Organism: Streptococcus pyogenes
The group A streptococcus bacterium is responsible for most cases of streptococcal illness. Other types (B, C, D, and G) may also cause infection. Group B streptococci cause most streptococcal infections in newborns and maternal post-labor/delivery infections.
Some of the major syndromes associated with group A strep infection are:
- streptococcal pharyngitis or "strep throat"
- scarlet fever, most often preceded by a sore throat
- skin infections (impetigo, cellulitis/erysipelas)
- focal infections, limited to a particular body site, e.g., pneumonia, septic arthritis
- bacteremia, sepsis, streptococcal toxic shock syndrome
- necrotizing fasciitis
- the complications of streptococcal infections, acute rheumatic fever and poststreptococcal glomerulonephritis
Signs and Symptoms
The signs and symptoms of strep throat are red, sore throat with white patches on tonsils, swollen lymph nodes in neck, fever, and headache. Nausea, vomiting, and abdominal pain more common in children.
Transmission
The illness is caused by the bacterium '\'Streptococcus pyogenes'' and is spread by direct, close contact with patients via respiratory droplets (coughing or sneezing). Casual contact rarely results in transmission. Rarely, contaminated food, especially milk and milk products, can result in outbreaks. Untreated patients are most infectious for 2-3 weeks after onset of infection. Incubation period, the period after exposure and before symptoms show up, is 2-4 days. Patient is no longer infectious within 24 hrs. after treatment begins.
Diagnosis
Throat is swabbed for culture or for a rapid strep test (10-20 minutes) which can be done in the doctor's office. If the rapid test is negative, a follow-up culture (which takes 24-48 hrs.) may be performed. A negative culture suggests a viral infection, in which case antibiotic treatment should be withheld or discontinued.
Treatment
Antibiotic treatment will reduce symptoms, minimize spread (transmission), and reduce the likelihood of complications. Treatment consists of penicillin (oral drug for 10 days; or single intramuscular injection of penicillin G). Erythromycin is recommended for penicillin-allergic patients. Second-line antibiotics include amoxicillin, clindamycin, and oral cephalosporins. Although symptoms subside within 4 days even without treatment, it is very important to complete the full course of antibiotics to prevent complications.
Scarlet fever is a streptococcal infection that occurs most often in association with a sore throat and rarely with impetigo or other streptococcal infections. It is characterized by sore throat, fever and a rash over the upper body that may spread to cover almost the entire body.
Signs and Symptoms: Persons with scarlet fever have a characteristic rash that is fine, red, rough-textured and blanches upon pressure. Scarlet fever also produces a bright red tongue with "strawberry" appearance. The skin often "desquamates," or peels, after recovery, usually on tips of fingers and toes.
Transmission
The illness is spread by the same means as strep throat.
Treatment
Other than the occurrence of the rash, the treatment and course of scarlet fever are no different from those of any strep throat.
Impetigo is a superficial skin infection most common among children age 2-6 years. Skin infections are usually caused by different streptococci strains than those that cause strep throat.
Signs and Symptoms
One or more pimple-like lesion surrounded by reddened skin. Lesions fill with pus, then break down over 4-6 days and form a thick crust. Impetigo is often associated with insect bites, cuts, and other forms of trauma to the skin. Itching is common. Scratching may spread the lesions.
Transmission
The infection is spread by direct contact with lesions or with nasal carriers. The incubation period is 1-3 days. Dried streptococci in the air are not infectious to intact skin.
Diagnosis''
The diagnosis is made based on the typical appearance of the skin lesion.
Treatment
Topical or oral antibiotics are usually prescribed.
This illness results in inflammation of skin and underlying tissues.
Signs and Symptoms
The skin is painful, red, and tender. Patients experience fever and chills. Lymph nodes may be swollen. The skin may blister and then scab over. Perianal cellulitis may also occur with itching and painful bowel movements. The erysipelas rash may occur on face, arms, or legs and has raised borders. The infection may recur, causing chronic swelling of extremities (lymphadenitis).
Transmission
Cellulitis begins with minor trauma, such as a bruise, usually to an extremity.
Diagnosis
The organism may be cultured from skin lesions or recovered from blood.
Treatment
Depending on the severity, treatment involves either oral or intravenous antibiotics.
Some strains of group A streptococci (GAS) cause severe infection. Those at greatest risk include children with chickenpox; persons with suppressed immune systems; burn victims; elderly persons with cellulitis, diabetes, blood vessel disease, or cancer; and persons taking steroid treatments or chemotherapy. Intravenous drug users also are at high risk. Severe GAS disease may also occur in healthy persons with no known risk factors. All severe GAS infections may lead to shock, multisystem organ failure, and death. Early recognition and treatment are critical. Diagnostic tests include blood counts and urinalysis as well as cultures of blood or fluid from a wound site. Antibiotics of choice include penicillin, erythromycin, and clindamycin.
The infection occasionally starts with a sore throat, but more often begins locally, at a site of trauma, which may be severe (such as the result of surgery), minor or even non-apparent. The affected skin is very painful, red, hot and swollen. Skin color may progress to violet and blisters may form, with subsequent necrosis (death) of subcutaneous tissues. Patients with necrotizing fasciitis typically have a fever and appear very ill. More severe cases progress within hours, and the death rate is high. Neocrotizing fasciitis is diagnosed by either blood cultures or aspiration of pus from tissue. Surgical exploration may be necessary. Early medical treatment is critical. Treatment often includes intravenous penicillin and clindamycin, along with aggressive surgical debridement (removal of infected tissue). Limb amputation may be necessary.
This disease is one of the fastest spreading infections known, and tissue may be consumed at a rate of three centimeters per hour. For this reason, it is popularly called "flesh-eating disease" and, although rare, became well-known to the public in the 1990s. Possibly its most famous victim is former Quebec premier Lucien Bouchard, who became infected while leader of the federal official opposition Bloc Québécois party. He lost a leg to the illness.Strep throat
Scarlet fever (Scarlatina)
Superficial streptococcal skin infections
Impetigo
Cellulitis/Erysipelas
Severe streptococcal infections
Bacteremia
An invasion of bacteria into the bloodstream. Once in the bloodstream, the infection can spread to other parts of body, producing abscesses, peritonitis (inflammation of abdominal cavity), endocarditis (inflammation of the heart), or meningitis. Bacteremia may lead to sepsis or shock, causing a systemic illness with high fever, blood coagulation (thickening) and eventually organ failure.Focal infections with or without bacteremia
GAS can cause focal infections, which are limited to a particular site. These include pneumonia, abscess of tissues near the tonsils, joint infections (septic arthritis), bone infections (osteomyelitis), peritonitis, and meningitis. Bacteremia can be associated with these infections, but it is not always present. Treatment depends on the specific clinical findings.Toxic shock syndrome
Streptococcal toxic shock syndrome begins with flu-like symptoms (fever, chills, and muscle aches). Pain is common, usually in an extremity, sometimes in the abdomen or chest. The condition progresses to confusion and coma. Blood pressure drops, kidneys malfunction, and soft tissues may be infected. The source of streptococcus, when identified, is most often the site of a minor wound or bruise. The syndrome occurs most often in healthy adults between the ages of 20-50.Necrotizing fasciitis
A serious but rare infection of the deeper layers of skin and fatty subcutaneous tissues (fascia). While many other types of bacteria can cause necrotizing fasciitis, most cases result from Group A streptococcus.