Lab Test

Culture, Staph. aureus

Cardiovascular Service Staphylococcus aureus Culture, CVS Culture, Orthopaedic Surgery S. aureus Culture, Neurosurgical S. aureus Culture

Test Codes

EPIC: LAB5501

Instructions

  • This test is used for preoperative specimens for Cardiovascular Services, Orthopaedic Surgery, and Neurosurgery.
  • For suspected cases of Staph. aureus sinusitis, order Culture, Respiratory.
  • For MRSA screening related to isolation protocols, see Staphylococcus aureus/MRSA by PCR, Nares (LAB3666).
  • Specimens must be obtained before starting nasal antibiotic therapy.

Specimen Collection Criteria

Collect: Using an ESwab, swab both anterior nares using a swirling circular motion with the same sterile swab (use only one swab).

  • It is only necessary to enter the nares approximately 1/4 inch to obtain the specimen.
  • 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 (20-25°C or 68-77°F) prior to transport.

Preparation for Courier Transport

Transport: ESwab 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).
  • Dry swabs or 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 Pointe, and Troy sent to Royal Oak Microbiology Laboratory for testing.

Performed

Sunday – Saturday, 24 hours a day.
Final negative results available within 48 hours. Final positive results may take up to four days.

Reference Range

No Staph. aureus recovered.

Test Methodology

Bacterial Culture, Antimicrobial Susceptibility Testing to determine MRSA.

Clinical Utility

Approximately 25% to 30% of people have S. aureus in their nares but less than 2% have MRSA. Persons with MRSA in their nares have a high risk of having the same bacteria in a wound following surgery. If healthcare providers are aware of the presence of MRSA, appropriate antibacterial agents can be prescribed to prevent infection of the surgical site. Additionally, steps will be taken to prevent spread within the hospital.

Clinical Disease

Methicillin resistant Staphylococcus aureus (MRSA) are a major concern 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 that is outbreak related.

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.

In 2010, CDC reported that invasive (life-threatening) MRSA infections in healthcare settings were declining. Invasive MRSA infections that began in hospitals declined 28% from 2005 through 2008. Decreases in infection rates were even greater for patients with bloodstream infections. By 2012, rates of MRSA bloodstream infections had decreased by 17.1% each year. Declines in MRSA bloodstream infections slowed from 2013-2016, when no significant change was detected. 

Incubation Period

Variable.

Transmission

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

Reference

  1. http://www.cdc.gov/mrsa.
  2. Becker, S.J. and B., von Eiff, C. 2014. Staphylococcus, Micrococcus and Other Catalase-Positive Cocci. Manual of Clinical Microbiology, 10th ed., p. 308-330. 

CPT Codes

87081
LOINC:  20966-8

Contacts

Last Updated

8/27/2021

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