Table 2.
The result of multilocus sequence typing (MLST), efflux pump inhibition assay, relative expression level of acrB and ramA, mutation analysis among regulators of AcrAB-TolC efflux pump, and presence of tigecycline-resistance genes in 15 C-C-RKP isolates.
| No. | Project no. | ST | Efflux pump inhibition assay | Gene expression level | Mutation analysisa | Tigecycline resistant genes | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TGC MIC | TGC MIC + CCCP | Fold reduction | acrB | ramA | RamR | RamR recognition site (PI) (nucleotide sequence)b | RamR recognition site (PII) (nucleotide sequence) | AcrR | Lon protease | MarR | SoxR | OqxR | rpsJ | tet(X) | tet(A) | tmexCD1-toprJ1 | |||
| 1 | XDR-KP-034 | 16 | 1 | 0.25 | 4 | 2.63 ± 0.112 | 3.96 ± 0.384 | M184V | – | – | – | – | S82G | – | – | – | – | – | – |
| 2 | XDR-KP-100 | 16 | 1 | 0.25 | 4 | 1.36 ± 0.113 | 4.44 ± 0.419 | I141T | C139T | – | – | – | S82G | – | – | – | – | – | – |
| 3 | XDR-KP-059 | 147 | 2 | 0.125 | 16 | 1.50 ± 0.130 | 1.50 ± 0.385 | – | – | – | R13W | – | S82G | – | – | – | – |
tet(A) (X61367) |
– |
| 4 | XDR-KP-110 | 16 | 2 | 0.5 | 4 | 2.49 ± 0.131 | 9.83 ± 0.169 | Y59C, I141T | C139T | – | – | – | S82G | – | – | – | – | – | – |
| 5 | XDR-KP-117 | 16 | 2 | 0.5 | 4 | 1.97 ± 0.129 | 1.94 ± 0.128 | I141T | C139T | – | – | – | S82G | – | – | – | – | – | – |
| 6 | XDR-KP-189 | 15 | 2 | 0.25 | 8 | 1.26 ± 0.170 | 3.56 ± 0.251 | A19V | T131A | – | – | – | S82G | – | – | – | – | – | – |
| 7 | XDR-KP-051 | 101 | 4 | 1 | 4 | 5.61 ± 0.178 | 6.31 ± 0.193 | A20D | – | – | W50R | – | S82G | – | – | – | – | – | – |
| 8 | XDR-KP-069 | 16 | 4 | 1 | 4 | 5.79 ± 0.082 | 24.97 ± 0.136 | C99ins- frameshift mutation, E53* | C139T | – | – | – | S82G | – | – | – | – | – | – |
| 9 | XDR-KP-070 | 16 | 4 | 1 | 4 | 9.34 ± 0.08 | 3.06 ± 0.223 | C100ins- frameshift mutation, E53* | C139T | – | – | – | S82G | – | – | – | – | – | – |
| 10 | XDR-KP-072 | 147 | 4 | 0.125 | 32 | 1.56 ± 0.173 | 2.46 ± 0.284 | S157P | – | – | – | – | S3N, S82G | – | – | – | – |
tet(A) (X61367) |
– |
| 11 | XDR-KP-185 | 15 | 4 | 1 | 4 | 1.28 ± 0.326 | 2.06 ± 0.344 | A19V | – | – | – | – | S82G | – | – | – | – | – | – |
| 12 | XDR-KP-206 | 16 | 4 | 1 | 4 | 4.78 ± 0.039 | 2.82 ± 0.338 | I141T | C139T | – | L154R | – | S82G | – | – | – | – | – | – |
| 13 | XDR-KP-011 | 147 | 8 | 1 | 8 | 3.29 ± 0.265 | 5.08 ± 0.337 | S157P | – | – | – | – | S3N, S82G | – | – | – | – |
tet(A) (X61367) |
– |
| 14 | XDR-KP-047 | 147 | 8 | 1 | 8 | 4.82 ± 0.302 | 10.07 ± 0.043 | – | – | – | R13Q | – | S3N, S82G | – | – | – | – |
tet(A) (X61367) |
– |
| 15 | XDR-KP-113 | 16 | 8 | 1 | 8 | 8.15 ± 0.364 | 4.33 ± 0.222 | A28T, I141T | C139T | – | – | – | S82G | – | – | – | – | – | – |
aThe sequence of the isolates was compared to K. pneumoniae ATCC 13883. bNucleotide numbering system was according to Rosenblum et al.51.