9.2.1 Carbapenemases in Enterobacterales

Confirmation of carbapenemase in Enterobacterales can be done by several methods in basic laboratories:

• Biochemical (colorimetric) tests, for example the CarbaNP^TM test which detects the hydrolysis of carbapenem, thus confirming the presence of a carbapenemase enzyme
• Immunochromatographic tests to detect specific carbapenemases. Lateral flow tests are now becoming more readily available and are practical to use in most laboratories (Figure 16)
• For laboratories with a suitable commercial, rapid PCR platform, PCR tests for example, Cepheid, Xpert® and Carba-R, are easy to use and can identify several carbapenmases.

Figure 16 Lateral flow test kit for carbapenemases. Note this kit can be used for several different enzymes

Other methods are possible in reference and research laboratories:

• combination disk testing – this follows the same principles as for ESBL and can potentially identify specific carbapenemases. This is more likely to be used in a reference laboratory.
• CIM (Carbapenem Inactivation Method) test and detection of carbapenem hydrolysis via MALDI-TOF are also possible, but at present do not add anything extra in the routine laboratory context.
• genotypic methods.