TABLE 2.
MICs of antibiotics against 11 colistin-resistant E. coli strainsa
| Strain | MIC (mg/liter) |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CFZ | AMP | TZP | CRO | CAZ | FEP | IMP | GEM | AMK | LVX | CIP | SXTb | |
| TSAREC01 | 8 | >32 | <4 | <1 | <1 | <1 | <0.25 | <1 | <2 | <0.12 | <0.25 | <20 |
| TSAREC02 | 32 | >32 | 16 | <1 | <1 | <1 | <0.25 | >16 | <2 | 1 | 1 | >320 |
| TSAREC03 | <4 | >32 | <4 | <1 | <1 | <1 | <0.25 | >16 | <2 | 0.5 | <0.25 | <20 |
| TSAREC04 | <4 | <2 | <4 | <1 | <1 | <1 | <0.25 | <1 | <2 | >8 | >4 | <20 |
| TSAREC05 | >64 | >32 | 32 | 16 | 16 | <1 | <0.25 | >16 | 4 | >8 | >4 | >320 |
| TSAREC06 | <4 | 4 | <4 | <1 | <1 | <1 | <0.25 | <1 | <2 | >8 | >4 | <20 |
| TSAREC07 | >64 | >32 | <4 | >64 | 16 | 4 | <0.25 | <1 | <2 | 1 | 1 | >320 |
| TSAREC08 | >64 | >32 | 16 | >64 | >64 | 4 | 1 | <1 | <2 | >8 | >4 | >320 |
| TSAREC10 | <4 | >32 | <4 | <1 | <1 | <1 | <0.25 | >16 | <2 | >8 | >4 | <20 |
| TSAREC37 | >64 | >32 | 64 | >64 | 2 | 2 | <0.25 | >16 | <2 | >8 | >4 | <20 |
| TSAREC41 | <4 | <2 | <4 | <1 | <1 | <1 | <0.25 | <1 | <2 | 0.5 | <0.25 | <20 |
a
CFZ, cefazolin; AMP, ampicillin; TZP, piperacillin-tazobactam; CRO, ceftriaxone; CAZ, ceftazidime; FEP, cefepime; IMP, imipenem-cilastatin; GEM, gentamicin; AMK, amikacin; LVX, levofloxacin; CIP, ciprofloxacin; SXT, trimethoprim-sulfamethoxazole.
b
SXT MICs are reported as the sum of trimethoprim and sulfamethoxazole MICs, which are present in a ratio of 1:19, according to the Vitek 2 automated system. The SXT resistance breakpoint in this system is >80 mg/liter.