Streptococcal infections
Streptococcal (strep) infections are communicable diseases that develop whenStreptococcus 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,and some are fatal.
Most people have had some form of strep bacteria in their body at some pointin their lives; people who host bacteria without showing signs of infection are considered to be carriers.
Primary strep infections invade healthy tissue (usually the throat). Secondary strep infections invade tissue already weakened by injury or illness, suchas the bones, ears, eyes, joints, or intestines. Both primary and secondary strep infections can travel from affected tissues to the lymph glands, where they 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 strep (GAS) is the form of strep bacteria most apt to be associated with serious illness. Between 10,000and 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 (flesh-eating bacteria) which destroys muscle tissue and fat, and toxic shock syndrome (a rapidly progressive disorder that causes shock and damages internalorgans).
GAS is transmitted by direct contact with the saliva, nasal discharge, or open wounds of an infected person. 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 nosymptoms 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.
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% to 25% of all pregnant women. Although nomore than 2% of these women develop invasive infection, 40% to 73% transmit bacteria to their babies during delivery.
About 12,000 of the 3,500,000 babies born in this country 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 firstweek of life, this condition causes inflammation of the membranes covering the brain and spinal cord, (meningitis), pneumonia, blood infection, and otherproblems.
Late-onset GBS develops between the ages of seven days and three months, andoften 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 also has been linked to a history of breast cancer.
Group C strep (GCS) is a common source of infection in animals, but rarely causes human illness.
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 strep (GGS) is normally present on the skin, in the mouth and throat,and in the intestines and genital tract, and 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. GGScan cause a variety of infections, including:
- Bacteria in the bloodstream
- Bursitis (Inflammation of the connective tissue structure surrounding a joint)
- Endocarditis (a condition that affects the lining of the heart chambers and the heart valves)
- Meningitis
- Osteomyelitis) (inflammation of bone and bone marrow)
- Peritonitis (inflammationof the lining of the abdomen).
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 hoursor 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 thefirst few months of life develop brain disorders. An equal number of them die.
Among men, and in women who are not pregnant, the most common consequences ofGBS infection are pneumonia and infections of blood, skin, and soft tissue.para>Other symptoms associated with strep infection include:
- Anemia
- Elevated white blood cell counts
- Inflammation of the epiglottis
- Heart murmur
- High blood pressure
- Infection of the heart muscle
- Kidney inflammation
- Swelling of the face and ankles.
To diagnose a strep infection, the doctor must obtain some bacteria 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 beencollected.
Penicillin and other antibiotics are used to treat strep infections. It takesless than 24 hours for antibiotics to stop 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 giving 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 throughthe 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 lossand other permanent disabilities.
Conventional medicine is very successful in treating strep infections. However, several alternative therapies may relieve symptoms. For example, several herbs, including garlic, echinacea, and goldenseal are believed to strengthenthe immune system, thus helping the body fight a current infection as well ashelping prevent future infections.
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% to 15% of non-GAS strep infections are fatal. Antibiotic therapy, begun when symptoms first appear, may increase a patient's chance of survival.
Washing hands frequently (especially before eating and after using the toilet) 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 dosesof oral or injected antibiotics may prevent some types of recurrent infection.