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MRSA Screening Test

Last updated July 15, 2019

Approved by: Maulik P. Purohit MD, MPH

The MRSA Screening Test is a culture test that detects the presence of methycillin-resistant Staphylococcus aureus.

What are the other Names for this Test? (Equivalent Terms)

  • Methycillin-Resistant Staphylococcus Aureus Screening Test 

What is MRSA Screening Test? (Background Information)

  • Methycillin-resistant Staphylococcus aureus (MRSA) is a group of S. aureus or staph, “superbugs” that exhibits multi-drug resistance (XDR). This means that it responds ‘minimally’ or ‘not at all’ to several classes of antibiotics
  • S. aureus inhabits 25-30% of the adults. Normally, it is harmless, except during a suppressed immune system or a break in the skin. In these cases, it may cause an infection that is treated by antibiotics
  • MRSA inhabits less than 2% of the population. It is resistant to several classes of antibiotics, making infection by MRSA extremely difficult to treat
  • Antibiotics to which MRSA is resistant include vancomycins, macrolides, lincosamides, tetracyclines, streptogramins, aminoglycosides, and beta-lactams, such as methycillin and penicillin
  • Penicillin was first made commercially available in 1943 to combat infections by S. aureus and other bacteria. However, because of a widespread and sometimes unnecessary usage, it took only 4 years for cases of resistance to emerge
  • MRSA obtains its resistance by producing proteins that bind and deactivate drugs, such as penicillin. This mechanism developed over time, due to mutations
  • The antibiotic resistance genes are easily transferrable between MRSA cells. This has led to widespread antibiotic resistance fairly quickly
  • MRSA is present in communities, but is especially prevalent in hospitals. Hospital patients with suppressed immune systems, as a result of surgery or other hospital treatments, are susceptible to MRSA
  • The MRSA Screening Test is a culture test that detects the presence of methycillin-resistant Staphylococcus aureus. It is used to determine, if an individual is a carrier of MRSA 

What are the Clinical Indications for performing the MRSA Screening Test?

Following are the clinical indications for performing a MRSA Screening Test:

  • Containing a MRSA outbreak in a community, by public health officials
  • Determining the origin of a MRSA outbreak
  • Physical contact with an individual, who is a known MRSA carrier
  • Small red bumps resembling pimples or insect bites
  • Abscess formation on various parts of the body 

How is the Specimen Collected for MRSA Screening Test?

Following is the specimen collection process for MRSA Screening Test:

Sample required: Nasal swab

Process: Dabbing of the inside of the nose using a sterile swab resembling a Q-tip

Preparation required: No special preparation is needed prior to the test. 

What is the Significance of the MRSA Screening Test Result?

  • A positive MRSA Screening Test indicates colonization by MRSA 

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario. 

Additional and Relevant Useful Information:

  • It is helpful to perform MRSA screening test in intensive-care units (ICUs). It is recommended to administer nasal antibiotics to all patients admitted to ICUs, which research has shown to be far more effective at preventing and managing MRSA outbreaks, than MRSA screening
  • It is estimated that the cost of nosocomial or hospital-acquired infections, stands at $10-15 billion per year. The cost of community-acquired infections stands at $14-21 billion per year

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

References and Information Sources used for the Article:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Sept. 21, 2014
Last updated: July 15, 2019