TABLE 1.
Primary characteristics of E. coli strains used for this study
| Strain | ST determined by MLSTb | Day after initial patient hospitalization | Sourcec | Presence of mcr-1d | MIC (μg/ml)a |
|||
|---|---|---|---|---|---|---|---|---|
| CST | CIP | LVX | NIT | |||||
| MRSN 352231 | 617 | 1 | Perirectal | + | 4 | >2 | >4 | 32 |
| MRSN 346355 | 617 | 6 | Groin | + | 4 | >2 | >4 | 32 |
| MRSN 346595 | 617 | 26 | Groin | + | 4 | >2 | >4 | 32 |
| MRSN 346647 | 32 | 26 | Groin | − | ≤0.5 | 1 | ≤1 | ≤16 |
| MRSN 346638 | 617 | 30 | Perirectal | + | 4 | >2 | >4 | 32 |
| MRSN 346629 | 32 | 30 | Perirectal | − | ≤0.5 | 1 | ≤1 | ≤16 |
| MRSN 418111 | 32 | 258 | Perirectal | − | ≤0.5 | 1 | ≤1 | ≤16 |
| MRSN 418944 | 32 | 291 | Perirectal | − | ≤0.5 | 1 | ≤1 | ≤16 |
Abbreviations: CST, colistin; CIP, ciprofloxacin; LVX, levofloxacin; NIT, nitrofurantoin. All isolates were resistant to amoxicillin-clavulanic acid, aztreonam, cefepime, ceftazidime, ertapenem, imipenem, tetracycline, and trimethoprim-sulfamethoxazole. All isolates were sensitive to the aminoglycosides amikacin, gentamicin, and tobramycin. Differences in antibiotic susceptibilities in the ST-32 isolates compared to the ST-617 isolates are highlighted in bold.
In silico multilocus sequence type based on the MLST scheme developed by the University of Warwick, United Kingdom (http://mlst.warwick.ac.uk/mlst/dbs/Ecoli).
Clinical sites where surveillance swabs were used to culture the isolate.
Presence (+) or absence (−) of mcr-1, based on real-time PCR and confirmed by sequencing.