Diagnosis of MRSA

Staph infection diagnosis is based on identifying Staphylococcus aureus bacteria. To make the diagnosis, a diagnostic test called a culture usually is performed. In this test, a sample is taken from the infection site, grown in a laboratory setting that encourages bacterial growth, and examined under a microscope for the presence of S. aureus.

Once S. aureus bacteria are identified, they are cultured in the presence of methicillin and other antibiotics. If they grow in the presence of antibiotics, the condition is diagnosed as MRSA infection.

Cultures can be performed using nasal and throat secretions, or samples from infected areas of skin and other tissues (e.g., blood, joint fluid, bone marrow, cerebral spinal fluid [CSF]). Results of a culture can take as many as 48 hours. Because prompt MRSA diagnosis and treatment can help prevent complications in some cases, newer diagnostic tests that can detect staph bacteria more quickly are being developed.

MRSA Treatment

Treatment for MRSA infection usually involves intravenous (i.e., through a vein) antibiotics. IV antibiotics provide a more effective concentration of medication in the bloodstream than commonly used antibiotics that are administered orally. Oral administration may result in decreased absorption of the antibiotics in the digestive tract. Vancomycin (Vancocin, Vancoled), linezolid (Zyvox), daptomycin (Cubicin), dalbavancin (Dalvance; approved in May 2014), tedizolid phosphate (Sivextro; approved in June 2014), and oritavancin (Orbactiv; approved in August 2014) may be used to treat MRSA infection and other bacterial skin infections.

To help reduce the development of drug-resistant bacteria, antibiotics should always be used as directed. When oral antibiotics are prescribed, patients should be sure to finish all medication, as unfinished doses can lead to additional drug resistance.

Treatment for MRSA infection also may include surgery to drain the infection and/or remove damaged tissue. Other types of treatment may be used to relieve symptoms and complications caused by MRSA infection. These treatments include medications, oxygen therapy, and dialysis.

In some cases, staph infections, including MRSA, recur (reappear) and require additional treatment. If left untreated, MRSA infections can lead to organ failure and death.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 19 Feb 2008

Last Modified: 15 Sep 2015