Table 3.
Characteristics of E. coli strains used in the study.
| Strain | Specimen | Sero- group |
Phylo- genetic group |
MLST | MICa(μg/mL) | Growth on M9 agar supplemented with: |
uhpT expression induced by G6Pb | Amino acid residue alternations in proteins encoded by glpT, ptsI, cyaA, murA, uhpA, and uhpT genesc | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| G6P − | G6P + | G6P+ cAMP+ |
G3P | G6P | cyaA | glpT | murA | ptsI | uhpA | uhpT | ||||||
| SRE257 | Urine | O1 | B2 | 95 | 1024 | 1024 | 1024 | + | − | 1.24 | — | — | — | Val399Leu | 163~188 deletion | — |
| SRE91 | Aspiration tube | O1 | D | 648 | 128 | 128 | 32 | − | − | 3.78 | — | 155~158 deletion Phe176Leu |
— | — | Thr3Ala | — |
| SRE49 | Urine | O25b:H4 | B2 | 131 | 128 | 128 | 128 | + | − | NT | His716Leu | — | — | Lys410Arg | ND | ND |
| SRE54 | Urine | O25b:H4 | B2 | 131 | 64 | 64 | 64 | + | − | 1.59 | His716Leu | — | — | Ala443Thr Gly452Asp |
— | — |
| SRE237 | Urine | O25b:H4 | B2 | 131 | 64 | 64 | 64 | + | − | 1.59 | His716Leu | — | — | — | — | — |
| SRE29 | Urine | O25b:H4 | B2 | 131 | 32 | 32 | 32 | + | + | 1226.22 | — | — | — | — | — | — |
| SRE252 | Urine | O25a | D | 73 | 32 | 32 | 4 | − | − | 3.68 | ND | Ile171Thr | — | Lys145Asn | — | — |
| SRE280 | Ascites | O12 | D | 1486 | 32 | 32 | 32 | + | − | 0.56 | Ser142Asn | — | — | — | — | — |
| SRE18 | Urine | ND | D | 405 | 16 | 16 | 16 | + | − | 2.22 | — | — | — | — | Met1Ile | — |
| SRE253 | Urine | O18 | B2 | 95 | 8 | 8 | 8 | − | − | 198.09 | His716Leu | — | — | — | — | — |
| SRE40 | Decubitus | O25a | D | 501 | 32 | 0.5 | NT | + | + | 284.05 | ||||||
| SRE41 | Catheter urine | O1 | D | 648 | 8 | 0.5 | NT | + | + | 328.56 | ||||||
| SRE110 | Catheter urine | O25b:H4 | B2 | 131 | 8 | 0.5 | NT | + | + | 190.02 | ||||||
| SRE205 | Urine | ND | A | 131 | 8 | 0.5 | NT | + | + | 734.19 | ||||||
| SRE227 | Pus | O1 | B2 | 95 | 8 | 0.5 | NT | + | + | 247.28 | ||||||
| SRE30 | Urine | O1 | D | 648 | 8 | 0.25 | NT | + | + | 719.08 | ||||||
| ATCC 25922 | NT | NT | 32 | 0.5 | NT | + | + | 308.69 | ||||||||
aFOM MICs were determined in the presence (+) or absence (−) of glucose-6-phosphate (G6P) and/or cAMP.
b E. coli cells were incubated in M9 minimum salt solution in the presence or absence of G6P. The uhpT mRNA levels were determined by real-time RT-PCR, and the data were normalized to rpoD mRNA levels. Induction of uhpT expression by G6P was calculated by dividing the uhpT mRNA level in the presence of G6P by the uhpT mRNA level in the absence of G6P.
cAmino acid mutations found only in strains with reduced FOM susceptibility (MIC ≥ 8 μg/mL) compared with strains with FOM MIC < 1 μg/mL.
ND: not detected. NT: not tested.