Test Catalog

Test ID: OXVRP    
OXA-48-like (blaOXA-48-like) and VIM (blaVIM) in Gram-Negative Bacilli, Molecular Detection, PCR

Useful For Suggests clinical disorders or settings where the test may be helpful

Assessing pure isolates of Gram-negative bacilli for mechanism of carbapenem resistance

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

In the United States, Klebsiella pneumoniae carbapenemase (KPC) is the most common carbapenemase, followed by New Delhi metallo-beta-lactamase (NDM). OXA-48-like and VIM carbapenemases predominate in other parts of the globe, but do occur in the United States. The genes blaOXA-48-like and blaVIM encode OXA-48-like and VIM enzyme production, respectively. PCR is a sensitive, specific, and rapid means of identifying these genes. This test detects the genes encoding OXA-48-like (oxacillin-hydrolyzing beta-lactamase) and VIM (Verona integron-encoded metallo-beta-lactamase) types of beta-lactamases in bacterial isolates.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Not applicable

Interpretation Provides information to assist in interpretation of the test results

This PCR detects and differentiates blaOXA-48-like and blaVIM. A positive blaOXA-48-like (oxacillin-hydrolyzing beta-lactamase) PCR indicates that the isolate carries blaOXA-48-like. A positive VIM (Verona integron-encoded metallo-beta-lactamase) PCR indicates the isolate carries blaVIM. A negative result indicates the absence of detectable DNA.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

False-negative results may occur due to inhibition of PCR, sequence variability underlying primers and probes, or the presence of the blaOXA-48-like or blaVIM genes in quantities lower than the limit of detection of the assay.

Supportive Data

The assay was validated using 46 Gram-negative bacilli, including 30 carbapenemase-producers (26 OXA/VIM-type, 1 NMC/IMI, 1 NDM-1, and 2 KPC) and 2 Gram-positive organisms. The assay provided 100% sensitivity and specificity for both targets.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Fernandez J, Cunningham SA, Fernandez-Verdugo A, et al: Evaluation of a real-time PCR assay for rectal screening of OXA-48-producing Enterobacteriaceae in a general intensive care unit of an endemic hospital. Diagnostic Microbiology and Infectious Disease 2017 July;88(3):252-258 doi.org/10.1016/j.diagmicrobio.2017.04.001

2. Bush K, Fisher JF: Epidemiological expansion, structural studies, and clinical challenges of new beta-lactamases from gram-negative bacteria. Annual Review of Microbiology 2011;65:455-478

3. Poirel L, Potron A, Nordmann P: OXA-48-like carbapenemases: the phantom menace. Journal of Antimicrobial Chemotherapy 2012;67:1597-1606

4. Nordmann P, Naas T, Poirel L: Global spread of carbapenemase-producing Enterobacteriaceae. Emerging Infectious Diseases 2011;17:1791-1798

Special Instructions Library of PDFs including pertinent information and forms related to the test