Streptococcal Infections

What Are Streptococcal Infections?

Group A Streptococcus (GAS) Infections

Group B Streptococcus (GBS) Infections

Alpha-Hemolytic Streptococcus Infections

Resources

Streptococcal (strep-tuh-KAH-kul) infections are caused by various strains* of Streptococcus (strep-tuh-KAH-kus) bacteria.

*strains

are various subtypes of organisms, such as viruses or bacteria.

KEYWORDS

for searching the Internet and other reference sources

Alpha-hemolytic streptococci

Beta-hemolytic streptococci

Cellulitis

Group A streptococcal (GAS) infections

Group B streptococcal (GBS) infections

Impetigo

Necrotizing fasciitis

Scarlet fever

Sepsis

Strep throat

Toxic shock syndrome

What Are Streptococcal Infections?

Streptococci (strep-tuh-KAH-kye) are common bacteria that live in the human body, including the nose, skin, and genital tract. These bacteria can destroy red blood cells, damage them, or cause no damage at all. The amount of damage they do is used to classify streptococcus strains. The ones that destroy red blood cells are known as beta-hemolytic (he-muh-LIH-tik), and these strains are categorized as groups A through G.

Groups A and B streptococci are most often associated with disease. Group A strep (GAS) infections range from superficial skin infections and strep throat to serious and life-threatening illnesses such as toxic shock syndrome and necrotizing fasciitis (NEH-kro-tie-zing fash-e-EYE-tis). Group B strep (GBS) is the leading cause of life-threatening infections in newborns. In pregnant women, GBS can lead to bladder infections, infections of the womb, and death of the fetus*.

*fetus

(FEE-tus) is the term for an unborn human after it is an embryo, from 9 weeks after fertilization until childbirth.

Alpha-hemolytic streptococci are strains that damage red blood cells but do not destroy them. Two important strains are S. viridans (VEER-ih-dans), which is found in the mouth and is involved in tooth decay and endocarditis*, and S. pneumoniae (nu-MO-nye), which can cause pneumonia*, middle ear infection, and meningitis*.

*endocarditis

(en-do-kar-DYE-tis) is an inflammation of the valves and internal lining of the heart, known as the endocardium (en-doh-KAR-dee-um), usually caused by an infection.

*pneumonia

(nu-MO-nyah) is inflammation of the lung.

*meningitis

(meh-nin-JY-tis) is an inflammation of the meninges, the membranes that surround the brain and the spinal cord. Meningitis is most often caused by infection with a virus or a bacterium.

Group A Streptococcus (GAS) Infections

How common are they?

According to the National Institute of Allergy and Infectious Diseases (NIAID), more than 10 million cases of mild GAS infections, such as skin and throat infections, are diagnosed each year. Between 9,000 and 10,000 cases of more serious infections, including toxic shock syndrome and necrotizing fasciitis, occur annually. People with immune systems weakened by diseases such as diabetes or cancer, are at a greater risk for developing serious GAS infections.

Are they contagious?

GAS bacteria are contagious and spread through contact with fluid from the mouth or nose of an infected person or contact with infected skin lesions*.

*lesions

(LEE-zhuns) is a general term referring to sores or damaged or irregular areas of tissue.

Some GAS infections

• Strep throat, or streptococcal pharyngitis (fair-un-JY-tis), is a painful inflammation of the throat. Symptoms include a sore throat with white patches on the tonsils*, swollen lymph nodes* in the neck, fever, and headache.
• Scarlet fever often occurs along with strep throat or other strep infections. It is caused by strains of group A strep that produce a toxin (or poison) that results in a very red rash and a bright red tongue, along with a high fever.
• Impetigo (im-pih-TEE-go) is a superficial skin infection common in young children. Symptoms include fluid-filled blisters (one or more) surrounded by red skin. The blisters eventually break and form a honey-colored crust.
• Cellulitis (sel-yoo-LYE-tis) is an inflammation of the skin and/or its underlying soft tissues. Symptoms include skin that is red, tender, and painful to the touch; fever; and chills.
• Bacteremia (bak-tuh-REE-me-uh) is the presence of bacteria in the bloodstream, which can spread infection to other organs. Bacteremia that causes symptoms, which is known as sepsis, is associated with fever, rapid heart rate, and low blood pressure that may lead to shock*.
• Toxin-producing strains of GAS can cause a rare but serious illness called streptococcal toxic shock syndrome. The infection may occur anywhere in the body, and the toxin (poison) is released into the bloodstream, causing low blood pressure and shock.
• Necrotizing fasciitis (or flesh-eating disease) is a rare, rapidly progressing infection of the deeper layers of skin, muscle and other tissues. Symptoms usually start at the site of an injury, where the skin becomes painful, swollen, discolored (such as red, purple, or bronze), and hot to the touch. The skin gradually becomes darker and blisters can form while the tissues beneath the skin are being damaged. Fever, shock, and multiple organ damage may accompany this serious infection.
• Rheumatic (roo-MAH-tik) fever, a syndrome involving arthritis* and inflammation of the heart, is actually a complication of untreated strep throat. Rashes and neurological problems also may occur, and people with rheumatic fever may have permanent damage to one or more heart valves.

*tonsils

are paired clusters of lymphatic tissue in the throat that help protect the body from bacteria and viruses that enter through a person’s nose or mouth.

*lymph

(LIMF) nodes are small, bean-shaped masses of tissue that contain immune system cells that fight harmful microorganisms. Lymph nodes may swell during infections.

*shock

is a serious condition in which blood pressure is very low and not enough blood flows to the body’s organs and tissues. Untreated, shock may result in death.

*arthritis

(ar-THRY-tis) refers to any of several disorders characterized by inflammation of the joints.

Making the diagnosis

With skin infections, a doctor may take a sample from the affected area to culture*. For other types of suspected infections, blood samples are drawn and swabs of fluid from the patient’s nose and throat are cultured for bacteria. A rapid strep test on a sample taken with a throat swab can also be done in a doctor’s office.

*culture

(KUL-chur) is a test in which a sample of fluid or tissue from the body is placed in a dish containing material that supports the growth of certain organisms. Typically, within days the organisms will grow and can be identified.

Treatment

Superficial skin infections often are treated with topical (on the skin) antibiotic ointments. Other GAS infections are treated with oral (by mouth) or intravenous* (IV) antibiotics. Serious GAS infections require hospitalization, where patients receive IV fluids and antibiotics. In some cases, such as with necrotizing fasciitis, surgical removal of damaged tissue is necessary. Treatment of rheumatic fever depends on the severity of the disease but includes using antibiotics to treat strep infections, anti-inflammatory medicines such as high-dose aspirin, and medications to treat heart complications.

*intravenous

(in-tra-VEE-nus), or IV, means within or through a vein. For example, medications, fluid, or other substances can be given through a needle or soft tube inserted through the skin’s surface directly into a vein.

What to expect

Symptoms of strep throat usually improve within 1 to 2 days after starting antibiotics. Skin infections often clear up within a week, but more serious infections can take weeks or even months to heal. Complications from serious bacterial infections include sepsis, shock, organ damage and failure, and death.

Prevention

Maintaining good health and hygiene can help reduce the risk of bacterial infection. Not sharing food or eating utensils, washing hands frequently, and cleaning and bandaging cuts and scrapes can help prevent the spread of bacteria.

Group B Streptococcus (GBS) Infections

How common are they?

According to the Centers for Disease Control and Prevention, GBS is the most frequent cause of life-threatening infections in newborns. Early screening of pregnant women for GBS and treatment have reduced infection rates by approximately 70 percent. Currently, 17,000 cases of GBS infection occur annually in the United States.

Are they contagious?

GBS infections are contagious and can pass from mother to child before or during birth. At least 25 percent of women are carriers of GBS at some point in their life but do not become ill from it. The bacteria can be found in the bowel, vagina*, bladder, and throat.

*vagina

(vah-JY-nah) is the canal, or passageway, in a woman that leads from the uterus to the outside of the body.

Some GBS infections

• Newborns can develop sepsis, pneumonia, and meningitis due to infection with GBS. Symptoms of GBS infection in newborns include fever, irritability, extreme sleepiness, breathing difficulties, and poor feeding.
• GBS bacteria in pregnant women can cause urinary tract infections* as well as chorioamnionitis (kor-e-o-am-nee-on-EYE-tis, infection of the womb and membranes surrounding the fetus) and stillbirth (a fetus that is dead at birth). Symptoms of urinary tract infection include fever, pain, and a burning sensation during urination. Women with chorioamnionitis often do not show symptoms of infection until after childbirth. Symptoms include fever, belly pain, and rapid pulse.

*urinary

(YOOR-ih-nair-e) tract infection , or UTI, is an infection that occurs in any part of the urinary tract. The urinary tract is made up of the urethra, bladder, ureters, and kidneys.

• The most common GBS infections in other people are urinary tract infections, sepsis, tissue infections, and pneumonia. GBS infections, including pneumonia and sepsis, are more likely to be found in people with weakened immune systems or chronic diseases, such as diabetes.

Shaking Hands with Semmelweis

Ignaz Philipp Semmelweis (1818—1865) was a Hungarian physician who suspected that doctors could spread disease by not washing their hands thoroughly after working with cadavers before delivering babies. At the time, up to 30 percent of women who gave birth in hospitals died of puerperal (pyoo-ER-puh-rul) fever, a group A strep bacterial infection that occurred after childbirth. Semmelweis noticed that women who delivered their babies with midwives were less likely to become ill. He had his student doctors wash their hands with an antiseptic, which is a solution that prevents the growth of bacteria. Because the idea that germs could cause disease had not yet been introduced, Semmelweis’ ideas about hand washing were not well received until many years later.

Making the diagnosis

GBS infections are diagnosed by performing cultures of blood, urine, or cerebrospinal fluid* to identify the bacteria.

*cerebrospinal

(seh-ree-bro-SPY-nuhl) fluid is the fluid that surrounds the brain and spinal cord.

Treatment

GBS infections are treated with antibiotics, often intravenously, and they usually require a hospital stay, particularly for newborns. Pregnant women with urinary tract infections usually are treated with antibiotics as well.

What to expect

Recovery can take several weeks. Complications in infants, particularly those with meningitis, include hearing and vision loss and brain damage. Approximately 5 percent of cases of GBS disease in newborns are fatal.

Prevention

Most newborn cases can be prevented by testing women in the thirty-fifth to thirty-seventh week of pregnancy for the bacteria. A culture of fluid from the vagina and rectum* can determine whether a woman has GBS. If she does, giving IV antibiotics during labor reduces the risk of passing GBS to the baby. Vaccines* to prevent GBS infections during pregnancy are being developed.

*rectum

is the final portion of the large intestine, connecting the colon to the anus.

*vaccines

(vak-SEENS) are preparations of killed or weakened germs, or a part of a germ or product it produces, given to prevent or lessen the severity of the disease that can result if a person is exposed to the germ itself. Use of vaccines for this purpose is called immunization.

Alpha-Hemolytic Streptococcus Infections

How common are they?

Infections with alpha-hemolytic strep bacteria are common; many strains live naturally in humans.

Some alpha-hemolytic strep infections

S. PNEUMONIAE (NU-MON-YI) INFECTIONS

• Bacterial pneumonia is an inflammation of the lungs that often occurs after or along with an upper respiratory infection. Symptoms may develop quickly and can include fever, chills, cough, rapid breathing, chest pain, belly pain, and vomiting. Before antibiotics were developed, bacterial pneumonia was the most common cause of death in adults.
• Otitis (o-TIE-tis) media is an inflammation of the middle ear. The infection usually is associated with ear pain and sometimes with fever.
• Sinusitis (sy-nyoo-SY-tis) is an inflammation of the sinuses*, usually due to infection. Symptoms include a stuffy nose, colored discharge (green, yellow, or tinged with blood) from the nose, tenderness around the eyes, and headache or a feeling of pressure in the head.
• Meningitis is an inflammation of the membranes covering the brain and the spinal cord. Symptoms include fever, weakness, vomiting, irritability, and stiff neck.

*sinuses

(SY-nuh-ses) are hollow, air-filled cavities in the facial bones.

S. VIRIDANS (VEER-IH-DANZ) INFECTION

• Endocarditis is an infection of the inner surface of the heart or heart valves that can be caused by S. viridans and other bacteria. Bacteria can enter the bloodstream (during a dental procedure, for example) and attach to already damaged heart tissue or an abnormal heart valve, causing more damage. Symptoms include extreme tiredness, weakness, fever, chills, night sweats, and weight loss. The infection can progress, resulting in problems with heart function in some cases.

Making the diagnosis

Depending on the type of infection, a diagnosis is made by testing blood, sputum*, or cerebrospinal fluid samples for signs of the bacteria.

*sputum

(SPYOO-tum) is a substance that contains mucus and other matter coughed out from the lungs, bronchi, and trachea.

Treatment

Oral or IV antibiotics are used, depending on the severity of the infection. A hospital stay may be needed, particularly in cases of pneumonia or meningitis. Long courses of antibiotics, lasting several weeks or more, may be required to treat endocarditis.

Prevention

Vaccines against S. pneumoniae are now given routinely to infants and the elderly, as well as to children and adults with weakened immune systems or certain medical conditions. People with abnormal or damaged heart valves are given courses of antibiotics when they have some types of surgical procedures, including dental work, to help prevent endocarditis from developing from the shedding of bacteria into the bloodstream that occurs with these procedures.

See also

Congenital Infections

Endocarditis, Infectious

Meningitis

Otitis (Ear Infections)

Pneumonia

Sepsis

Sinusitis

Skin and Soft Tissue Infections

Sore Throat

Urinary Tract Infections

Resources

Organizations

U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA 30333. The CDC posts information about streptococcal infections at its website.

Telephone 800-311-3435 http://www.cdc.gov

U.S. National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894. The National Library of Medicine has a website packed with information on diseases (including streptococcal infections), consumer resources, dictionaries and encyclopedias of medical terms, and directories of doctors and helpful organizations.

Telephone 888-346-3656 http://www.nlm.nih.gov

Website

KidsHealth.org. KidsHealth is a website created by the medical experts of the Nemours Foundation and is devoted to issues of children’s health. It contains articles on a variety of health topics, including streptococcal infections.

http://www.KidsHealth.org

Streptococcal infections

Definition

Streptococcal (strep) infections are communicable diseases that develop when bacteria of the family Streptococcus invade parts of the body and contaminate blood or tissue.

Description

Most people have some form of strep bacteria in their body at some point. A person who hosts bacteria without showing signs of infection is considered a carrier.

Types of infection

Primary strep infections invade healthy tissue and most often affect the throat. Secondary strep infections invade tissue already weakened by injury or illness. They frequently affect the bones, ears, eyes, joints, or intestines. Both primary and secondary strep infections can travel from affected tissues to lymph glands, enter the bloodstream, and spread throughout the body. Numerous strains of streptococcal bacteria have been identified. Types A, B, C, D, and G are most likely to make people sick.

GROUP A Group A strep (GAS) is the form of streptococcal bacteria most apt to be associated with serious illness. Two of the most severe invasive GAS infections are necrotizing fasciitis or flesh-eating bacteria (destruction of muscle tissue and fat) and toxic shock syndrome (a rapidly progressive disorder that causes shock and damages internal organs). GAS is also the type of strep responsible for strep throat . Strep throat is common and not usually serious. If untreated, however, strep throat can develop into rheumatic fever which can permanently damage the heart and other organs.

GROUP B Group B strep (GBS) most often affects pregnant women, infants, the elderly, and chronically ill adults. Streptococcal infection occurs when bacteria contaminate cuts or open sores or otherwise penetrate the body's natural defenses. The bacteria can be passed from pregnant women to their newborns during childbirth .

GROUP C Group C strep (GCS) is a common source of infection in animals. It rarely causes human illness.

GROUP D Group D strep (GDS) is a common cause of wound infections in hospital patients. GDS is also associated with the following:

• abnormal growth of tissue in the gastrointestinal tract
• urinary tract infection (UTI)
• womb infections in women who have just given birth

GROUP G Normally present on the skin, in the mouth and throat, and in the intestines and genital tract, Group G strep (GGS) is most likely to lead to infection in alcoholics and in people who have cancer , diabetes mellitus , rheumatoid arthritis, and other conditions that suppress immune-system activity.

GGS can cause a variety of infections, including the following:

• bacteria in the bloodstream (bacteremia)
• inflammation of the connective tissue structure surrounding a joint (bursitis)
• endocarditis, a condition that affects the lining of the heart chambers and the heart valves
• meningitis
• inflammation of bone and bone marrow (osteomyelitis)
• inflammation of the lining of the abdomen (peritonitis)

Causes and symptoms

GAS

GAS is transmitted by direct contact with saliva, nasal discharge, or open wounds of someone who has the infection. Chronic illness, kidney disease treated by dialysis, and steroid use increase vulnerability to infection. About one of five people with GAS infection develops a sore, inflamed throat and pus on the tonsils (strep throat). The majority of those infected by GAS either have no symptoms or develop enlarged lymph nodes, fever , headache , nausea , vomiting , weakness, and a rapid heartbeat.

Flesh-eating bacteria is characterized by fever, extreme pain , swelling, and redness at a site where skin is broken. Symptoms of toxic shock include abdominal pain, confusion, dizziness , and widespread red skin rash.

GBS

A pregnant woman who has GBS infection can develop infections of the bladder, blood, and urinary tract, and deliver a baby who is infected or stillborn. The risk of transmitting GBS infection during birth is highest in a woman whose labor begins before the thirty-seventh week of pregnancy or lasts more than 18 hours or who has the following conditions:

• has a GBS urinary-tract infection
• has already given birth to a baby infected with GBS
• develops a fever during labor

More than 13 percent of babies who develop GBS infection during birth or within the first few months of life develop neurological disorders. An equal number of them die.

Miscellaneous symptoms

Other symptoms associated with strep infections include the following:

• anemia
• elevated white blood cell counts
• inflammation of the epiglottis (epiglottitis)
• heart murmur
• high blood pressure
• infection of the heart muscle
• kidney inflammation (nephritis)
• swelling of the face and ankles

Demographics

Between 10,000 and 15,000 invasive GAS infections occur in the United States every year. In 1999, there were 300 cases of toxic shock associated with GAS infection and 600 cases of necrotizing fasciitis. There are millions of cases of strep throat every year, and similar numbers of cases of relatively mild skin infections. Strep throat is most common among school-age children and people who live in group settings (for example, dorms, boarding schools, the military).

Since first emerging in the 1970s, GBS has been the primary cause of life-threatening illness and death in newborns. GBS exists in the reproductive tract of 20 to 25 percent of all pregnant women. Although no more than 2 percent of these women develop invasive infection, if untreated 40 to 73 percent transmit bacteria to their babies during delivery. About 12,000 of the 3.5 million babies born in the United States each year develop GBS disease in infancy. About 75 percent of them develop early-onset infection. Sometimes evident within a few hours of birth and always apparent within the first week of life, this condition causes inflammation of the membranes covering the brain and spinal cord (meningitis), pneumonia , blood infection (sepsis), and other problems.

Late-onset GBS develops between the ages of seven days and three months. It often causes meningitis. About half of all cases of this rare condition can be traced to mothers who are GBS carriers. The cause of the others is unknown. GBS has also been linked to a history of breast cancer. Approximately 5 percent of babies who develop GBS die. However, those who survive often have debilitating problems after the disease. Infections caused by the other types of strep are rare.

When to call the doctor

If the child has a fever and sore throat , a wound that seems to be infected, a rash, is acting very sick, or has any other symptoms of strep infection, the doctor should be consulted.

Diagnosis

Strep bacteria can be obtained by swabbing the back of the throat, the vagina, the rectum, or the infected area with a piece of sterile cotton. A blood sample can also be taken. Microscopic examination of the smear can identify which type of bacteria has been collected. A rapid strep test may be done to test for step throat infection. This kind of test gives results within the hour. A sample may also be sent to a lab for traditional culturing, which takes from one to two days, because this form of testing is more accurate than the rapid strep test.

Treatment

Penicillin and other antibiotics are used to treat GAS and other types of strep infection. It usually takes less than 24 hours for antibiotics to eliminate an infected person's ability to transmit the infection, but antibiotics always need to be taken for the full course prescribed by the doctor to prevent reinfection or other complications.

Guidelines developed by the American Academy of Obstetrics and Gynecology (AAOG), the American Academy of Pediatrics (AAP), and the Centers for Disease Control and Prevention (CDC) recommend administering intravenous antibiotics during labor to a woman at high risk of passing GBS infection on to her child and offering the medication to any pregnant woman who wants it.

Initiating antibiotic therapy at least four hours before birth allows medication to become concentrated enough to protect the baby during passage through the birth canal. Babies infected with GBS during or shortly after birth need to be treated right away, but they may still die. Those who survive often require lengthy hospital stays and develop vision or hearing loss and other permanent disabilities.

Alternative treatment

Conventional medicine is very successful in treating strep infections. However, several alternative therapies, including homeopathy and botanical medicine, may help relieve symptoms or support the person with a strep infection. For example, several herbs, including garlic (Allium sativum ), echinacea (Echinacea spp.), and goldenseal (Hydrastis canadensis ), are believed to strengthen the immune system, thus helping the body fight a current infection, as well as helping prevent future infections.

Prognosis

GAS is responsible for more than 2,000 deaths a year. About one in five people infected with flesh-eating bacteria die. So do three out of every five people who develop streptococcal toxic shock syndrome. Strep throat, however, is almost never fatal, although left untreated it can result in diseases such as rheumatic fever that can affect the heart.

Early-onset GBS kills 15 percent of the infants it affects. Late-onset disease claims the lives of 10 percent of babies who develop it. GBS infections are fatal in about 20 percent of the men and non-pregnant women who develop them. About 10 to 15 percent of non-GAS strep infections are fatal. Antibiotic therapy, begun when symptoms first appear, may increase a patient's chance of survival.

Prevention

Washing the hands frequently, especially before eating and after using the bathroom, and keeping wounds clean can help prevent strep infection. Exposure to infected people should be avoided, and a family physician should be notified if the child develops an extremely sore throat or pain, redness, swelling, or drainage at the site of a wound or break in the skin.

Until vaccines to prevent strep infection become available, 12 monthly doses of oral or injected antibiotics may prevent some types of recurrent infection if necessary. Pregnant women should be screened for GBS during the last few weeks of pregnancy. About one fourth of pregnant women are thought to carry GBS in their vaginal or rectal tracts. If GBS is found to be present, antibiotics can be administered intravenously during labor. This greatly reduces the chance of GBS being transmitted from mother to baby when the baby is in the birth canal. The chances are believed to be reduced from one in 200 that the baby will develop GBS infection to one in 4000.

Parental concerns

Strep infections can develop into life-threatening or debilitating problems if not treated promptly. Ensuring the child takes the full course of antibiotics prescribed by the doctor even if the symptoms have gone away can prevent life-threatening complications such as rheumatic fever. Pregnant women should be screened for GBS during the last weeks of pregnancy to help ensure that GBS does not infect their newborns.

KEY TERMS

Bacteremia —Bacterial infection of the blood.

Bursitis —Inflammation of a bursa, a fluid-filled cavity or sac. In the body, bursae are located at places where friction might otherwise develop.

Osteomyelitis —An infection of the bone and bone marrow, usually caused by bacteria.

Resources

BOOKS

Laskey, Elizabeth. Strep Throat. Chicago: Heinemann Library, 2003.

Tomasz, Alexander, ed. Streptococcus Pneumoniae: Molecular Biology & Mechanisms of Disease. Larchmont: Mary Ann Liebert, Inc., 2000.

PERIODICALS

"Early Results Show Promise for Strep Vaccine." Vaccine Weekly (September 2004): 76.

Tish Davidson, A.M. Maureen Haggerty

Streptococcal Infections

Definition

Streptococcal (strep) infections are communicable diseases that develop when bacteria normally found on the skin or in the intestines, mouth, nose, reproductive tract, or urinary tract invade other parts of the body and contaminate blood or tissue.

Some strep infections don't produce symptoms. Some are fatal.

Description

Most people have some form of strep bacteria in their body at some time. A person who hosts bacteria without showing signs of infection is considered a carrier.

Types of infection

Primary strep infections invade healthy tissue, and most often affect the throat. Secondary strep infections invade tissue already weakened by injury or illness. They frequently affect the bones, ears, eyes, joints, or intestines.

Both primary and secondary strep infections can travel from affected tissues to lymph glands, enter the bloodstream, and spread throughout the body.

Numerous strains of strep bacteria have been identified. Types A, B, C, D, and G are most likely to make people sick.

Group A

Group A strep (GAS) is the form of strep bacteria most apt to be associated with serious illness.

Between 10,000 and 15,000 GAS infections occur in the United States every year. Most are mild inflammations of the throat or skin, where the bacteria are normally found; however, GAS infections can be deadly.

Two of the most severe invasive GAS infections are necrotizing fasciitis or flesh-eating bacteria (destruction of muscle tissue and fat) and toxic shock syndrome (a rapidly progressive disorder that causes shock and damages internal organs).

GROUP B. Group B strep (GBS) most often affects pregnant women, infants, the elderly, and chronically ill adults.

Since first emerging in the 1970s, GBS has been the primary cause of life-threatening illness and death in newborns. GBS exists in the reproductive tract of 20-25% of all pregnant women. Although no more than 2% of these women develop invasive infection, 40-73% transmit bacteria to their babies during delivery.

About 12,000 of the 3.5 million babies born in the United States each year develop GBS disease in infancy. About 75% of them develop early-onset infection. Sometimes evident within a few hours of birth and always apparent within the first week of life, this condition causes inflammation of the membranes covering the brain and spinal cord (meningitis), pneumonia, blood infection (sepsis ) and other problems.

Late-onset GBS develops between the ages of seven days and three months. It often causes meningitis. About half of all cases of this rare condition can be traced to mothers who are GBS carriers. The cause of the others is unknown.

GBS has also been linked to a history of breast cancer.

GROUP C. Group C strep (GCS) is a common source of infection in animals. It rarely causes human illness.

GROUP D. Group D strep (GDS) is a common cause of wound infections in hospital patients. GDS is also associated with:

• abnormal growth of tissue in the gastrointestinal tract
• urinary tract infection (UTI)
• womb infections in women who have just given birth

GROUP G. Normally present on the skin, in the mouth and throat, and in the intestines and genital tract, Group G strep (GGS) is most likely to lead to infection in alcoholics and in people who have cancer, diabetes mellitus, rheumatoid arthritis, and other conditions that suppress immune-system activity.

GGS can cause a variety of infections, including:

• bacteria in the bloodstream (bacteremia)
• inflammation of the connective tissue structure surrounding a joint (bursitis)
• endocarditis (a condition that affects the lining of the heart chambers and the heart valves)
• meningitis
• inflammation of bone and bone marrow (osteomyelitis)
• inflammation of the lining of the abdomen (peritonitis)

Causes and symptoms

Streptococcal infection occurs when bacteria contaminate cuts or open sores or otherwise penetrate the body's natural defenses.

GAS

GAS is transmitted by direct contact with saliva, nasal discharge, or open wounds of someone who has the infection. Chronic illness, kidney disease treated by dialysis, and steroid use increase vulnerability to infection.

About one of five people with GAS infection develops a sore, inflamed throat, and pus on the tonsils. The majority of those infected by GAS either have no symptoms or develop enlarged lymph nodes, fever, headache, nausea, vomiting, weakness, and a rapid heartbeat.

Flesh-eating bacteria is characterized by fever, extreme pain, and swelling and redness at a site where skin is broken.

Symptoms of toxic shock include abdominal pain, confusion, dizziness, and widespread red skin rash.

GBS

A pregnant woman who has GBS infection can develop infections of the bladder, blood, and urinary tract, and deliver a baby who is infected or stillborn. The risk of transmitting GBS infection during birth is highest in a woman whose labor begins before the 37th week of pregnancy or lasts more than 18 hours or who:

• becomes a GBS carrier during the final stages of pregnancy
• has a GBS urinary-tract infection
• has already given birth to a baby infected with GBS
• develops a fever during labor

More than 13% of babies who develop GBS infection during birth or within the first few months of life develop neurologic disorders. An equal number of them die.

Among men, and in women who are not pregnant, the most common consequences of GBS infection are pneumonia and infections of blood, skin, and soft tissue.

Miscellaneous symptoms

Other symptoms associated with strep infection include:

• anemia
• elevated white blood cell counts
• inflammation of the epiglottis (epiglottitis)
• heart murmur
• high blood pressure
• infection of the heart muscle
• kidney inflammation (nephritis )
• swelling of the face and ankles

Diagnosis

Strep bacteria can be obtained by swabbing the back of the throat or the rectum with a piece of sterile cotton. Microscopic examination of the smear can identify which type of bacteria has been collected.

Treatment

Penicillin and other antibiotics are used to treat strep infections.

It takes less than 24 hours for antibiotics to eliminate an infected person's ability to transmit GAS.

Guidelines developed by the American Academy of Obstetrics and Gynecology (AAOG), the American Academy of Pediatrics (AAP), and the Centers for Disease Control and Prevention (CDC) recommend administering intravenous antibiotics to a woman at high risk of passing GBS infection on to her child, and offering the medication to any pregnant woman who wants it.

Initiating antibiotic therapy at least four hours before birth allows medication to become concentrated enough to protect the baby during passage through the birth canal.

Babies infected with GBS during or shortly after birth may die. Those who survive often require lengthy hospital stays and develop vision or hearing loss and other permanent disabilities.

Alternative treatment

Conventional medicine is very successful in treating strep infections. However, several alternative therapies, including homeopathy and botanical medicine, may help relieve symptoms or support the person with a strep infection. For example, several herbs, including garlic (Allium sativum ), echinacea (Echinacea spp.), and goldenseal (Hydrastis canadensis ), are believed to strengthen the immune system, thus helping the body fight a current infection, as well as helping prevent future infections.

Prognosis

GAS is responsible for more than 2,000 deaths a year. About 20% of people infected with flesh-eating bacteria die. So do three of every five who develop toxic shock syndrome.

Early-onset GBS kills 15% of the infants it affects. Late-onset disease claims the lives of 10% of babies who develop it.

GBS infections are fatal in about 20% of the men and non-pregnant women who develop them.

About 10-15% of non-GAS strep infections are fatal. Antibiotic therapy, begun when symptoms first appear, may increase a patient's chance of survival.

Prevention

Washing the hands frequently, especially before eating and after using the bathroom, and keeping wounds clean can help prevent strep infection. Exposure to infected people should be avoided, and a family physician should be notified by anyone who develops an extremely sore throat or pain, redness, swelling, or drainage at the site of a wound or break in the skin.

Until vaccines to prevent strep infection become available, 12 monthly doses of oral or injected antibiotics may prevent some types of recurrent infection.

Resources

OTHER

"Infectious Diseases." The Merck Page. June 17, 1998. 〈http://www.merck.com〉.

STREPTOCOCCAL INFECTION

Among the large family of streptococci, the most dangerous is group A hemolytic streptococcus, formerly known as Streptococcus pyogenes, the pusproducing streptococcus. This is responsible for several diseases that in the past have had great public health importance, and still do in developing countries. Streptococcus pyogenes was the principal cause of puerperal sepsis, or childbed fever, once a leading cause of death in the immediate postpartum period when delivery of the baby introduced virulent pathogenic organisms into the birth canal and uterus. Streptococcal tonsillitis is a precursor of rheumatic fever and acute nephritis when the toxin produced by the invading pathogens provokes an autoimmune response. Streptococcal infection also causes scarlet fever, formerly a common and sometimes deadly infection of early childhood.

All these diseases have become rare since the discovery and development of chemotherapy and antibiotics to which the streptococcus is sensitive. However, streptococcal infection has not become extinct. Erysipelas, a skin infection, remains common; streptococcal septicemia occurs occasionally; and the rare but dramatic streptococcal cellulitis, known as flesh-eating disease, captures headlines when it attacks, disfigures, and sometimes kills a previously healthy young adult. Humans are the main reservoir of infection, which is transmitted person-to-person by direct contact or droplet spread, with a brief incubation period of one to three days.

Outbreaks of all these forms of streptococcal infection occur when social and economic conditions deteriorate, as in post–Soviet Russia and its satellites, and in many of the world's combat zones where hygiene and public health facilities are rudimentary or have deteriorated to the stage of being ineffectual. Treatment of streptococcal infection relies on antibiotics, and prevention requires good hygiene, cleanliness, and education about ways to minimize the risks of transmission of this and other pathogens.

John M. Last

(see also: Antibiotics; Communicable Disease Control; Contagion; Drug Resistance; Maternal and Child Health; Staphylococcal Infection )