Table 1.
Antibiotic susceptibility and the expressions of smeE, smeW, smqnr, and rpoE genes of S. maltophilia isolates.
| MICa (μg/ml) |
RT-qPCRb (fold) |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| FQ |
CHL | TET | Macrolide |
smeE | smeW | smqnr | rpoE | |||
| Isolate | CIP | LEV | ERV | LM | ||||||
| KJ | 1 | 1 | 8 | 16 | 64 | 256 | 1 | 1 | 1 | 1/5.9 ± 1.9c |
| KJΔRseA | 1 | 1 | 8 | 16 | 64 | 256 | 0.9 ± 0.1 | 1.3 ± 0.2 | 1.5 ± 0.1 | 4.5 ± 2.3 |
| KJΔRpoEΔRseA | 1 | 1 | 8 | 16 | 64 | 256 | 1.3 ± 0.3 | 0.8 ± 0.1 | 0.7 ± 0.2 | – – |
| V47 | 16 | 16 | 128 | 16 | 128 | 1024 | 4.9 ± 0.1 | 6.5 ± 1.0 | 5.7 ± 0.0 | 5.5 ± 1.3 |
| V53 | 8 | 16 | 32 | 16 | 512 | 4096 | 69.0 ± 4.0 | 0.5 ± 0.4 | 2.6 ± 0.4 | 2.4 ± 0.5 |
| V56 | 16 | 8 | 64 | 128 | 512 | 2048 | 0.7 ± 0.0 | 18.4 ± 1.4 | 1.9 ± 0.1 | 14 ± 9.5 |
| V61 | 8 | 8 | 32 | 64 | 512 | 4096 | 48.4 ± 2.7 | 0.9 ± 0.0 | 15.7 ± 4.5 | 5.7 ± 0.4 |
| V62 | 8 | 8 | 8 | 128 | 128 | 4096 | 0.7 ± 0.0 | 0.3 ± 0.0 | 0.8 ± 0.0 | 10.5 ± 1.5 |
| V63 | 8 | 8 | 32 | 64 | 512 | 4096 | 67.4 ± 14.1 | 0.6 ± 0.0 | 2.1 ± 0.1 | 2.7 ± 0.2 |
| V78 | 32 | 32 | 64 | 256 | 256 | 2048 | 54.6 ± 8.4 | 0.6 ± 0.1 | 58.9 ± 6.8 | 8.5 ± 1.7 |
| V80 | 8 | 16 | 32 | 64 | 256 | 4096 | 0.6 ± 0.0 | 0.5 ± 0.2 | 0.7 ± 0.0 | 3.9 ± 0.7 |
| V82 | 4 | 8 | 128 | 16 | 256 | 2048 | 21.4 ± 0.8 | 0.6 ± 0.0 | 1.3 ± 0.1 | 0.4 ± 0.1 |
| V84 | 16 | 16 | 32 | 64 | 512 | 4096 | 99.7 ± 18.6 | 0.2 ± 0.0 | 1.8 ± 0.0 | 12.9 ± 2.0 |
| V90 | 8 | 16 | 16 | 32 | 512 | 4096 | 73.7 ± 6.4 | 38.0 ± 0.5 | 4.9 ± 3.1 | 2.1 ± 1.6 |
| V93 | 16 | 32 | 32 | 64 | 512 | 4096 | 92.3 ± 4.1 | 0.6 ± 0.0 | 2.3 ± 0.1 | 0.5 ± 0.1 |
| V95 | 8 | 16 | 64 | 16 | 256 | 2048 | 3.2 ± 0.0 | 4.4 ± 1.6 | 0.3 ± 0.1 | 1.5 ± 0.5 |
| V96 | 32 | 32 | 64 | 256 | 256 | 1024 | 6.1 ± 0.4 | 0.6 ± 0.2 | 4.9 ± 0.6 | 2.8 ± 0.2 |
| V99 | 8 | 16 | 128 | 8 | 256 | 1024 | 0.5 ± 0.0 | 8.6 ± 0.8 | 0.4 ± 0.0 | 5.4 ± 0.9 |
| V101 | 4 | 8 | 64 | 16 | 128 | 1024 | 4.3 ± 1.6 | 0.5 ± 0.1 | 20.2 ± 2.1 | 2.9 ± 1.4 |
| V104 | 8 | 16 | 32 | 64 | 256 | 4096 | 59.3 ± 3.3 | 7.8 ± 1.6 | 4.9 ± 0.0 | 2.1 ± 1.1 |
| V105 | 8 | 16 | 32 | 64 | 256 | 4096 | 0.4 ± 0.0 | 0.7 ± 0.0 | 0.5 ± 0.0 | 3.3 ± 0.3 |
aMIC, minimal inhibitory concentration. bThe transcript levels of smeE, smeW, Smqnr, and rpoE in the clinical isolates were normalized with those in S. maltophilia KJ, a quinolone susceptible strain, cultured at 37°C. All isolates were cultured at 37°C, except KJ cells, which were cultured at 37 and 42°C. cThe relative rpoE transcript of KJ cells at 37 and 42°C. FQ, fluoroquinolone; CIP, ciprofloxacin; LEV, levofloxacin; ERY, erythromycin; LM, leucomycin; CHL, chloramphenicol; TET, tetracycline.