Table I
Oligonucleotide sequences used in this study.
| Primer name | Sequence (5’–3’) | Size of product (bp) | References |
|---|---|---|---|
| KPC-F | ATGTCACTGTATCGCCGTCT | 918 | This study |
| KPC-R | TTACTGCCCGTTGACGC | ||
| NDM-F | ATGGAATTGCCCAATATTATGC | 813 | This study |
| NDM-R | TCAGCGCAGCTTGTCGG |
Table II
Oligonucleotide sequences used in this study.
| Primer name | Sequence (5’–3’) | Size of product (bp) | References |
|---|---|---|---|
| KPC-F | ATCTCGGAAAAATATCTGACAACAGGCATGACGGTG | 309 | [14] |
| KPC-R | CGGTCGTGTTTCCCTTTAGCCAATCAACAAAACTGCT | ||
| NDM-F | TCGCACCGAATGTCTGGCAGCACACTTCCTAT | 278 | [14] |
| NDM-R | GTTCGACAACGCATTGGCATAAGTCGCAATCC |
Table III
Carbapenemase-resistant spectra of the 58 strains.
| Antimicrobial | S | I | R |
|---|---|---|---|
| Amikacin | 36 | – | 22 |
| Ertapenem | – | – | 58 |
| Imipenem | 1 | – | 57 |
| Meropenem | – | 1 | 57 |
| Cefazolin | – | 1 | 57 |
| Ceftazidime and avibactam | 20 | – | 38 |
| Cefepime | – | – | 58 |
| Aztreonam | 12 | – | 46 |
| Amoxicillin and clavulanate potassium | – | 1 | 57 |
| Polymyxin | 57 | – | 1 |
| Levofloxacin | 2 | 9 | 47 |
| Tigecycline | 50 | 1 | 7 |
Fig. 1.
Apb/EDTA method for the detection of carbapenemase
Fig. 2.
A) Electrophoretic bands showed positive KPC; B) electrophoretic bands showed positive NDM
Fig. 3.
NG-test Carba 5 demonstration of carbapenemase detection.
Table IV
Xpert Carba-R assay results by target carbapenemase genes.
| Xpert Carba-R assay results | Specimens (n = 58) |
|---|---|
| KPC | 29 |
| IMP | 0 |
| NDM | 29 |
| OXA-48 | 0 |
| VIM | 0 |
Fig. 4.
A represents the fluorescence diagram of DETECTR for pre-experimental detection of KPC gene NDM gene amplification, and B represents the partial fluorescence display diagram of carbapenemase detection with DETECTR.
Fig. 5.
Characterization of five carbapenemase methods for detecting specimen No. 36.
A) mAPB/EDTA method (panel A) ertapenem (10 mg), 6 mm; (panel B) ertapenem plus APB (300 mg), 6 mm; (panel C) ertapenem plus EDTA (292 mg), ≥ 11 mm; (panel D) ertapenem plus APB and EDTA, ≥ 11 mm; judged as carbapenemase category B positive. B) PCR: NDM negative. C) NG-test Carba 5: NDM negative. D) GeneXpert Carba-R: NDM positive. E) DETECTR: NDM positive.
Table V
Results of carbapenemase detection using five assays.
| No. | WGS | APB/EDTA | NG-test Carba 5 | PCR | DETECTR | geneXpert |
|---|---|---|---|---|---|---|
| 1–7381-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 2–7592-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 3–4619-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 4–7135-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 5–7056-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 6–4375-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 7–6553-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 8–8247-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 9-8046-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 10-9261-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 11-4963-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 12-6310-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 13-7353-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 14-4530-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 15-4658-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 16-6441-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 17-7984-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 18-8961-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 19-7862-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 20-8024-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 21-7926-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 22-4420-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 23-8986-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 24-9990-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 25-7005-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 26-7615-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 27-4480-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 28-9899-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 29-4650-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 30-7972-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 31-6993-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 32-4610-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 33-7985-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 34-7407-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 35-4812-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 36-7467-kp | NDM-1 | category B | Not detected | Not detected | NDM | NDM |
| 37-7973-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 38-6887-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 39-6186-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 40-9059-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 41-7519-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 42-8918-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 43-9777-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 44-6434-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 45-6440-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 46-7820-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 47-6071-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 48-6322-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 49-4865-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 50-8052-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 51-4906-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 52-7979-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 53-4669-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 54-4947-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 55-7052-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 56-10015-kp | NDM-1 | category B | NDM | NDM | NDM | NDM |
| 57-4919-kp | KPC-2 | category A | KPC | KPC | KPC | KPC |
| 58-7380-E. coli | NDM-1 | category B | NDM | NDM | NDM | NDM |