Volume 22, Number 12—December 2016
Letter
Pathogenic Lineage of mcr-Negative Colistin-Resistant Escherichia coli, Japan, 2008–2015
, Akira Fukuda, Yuuki Suzuki, Tsukasa Shiraishi, Hiroyuki Honda, Masaaki Shinagawa, Soh Yamamoto, Noriko Ogasawara, Masaru Usui, Hiroki Takahashi, Satoshi Takahashi, Yutaka Tamura, and Shin-ichi Yokota
Table
Characterization of colistin-resistant Escherichia coli isolates, Japan, 2008–2105*
| Strain | Specimen type | Patient age, y/sex | Year | Serotype | ST | MIC, mg/L† |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PIP | CAZ | CPD | FEP | IPM | GEN | AMK | CIP | CST | PMB | ||||||
| SRE34 |
Urine catheter |
UNK/F |
2008 |
O25b:H4 |
131-
H30Rx |
128 (R) |
1
(S) |
1
(S) |
0.06 (S) |
0.125 (S) |
0.5 (S) |
2
(S) |
32 (R) |
16 (R), 16 (R)‡ |
8,
8‡ |
| SRE44 |
Urine catheter |
UNK/M |
2008 |
O25b:H4 |
131-
H30Rx |
64 (R) |
2
(S) |
1
(S) |
0.13
(S) |
0.25 (S) |
0.5 (S) |
1
(S) |
64 (R) |
16 (R), 16 (R)‡ |
16,
8‡ |
| SME222 |
Indwelling pericardial drain |
76/M |
2015 |
O18 |
416 |
2
(S) |
0.5 (S) |
0.5 (S) |
<0.03 (S) |
0.13 (S) |
0.5 (S) |
2
(S) |
0.03 (S) |
4 (R),
4 (R)‡ |
8,
4‡ |
| SME296 | Urine | 67/M | 2015 | O25b:H4 | 131- H30R | >128 (R) | 32 (R) | >128 (R) | 16 (R) | 0.13 (S) | 0.5 (S) | 2 (S) | 64 (R) | 4 (R), 8 (R)‡ | 1, 4‡ |
*All isolates were phylogentic group B2. AMK, amikacin; CAZ, ceftazidime; CIP, ciprofloxacin; CPD, cefpodoxime; FEP, cefepime; CST, colistin; GEN, gentamicin; IPM, imipenem; PIP, piperacillin; PMB, polymyxin B; R, resistant; S, susceptible; ST, sequence type; UNK, unknown.
†EUCAST (http://www.eucast.org/) breakpoints were used for resistance determination because the colistin breakpoint for E. coli was undetermined by the Clinical and Laboratory Standards Institute. MICs were determined by the agar dilution method unless otherwise stated. Breakpoints: PIP, >16; CAZ, >16; CPD, >1; FEP, >4; IPM, >8; GEN, >4; AMK, >16; CIP, >1; CST, >2.
‡Broth microdilution method.