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Test Code MECPI Methicillin Resistance Gene, Molecular Detection, PCR, Varies

Infectious


Shipping Instructions


1. For shipping information, see Infectious Specimen Shipping Guidelines.

2. Place specimen in a large infectious container and label as an etiologic agent/infectious substance.



Necessary Information


Organism identification and specimen source are required.



Specimen Required


Supplies: Infectious Container, Large (T146)

Container/Tube: Agar slant or other appropriate media

Specimen Volume: Organism in pure culture

Collection Instructions:

1. Perform isolation of bacteria.

2. Organism must be in pure culture, actively growing. Do not submit mixed cultures.


Secondary ID

621419

Useful For

Detecting mecA in staphylococcal bacterial isolates

 

Evaluating treatment options when oxacillin or cefoxitin breakpoints are unavailable (eg, certain Staphylococcus species other than Staphylococcus aureus)

 

Predicting antimicrobial resistance when bacterial growth is inadequate for phenotypic antimicrobial susceptibility testing (eg, staphylococcal small colony variants)

 

Assessing discrepancies amongst cefoxitin and oxacillin phenotypic testing results or penicillin-binding protein 2a test results

Method Name

Real-Time Polymerase Chain Reaction (PCR)/Reverse Transcription PCR (RT-PCR)

Reporting Name

Methicillin Resistance Gene, Varies

Specimen Type

Varies

Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)
  Refrigerated 

Reject Due To

Agar plate
Mixed culture		 Reject

Clinical Information

The presence of mecA has been associated with methicillin resistance in staphylococcal isolates. Rapid identification of mecA in staphylococcal isolates will help in determining which antimicrobial therapy to use when treating infections due to methicillin-resistant Staphylococcus aureus or methicillin-resistant Staphylococcus species other than S aureus.

 

Bacteria can acquire resistance to certain beta-lactam antibiotics through a variety of mechanisms. One such mechanism is the mecA gene. The mecA gene encodes penicillin-binding protein 2a (PBP2a), which has a low affinity for beta-lactam antibiotics. Bacteria expressing this gene can maintain cell wall synthesis even in the presence of beta-lactam antibiotics.

 

Testing of bacterial isolates by molecular methods may be needed when oxacillin or cefoxitin breakpoints are unavailable (eg, certain Staphylococcus species other than S aureus) or when discrepancies exist among cefoxitin and oxacillin phenotypic antimicrobial susceptibility testing results or PBP2a results. Use of this assay may also be helpful when isolates do not grow adequately for phenotypic antimicrobial susceptibility testing (eg, staphylococcal small colony variants).

Reference Values

Not detected

Interpretation

A positive result indicates the presence of the methicillin resistance gene (mecA) in the bacterial isolate.

 

A negative result indicates the absence of detectable DNA in the bacterial isolate.

CPT Code Information

87641

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MECPI Methicillin Resistance Gene, Varies 48813-0

 

Result ID Test Result Name Result LOINC Value
MECPR mecA Resistance Gene 48813-0
MEORG Organism Identified by Client In Process
MESCR Specimen Source 31208-2