Staph infections

Overview

Staph infections are caused by staphylococcus bacteria. These types of germs are commonly found on the skin or in the nose of many healthy people. Most of the time, these bacteria cause no problems or cause relatively minor skin infections.

But staph infections can turn deadly if the bacteria invade deeper into your body, entering your bloodstream, joints, bones, lungs or heart. A growing number of otherwise healthy people are developing life-threatening staph infections.

Treatment usually involves antibiotics and cleaning of the infected area. However, some staph infections no longer respond, or become resistant, to common antibiotics. To treat antibiotic-resistant staph infections, health care providers may need to use antibiotics that can cause more side effects.

Symptoms

Staph infections can range from minor skin problems to life-threatening illness. For example, endocarditis, a serious infection of the inner lining of your heart (endocardium) can be caused by staph bacteria. Signs and symptoms of staph infections vary widely, depending on the location and severity of the infection.

Skin infections

Skin infections caused by staph bacteria include:

Boils. The most common type of staph infection is the boil. This is a pocket of pus that develops in a hair follicle or oil gland. The skin over the infected area usually becomes red and swollen.

If a boil breaks open, it will probably drain pus. Boils occur most often under the arms or around the groin or buttocks.
Impetigo. This contagious, often painful rash can be caused by staph bacteria. Impetigo usually has large blisters that may ooze fluid and develop a honey-colored crust.
Cellulitis. Cellulitis is an infection of the deeper layers of skin. It causes redness and swelling on the surface of your skin. Sores or areas of oozing discharge may develop, too.
Staphylococcal scalded skin syndrome. Toxins produced by the staph bacteria may cause staphylococcal scalded skin syndrome. Affecting mostly babies and children, this condition includes a fever, a rash and sometimes blisters. When the blisters break, the top layer of skin comes off. This leaves a red, raw surface that looks like a burn.

Food poisoning

Staph bacteria are one of the most common causes of food poisoning. The bacteria multiply in food and produce toxins that make you sick. Symptoms come on quickly, usually within hours of eating a contaminated food. Symptoms usually disappear quickly, too, often lasting just half a day.

A staph infection in food usually doesn't cause a fever. Signs and symptoms you can expect with this type of staph infection include:

Nausea and vomiting
Diarrhea
Dehydration
Low blood pressure

Bacteremia

Also known as a bloodstream infection, bacteremia occurs when staph bacteria enter the bloodstream. A fever and low blood pressure are signs of bacteremia. The bacteria can travel to locations deep within your body to cause infections that affect:

Internal organs, such as your brain (meningitis), heart (endocarditis) or lungs (pneumonia)
Bones and muscles
Surgically implanted devices, such as artificial joints or cardiac pacemakers

Toxic shock syndrome

This life-threatening condition results from toxins produced by some strains of staph bacteria. The condition has been linked to certain types of tampons, skin wounds and surgery. It usually develops suddenly with:

A high fever
Nausea and vomiting
A rash on your palms and soles that looks like a sunburn
Confusion
Muscle aches
Diarrhea
Stomach pain

Septic arthritis

Septic arthritis is often caused by a staph infection. The bacteria often target the knees, shoulders, hips, and fingers or toes. Artificial joints may also be at risk of infection. Signs and symptoms may include:

Joint swelling
Severe pain in the affected joint
Fever

When to see a doctor

Go to your health care provider if you or your child has:

An area of red, irritated or painful skin
Pus-filled blisters
Fever

You may also want to talk to your provider if:

Skin infections are being passed from one family member to another
Two or more family members have skin infections at the same time

Causes

Many people carry staph bacteria on their skin or in their nose and never develop staph infections. However, if you develop a staph infection, there's a good chance that it's from bacteria you've been carrying around for some time.

Staph bacteria can also be spread from person to person. Because staph bacteria are so hardy, they can live on objects such as pillowcases or towels long enough to transfer to the next person who touches them.

Staph bacteria can make you sick by causing an infection. You can also become sick from the toxins produced by the bacteria.

Staph bacteria can survive:

Drying
Extremes of temperature
Stomach acid

Risk factors

Many factors — including the health of your immune system or the types of sports you play — can increase your risk of developing staph infections.

Underlying health conditions

Certain disorders or the medications used to treat them can make you more likely to get staph infections. People who may be more likely to get a staph infection include those with:

Diabetes who use insulin
HIV/AIDS
Kidney failure requiring dialysis
Weakened immune systems — either from a disease or medications that suppress the immune system
A transplant
Cancer, especially those who are being treated with chemotherapy or radiation
Skin damage from conditions such as eczema, insect bites or minor trauma that opens the skin
Lung (respiratory) illness, such as cystic fibrosis or emphysema

Current or recent hospitalization

Despite strong attempts to get rid of them, staph bacteria stay present in hospitals, where they can infect people who are most at risk of infection. This can include people with:

Weakened immune systems
Burns
Surgical wounds

Sometimes people admitted to the hospital may be screened to see if they're carrying staph bacteria. Screening is done using a nasal swab. Treatment to get rid of the bacteria may be given to help prevent infection and decrease the spread to others.

Invasive and implanted devices

Staph bacteria can get into the body by traveling along medical tubing. These devices make a connection between the outside and the inside of your body. Examples are:

Urinary catheters
Tubing placed in a vein (intravenous catheters)

Also, staph bacteria are attracted to implanted devices, where they grow on the surface and cause infection. These include surgically implanted devices such as:

Artificial joints
Cardiac pacemakers

Contact sports

Staph bacteria can spread easily through cuts, scrapes and skin-to-skin contact. Staph infections may also spread in the locker room through shared razors, towels, uniforms or equipment.

Unsanitary food preparation

Food handlers who don't properly wash their hands can transfer staph bacteria from their skin to the food they're preparing. The bacteria multiply in the food and produce toxins that make you sick. Cooking can kill the bacteria. But the toxins are still in the food. Foods that are contaminated with staph bacteria do not look or taste differently.

Complications

If staph bacteria invade your bloodstream, you may develop a type of infection that affects your entire body. Called sepsis, this infection can lead to septic shock. This is a life-threatening episode when your blood pressure drops to an extremely low level.

Staph infections can also turn deadly if the bacteria invade deep into your body, entering your bloodstream, joints, bones, lungs or heart.

Prevention

These commonsense precautions can help lower your risk of getting staph infections:

Wash your hands. Thorough hand washing is your best defense against germs. Wash your hands with soap and water briskly for at least 20 seconds. Then dry them with a disposable towel and use the towel to turn off the faucet. If your hands aren't visibly dirty or you aren't able to wash your hands, you can use an alcohol-based hand sanitizer.

Wash your hands with soap and water regularly, such as before, during and after making food; after handling raw meat or poultry; before eating; after using the bathroom; and after touching an animal or animal waste.
Keep wounds covered. Keep cuts and scrapes clean and covered with sterile, dry bandages until they heal. The pus from infected sores often contains staph bacteria. Keeping wounds covered will help keep the bacteria from spreading.
Reduce tampon risks. Toxic shock syndrome is caused by staph bacteria. Tampons left in for long periods can grow staph bacteria. You can reduce your chances of getting toxic shock syndrome by changing your tampon frequently — at least every 4 to 8 hours. Use the lowest absorbency tampon you can. Try to alternate tampons with sanitary napkins whenever possible.
Keep personal items personal. Avoid sharing personal items such as towels, sheets, razors, clothing and athletic equipment. Staph infections can spread on objects, as well as from person to person.
Wash clothing and bedding. Staph bacteria can spread on clothing, towels and bedding. To remove bacteria, wash and dry items at the warmest temperature recommended by the items' labels. It's OK if you can't use hot water, as using detergent in your wash is enough to make items clean and safe for use. You can use bleach on any bleach-safe materials.
Take food safety precautions. Wash your hands before handling food. If food will be out for a while, make sure that hot foods stay hot — above 140 F (60 C). Make sure that cold foods stay at 40 F (4.4 C) or below. Refrigerate leftovers as soon as possible. Wash cutting boards and counters with soap and water.

Diagnosis

To diagnose a staph infection, your health care provider typically will:

Perform a physical exam. During the exam, your provider examines any skin sores or reddened areas you may have. Your provider can also review any other symptoms.
Collect a sample for testing. Most often, providers diagnose staph infections by checking blood, urine, skin, infected material or nasal secretions for signs of the bacteria. Additional tests can help your provider choose the antibiotic that will work best against the bacteria.
Recommend other tests. If you're diagnosed with a staph infection, your provider may order an imaging test called an echocardiogram. This test can check if the infection has affected your heart. Your provider may order other imaging tests, depending on your symptoms and the exam results.

Treatment

Treatment of a staph infection may include:

Antibiotics. Your health care provider may perform tests to identify the staph bacteria behind your infection. This can help your provider choose the antibiotic that will work best for you. Antibiotics commonly prescribed to treat staph infections include cefazolin, nafcillin, oxacillin, vancomycin, daptomycin and linezolid.

For serious staph infections, vancomycin may be required. This is because so many strains of staph bacteria have become resistant to other traditional antibiotics. This means other antibiotics can no longer kill the staph bacteria. Vancomycin and some other antibiotics used for antibiotic-resistant staph infections have to be given through a vein (intravenously).

If you're given an oral antibiotic, be sure to take it as directed. Finish all the medication your provider gives you. Ask your provider what signs and symptoms you should watch for that might mean your infection is getting worse.
Wound drainage. If you have a skin infection, your provider may make a cut (incision) into the sore to drain fluid that has collected there. The area is also thoroughly cleaned.
Device removal. If your infection involves a medical device, such as a urinary catheter, cardiac pacemaker or artificial joint, prompt removal of the device may be needed. For some devices, removal might require surgery.

Antibiotic resistance

Staph bacteria are very adaptable. Many varieties have become resistant to one or more antibiotics. For example, today, most staph infections can't be cured with penicillin.

Antibiotic-resistant strains of staph bacteria are often described as methicillin-resistant Staphylococcus aureus (MRSA) strains. The increase in antibiotic-resistant strains has led to the use of IV antibiotics, such as vancomycin or daptomycin, with the potential for more side effects.

Preparing for your appointment

While you may first see your family health care provider, you may be referred to a specialist, depending on which of your organ systems is affected by the infection. For example, you may be referred to a specialist in treating skin conditions (dermatologist), heart disorders (cardiologist) or infectious diseases.

What you can do

Before your appointment, you may want to make a list that includes:

Detailed descriptions of your symptoms
Information about medical problems you've had
Information about the medical problems of your parents or siblings
All medications, herbs, vitamins and other supplements you take
Questions you want to ask your health care provider

For a staph infection, some basic questions to ask include:

What's the most likely cause of my symptoms?
What kind of tests do I need?
What's the best treatment for a staph infection?
Am I contagious?
How can I tell if my infection is getting better or worse?
Are there any activity restrictions that I need to follow?
I have other health conditions. How can I best manage these conditions together?
Do you have any brochures or other printed material that I can take? What websites do you recommend?

What to expect from your doctor

Your health care provider will likely ask you a number of questions, such as:

When did you first notice your symptoms? Could you describe them to me?
How severe are your symptoms?
Have you been around anyone with a staph infection?
Do you have any implanted medical devices, such as an artificial joint or a cardiac pacemaker?
Do you have any ongoing medical conditions, including a weakened immune system?
Have you recently been in the hospital?
Do you play contact sports?

What you can do in the meantime

If you suspect that you have a staph infection on your skin, keep the area clean and covered until you see your health care provider so that you don't spread the bacteria. And until you know whether or not you have a staph infection, don't share towels, clothing and bedding and don't prepare food for others.