Staphylococcus aureus Infections

Skin infections due to Staphylococcus aureus can include the following:

All staphylococcal skin infections are very contagious.

Breast infections (mastitis Breast Infection A breast infection ( mastitis) can occur after delivery ( postpartum infection), usually during the first 6 weeks and almost always in women who are breastfeeding. If the baby is not positioned... read more ), which may include cellulitis and abscesses, can develop 1 to 4 weeks after delivery. The area around the nipple is red and painful. Abscesses often release large numbers of bacteria into the mother’s milk. The bacteria may then infect the nursing infant.

Pneumonia often causes a high fever, shortness of breath, and a cough with sputum that may be tinged with blood. Lung abscesses Abscess in the Lungs A lung abscess is a pus-filled cavity in the lung surrounded by inflamed tissue and caused by an infection. A lung abscess is usually caused by bacteria that normally live in the mouth and are... read more may develop. They sometimes enlarge and involve the membranes around the lungs and sometimes cause pus to collect (called an empyema Types of fluid ). These problems make breathing even more difficult.

Bloodstream infection is a common cause of death in people with severe burns. Symptoms typically include a persistent high fever and sometimes shock.

Endocarditis can quickly damage heart valves, leading to heart failure Heart Failure (HF) Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more (with difficulty breathing) and possibly death.

Osteomyelitis causes chills, fever, and bone pain. The skin and soft tissues over the infected bone become red and swollen, and fluid may accumulate in nearby joints.

Staphylococcal skin infections are usually diagnosed based on their appearance.

Other infections require samples of blood or infected fluids, which are sent to a laboratory to grow (culture), identify, and test the bacteria. Laboratory results confirm the diagnosis and determine which antibiotics can kill the staphylococci (called susceptibility testing Testing a Microorganism's Susceptibility and Sensitivity to Antimicrobial Drugs Infectious diseases are caused by microorganisms, such as bacteria, viruses, fungi, and parasites. Doctors suspect an infection based on the person's symptoms, physical examination results,... read more ).

If a doctor suspects osteomyelitis, x-rays, computed tomography (CT), magnetic resonance imaging (MRI), radionuclide bone scanning Radionuclide Scanning Radionuclide scanning is a type of medical imaging that produces images by detecting radiation after a radioactive material is administered. During a radionuclide scan, a small amount of a radionuclide... read more , or a combination is also done. These tests can show where the damage is and help determine how severe it is.

Bone biopsy is done to obtain a sample for testing. The sample may be removed with a needle or during surgery.

Infections due to Staphylococcus aureus are treated with antibiotics. Doctors try to determine whether the bacteria are resistant to antibiotics and, if so, to which antibiotics.

Infection that is acquired in a hospital is treated with antibiotics that are effective against MRSA. They include vancomycin, linezolid, tedizolid, quinupristin plus dalfopristin, ceftaroline, telavancin, daptomycin, and other antibiotics. If results of testing later indicate that the strain is susceptible to methicillin and the person is not allergic to penicillin, a drug related to methicillin, such as nafcillin or oxacillin, is used. Depending on how severe the infection is, antibiotics may be given for weeks.

MRSA infection can be acquired outside of a health care facility. The community-acquired MRSA strains are usually susceptible to other antibiotics, such as trimethoprim/sulfamethoxazole, clindamycin, minocycline, or doxycycline, as well as to the antibiotics used to treat MRSA infections acquired in the hospital.

Mild skin infections due to MRSA, such as folliculitis, are usually treated with an ointment, such as one that contains bacitracin, neomycin, and polymyxin B (available without a prescription) or mupirocin (available by prescription only). If more than an ointment is required, antibiotics effective against MRSA are given by mouth or intravenously. Which antibiotic is used depends on the severity of the infection and the results of susceptibility testing.

If an infection involves bone or foreign material in the body (such as heart pacemakers, artificial heart valves and joints, and blood vessel grafts), rifampin and possibly another antibiotic are sometimes added to the antibiotic regimen. Usually, infected bone and foreign material has to be removed surgically to cure the infection.

Abscesses, if present, are usually drained.

People can help prevent the spread of these bacteria by always thoroughly washing their hands with soap and water or applying an alcohol-based hand sanitizer.

Some doctors recommend applying the antibiotic mupirocin inside the nostrils to eliminate staphylococci from the nose. However, because overusing mupirocin can lead to mupirocin resistance, this antibiotic is used only when people are likely to get an infection. For example, it is given to people before certain operations or to people who live in a household in which the skin infection is spreading.

If carriers of staphylococci need to have certain types of surgery, they are often treated with an antibiotic before the surgery.

People with a staphylococcal skin infection should not handle food.

In some health care facilities, people are routinely screened for MRSA when they are admitted. Some facilities screen only people who are at increased risk of getting a MRSA infection, such as those who are about to have certain operations. Screening involves testing a sample taken from the nose with a cotton swab. If MRSA strains are detected, people are isolated to prevent spread of the bacteria.