Table 1.
Susceptibilities of E. coli strains to bis-benzimidazoles
| DCA |
DFA |
DMA |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| Strain description | MIC (μM)/mg/L) | PAE (h) | MBC (μM) | MIC (μM)/mg/L) | PAE (h) | MBC (μM) | MIC (μM)/mg/L) | PAE (h) | MBC (μM) |
| E. coli DH5α | 8.0 ± 0.017/3.8 | 22.2 ± 1.8 | 16.0 | 4.0 ± 0.007/1.78 | 23.6 ± 0.4 | 8.0 | 8.0 ± 0.012/3.74 | 20.8 ± 1.1 | 16.0 |
| E. coli BL21 | 16.0 ± 0.072/7.6 | 21.9 ± 2.1 | 32.0 | 8.0 ± 0.013/3.55 | 22.0 ± 2.0 | 16.0 | 16.0 ± 0.032/7.49 | 23.8 ± 0.2 | 32.0 |
| ATCC 25922 | 32.0 ± 0.066/15.2 | 24 ± 0.1 | 64.0 | 32.0 ± 0.031/14.21 | 21.2 ± 2.8 | 64.0 | 32 ± 0.054/14.98 | 22.3 ± 1.3 | 64.0 |
| E. coli 72R | ND | ND | ND | 32.0 ± 0.057/14.21 | ND | 64.0 | 8.0 ± 0.011/3.74 | ND | 16.0 |
| E. coli 118R | 32.0 ± 0.057/15.2 | >24 ± 0.2 | 64.0 | 32.0 ± 0.044/14.21 | >24 ± 0.1 | 64.0 | 8.0 ± 0.042/3.74 | 24 ± 0.9 | 16.0 |
| E. coli 85R | 64.0 ± 0.055/30.4 | ND | 128.0 | 32.0 ± 0.039/14.21 | 24 ± 0.2 | 64.0 | 8.0 ± 0.015/3.74 | 24 ± 0.7 | 16.0 |
| E. coli 360R | 8.0 ± 0.028/3.8 | 20.8 ± 1.3 | 16.0 | 8.0 ± 0.029/3.55 | 2.3 ± 0.6 | 16.0 | 8.0 ± 0.023/3.74 | 24 ± 0.1 | 16.0 |
| E. coli 451R | 128 ± 0.090/60.8 | ND | ND | 64.0 ± 0.077/28.43 | ND | 128.0 | 8.0 ± 0.003/3.74 | 22 ± 0.5 | 16.0 |
| E. coli 59R | 64.0 ± 0.064/30.4 | ND | 128.0 | 16.0 ± 0.054/7.1 | 22.2 ± 1.6 | 32.0 | 16.0 ± 0.072/7.49 | 1.6 ± 0.1 | 32.0 |
| E. coli 81R | 64.0 ± 0.069/30.4 | ND | 128.0 | 32.0 ± 0.030/14.21 | 20.3 ± 1.1 | 64.0 | 16.0 ± 0.031/7.49 | 23.6 ± 0.6 | 32.0 |
| E. coli 132R | 32.0 ± 0.042/15.2 | 10 ± 1.3 | 64.0 | 32.0 ± 0.047/14.21 | 0.9 ± 0.1 | 64.0 | 16.0 ± 0.046/7.49 | >24 ± 0.1 | 32.0 |
| E. coli 151R | 32.0 ± 0.037/15.2 | >24 ± 0.1 | 64.0 | 32.0 ± 0.041/14.21 | 15.6 ± 1.4 | 64.0 | 16.0 ± 0.033/7.49 | 21.6 ± 0.4 | 32.0 |
| E. coli 401R | 32.0 ± 0.029/15.2 | >24 ± 0.5 | 64.0 | 128.0 ± 0.063/56.86 | ND | ND | 32.0 ± 0.023/14.98 | 16 ± 1.5 | 64.0 |
| E. coli 555R | ND | ND | ND | ND | ND | ND | 32.0 ± 0.071/14.98 | 24 ± 2.2 | 64.0 |
AMP, ampicillin; CHL, chloramphenicol; CIP, ciprofloxacin; GEN, gentamicin; KAN, kanamycin; NAL, nalidixic acid; TMP, trimethoprim; TET, tetracycline; ND, not determined.
All the MIC, PAE and MBC experiments were done in triplicate and values shown are averages of three experiments (±SD).
E. coli DH5α, E. coli BL21 and E. coli ATCC 25922 were reference strains for E. coli susceptibility testing.
E. coli 72R, resistant to CIP; E. coli 118R, resistant to AMP, TMP and NAL; E. coli 85R, resistant to CHL, AMP, KAN, TMP, CIP and NAL; E. coli 360R, resistant to GEN, KAN, TET and NAL; E. coli 451R, resistant to AMP, TET and GEN; E. coli 59R, resistant to CHL, AMP, TMP, CIP and NAL; E. coli 81R, resistant to AMP, KAN, TMP, TET, CIP and NAL; E. coli 132R, resistant to CHL, AMP, KAN, TMP, CIP and NAL; E. coli 151R, resistant to CHL, AMP, KAN, TMP, CIP and NAL; E. coli 401R, resistant to AMP, CHL, CIP, GEN and TET; E. coli 555R, resistant to AMP, CIP, GEN and TET.