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Methicillin-resistant Staphylococcus aureus (MRSA)

MRSA in Arizona

Arizona Department of Health Services (ADHS) requires laboratories to report invasive MRSA infections. This means that only cases where a positive laboratory test identified the bacteria in a normally sterile part of the body (i.e. blood, bones) are counted. These are typically Healthcare-Associated MRSA (HA-MRSA). Skin infections, which are typically caused by Community-Associated MRSA (CA-MRSA), are not tracked by ADHS. ADHS also does not collect information on deaths due to MRSA.

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What is Staphylococcus aureus?

Staphylococcus aureus, often referred to as "staph", are bacteria commonly carried on the skin or in the nose of healthy people. Staph can sometimes cause an infection. Most of these are minor skin infections and can be treated without antibiotics. However, staph also can cause serious infections such as surgical wound infections or pneumonia.

What is methicillin-resistant Staphylococcus aureus (MRSA)?

Some staph are resistant to commonly prescribed antibiotics such as penicillin, amoxicillin, and cephalexin.

Who gets staph or MRSA infections?

The majority of MRSA infections occur in hospitals or other healthcare settings. These infections are called healthcare-associated MRSA (HA-MRSA).

Staph and MRSA can also cause illness in healthy persons in the community. MRSA infections in persons who have not been hospitalized or had a medical procedure in the past year are known as Community-Associated (CA-MRSA) infections. CA-MRSA usually causes skin infections, such as pimples, boils, and "spider bites," and occur in otherwise healthy people. These infections can be found in schools, in prisons, and on athletic teams.

Where can I find more information on MRSA?

For the General Public Source
Information for Parents and Students (flyer) Arizona Department of Health Services
Información sobre el SARM para Padres y Estudiantes Arizona Department of Health Services
Centers for Disease Control and Prevention (CDC) MRSA Website Centers for Disease Control and Prevention
For Schools  
Letter to School Administrators Arizona Department of Health Services
For Clinicians  
Clinician Fact Sheet Arizona Department of Health Services

Technical Information


  • Etiologic Agent: Methicillin-resistant Staphylococcus aureus, or MRSA is a strain of the S. aureus bacteria that is resistant to the beta-lactam group of antimicrobials, which includes common antimicrobials such as penicillin and amoxicillin.
  • Mode of Transmission: MRSA is transmitted mainly through direct skin-to-skin contact or contact with a contaminated personal item such as a razor or towel.
  • Period of Communicability: As long as sores are draining. Autoinfection may continue for the period of nasal colonization.
  • Incubation Period: Variable and indefinite.
  • Clinical Features: Staphylococcus aureus can present in a variety of ways, ranging from skin or soft tissue infection to bacteremia involving various organs (e.g., endocarditis, pneumonia, osteomyelitis). Community-associated MRSA (CA-MRSA) typically presents in the form of a skin infection (e.g., boil, abscess, or pimple) Healthcare-associated MRSA (HA-MRSA) can present in a number of ways (e.g., surgical wound infection, blood infection, or pneumonia).

Lab Tests

Lab Criteria for Diagnosis (invasive disease)

  • Isolation of Staphylococcus aureus from a normally sterile site. Examples of sterile sites include, but are not limited to: cerebral spinal fluid, blood, peritoneal fluid, or pleural fluid.


  • Intermediate or high level resistance of the Staphylococcus aureus isolate to methicillin, detected and defined according to the standards and guidelines approved by the National Committees for Clinical Laboratory Standards (NCCLS) (MIC: 4-8 mg/L for intermediate and >16 mg/L for high (NCCLS 2006)).

Healthcare-Associated Methicillin-resistant Staphylococcus aureus (HA-MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacteria that is resistant to certain antibiotics. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin. Staph infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities (such as nursing homes and dialysis centers) who have weakened immune systems. These infections are typically invasive, occurring in a normally sterile part of the body (i.e. blood, bones).

Invasive MRSA in Arizona

ADHS has been tracking invasive MRSA infections since October, 2004. In 2005 there were 1,432 invasive MRSA infections reported in Arizona. In 2006 there were 1,336 reported. These numbers only includes cases where a positive laboratory test identified the disease in a normally sterile part of the body, like the blood.

Community-Associated Methicillin-resistant Staphylococcus aureus (CA-MRSA)

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What does a staph/CA-MRSA infection look like?

Staph bacteria, including MRSA, can cause skin infections that may look like a pimple or boil and can be red, swollen, painful, or have pus or other drainage. Some people describe them as looking like spider bites.

Are certain people at increased risk for CA-MRSA infections?

Centers for Disease Control and Prevention (CDC) has investigated clusters of CA-MRSA skin infections among athletes, military recruits, children, Pacific Islanders, Alaskan Natives, Native Americans, men who have sex with men, and prisoners.

Factors that have been associated with the spread of MRSA skin infections include: close skin-to-skin contact, openings in the skin such as cuts or abrasions, contaminated items and surfaces, crowded living conditions, and poor hygiene.

How can I prevent staph or MRSA skin infections?

Practice good hygiene:

  1. Keep your hands clean by washing thoroughly with soap and water or using an alcohol-based hand sanitizer.
  2. Keep cuts and scrapes clean and covered with a bandage until healed.
  3. Avoid contact with other people's wounds or bandages.
  4. Avoid sharing personal items such as towels or razors.

Are people who are positive for the human immune deficiency virus (HIV) at increased risk for MRSA? Should they be taking special precautions?

People with weakened immune systems, which include some patients with HIV infection, may be at risk for more severe illness if they get infected with MRSA. People with HIV should follow the same prevention measures as those without HIV to prevent staph infections, including the practice of good hygiene.

Can I get a staph or MRSA infection at my health club?

In the outbreaks of MRSA, the environment has not played a significant role in the transmission of MRSA. MRSA is transmitted most frequently by direct skin-to-skin contact. You can protect yourself from infections by practicing good hygiene (e.g., keeping your hands clean by washing with soap and water or using an alcohol-based hand rub and showering after working out); covering any open skin area such as abrasions or cuts with a clean dry bandage; avoiding sharing personal items such as towels or razors; using a barrier (e.g., clothing or a towel) between your skin and shared equipment; and wiping surfaces of equipment before and after use.

What should I do if I think I have a staph or MRSA infection?

See your healthcare provider.

Are staph and MRSA infections treatable?

Yes. Most staph and MRSA infections are treatable with antibiotics. If you are given an antibiotic, take all of the doses, even if the infection is getting better, unless your doctor tells you to stop taking it. Do not share antibiotics with other people or save unfinished antibiotics to use at another time. However, many staph skin infections may be treated by draining the abscess or boil and may not require antibiotics. Drainage of skin boils or abscesses should only be done by a healthcare provider.

If after visiting your healthcare provider the infection is not getting better after a few days, contact them again. If other people you know or live with get the same infection tell them to go to their healthcare provider.

If I have a staph, or MRSA, skin infection, what can I do to prevent others from getting infected?

You can prevent spreading staph or MRSA skin infections to others by following these steps:

  1. Cover your wound. Keep wounds that are draining or have pus covered with clean, dry bandages. Follow your healthcare provider's instructions on proper care of the wound. Pus from infected wounds can contain staph and MRSA, so keeping the infection covered will help prevent the spread to others. Bandages or tape can be discarded with the regular trash.
  2. Clean your hands. You, your family, and others in close contact should wash their hands frequently with soap and warm water or use an alcohol-based hand sanitizer, especially after changing the bandage or touching the infected wound.
  3. Do not share personal items. Avoid sharing personal items such as towels, washcloths, razors, clothing, or uniforms that may have had contact with the infected wound or bandage. Wash sheets, towels, and clothes that become soiled with water and laundry detergent. Drying clothes in a hot dryer, rather than air-drying, also helps kill bacteria in clothes.
  4. Talk to your doctor. Tell any healthcare providers who treat you that you have or had a staph or MRSA skin infection.

How can I clean a surface exposed to MRSA?

  • Skin: Wash with soap and water. If soap and water are not available, use a alcohol-based hand sanitizer.
  • Material: Wash sheets, towels, and clothes that become soiled with hot water and laundry detergent. Drying clothes in a hot dryer, rather than air-drying, also helps kill bacteria in clothes.
  • Other surfaces: Use a disinfectant that is certified by the Environmental Protection Agency to kill MRSA.

What should schools do to prevent transmission of MRSA?

Arizona Department of Health Services does not recommend school closures due to MRSA infections. Provided the following recommendations are observed, there is minimal to no health risk to other students, faculty, and staff.

  • Promote good hygiene. Ensure access to sinks, soaps, and clean towels for the cleaning of hands. If soap and water are not available, ensure the availability of alcohol-based hand sanitizers.
  • School attendance. Students and staff with a MRSA infection can attend school regularly as long as the wound is covered with a clean, dry dressing and they are receiving proper treatment. They do not need to be isolated or sent home in the middle of the day if a suspected staph or MRSA infection is noticed. They should wash the area with soap and water and cover it lightly. They should also be encouraged to have the wound looked at by their healthcare provider. Those who touch the wound should wash their hands immediately.
  • Follow routine procedures for cleaning the environment. In general, use routine procedures with a freshly prepared solution of commercially available cleaner such as detergent, disinfectant-detergent or chemical germicide.

If a student athlete has a MRSA infection, should other athletes be tested?

It is not recommended that athletes without skin infections be tested. Athletes with skin infections should immediately report them to their coach and see a health care provider. If multiple athletes develop skin infections and there is concern of an outbreak, contact your local health department.