Table 2. Strain source, susceptibility to commonly used antibiotics and mcr-1 expression levels of mcr-1-positive isolates.
| Bacterial | Year | provinces | specimen | MLST | Serotype | mcr-1- plasmid | blaNDM- plasmid | MIC (mg/L) | ΔΔCt expression** (average ± StdDev) |
||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IPM | MEM | ETP | CMZ | CAZ | CTX | TZP | SCF | CAV | FEP | PE | TGC | CIP | AK | ATM | |||||||||
| 1 April 2014–20 February | |||||||||||||||||||||||
| TJ-2 | 2015 | Tianjin | sputum | 167 | O89:H9 | IncX4 | Na* | 32 | 64 | 128 | >128 | >128 | >128 | >256/4 | >256/4 | >64/4 | >64 | ≤0.5 | ≤0.25 | >32 | >128 | 32 | 2.279 ± 0.547 |
| GD133 | 2015 | Guangdong | blood | 10 | O89:H10 | IncHI2 | IncX3 | 16 | 16 | 32 | 16 | >128 | >128 | 256/4 | 256/4 | >64/4 | 64 | 1 | ≤0.25 | 32 | ≤4 | 16 | 227.873 ± 41.474 |
| GD119 | 2015 | Guangdong | sputum | 10 | O89:H10 | IncHI2 | IncX3 | 16 | 64 | 64 | >128 | >128 | >128 | >256/4 | >256/4 | >64/4 | >64 | ≤0.5 | ≤0.25 | >32 | ≤4 | >128 | 289.955 ± 55.608 |
| SC-6 | 2015 | Sichuan | sputum | 167 | O89:H9 | IncX4 | IncX3 | 32 | 128 | 128 | >128 | >128 | >128 | >256/4 | >256/4 | >64/4 | >64 | 2 | ≤0.25 | 32 | ≤4 | 16 | 107.323 ± 17.276 |
| C34 | 2015 | Zhejiang | Secretion | 5229 | O177:H51 | IncX4 | IncX3 | 32 | 128 | 128 | >128 | >128 | >128 | >256/4 | >256/4 | >64/4 | >64 | ≤0.5 | ≤0.25 | >32 | >128 | >128 | Na. * |
| 21 February 2017–30 April 2019 | |||||||||||||||||||||||
| TJ-71 | 2017 | Tianjin | Drainage | 617 | O89:H9 | IncI2 | IncFII | 8 | 32 | 64 | >128 | >128 | >128 | >256/4 | >256/4 | >64/4 | >64 | 2 | ≤0.25 | 32 | >128 | >128 | 107.539 ± 19.591 |
| 363 | 2017 | Zhejiang | sputum | 4380 | O116:H9 | IncHI2A/HI2 | Na* | 16 | 32 | 32 | 64 | >128 | >128 | 256/4 | >256/4 | >64/4 | 64 | 2 | ≤0.25 | 32 | ≤4 | ≤4 | 133.119 ± 15.133 |
| 404 | 2017 | Zhejiang | sputum | 23 | O78:H9 | IncHI2 | IncX3 | 8 | 16 | 32 | 16 | >128 | >128 | >256/4 | 256/4 | >64/4 | 64 | 2 | ≤0.25 | ≤1 | ≤4 | ≤4 | 448.233 ± 116.063 |
| 34 | 2017 | Zhejiang | sputum | 10 | O60:H12 | IncX4 | IncX4 | 8 | 16 | 32 | 16 | >128 | >128 | 128/4 | 256/4 | >64/4 | 64 | 2 | ≤0.25 | ≤1 | ≤4 | ≤4 | 522.624 ± 84.262 |
| 76 | 2017 | Zhejiang | Pus | 2179 | O9:H9 | IncHI2 | IncX3 | 16 | 32 | 32 | 8 | >128 | >128 | 128/4 | 256/4 | >64/4 | 32 | 2 | ≤0.25 | 16 | ≤4 | ≤4 | 246.972 ± 39.069 |
| 182 | 2017 | Zhejiang | Throat swab | 189 | O37:H21 | IncY | IncX3 | 8 | 16 | 32 | 32 | >128 | >128 | 128/4 | 256/4 | >64/4 | 64 | 2 | ≤0.25 | 16 | ≤4 | ≤4 | 107.892 ± 21.309 |
| 362–1 | 2017 | Zhejiang | blood | 4380 | O116:H9 | IncHI2A/HI2 | Na* | 8 | 8 | 16 | 128 | >128 | >128 | 128/4 | 128/4 | >64/4 | 16 | 2 | ≤0.25 | ≤1 | ≤4 | 32 | 189.66 ± 43.697 |
| shaw79 | 2019 | Zhejiang | sputum | 617 | O89:H9 | IncI2 | IncFII | 8 | 16 | 64 | >128 | >128 | >128 | >256/4 | >256/4 | >64/4 | >64 | 2 | ≤0.25 | >32 | ≤4 | ≤4 | 194.778 ± 43.785 |
| sz16 | 2019 | Zhejiang | blood | 297 | Ounknown:H9 | IncI2 | IncFII | 8 | 32 | 32 | >128 | >128 | >128 | >256/4 | >256/4 | >64/4 | >64 | 2 | ≤0.25 | 8 | ≤4 | >128 | 190.368 ± 35.552 |
IMP, imipenem; MEM, meropenem; ETP, ertapenem; CMZ, cefmetazole; CAZ, ceftazidime; CTX, cefotaxime; TZP, piperacillin/tazobactam; SCF, cefoperazone/sulbactam; CAV, ceftazidime/avibactam; FEP, cefepime; PE, polymyxin E; TGC, tigecycline; CIP, ciprofloxacin; AK, amikacin; ATM, aztreonam.
*Na, not applicable; **ΔΔCt here was used to describe the relative mcr-1 gene expression levels in the strains.