Table 1.
Results of the MALDIxin test on K. pneumoniae clinical isolates
| Isolate name | Colistin MIC (mg/L) | Resistance mechanism to polymyxins | β-Lactam resistance mechanisms (ESBLs, carbapenemases, …) | Percentage modified lipid Aa | Percentage pEtNa | Percentage l-Ara4Na | Reference |
|---|---|---|---|---|---|---|---|
| Colistin-susceptible isolates | |||||||
| 1609079984 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 1609056413 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 1609078951 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 1609078870 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 1609068884 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 1609059262 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 1609061149 | 1 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 1609072327 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 1609075598 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 1609071256 | 0.5 | WT | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 2 E8 | 0.5 | CTX-M-3 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 2 F1 | 0.5 | CTX-M-14 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 2 F4 | 0.5 | CTX-M-15 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 18 | |
| 2 F5 | 0.5 | CTX-M-15 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 18 | |
| 2 I5 | 0.5 | CTX-M-15 + TEM-1 + SHV-11 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 3 C4 | 0.5 | CTX-M-15 + TEM-1B + SHV-11 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 3 D6 | 0.5 | CTX-M-15 + TEM-1B + SHV-28 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 3 D7 | 0.5 | CTX-M-15 + TEM-1B + SHV-83 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 2 I3 | 0.5 | CTX-M-15 + TEM-1 + SHV-11 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 18 | |
| 2 I4 | 0.5 | CTX-M-15 + TEM-1 + SHV-11 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 1 F7 | 0.5 | KPC-2 + SHV-11 + CTX-M-15 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 3 B4 | 0.5 | KPC-3 + TEM-1A, OXA-9, SHV-11 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 3 B7 | 0.5 | GES-5 + SHV-12 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 1 B6 | 0.5 | NDM-1 + TEM-1 + CTX-M-15 + SHV-12 + OXA-9 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 1 C9 | 0.5 | VIM-1 + SHV-5 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 1 E3 | 0.5 | IMP-1 + TEM-15 + CTX-M-15 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | this study | |
| 2 B1 | 0.5 | OXA-48 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 18 | |
| 2 C6 | 0.5 | NDM-1 + OXA-181 + CTX-M-15 + TEM-1 + OXA-1 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 2 D2 | 0.5 | OXA-204 + CMY-4 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 17 | |
| 2 D8 | 0.5 | OXA-232 + TEM-1 + CTX-M-15 + OXA-1 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 18 | |
| S15 | 0.25 | mgrB truncated in ORF by ISKpn25 + PhoP (I201N) | KPC-2 + OXA-9 + TEM-1 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 19 |
| S17 | 0.5 | mgrB truncated in ORF by ISKpn25 + ArnC (C161Y) | KPC-2 + OXA-9 + TEM-1 | 0.0±0.0 | 0.0±0.0 | 0.0±0.0 | 19 |
| Chromosome-encoded resistance | |||||||
| TUN-ST-15 | >128 | frameshift mgrB | CTX-M-15 + OXA-1 + SHV-28 | 10.6±1.5 | 0.0±0.0 | 100±0.0 | 20 |
| TUN-ST-101 | 8 | frameshift mgrB | OXA-48 + CTX-M-15 + OXA-1 | 19.5±6.6 | 0.0±0.0 | 100±0.0 | 20 |
| CNR 111 C2 | 16 | frameshift mgrB | OXA-48 + BLSE | 17.0±5.0 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20140042 | 16 | MgrB N42Y and K43I | OXA-48 type + CTX-M grp1 | 18.9±3.4 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20140423 | 32 | MgrB N42Y and K43I | OXA-48 type + CTX-M grp1 | 26.5±7.6 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20140661 | 64 | MgrB Q30 stop | KPC type | 29.7±4.6 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150586 | 64 | MgrB Q30 stop | ESBL | 15.0±3.7 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150324 | 32 | MgrB Q30 stop | ESBL | 11.8±1.8 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150655 | 64 | MgrB Q30 stop | CTX-M grp1 | 15.8±7.5 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150542 | 32 | MgrB L4 stop | OXA-48 type + CTX-M grp1 | 15.2±5.7 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20151119 | 64 | MgrB L4 stop | OXA-427 | 16.7±3.8 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150622 | 64 | MgrB Y41 stop | KPC type + ESBL | 27.6±11.4 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150777 | 128 | MgrB Y41 stop | CTX-M grp1 | 27.2±9.2 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20140698 | 32 | MgrB modified from AA 42 (I) | KPC type | 31.1±9.9 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150944 | 64 | MgrB modified from AA 42 (I) | KPC type | 42.6±8.4 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150309 | 64 | MgrB modified from AA 37 (V) | KPC type + CTX-M grp1 | 18.7±3.9 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150675 | 64 | mgrB truncated in ORF by IS10 | OXA-427 + CTX-M grp1 | 30.6±8.6 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150276 | 32 | mgrB truncated in ORF by IS10 | OXA-427 + CTX-M grp1 | 34.8±12.0 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20140483 | 32 | mgrB truncated in ORF by IS1R-like | OXA-48 type + CTX-M grp1 | 28.3±7.5 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20140563 | 64 | mgrB truncated in ORF by IS1R | OXA-48 type + DHA type | 31.7±9.3 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150295 | 8 | mgrB truncated in ORF by IS1R | OXA-48 type + CTX-M grp1 | 16.7±4.5 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150713 | 64 | mgrB truncated in ORF by IS1R | OXA-48 type + CTX-M grp1 | 20.9±3.4 | 0.0±0.0 | 100±0.0 | this study |
| S20-003 | 64 | mgrB truncated in ORF by IS1R | OXA-48 type | 17.3±4.3 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150736 | 32 | mgrB truncated in ORF by IS1R | OXA-48 type + CTX-M grp1 | 34.0±4.3 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150960 | 32 | mgrB truncated in ORF by IS1R | ND | 16.8±2.9 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20151181 | 32 | mgrB truncated in ORF by IS1R | OXA-48 type + CTX-M grp1 | 247.6±8.9 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150050 | 32 | mgrB truncated in promoter by IS1R | DHA type | 22.1±5.9 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150943 | 32 | mgrB truncated in promoter by IS1R | DHA type | 26.8±11.7 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20140591 | 64 | mgrB truncated in ORF by IS5-like | KPC type + ESBL | 31.3±11.0 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20140862 | 16 | mgrB truncated in ORF by IS5-like | ND | 23.9±6.5 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20150573 | 32 | mgrB truncated in ORF by IS5-like | NDM type + OXA-48 type + CTX-M grp1 | 38.4±25.4 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20140550 | 32 | mgrB truncated in promoter by IS903D | KPC type + CTX-M grp9 | 31.9±8.6 | 0.0±0.0 | 100±0.0 | this study |
| CNR 20151285 | 32 | mgrB truncated in ORF by IS903-like | CTX-M grp1 | 21.3±10.9 | 0.0±0.0 | 100±0.0 | 17 |
| S12-172 | 32 | mgrB truncated in ORF by IS903-like | NDM type | 29.6±4.1 | 0.0±0.0 | 100±0.0 | this study |
| S14-002 | 64 | mgrB truncated in promoter by ISKpn14 | KPC type | 44.2±19.2 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20140101 | 32 | ΔmgrB | OXA-48 type + CTX-M grp1 | 23.4±5.3 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150078 | 32 | ΔmgrB | OXA-48 type + CTX-M grp9 | 20.1±4.7 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20150066 | 16 | ΔmgrB | OXA-48 type + BLSE | 23.4±3.8 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 20151223 | 32 | ΔmgrB | carbapenem resistant via impermeability | 51.3±8.6 | 0.0±0.0 | 100±0.0 | 17 |
| S1 | 128 | mgrB truncated in ORF by ISKpn25 | KPC-2 + OXA-9 + TEM-1 | 40.9±13.6 | 0.0±0.0 | 100±0.0 | 19 |
| S12 | 64 | mgrB truncated in ORF by ISKpn25 | KPC-2 + OXA-9 + TEM-1 | 26.6±3.8 | 0.0±0.0 | 100±0.0 | 19 |
| CNR 1630 | 32 | mgrB truncated in ORF by IS5 | ND | 27.2±9.1 | 0.0±0.0 | 100±0.0 | 17 |
| CNR 1631 | 8 | mgrB truncated in ORF by IS5 | ND | 42.5±24.7 | 0.0±0.0 | 100±0.0 | this study |
| CNR 1795 | 128 | mgrB truncated in ORF by IS5 | ND | 34.0±4.3 | 0.0±0.0 | 100±0.0 | this study |
| CNR 1861 | 16 | mutated PmrB (T157P) | ND | 28.8±5.1 | 0.0±0.0 | 100±0.0 | 17 |
| MCR-related resistance to colistin | |||||||
| CNR 1732 | 4 | mcr-1 | ND | 32.1±7.7 | 100±0.0 | 0.0±0.0 | 17 |
| CNR 1853 | 4 | mcr-1 | ND | 34.4±11.8 | 95.3±6.2 | 4.7±6.2 | 17 |
| CNR 186 G1 | 8 | mcr-8 | SHV-27 + TEM-1B + SCO-1 | 24.4±5.6 | 100±0.0 | 0.0±0.0 | this study |
| MCR + chromosome-encoded resistance to colistin | |||||||
| CNR 1601 | 32 | mcr-1 + mgrB truncated in ORF by IS5 | ND | 33.6±19.6 | 46.1±13.1 | 53.9±13.1 | 17 |
ND, not determined.
Carbapenemases are shown in bold and ESBLs are underlined.
a
Mean±standard error of the mean.