CPE tests in the clinical microbiology laboratory
| Category | Method | Explanation | Strengths |
Time required |
|---|---|---|---|---|
| Phenotypic | MHT | Measuring carbapenem disk activity in the presence or absence of carbapenemase | ○ No need for a special reagent and medium ● Requires overnight incubation ● Difficult to detect certain carbapenemase types ● Decreased objectivity in results interpretation |
18-24 h |
| mCIM with/without eCIM | Measuring carbapenem disk activity in the presence or absence of carbapenemase and its inhibitor | ○ No need for a special reagent and medium ● Requires additional incubated steps (broth culture with carbapenem disk) and overnight incubation |
≥4 h + 18-24 h |
|
| Chromogenic agar | Incubation in a selective medium supplemented with antibiotics and chromogenics | ○ Easy to perform ● Requires overnight incubation ● Relatively low selectivity to detect carbapenemase-producing organisms |
18-24 h | |
| Carba NP | Using pH color indicators to determine carbapenem hydrolysis | ○ Rapid ● Requires special reagents or kits ● Difficult to detect certain carbapenemase types |
30 min-2 h | |
| Immunoassay | Using antigen-antibody reaction for detecting enzyme carbapenemase | ○ Rapid ● Requires special kits ● Detects only the carbapenemase type included in the kit |
15 min | |
| Mass spectrometry | Detecting carbapenem and/or carbapenem degradation products | ○ Rapid ● Requires special equipment ● No established method yet |
≥2 h (var)+10 min | |
| Molecular | PCR Microarray Sequencing |
Detecting nucleic acid (genetic material) encoding carbapenemase | ○ High sensitivity ○ Possible to use direct specimens such as rectal swabs ● Requires special technicians, equipment, and kits ● Commercial kit: easy to use, but detects only carbapenemase type included in the kit |
1 h-days |
*○, Strength. †●, limitation.
Abbreviations: MHT, modified Hodge test; mCIM, modified carbapenem inactivation method; eCIM, EDTA-modified carbapenem inactivation method; var, variable.
Korean J healthc assoc Infect Control Prev 2023;28:42~49 https://doi.org/10.14192/kjicp.2023.28.1.42
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