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HelpTest Code CRPCR Carbapenem Resistance Genes, Molecular Detection, PCR, Rectal Swab
Ordering Guidance
This test is performed on rectal and perirectal swab specimens from patients at risk for intestinal colonization with bacteria not susceptible to carbapenem antimicrobials.
Other mechanisms of carbapenem resistance, including carbapenemases not targeted by this assay, porin mutations, and hyperexpression of drug efflux pumps, may result in carbapenem resistance. These mechanisms are not detected by this assay.
Specimen Required
Specimen Type: Rectal/perirectal swab
Supplies: Culturette (BBL Culture Swab) (T092)
Container/Tube: Culture transport swab
Specimen Volume: Entire collection
Useful For
Detecting and differentiating the blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP gene sequences associated with carbapenem intermediate or resistant results
Aiding in infection control in the detection of gastrointestinal colonization of patients in healthcare settings with bacteria not susceptible to carbapenems using rectal or perirectal swabs
Method Name
Real-Time Polymerase Chain Reaction (RT-PCR)
Reporting Name
Carbapenem Resistance Genes, PCRSpecimen Type
SwabSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Swab | Ambient | 5 days |
Reject Due To
| Gross lipemia | Reject |
| Incorrect swab used | Reject |
Clinical Information
The global spread of carbapenemase-producing Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter species (organisms not susceptible to carbapenem antimicrobials) is a critical public health issue. These bacteria are often resistant to all beta-lactam agents and, frequently, are also resistant to multiple classes of other antimicrobial agents leaving very few treatment options. Tracing the spread of organisms not susceptible to carbapenems is complicated by the diversity of carbapenem-hydrolyzing enzymes that have emerged and the ability of the genes to spread among multiple bacterial species.
Reference Values
Not detected
Interpretation
A detected result is when blaKPC, blaNDM, blaVIM, blaOXA-48, or blaIMP target DNA is detected. This indicates the presence of gene sequences associated with carbapenem intermediate or resistant results.
A not detected result is when blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP target DNA is not detected.
A not detected Xpert Carba-R Assay result does not preclude the presence of other carbapenem resistance mechanisms.
Cautions
The Xpert Carba-R Assay detects blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP from rectal and perirectal specimens and is not for bacterial identification. Detection of these gene sequences does not indicate the presence of viable organisms.
The Xpert Carba-R Assay is not a genetic-relatedness subtyping tool and does not report variants of the blaKPC, blaNDM, blaVIM, blaOXA-48, or blaIMP genes.
Imipenemase-type metallo-beta-lactamase (IMP) types detected by this assay include only IMP-1, 2, 4, 6, 10, and 11.
Rectal and perirectal specimens from pediatric patients have not been evaluated.
Certain bacterial species, such as Pseudomonas aeruginosa and Acinetobacter baumannii, have been shown to exhibit resistance to the carbapenem antimicrobial ertapenem due to intrinsic resistance mechanisms.
The detection of OXA-carbapenemase genes, besides blaOXA-48 and blaOXA-181, has not been evaluated with this assay.
Variants or alterations in primer or probe binding regions may affect detection of current, new, or unknown blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP variants, resulting in a false-negative result.
Testing with the Xpert Carba-R assay should be used as an adjunct to other available methods.
Cocolonization with 2 or more carbapenemase-producing organisms has been reported with the Xpert Carba-R Assay, but it is rare.
Carbapenem-resistant anaerobes potentially present in fecal specimens have not been evaluated by the Xpert Carba-R assay.
Supportive Data
The Xpert Carba-R Assay is a US Food and Drug Administration-cleared test. The Xpert Carba-R was further verified for use with a Zeptometrix verification panel and organisms (Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter bacteria) with known carbapenem antimicrobial susceptibility test results. The verification passed, and this test is acceptable for patient testing.
Clinical Reference
1. McConville TH, Sullivan SB, Gomez-Simmonds A, Whittier S, Uhlemann AC. Carbapenem-resistant Enterobacteriaceae colonization (CRE) and subsequent risk of infection and 90-day mortality in critically ill patients, an observational study. PLoS One. 2017;12(10):e0186195
2. Tenover FC, Nicolau DP, Gill CM. Carbapenemase-producing Pseudomonas aeruginosa an emerging challenge. Emerg Microbes Infect. 2022;11(1):811-814
3. Clinical and Laboratory Standards Institute (CLSI). Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically. 11th ed. CLSI standard M07. CLSI; 2018
Method Description
The GeneXpert Dx System automates and integrates sample purification, nucleic acid amplification, and detection of the target sequence in simple or complex specimens using a real-time polymerase chain reaction (PCR) assay. The system requires the use of single-use disposable cartridges that hold the PCR reagents and host the PCR process. Because the cartridges are self-contained, cross-contamination between samples is eliminated. The primers and probes in the Xpert Carba-R Assay detect proprietary sequences for the blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP gene sequences associated with carbapenem intermediate or resistant results in gram-negative bacteria.(Package insert: Xpert Carba-R. Cepheid; 01/2018)
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 daySpecimen Retention Time
5 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
87798
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CRPCR | Carbapenem Resistance Genes, PCR | 85502-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| IMPCR | IMP Resistance Gene | 85498-4 |
| VIMCR | VIM Resistance Gene | 85501-5 |
| NDMCR | NDM Resistance Gene | 73982-1 |
| KPPCR | KPC Resistance Gene | 49617-4 |
| OXACR | OXA-48-like Resistance Gene | 85503-1 |
NY State Approved
YesForms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.