics can also help kill any group A strep bacteria left in your body.

Very rare but potentially life-threatening types of strep A infections include:

Necrotizing Fasciitis

Symptoms often begin with sudden pain, swelling, and redness in the affected area. It may look like a simple skin injury at first. As the infection spreads, the skin may turn dark, blister, or die. Necrotizing fasciitis is not contagious.

Streptococcal Toxic Shock Syndrome (STSS)

This rare but life-threatening illness is caused by toxins produced by group A strep bacteria.

Symptoms begin suddenly and include fever, chills, low blood pressure, muscle aches, and confusion. As the illness becomes, it can lead to organ failure and shock.

Group B streptococcus, also known as group B strep or GBS, is a type of bacteria that can cause illnesses in people of all ages. But it can be particularly severe in newborns, most commonly causing sepsis, pneumonia, and meningitis.

• Urinary tract infections
• Skin infections
• Bloodstream infections
• Pneumonia
• Skin and soft-tissue infections
• Bone and joint infections

Group B Streptococcus in Babies

In babies, group B strep infections occur as either early onset (younger than 1 week old) or late onset (1 week to 3 months old).

“The source of infection is often unknown for infants with group B strep illness that begins more than a week after birth,” Sokol says. “There are effective strategies to prevent early-onset infection but not late-onset disease.”

“There is no preventive antibiotic given to the infant or special testing required,” Sokol says.

Symptoms of GBS infection in newborn babies usually develop within the first few hours or days after birth. The symptoms include being floppy or unresponsive, poor feeding, grunting when breathing, and unusually fast or slow breathing and heartbeat.

Group B Streptococcus in Adults

Group B strep infections occur less often in adults than in babies, but it can affect anyone. The sources of disease caused by GBS in adults are often unknown. The gastrointestinal and genitourinary tracts may be the sources of infection.

• Fever
• Cough
• Ear pain
• Shortness of breath
• Stiff neck

The U.S. Centers for Disease Control and Prevention (CDC) recommends the pneumococcal vaccine for:

• All children younger than 5 years old
• People 5 through 49 years old with certain risk conditions
• Adults 50 years or older

Groups C and G streptococci are much less well-understood than strep A and B, because the diseases caused by these bacteria are far less common.

The best way to prevent common strep infections is through good hygiene: regular handwashing, covering coughs and sneezes, and avoiding close contact with people who have strep, says Sokol.

Most strep infections can be treated with antibiotics, which help reduce symptoms, prevent complications, and lower the risk of spreading the infection to others. Prompt treatment is especially important for more-serious cases, and taking the full course of antibiotics as prescribed is a must.

According to Hagerty, strep bacteria can go deeper into your throat and cause more serious infections.

“It can also enter the bloodstream and affect the heart, making you very sick,” he says. “Although these risks are rare, we recommend treating strep throat because the treatment is very safe.”

• There are several different types of streptococcus bacteria. Groups A and B are the most common types.
• Group A strep is responsible for strep throat, scarlet fever, impetigo, and a few rare but potentially life-threatening infections.
• Group B strep most commonly affects newborns during birth.
• Prevention measures include good hand hygiene, and avoiding sharing drinking glasses and utensils with others.
• Strep infections can be treated with antibiotics. Without treatment, they can cause serious complications.