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Carbapenemase (CPE) Screening

Carbapenemase (CPE) Screening

Code:
CARB

Sample Type:

Rectal swab with visible stool present

Send to laboratory as quickly as possible. If delays likely, refrigerate at 2 to 8 °C

Ref Ranges/Units:

N/A

Turnaround:

1-2 days

Special Precautions/Comments:

Interferences: Excess (heavily soiled) stool sample on the rectal swab may invalidate PCR testing.

Method: Culture on selective media. Isolates will be identified using MALDI-ToF. Significant isolates may undergo further testing, this includes further selective culture, antibiotic susceptibility and PCR testing. Calibration: N/A (culture). Cepheid (PCR). EQA scheme: QCMD and NEQAS EQA schemes. IQC: Media batch accepted using culture collections K. pneumoniae NCTC 13442. Third party control (PCR).

Interpretation: Negative cultures and isolates identified as Non-Enterobacterales will be reported as CPE not isolated by culture. Isolates identified as Enterobacterales will subject to further testing. Final results will be based on both antibiotic susceptibility and real-time polymerase chain reaction (PCR) results. PCR results will only be reported if positive, and where possible the detected CPE type will also be reported (KPC, NDM, IMP-1, VIM or OXA-48).

Additional Information:

Background: The term ‘carbapenemase’, refers to a β-lactamase enzyme that can hydrolyse carbapenem antibiotics. Many acquired carbapenemases enzyme are plasmid-mediated (especially when found in Enterobacterales) which can easily spread to other strains genera and species of organisms. This poses as a major infection control risk within a hospital setting. Rarely, Pseudomonas and Acinetobacter species can also have acquired carbapenemases.

There are many different types of carbapenemase enzymes, and there are many variants within those. The ‘big 5’ carbapemases are KPC, VIM, IMP, NDM and OXA-48-like. These are most commonly seen in the UK.

Both Gateshead and South Tyneside and Sunderland NHSFT have separate infection control policies designed to promptly identify and contain cases of CPE in the two trusts. Both policies are based on the national ‘Framework of actions to contain CPE’ published by PHE in 2020. At risk patents identified in the national framework document will undergo CPE screening upon admission.