Laboratory: Clinical Microbiology
Test Name:
METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA), CULTURE, AEROBIC BACTERIA, SURVEILLANCE, NASAL SWAB/WOUND SWAB - (SWAB)
Test Code: MRSA
Clinical Information:
Test Indications:
To determine if a patient is colonized with methicillin-resistant Staphylococcus aureus (MRSA).
MRSA are strains that are resistant to methicillin, oxacillin, cloxacillin and all other ß-lactam antibiotics.  Infections caused by MRSA are not inherently more serious than infections caused by methicillin-sensitive S. aureus (MSSA), but treatment options for the management of serious MRSA infections are limited.
Screening for MRSA is done using a culture-based test.

Recommendations:
1.  For MRSA screening criteria please refer to the Winnipeg Regional Health Authority - Acute Care Infection Prevention & Control Manual and/or Manitoba Health, Seniors and Active Living - Guidelines for the Prevention and Control of Antimicrobial-Resistant Organisms.
2.  The site, e.g., nose or site of wound, must be specified.
3.  Patients should be off effective antibiotics for 48 hours prior to collection to reduce the chance of a false-negative result.
4.  Accurate patient identification must be made prior to sample collection.
Sample and requisitions must be labeled/completed in accordance with the Shared Health Specimen Acceptance Policy.

Patient Preparation Instructions:
Not applicable.
Collection Devices:
Preferred Device:
Nasal swab:
1.  Insert swab, pre-moistened with sterile physiologic saline, approximately 2 cm into the nares.
2.  Rotate the swab against the nasal mucosa.  Note: Both nares should be sampled using the same swab.
Wound swab:
1.  If wound swab is dry, moisten a swab with sterile physiologic saline and collect the sample.
2.  Collect surveillance cultures BEFORE cleansing.
Specimen Required: Nasal swab, Wound swab (indicate site) (Adult and Pediatric)
The site, e.g., nose or site of wound, must be specified.
Referral:
Requisition:
Reference Values:
Negative for MRSA.
For positive samples, a descriptive report will be provided.
Availability:
Daily
See Also:
More Information:
Specimen Handling:
Store at room temperature ≤24 hours.
Specimen must be delivered to the laboratory as soon as possible and ideally within 24 hours of collection.  Specimens received beyond 48 hours of collection will be processed but results may be compromised because of the prolonged transit time (a comment to this effect will be added to all negative reports).