Lab Test

Staphylococcus aureus/MRSA by PCR, Nares

MSSA, Methicillin-sensitive Staphylococcus aureus, MRSA, Methicillin-resistant Staphylococcus aureus

Test Codes

EPIC: LAB7222

Instructions

  • This test is for routine MSSA/MRSA screening cultures
  • For preoperative specimens for Cardiovascular Services, Orthopedic Surgery, and Neurosurgery, order Culture, Staph. aureus
  • For suspected cases of Staph. aureus sinusitis, order Culture, Respiratory.

Specimen Collection Criteria

Collect: 

ESwab

  • Carefully insert the swab into the patient’s nostril. The swab tip should be inserted up to 1 inch from the edge of the nares.
  • Roll the swab along the mucosa inside the nostril 5 times.
  • Repeat the steps above using the same swab in the second nostril.
  • Replace the swab in its transport tube.
  • The specimen must be labeled with the date and time of collection, as well as the patient's name, medical record number, and source of specimen (nares).

    Red BBL CultureSwab

  • Moisten the swabs with two drops of sterile saline or use dry
  • Carefully insert a swab into the patient’s nostril. The swab tip should be inserted up to 1 inch from the edge of the nares.
  • Roll the swab along the mucosa inside the nostril 5 times.
  • Repeat the steps above using the second swab in the second nostril.
  • Replace the swab in its transport tube.
  • The specimen must be labeled with the date and time of collection, as well as the patient's name, medical record number, and source of specimen (nares).

Physician Office/Draw Specimen Preparation

Maintain specimens at room temperature (20-26°C or 68-78.8°F) prior to transport.

Preparation for Courier Transport

Transport: ESwab or Red BBL CultureSwab specimen, at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

  • Specimens that have been delayed in transit (greater than 24 hours from time of collection)
  • Swabs submitted in an expired collection system.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 24 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Room Temperature (20-26°C or 68-78.8°F): 7 days

Laboratory

Dearborn Microbiology Laboratory
Taylor, Trenton and Wayne sent to Dearborn Microbiology Laboratory for testing 

Royal Oak Microbiology Laboratory
Farmington Hills, Grosse Point, and Troy sent to Royal Oak Microbiology Laboratory for testing.

Performed

Final results available within 24 hours.

Reference Range

No Staphylococcus aureus recovered.

Test Methodology

Nucleic Acid Amplification (FDA Approved; BD MAXTM StaphSR).

Clinical Utility

Approximately 25% to 30% of people have S. aureus in their nares but less than 2% have MRSA. If healthcare providers are aware of the presence of MRSA, appropriate antibacterial agents can be prescribed to prevent infections. Additionally, steps will be taken to prevent the spread within the hospital.

Clinical Disease

Methicillin resistant Staphylococcus aureus (MRSA) are major concerns in the healthcare setting where they may cause more severe and potentially life-threatening infections of the bloodstream, surgical sites, or lungs. Persons with MRSA in their nares have a greater chance of having the same MRSA strain cause a wound infection following surgery. In the community, most MRSA infections are skin infections that may appear as pustules or boils that are red, swollen, painful, or have pus or other drainage. These skin infections commonly occur at sites of visible skin trauma, such as cuts and abrasions, and areas of the body covered by hair.

Disease Reporting

Not reportable to public health unless there is unusual disease or there is an unusual antimicrobial susceptibility pattern of an isolate in an outbreak.

Epidemiology

S. aureus/MRSA can be carried in the nares either persistently or intermittently and then transferred to the skin or other body areas. Health care workers may have a high rate of carriage of S. aureus/MRSA in the nares as do persons with chronic illnesses such as insulin-dependent diabetics, persons on long-term hemodialysis and users of illegal intravenous drugs. Other sites where S. aureus/MRSA can be found in the body include the intertriginous skin folds, the axillae, the perineum and the vagina. S. aureus/MRSA is most commonly transmitted from patient to patient by unwashed hands. Infected pets and livestock can also transmit the organism.

The CDC has previously reported that invasive (life-threatening) MRSA infections in healthcare settings were declining. Invasive MRSA infections that began in hospitals dropped an estimated 54% between 2005 and 2011. A significant portion was due to the decrease in MRSA bloodstream infections, with rates decreasing by 17.1% each year during that time.

Incubation Period

Variable.

Transmission

Spread through contact transmission. Handwashing greatly decreases transmission within an institution.

Reference

  1. Becton, Dickinson and Company, BD MAX StaphSR Instructions for Use. Sparks, MD, US.
  2. https://www.cdc.gov/mrsa/
  3. Becker, K., R.L. Skov, and C. von Eiff, 2015. Staphylococcus, Micrococcus, and Other Catalase-Positive Cocci. Jorgensen, J.H. Editor in Chief. Manual of Clinical Microbiology, 11th Edition. ASM Press. Washington, D.C.

CPT Codes

87640 and 87641

Contacts

Last Updated

4/15/2021

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