What is a Staph Infection
Staphylococcus is a group of bacteria that can cause a number of diseases as a result of infection of various tissues of the body. Staphylococcus is more familiarly known as Staph (pronounced “staff”). Staph-related illness can range from mild and requiring no treatment to severe and potentially fatal.
The name Staphylococcus comes from the Greek staphyle, meaning a bunch of grapes, and kokkos, meaning berry, and that is what Staph bacteria look like under the microscope, like a bunch of grapes or little round berries. (In technical terms, these are gram-positive, facultative anaerobic, usually unencapsulated cocci.) Over 30 different types of Staphylococci can infect humans, but most infections are caused by Staphylococcus aureus. Staphylococci can be found normally in the nose and on the skin (and less commonly in other locations) of 25%-30% of healthy adults. In the majority of cases, the bacteria do not cause disease. However, damage to the skin or other injury may allow the bacteria to overcome the natural protective mechanisms of the body, leading to infection.
Who is at risk for Staph infections?
Anyone can develop a Staph infection, although certain groups of people are at greater risk, including newborn infants, breastfeeding women, and people with chronic conditions such as diabetes, cancer, vascular disease, and lung disease. Injecting drug users, those with skin injuries or disorders, intravenous catheters, surgical incisions, and those with a weakened immune system all have an increased risk of developing Staph infections.
Staph infections are contagious until the infection has resolved. Direct contact with an infected sore or wound, or with personal-care items such as razors, bandages, etc. are common routes of transmission. Casual contact such as kissing or hugging does not pose a great risk for transmission if there is no direct contact with the infected area.
What are the symptoms and signs of a Staph infection?
Staphylococcal disease of the skin usually results in a localized collection of pus, known as an abscess, boil, or furuncle, depending upon the exact type of lesion that is present. The affected area may be red, swollen, and painful. Drainage or pus is common. When Staph is in the blood (bacteremia or sepsis), it can cause high fevers, chills, and low blood pressure.
What types of diseases are caused by Staph?
Skin infections (see above) are the most common type of disease produced by Staphylococcus. Staph infections of the skin can progress to impetigo (a crusting of the skin) or cellulitis (inflammation of the connective tissue under the skin, leading to swelling and redness of the area). In rare situations, a serious complication known as scalded skin syndrome (see below) can develop. In breastfeeding women, Staph can result in mastitis (inflammation of the breast) or in abscess of the breast. Staphylococcal breast abscesses can release bacteria into the mother’s milk.
When the bacteria enter the bloodstream and spread to other organs, a number of serious infections can occur. Spread of the organisms to the bloodstream is known as bacteremia or sepsis. Staphylococcal pneumonia predominantly affects people with underlying lung disease and can lead to abscess formation within the lungs. Infection of the heart valves (endocarditis) can lead to heart failure. Spread of Staphylococci to the bones can result in severe inflammation of the bones known as osteomyelitis. When Staph bacteria are present in the blood, a condition known as staphylococcal sepsis (widespread infection of the bloodstream) or staphylococcal bacteremia exists. Staphylococcal sepsis is a leading cause of shock and circulatory collapse, leading to death, in people with severe burns over large areas of the body. When untreated, Staph aureus sepsis carries a mortality (death) rate of over 80%. Although not common, Staph aureus has been reported as a cause of chorioamnionitis and neonatal sepsis in pregnancy, but group B streptococci are the most common bacterial cause of this life-threatening condition for the fetus.
Staphylococcal infections are contagious and can be transmitted from person to person. Since pus from infected wounds may contain the bacteria, proper hygiene and handwashing is required when caring for Staph-infected wounds. Staphylococcal food poisoning is an illness of the bowels that causes nausea, vomiting, diarrhea, and dehydration. It is caused by eating foods contaminated with toxins produced by Staphylococcus aureus. Symptoms usually develop within one to six hours after eating contaminated food. The illness usually lasts for one to three days and resolves on its own. Patients with this illness are not contagious, since toxins are not transmitted from one person to another.