What is methicillin-resistant staph infection?

Definition

A methicillin-resistant staph (MRSA) infection is caused by the bacterium
Staphylococcus aureus. The bacterium can affect the skin, blood, bones, or lungs. A person can be infected or colonized with MRSA. When a person is infected, the bacterium produces symptoms. A person colonized also has the bacterium, but the bacterium may not cause any symptoms.

There are two types of MRSA infection: community acquired and nosocomial. People who have community-acquired MRSA infection were infected outside a hospital setting (such as a dormitory). Nosocomial MRSA infections occur in hospital settings.

Causes

An MRSA infection can spread through several mechanisms, including from contaminated surfaces, from person to person, and from one area of the body to another.

Risk Factors

The following factors increase the chance of community acquired infection:
impaired immunity, sharing crowded spaces (such as dormitories and locker rooms),
using intravenous drugs, serious illness, exposure to animals (as pet owners,
veterinarians, and pig farmers, for example), using antibiotics,
having a chronic skin disorder, and past MRSA infection. Also at higher risk
are young children, athletes, prisoners, and military personnel.

For nosocomial infection, the risk factors are impaired immunity, exposure to hospital or clinical settings, advanced age, chronic illness, using antibiotics, having a wound, living in a long-term-care center, and having an indwelling medical device (such as a feeding tube or intravenous catheter). Also, men are at higher risk.

Symptoms

The symptoms of MRSA include folliculitis (infection of hair follicles), boils (a skin
infection that may drain pus, blood, or an amber-colored liquid), scalded skin
syndrome (a skin infection characterized by a fever, rash, and sometimes
blisters), impetigo (large blisters on the skin), toxic shock
syndrome (a rare but serious bacterial
infection whose primary symptoms are a rash and high fever),
cellulitis (a skin infection characterized by a swollen, red
area that spreads quickly), and an abscess.

Screening and Diagnosis

A doctor will ask about symptoms and medical history and will perform a physical exam. Tests may include cultures, blood tests, urine tests, and a skin biopsy (removal of a sample of skin to test for infection).

Treatment and Therapy

Treatment options include medications such as antibiotics, prescribed to kill the bacteria, and incision and drainage of an abscess, in which the doctor (but not the patient) opens the abscess and allows the fluid to drain. Another treatment is cleansing the skin. To treat the infection and to keep it from spreading, one should wash skin with an antibacterial cleanser, apply an antibiotic, and cover skin with a sterile dressing.

Prevention and Outcomes

To help reduce the chance of getting an MRSA infection, one should thoroughly wash hands with soap and water, keep cuts and wounds clean and covered until healed, and avoid contact with other people’s wounds and with materials contaminated by wounds. Hospitalized persons’ visitors, and health care workers, may be required to wear special clothing and gloves to prevent spreading the infection to others.

Bibliography

Archer, G. L. “Staphylococcal Infections.” Andreoli and Carpenter’s Cecil Essentials of Medicine. Ed. Thomas E. Andreoli, et al. 8th ed. Philadelphia: Saunders, 2010. Print.

Centers for Disease Control and Prevention. “Seasonal Flu and Staph Infection.” Available at http://www.cdc.gov/flu/about/qa/flustaph.htm.

Crossley, Kent B., Kimberly K. Jefferson, and Gordon L. Archer, eds. Staphylococci in Human Disease. Hoboken: Wiley, 2009. Print.

Laibl, V. R., et al. “Clinical Presentation of Community-Acquired Methicillin-Resistant Staphylococcus aureus in Pregnancy.” Obstetrics and Gynecology 106 (2005): 461–65. Print.

"Methicillin-resistant Staphylococcus aureus (MRSA) Infections." CDC.gov. Centers for Disease Control and Prevention, 2015. Web. 31 Dec. 2015.