Background
Methods
Bacterial isolates
Determination of minimal inhibitory concentration (MIC)
Pulsed-field gel electrophoresis (PFGE)
Multilocus sequence typing (MLST)
Detection of carbapenemases, AmpC beta-lactamases, extended-spectrum beta-lactamases (ESBL) and outer membrane porin genes
Determination of genetic elements of Tn4401
Statistical analyses
Results
Overview of carbapenem resistant Klebsiella pneumoniae cases
Isolate | Gender/ Age (years) | Underlying diseases | Isolation site | Length of hospitalization prior to strain isolation (days) | Stay in ICU (days) | Undergone surgical procedure | Use of medical devicesa
| Prior antibiotic exposure (90 days prior to strain isolation) | Empiric antibiotic | Targeted antibiotic | Colonization / Infection | In-hospital death |
---|---|---|---|---|---|---|---|---|---|---|---|---|
K/1310-23 | M / 85 | SOT | Blood | 5 | 0 | No | MV, Cath | XM, CI | TZP | CT | Infection | Yes |
K/1311-36 | M / 72 | HPT | Drainage fluid | 37 | 17 | Yes | MV, Cath | CP, IPb, PM, CLX, TX, CI, TZP, VA, MPb
| VA, MP | MP, CT | Infection | Yes |
K/1308-12 | M / 67 | DM, HPT | Drainage fluid | 21 | 0 | Yes | MV, Cath | CP, MTZ | CI | IP, CT | Infection | No |
K/1312-3 | M / 60 | DM, HPT | Urine | 110 | 0 | Yes | MV, Cath | P, TZP, IPb
| XM, IP | IPd
| Colonization | Yes |
K/1310-33 | F / 63 | DM, HPT, CKD | Blood | 24 | 0 | Unknown | Cath | CFZ, TZ, VA, IPb
| CT | CT | Infection | No |
K/1311-35 | M / 71 | DM, HPT | Sputum | 108 | 5 | Yes | Unknown | VA, CI, MPb
| TZ | Nil | Colonization | No |
K/1312-17 | F / 77 | DM | Urine | 16 | 0 | Yes | Cath | CLX, AMS | CI | Nil | Colonization | No |
AN9 | F / 62 | HPT | Urine | 16 | 15 | No | MV, Cath | CP, MTZ, AMS | TZP, IPb
| IPd
| Colonization | No |
K/1309-5 | F / 48 | DM, HPT | Tissue | 21 | 0 | Yes | MV, Cath | AMS, AMC, TZP, IPb
| IPb
| Nil | Colonization | No |
K/1310-24 | F / 69 | DM, HPT | Swab | 155 | 0 | Yes | MV, Cath | VA, MTZ, CT, IPc, CI, XM, TZP | VA, TZP | VA, TZP | Colonization | No |
KLEB-2013-105 | F / 74 | SOT | Swab | 10 | 0 | Yes | MV, Cath | OTC | AMS | Nil | Colonization | No |
K/1309-18 | F / 74 | HPT | Tracheal secretion | 10 | 11 | Yes | MV, Cath | CP, MTZ | TZP | Nile
| Infection | Yes |
K/1309-39 | M / 60 | DM, HPT, CKD | Swab | 3 | 0 | Yes | Cath | AMS | AMS | IP, CT | Infection | No |
K/1304-16 | M / 57 | DM, HPT | Blood | 12 | 0 | Yes | Cath | CI, TX | TZP | IP, CT | Infection | No |
K/1309-38 | M / 62 | DM, SOT | Urine | 0 | 0 | Yes | MV, Cath | CI, CP, MTZ | TX | IP, CT | Infection | Yes |
K/1311-26 | F / 57 | DM, HPT, SOT | Blood | 0 | 0 | Unknown | Unknown | AMS, CI | TX | Nil | Colonization | No |
K/1310-35 | M / 60 | DM, HPT | Tracheal aspirate | 67 | 0 | Yes | MV, Cath | P, TZP | Nil | Nil | Colonization | Yes |
Characteristics | Survivors (n = 11) | Non-survivors (n = 6) |
P
|
---|---|---|---|
Age (years) | 64.09 ± 2.57 | 68.83 ± 4.09 | 0.351b
|
Ethnicity | |||
Malay | 2 | 2 | 0.317c
|
Chinese | 6 | 3 | 0.317c
|
Indian | 3 | 1 | 1.000c
|
Gender | |||
Male | 4 | 5 | 0.111c
|
Female | 7 | 1 | 0.034c
|
Underlying diseases | |||
Hypertension | 9 (82%) | 4 (67%) | 0.584 |
Diabetes mellitus | 9 (82%) | 3 (50%) | 0.280 |
Solid organ tumor | 2 (18%) | 2 (33%) | 0.584 |
Chronic kidney disease | 2 (18%) | 0 (0%) | 0.515 |
Site of isolation | |||
Blood | 3 (27.3%) | 1 (16.7%) | 0.515 |
Swabs | 3 (27.3%) | 0 (0%) | 0.515 |
Urine | 2 (18.2%) | 2 (33.3%) | 0.58 |
Drainage fluids | 1 (9.1%) | 1 (16.7%) | 1.000 |
Sputum | 1 (9.1%) | 0 (0%) | 1.000 |
Tissue | 1 (9.1%) | 0 (0%) | 1.000 |
Tracheal aspirate | 0 (0%) | 1 (16.7%) | 0.353 |
Tracheal secretion | 0 (0%) | 1 (16.7%) | 0.353 |
Length of hospitalization (days) | 35.09 ± 14.88 | 38.17 ± 17.65 | 1.000d
|
Stay in ICU | 2 (18%) | 2 (33%) | 0.584 |
Undergone surgical procedure | 8 (73%) | 5 (83%) | 1.000 |
Used ventilation devices | 5 (45%) | 6 (100%) |
0.043
|
Used catheter | 9 (82%) | 6 (100%) | 0.515 |
Antibiotic prescribed 90 days prior to strain isolation | |||
Cephalosporins | 6 (55%) | 4 (67%) | 1.000 |
Penicillins & beta-lactam/beta-lactamase inhibitors | 6 (55%) | 3 (50%) | 1.000 |
Carbapenems | 4 (36%) | 2 (33%) | 1.000 |
Colistin | 1 (9%) | 0 | 1.000 |
Others (ciprofloxacin, vancomycin, metronidazole & oxytetracycline) | 8 (73%) | 4 (67%) | 1.000 |
Empiric treatment | |||
Beta-lactam/beta-lactamase inhibitors | 5 (46%) | 2 (33%) | 1.000 |
Cephalosporins | 2 (18%) | 2 (33%) | 0.584 |
Carbapenems | 2 (18%) | 2 (33%) | 0.584 |
Ciprofloxacin | 2 (18%) | 0 | 0.515 |
Vancomycin | 1 (9%) | 1 (17%) | 1.000 |
Colistin | 1 (9%) | 0 | 1.000 |
Targeted therapy | |||
Carbapenem + Colistin | 3 (27%) | 2 (33%) | 1.000 |
Colistin | 1 (9%) | 1 (17%) | 1.000 |
Carbapenem (Meropenem / Imipenem) | 1 (9%) | 1 (17%) | 1.000 |
Vancomycin & Piperacillin-tazobactam | 1 (9%) | 0 | 1.000 |
Nila
| 5 (46%) | 2 (33%) | 1.000 |
Colonization / Infection | |||
Colonization | 7 (63%) | 2 (33%) | 0.162 |
Infection | 4 (36%) | 4 (67%) | 0.162 |
Resistance to antibiotics (MIC) | |||
Imipenem | 10 (91%) | 2 (33%) |
0.04
c
|
Meropenem | 9 (82%) | 6 (100%) | 0.515 |
Ertapenem | 9 (82%) | 5 (83%) | 0.232c
|
Carbapenemases | |||
OXA-48 | 8 (73%) | 4 (67%) | 1.000 |
KPC-2 | 5 (45%) | 3 (50%) | 1.000 |
IMP-8 | 2 (18%) | 0 (0%) | 0.515 |
NMC-A | 0 (0%) | 2 (33%) | 0.110 |
NDM-1 | 1 (9%) | 0 (0%) | 1.000 |
AmpC beta-lactamases | |||
FOX-7 | 11 (100%) | 6 (100%) | NA |
ESBL | |||
CTXM-2 | 11 (100%) | 6 (100%) | NA |
SHV | 11 (100%) | 6 (100%) | NA |
OXA-1 | 7 (64%) | 2 (33%) | 0.335 |
CTXM-15 | 6 (55%) | 4 (67%) | 1.000 |
TEM | 6 (55%) | 3 (50%) | 1.000 |
OXA-9 | 6 (55%) | 1 (17%) | 0.304c
|
Determination of minimal inhibitory concentration (MIC)
Strains | Antibiotics (MIC range in μg/ml) | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
aTGC (≤1: S, >2: R) | TC (≤4: S, 8 = I, ≥16: R) | FX (≤8: S, 16 = I, ≥32: R) | CT (≤1: S, 2 = I, ≥4: R) | TZ (≤4: S, 8 = I, ≥16: R) | TX (≤1: S, 2 = I, ≥4: R) | PM (≤2: S, 4-8 = SDD, ≥16: R) | IP (≤1: S, 2 = I, ≥4: R) | MP (≤1: S, 2 = I, ≥4: R) | ETP (≤0.5: S, 1 = I, ≥2: R) | GM (≤4: S, 8 = I, ≥16: R) | TM (≤4: S, 8 = I, ≥16: R) | AK (≤16: S, 32 = I, ≥64: R) | AT (≤4: S, 8 = I, ≥16: R) | CI (≤1: S, 2 = I, ≥4: R) | LE (≤2: S, 4 = I, ≥8: R) |
aCT (≤2: S, >2: R) | |
K/1310-23 | 2 | >256 | >256 | >256 | >256 | >256 | >256 | 1.5 | 6 | 8 | >256 | >256 | 32 | >256 | >32 | >32 | 1.5 |
K/1311-36 | 4 | 256 | >256 | 256 | >256 | >256 | >256 | 1.5 | >32 | 6 | 0.094 | 0.19 | 0.5 | >256 | 0.047 | 0.25 | 0.19 |
K/1308-12 | 1 | >256 | >256 | >256 | >256 | >256 | >256 | >32 | >32 | >32 | >256 | 48 | 24 | >256 | >32 | >32 | 0.38 |
K/1312-3 | 2 | >256 | 2 | >256 | >256 | >256 | 24 | 1 | 6 | 16 | 0.38 | 1.5 | 256 | 48 | >32 | 8 | 0.125 |
K/1310-33 | 0.75 | >256 | 128 | >256 | 48 | >256 | >256 | >32 | >32 | >32 | >256 | >256 | 64 | >256 | >32 | >32 | 0.06 |
K/1311-35 | 0.38 | 6 | 1.5 | 4 | 32 | 8 | 0.38 | 6 | 0.64 | 0.094 | 0.125 | 0.125 | 3 | 24 | 0.125 | 0.5 | 0.19 |
K/1312-17 | 0.75 | >256 | 128 | 6 | 1 | 4 | 16 | >32 | >32 | >32 | >256 | 128 | 3 | 0.125 | >32 | >32 | 0.125 |
AN9 | 1.5 | >256 | 48 | 4 | 0.38 | 2 | 1 | >32 | >32 | >32 | >256 | 8 | 3 | 0.19 | >32 | >32 | 0.125 |
K/1309-5 | 0.38 | >256 | >256 | >256 | 128 | >256 | >256 | 2 | >32 | >32 | >256 | >256 | 24 | >256 | >32 | >32 | 0.19 |
K/1310-24 | 0.5 | >256 | 2 | 0.75 | 0.19 | 1.5 | 1.5 | 6 | >32 | 6 | 0.19 | 0.19 | 1 | 0.047 | 0.5 | 0.5 | 0.125 |
KLEB 2013-105 | 0.19 | >256 | 64 | >256 | 128 | >256 | >256 | >32 | >32 | >32 | 96 | >256 | 24 | >256 | >32 | >32 | 0.25 |
K/1309-18 | 0.75 | >256 | >256 | 6 | 0.5 | 3 | 2 | >32 | >32 | >32 | >256 | 6 | 4 | 0.25 | >32 | >32 | 0.25 |
K/1309-39 | 0.25 | >256 | >256 | >256 | >256 | >256 | 64 | 12 | >32 | 16 | >256 | >256 | >256 | >256 | >32 | >32 | 0.125 |
K/1304-16 | 1 | >256 | 3 | 64 | 192 | >256 | 24 | 4 | 0.064 | 0.125 | >256 | >256 | >256 | 192 | >32 | >32 | 0.125 |
K/1309-38 | 0.19 | >256 | >256 | >256 | 128 | >256 | >256 | 4 | >32 | >32 | >256 | 24 | 12 | >256 | >32 | >32 | 0.38 |
K/1311-26 | 1 | >256 | 6 | 1 | 0.75 | 1 | 3 | 4 | >32 | 24 | >256 | 64 | 24 | 0.125 | >32 | >32 | 0.38 |
K/1310-35 | 0.25 | 6 | 3 | 0.75 | 0.094 | 1 | 0.125 | 3 | >32 | 0.75 | 0.125 | 0.25 | 2 | 0.047 | 0.023 | 0.125 | 0.19 |
Molecular typing via PFGE & MLST
Detection of carbapenemases, AmpC beta lactamases, extended spectrum beta lactamases (ESBL) and porin protein genes
Strain | Sequence Type (ST) | Carbapenemase | AmpC | ESBL | Porin protein | Genetic elements surrounding Tn4401
| |||||
---|---|---|---|---|---|---|---|---|---|---|---|
IRL |
tnpA
| ISKpn7 | ISKpn6 | Variable region | IRR | ||||||
K/1310-23 | 11 | - | FOX-7 | SHV-11, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | - | - | - | - |
K/1311-36 | 495 | KPC-2, NMC-A | FOX-7 | TEM-135, SHV-12, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | + | - | + | - | + | + |
K/1308-12 | 101 | OXA-48 | FOX-7 | TEM-1, SHV-28, OXA-1, OXA-9, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | - | - | - | - |
K/1312-3 | 13 | OXA-48, KPC-2, NMC-A | FOX-7 | TEM-135, SHV-148, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | + | - | + | + |
K/1310-33 | 101 | OXA-48, KPC-2 | FOX-7 | TEM-1, SHV-28, OXA-1, OXA-9, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | + | + | + | - |
K/1311-35 | 1245 | KPC-2 | FOX-7 | SHV-12, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | + | - | - | - | + |
K/1312-17 | 101 | OXA-48, KPC-2 | FOX-7 | SHV-28, OXA-1, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | - | + | - | - |
AN9 | 101 | OXA-48 | FOX-7 | SHV-28, OXA-1, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | - | - | - | - |
K/1309-5 | 101 | OXA-48, KPC-2 | FOX-7 | TEM-1, SHV-28, OXA-1, OXA-9, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | + | + | + | - |
K/1310-24 | 789 | OXA-48, KPC-2 | FOX-7 | SHV-121, CTXM-2 | OmpK35, OmpK37 | - | - | + | - | + | + |
KLEB 2013-105 | 101 | OXA-48 | FOX-7 | TEM-1, SHV-28, OXA-1, OXA-9, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | - | - | - | - |
K/1309-18 | 101 | OXA-48 | FOX-7 | SHV-28, OXA-1, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | - | - | - | - |
K/1309-39 | 147 | IMP-8, NDM-1 | FOX-7 | TEM-1, SHV-11, OXA-9, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | - | - | - | - |
K/1309-38 | 101 | OXA-48, KPC-2 | FOX-7 | TEM-1, SHV-28, OXA-1, OXA-9, CTXM-15, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | + | + | + | - |
K/1311-26 | 101 | OXA-48 | FOX-7 | SHV-28, OXA-1, CTXM-2 | OmpK35, OmpK36, OmpK37 | - | - | - | - | - | - |
K/1310-35 | 397 | OXA-48 | FOX-7 | SHV-1, CTXM-2 | OmpK35, OmpK36, OmpK37 | + | - | - | - | - | + |