Background

Group A Streptococcus comprises a number of strains of bacteria that can produce a wide range of illnesses. Some, like "strep throat" and impetigo, are quite common and easily treated. Others, including those referred to as invasive disease, are more rare and require immediate medical attention.

Common Strep Illnesses

• "Strep throat," the most common illness caused by this bacteria, is easily treated with a 10-day course of conventional antibiotics, usually penicillin. If left untreated or partially treated, however, it can be followed by rheumatic fever, which may result in permanent damage to the heart valves. Rheumatic fever, currently a rare disease, may occur when patients do not complete a full course of antibiotics to treat strep throat.
• Impetigo is the second most frequent illness caused by group A bacteria. This is a mild skin infection accompanied by open, draining sores. Complications are rare. It is easily treated with common antibiotics.
• Scarlet fever is characterized by a fever, sore throat, red sandpaper-like rash and a red "strawberry" tongue. It is caused by several different strains of the streptococcal bacteria, all of which produce a toxin that causes the characteristic red rash. It is treated in the same manner as strep throat.
• Rare and more serious, glomerulonephritis is a complication of streptococcal infections, usually strep throat or impetigo. Antibiotic treatment of the original infection does not necessarily prevent the condition, which usually resolves itself.

Invasive Infections

Certain strains of group A bacteria can lead to several forms of invasive disease, including pneumonia, meningitis, infection of the bone and an illness resembling toxic shock syndrome. Relatively uncommon, these streptococcal diseases first caught the public's notice in the late 1980s, when published reports in medical journals began to draw attention to them. The death of Muppet creator Jim Henson in 1990 as a result of an aggressive strep infection brought more visibility. In 1994, focus moved to the strain of group A Streptococcus causing necrotizing fasciitis.

Necrotizing Fasciitis

Necrotizing fasciitis is the medical term for a serious skin and muscle infection caused by certain strains of group A Streptococcus. These bacteria produce an enzyme that destroys tissue. While it occurs in less than 10 percent of the patients who develop an invasive group A infection, it can be fatal in 20 percent to 30 percent of these cases.

If necrotizing fasciitis does develop, it is usually in the wake of a skin wound that has allowed the bacteria to enter the body. The bacteria multiply in the wound and produce a toxic substance that kills skin, muscle tissue and the membrane covering the muscles. Not everyone infected with the bacteria will become ill, although the reason for this is unknown.

As is the case with other strains of group A Streptococcus, those that cause necrotizing fasciitis are treated with common antibiotics, although not necessarily the same ones used to treat milder diseases. Because of the extensive tissue damage associated with this kind of infection, physicians sometimes combine a regimen of antibiotics with the surgical removal of severely damaged skin and muscle tissue.

Incidence in Illinois

Illinois hospitals, physicians and other health care providers have been required to generally report all group A Streptococcus infections to local health departments. The rules governing the reporting of communicable diseases have been revised recently and now require that cases of invasive streptococcal disease, including necrotizing fasciitis, be specifically reported to public health officials.

The following table presents information on reported cases of group A streptococcal disease during the last several years.

Reported Group A Streptococcus Cases by Year in Illinois, 1994-2001

Transmission/Treatment/Prevention

Some persons may harbor group A Streptococcus in their noses or on their skin without exhibiting any symptoms. These bacteria are usually transmitted from person to person by direct contact and rarely by contact with articles handled by an infected person. An infected person also can contaminate some kinds of food, causing illness in those who ingest it.

Group A Streptococcus bacteria are known to be sensitive to penicillin, so it is the preferred antibiotic for most types of streptococcal infections. However, necrotizing fasciitis is sometimes thought to be more effectively treated with penicillin in combination with clindamycin, or another antibiotic, and surgery.

The spread of all types of group A Streptococcus infections may be reduced by good handwashing, especially after coughing and sneezing, before preparing foods and before eating. Persons with sore throats should be seen by a doctor who can perform tests to find out whether it is "strep throat"; if so, the person should stay home from work, school or day care until 24 hours or more after taking an antibiotic.

Since it is not clear why some infected persons develop necrotizing fasciitis and others do not, it is important that wounds be kept clean and covered with bandages. If a person has an infection (redness or inflammation around a wound) that does not stay centrally located, seek medical attention as soon as possible.