Abstract
Background: Rapid detection of carbapenemase-producing Enterobacterales (CPE) is desirable to guide antimicrobial therapy and infection control. The NG-Test Carba5 (Carba5; NG Biotech, France) rapid multiplex lateral flow immunoassay and BD MAX Check-Points CPO Assay (CPO; BD Diagnostic Systems, USA) fully automated real-time PCR assay were evaluated for the detection of KPC, NDM, VIM, IMP, and OXA-48-like group in a culture colony compared to genotyping using conventional PCR.Methods: Among the clinical isolates of carbapenem-resistant Enterobacterales (CRE) collected from 2013 to 2019, up to 20 isolates for each carbapenemase type, and approximately 60 carbapenemase-negative CRE were enrolled. Genotyping of carbapenemases were performed using single-target PCR for KPC, NDM, and OXA-48-like group and the multiplex PCR for VIM, IMP, GIM, SIM, and SPM. All isolates were tested with Carba5 and CPO. The discrepant results were resolved by single-target specific conventional PCR or GeneXpert Carba-R Assay (Carba-R; Cepheid, USA).Results: Of 147 CREs, 82 were CPE (55.8%) including 20 KPC, 22 NDM, 17 VIM, three IMP, and 13 OXA-48-like group, and seven double carbapenemase-positive (three KPC/VIM, two NDM/VIM, one KPC/NDM, and one NDM/OXA-48-like group) isolates. Carba5 and CPO detected all CPE correctly along with two more IMP-producing CPE. The sensitivity and specificity of both kits were equally 100% and 97%. Two false IMP-positives were confirmed IMP-positive with Carba-R and IMP-specific single-target PCR.Conclusion: Carba5 and CPO reliably detect and differentiate five common carbapenemases in cultured colonies. Carba5, faster and simpler, is preferred as a spot test.
Keywords
Carbapenemase Enterobacterales Genotype Immunoassay PCR
Figures & Tables
Table 1. Primer sequences for the carbapenemase genotyping
| Primer target | Sequence (5' to 3') | References |
| KPC | 5'-GGC AGT CGG AGA CAA AAC C-3' | [13] |
| 5'-CCC TCG AGC GCG AGT CTA-3' | ||
| NDM | 5'-ACC GCC TGG ACC GAT GAC CA-3' | [14] |
| 5'-GCC AAA GTT GGG CGC GGT TG-3' | ||
| IMP | 5'-GGA ATA GAG TGG CTT AAT TCT C-3' | [15] |
| 5'-CCA AAC CAC TAC GTT ATC T-3' | ||
| 5′-CAT GGT TTG GTG GTT CTT GT-3′* | [17] | |
| 5′-ATA ATT TGG CGG ACT TTG GC-3′* | ||
| VIM | 5'-GAT GGT GTT TGG TCG CAT A-3' | |
| 5'-CGA ATG CGC AGC ACC AG-3' | [15] | |
| OXA-48 like | 5'-TTG GTG GCA TCG ATT ATC GG-3' | |
| 5'-GAG CAC TTC TTT TGT GAT GGC-3' | [16] |
