Table 2.
Antimicrobial resistance genes and susceptibility profiles of four DHA-1/ESBL-producing K. pneumoniae isolates and their transconjugants in E. coli J53
| Bacterium | Resistance gene profile |
MIC (μg/ml)a |
Porin deficiencyb | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| bla | qnr | aac(6′)-Ib | 16S rRNA methylase | QRDRc |
CTX/CTX-CLA | FLO | CIP | AMK | TGC | ERT | |||
| gyrA | parC | ||||||||||||
| KP105 | blaCTX-M-14 | qnrB4 | aac(6′)-Ib-cr | armA | WT | >16/1 | 128 | 2 | >256 | 0.5 | 0.5 | None | |
| blaDHA-1 | |||||||||||||
| J53/pKP105 | blaCTX-M-14 | qnrB4 | aac(6′)-Ib-cr | armA | ND | >16/1 | 8 | 0.5 | >256 | 0.25 | 0.05 | ND | |
| blaDHA-1 | |||||||||||||
| KP134 | blaSHV-12 | qnrB4 | aac(6′)-Ib-cr | armA | WT | >16/1 | 128 | 2 | >256 | 0.5 | 0.5 | None | |
| blaCTX-M-14 | |||||||||||||
| blaDHA-1 | |||||||||||||
| J53/pKP134 | blaCTX-M-14 | qnrB4 | aac(6′)-Ib-cr | armA | ND | >16/1 | 64 | 0.25 | >256 | 0.25 | 0.5 | ND | |
| blaDHA-1 | |||||||||||||
| KP148 | blaSHV-12 | qnrB4 | aac(6′)-Ib-cr | armA | S83I | S80I | >16/1 | >128 | >32 | >256 | 0.5 | 2 | OmpK35 |
| blaCTX-M-14 | |||||||||||||
| blaDHA-1 | |||||||||||||
| J53/pKP148 | blaCTX-M-14 | qnrB4 | aac(6′)-Ib-cr | armA | ND | >16/1 | 8 | 1 | >256 | 0.25 | 0.012 | ND | |
| blaDHA-1 | |||||||||||||
| KP243 | blaCTX-M-14 | qnrB4 | aac(6′)-Ib-cr | armA | S83F | S80I | >16/1 | 64 | >32 | >256 | 1 | 1 | OmpK35 |
| blaDHA-1 | D87A | ||||||||||||
| J53/pKP243 | blaCTX-M-14 | qnrB4 | aac(6′)-Ib-cr | armA | ND | >16/1 | 32 | 0.5 | >256 | 0.5 | 1 | ND | |
| blaDHA-1 | |||||||||||||
| E. coli J53 | ND | 0.25/0.032 | 0.125 | 0.008 | 2 | 0.25 | 0.012 | ND | |||||
a
CTX, cefotaxime; CLA, clavulanic acid; FLO, flomoxef; CIP, ciprofloxacin; AMK, amikacin; TGC, tigecycline; ERT, ertapenem.
b
ND, not done.
c
QRDR, quinolone resistance-determining region; WT, wild type; ND, not done; S, serine; I, isoleucine; F, phenylalanine; D, aspartic acid; A, alanine.