Text A Staphylococcal Infections

Staphylococcal infectionsare those caused by staphylococci, which are common gram-positive bacteria.

Normally found in the nose and on the skin of 20 to 30 percent of healthy adults (and less com­monly in the mouth, mammary glands, and genitourinary, intestinal, and upper respiratory tracts), staphylococci do no harm most of the time. However, a break in the skin or another injury may allow the bacteria to penetrate the body’s defenses and cause infection.

People prone to Staphylococcal infections include newborns, breastfeeding women, people with chronic diseases (especially lung disease, diabetes, and cancer), those with skin conditions and surgical incisions, and those whose immune 'systems are suppressed by corticosteroids, ra­diation therapy, immunosuppressive drugs, or anticancer medications.

Symptoms

Staphylococci can infect any site in the body, and the symptoms depend on the location of the infection. The infection may be mild or life threat­ening. Commonly, Staphylococcal infections pro­duce pus-filled pockets, such as abscesses and boils (furuncles and carbuncles). Staphylococci can travel through the blood and cause abscesses in internal organs, such as the lungs, as well as infections of bones (osteomyelitis) and the inner lining of the heart and its valves (endocarditis).

Staphylococci tend to infect the skin. Staphy­lococcal abscesses on the skin appear as warm, pus-filled pockets below the surface. They usually rupture like a large pimple and ooze pus onto the skin, where further infection can occur if the pus isn't cleaned off. Staphylococci can also cause cellulitis, a spreading infection under the skin. Usually boils also are caused by staphylococci. Two particularly serious staphylococcal skin in­fections are toxic epidermal necrolysis and the scalded skin syndrome, both of which lead to large-scale peeling of skin.

Newborns may develop staphylococcal skin in­fections, usually within 6 weeks after birth. The most common symptom is large blisters filled with clear fluid or pus that appear in the armpit, groin, or neck skin-folds. More severe staphylo­coccal infections can cause many skin abscesses, sloughing of the skin in large patches, blood in­fection, infection of the membranes covering the brain and spinal cord (meningitis), and pneumonia.

Breastfeeding mothers may develop staphylo­coccal breast infections (mastitis) and abscesses 1 to 4 weeks after delivery. Such infections often are contracted by the infant in the hospital nurs­ery and transferred to the mother's breast during feeding.

Staphylococcal pneumonia is a severe infection. People with chronic lung diseases (such as chronic bronchitis and emphysema) and those with influenza are particularly at risk. Staphylo­coccal pneumonia often causes a high fever and severe lung symptoms, such as shortness of breath, rapid breathing, and cough productive of sputum that may be tinged with blood. In newborns—and sometimes adults—staphylococcal pneumonia may cause lung abscesses and an infection of the pleura (the membrane layers sur­rounding the lungs). The infection, called thoracic empyema, worsens the difficulties in breathing caused by the pneumonia.

Although a staphylococcal infection of the blood (staphylococcal bacteremia) often devel­ops from a staphylococcal infection elsewhere in the body, it usually comes from an infected intra­venous device, such as a catheter, which gives staphylococci direct access to the bloodstream. Staphylococcal bacteremia is a common cause of death in severely burned people. Typically, the bacteremia causes a persistent, high fever and sometimes shock.

Staphylococci in the bloodstream can lead to an infection of the inner lining of the heart and its valves (endocarditis), especially in injecting drug users. The infection can quickly damage the valves, leading to heart failure and death.

Bone infections (osteomyelitis) predominantly affect children, although they also affect the el­derly, especially those with deep skin ulcers (bedsores). Bone infections cause chills, fever, and bone pain. Redness and swelling appear over the infected bone, and fluid may build up in joints near the areas invaded by the bacteria. The site of infection may be painful, and the person usu­ally has a fever. Sometimes x-rays and other radiologic scans can identify an area of infection, but they generally don't help the doctor make an early diagnosis.

A staphylococcal infection of the intestine of­ten causes a fever, abdominal bloating and distention, a temporary halting of the intestine's normal contractile movements (ileus), and diarrhea. The infection is most common in hospitalized pa­tients, especially those who have undergone ab­dominal surgery or received antibiotic treatment.

Surgery increases the risk of staphylococcal in­fection. The infection may produce abscesses at the stitches or may cause extensive destruction of the incision site. Such infections usually appear a few days to several weeks after an operation but may develop more slowly if the person received antibiotics at the time of surgery. A postoperative staphylococcal infection may worsen and pro­gress to toxic shock syndrome.

Treatment

For most skin infections, oral antibiotics, such as cloxacillin, dicloxacillin, and erythromycin, are adequate. More severe infections, especially blood infections, require intravenous antibiotic therapy, often for up to 6 weeks.

The choice of an antibiotic depends on the site of infection, the severity of the illness, and which; of the antibiotics most effectively kills the particular bacteria. Methicillin-resistant staphylococcus aureus is resistant to most commonly used anti­biotics and is a major concern because the bac­terium is increasingly common in big city and university hospitals. Among the few antibiotics that are usually effective against methicillin-resistant; Staphylococcus aureus are vancomycin and trimethoprim-sulfamethoxazole.Vancomycin kills the bacteria, whereas trimethoprim-sulfamethoxazole acts by inhibiting their ability to multiple an abscess that develops must be drained. Draining an abscess on the skin is relatively sim­ple. A doctor makes a small cut in the area and applies pressure to clean out the infected mate­rial. Abscesses deeper in the body may require surgery.

Notes:

suppress подавлять

delivery родоразрешение

empyema скопление гноя в полости, эмпиема

newborn новорожденный

fill with заполнять

slough сходить(о коже), шелушиться

be tinged with иметь примесь чего-л

distention вздутие живота

Дата добавления: 2015-11-16