Supplementary Table 1. Antimicrobial Susceptibility of ESBL-Producing Enterobacteriaceae

Supplementary Table 1. Antimicrobial susceptibility of ESBL-producing Enterobacteriaceae

Antibiotics / E. coli (n=403) / K. pneumoniae (n=151)
Amoxicillin-clavulanate
Susceptible / 178 (44.2%) / 40 (26.5%)
Intermediate / 153 (38.0%) / 57 (37.7%)
Resistant / 72 (17.9%) / 54 (35.8%
Piperacillin-tazobactam
Susceptible / 285 (83.6%) / 46 (40.0%)
Intermediate / 14 (4.1% ) / 24 (20.9%)
Resistant / 42 (12.3%) / 45 (39.1%)
Cefepime
Susceptible / 203 (50.4%) / 70 (46.4%)
Intermediate / 72 (17.9%) / 23 (15.2%)
Resistant / 128 (31.8%) / 58 (38.4%)
Ertapenem
Susceptible / 229 (98.3%) / 59 (95.2%)
Intermediate / 2 (0.9%) / 0 (0.0%)
Resistant / 2 (0.9%) / 3 (4.8%)
Imipenem
Susceptible / 403 (100%) / 149 (99.3%)
Intermediate / 0 (0.0%) / 0 (0.0%)
Resistant / 0 (0.0%) / 1 (0.7%)
Meropenem
Susceptible / 167 (98.8%) / 87 (97.8%)
Intermediate / 0 (0.0%) / 1 (1.1%)
Resistant / 2 (1.2%) / 1 (1.1%)
Gentamicin
Susceptible / 217 (53.8%) / 63 (41.7%)
Intermediate / 14 (3.5%) / 4 (2.6%)
Resistant / 172 (42.7%) / 84 (55.6%)
Amikacin
Susceptible / 388 (97.2%) / 136 (91.3%)
Intermediate / 4 (1.0%) / 2 (1.3%)
Resistant / 7 (1.8%) / 11 (7.4%)
Ciprofloxacin
Susceptible / 78 (33.6%) / 21 (32.8%)
Intermediate / 14 (6.0%) / 4 (6.3%)
Resistant / 140 (60.3%) / 39 (60.9%)
Levofloxacin
Susceptible / 50 (29.4%) / 39 (44.8%)
Intermediate / 2 (1.2%) / 7 (8.0%)
Resistant / 118 (69.4%) / 41 (47.1%)

Data are expressed as the No. (%) of patients.

Abbreviation: ESBL, extended-spectrum beta-lactamase

Supplementary Table 2. Empirical and definitive antibiotics of patients with ESBL-B

Definitive
antibiotics / Empirical antibiotics
Carbapenem
(n=199) / BL/BLI*
(n=103) / Cephalosporin†
(n=179) / Aminoglycoside
(n=3) / Quinolone
(n=32) / Others
(n=38)
Carbapenem
(n=468) / 191 / 65 / 158 / 2 / 26 / 26
BL/BLI
(n=46) / 4 / 37 / 3 / 0 / 1 / 1
Cephalosporin
(n=5) / 0 / 0 / 4 / 0 / 1 / 0
Aminoglycoside
(n=3) / 0 / 0 / 0 / 1 / 0 / 2
Quinolone
(n=6) / 1 / 1 / 7 / 0 / 2 / 1
Others
(n=20) / 3 / 0 / 7 / 0 / 2 / 8
Data are expressed as the number of patients. *BL/BLI included piperacillin/tazobactam (n=100, 97.1%), ampicillin-sulbactam (n=2, 1.9%), and amoxicillin-clavulanate (n=1, 0.97%). †Cephalosporin included cefepime (n=43, 24.0%) and ceftriaxone (n=136, 76.0%).
Abbreviations: ESBL, extended-spectrum beta-lactamase; BL/BLI, Beta-lactam/Beta-lactamase inhibitors

Supplementary Table 3. Baseline characteristics of 232 patients with ESBL-B empirically treated with carbapenem or non-carbapenem, prior to definitive carbapenem therapy

Variables / Complete cohort / IPTW cohort*
Carbapenem
(n=183) / Non-carbapenem
(n=49) / P value / Carbapenem / Non-carbapenem / P value
Demographics
Age (median, IQR) / 61 (50-75) / 63 (53-73) / 0.66 / 61 (51-75) / 65 (53-73) / 0.78
Male / 102 (55.7%) / 21 (42.9%) / 0.11 / 97 (52.9%) / 23 (49.0%) / 0.68
Recent medical histories†
Recent operation history / 32 (17.5%) / 11 (22.4%) / 0.43 / 30 (16.5%) / 10 (22.3%) / 0.33
Recent admission history / 118 (64.5%) / 32 (65.3%) / 0.91 / 118 (64.3%) / 30 (64.4%) / 0.92
Recent antibiotics use / 110 (60.1%) / 26 (53.1%) / 0.37 / 108 (59.2%) / 27 (57.1%) / 0.85
Recent chemo/radio therapy / 51 (27.9%) / 10 (20.4%) / 0.29 / 50 (27.5%) / 9 (18.2%) / 0.20
Underlying diseases
Cardiovascular disease / 17 (9.3%) / 5 (10.2%) / 0.79 / 16 (8.8%) / 4 (8.2%) / 0.90
Pulmonary disease / 26 (14.2%) / 1 (2.0%) / 0.02 / 21 (11.6%) / 5 (10.2%) / 0.80
Liver disease / 32 (17.5%) / 5 (10.2%) / 0.22 / 34 (18.4%) / 8 (16.9%) / 0.83
Renal disease / 45 (24.6%) / 17 (34.7%) / 0.16 / 44 (23.9%) / 18 (37.4%) / 0.06
Neurologic disease / 34 (18.6%) / 7 (14.3%) / 0.48 / 34 (18.8%) / 8 (18.0%) / 0.93
Connective tissue disease / 6 (3.3%) / 2 (4.1%) / 0.68 / 6 (3.2%) / 1 (3.1%) / 0.96
Diabetes mellitus / 68 (37.2%) / 15 (30.6%) / 0.40 / 68 (37.3%) / 13 (27.6%) / 0.23
Solid cancer / 64 (35.0%) / 23 (46.9%) / 0.12 / 69 (37.7%) / 22 (47.1%) / 0.22
Curative setting / 33 (18.0%) / 9 (18.4%) / 0.96 / 33 (17.8%) / 9 (19.4%) / 0.78
Palliative setting / 31 (16.9%) / 14 (28.6%) / 0.07 / 36 (19.9%) / 13 (27.7%) / 0.23
Hematologic disease / 46 (25.1%) / 7 (14.3%) / 0.11 / 42 (22.9%) / 11 (23.8%) / 0.88
Leukemia / 27 (14.8%) / 4 (8.2%) / 0.23 / 24 (13.4%) / 4 (9.1%) / 0.44
Lymphoma / 20 (10.9%) / 3 (6.1%) / 0.42 / 18 (10.0%) / 7 (14.7%) / 0.35
Bone marrow transplantation / 10 (5.5%) / 1 (2.0%) / 0.47 / 9 (4.9%) / 1 (1.7%) / 0.33
Charlson’s WIC (median, IQR) / 2 (2-5) / 3 (1-6) / 0.91 / 2 (2-5) / 3 (1-6) / 0.99

Data are expressed as the No. (%) of patients, unless indicated otherwise. An episode of ESBL-B was defined as an isolation of ESBL-producing E. coli or K. pneumoniae from one or more sets of blood cultures with more than one of the following clinical findings: body temperature, 38°C or36°C; heart rate, 90 /min; hyperventilationevidenced by a respiratory rate of20/min or a PaCO2 of 32 mm Hg; anda white blood cell count of 12,000 cells/Lor 4,000/L .

*Propensity score weighting variables: age, sex, acquisition of infection, urinary tract infection, procalcitonin, transfer to ICU within 48hrs, APACHE II score, pulmonary disease, Charlson’s WIC score. †Within 3 months.

Abbreviations: ESBL, extended-spectrum beta-lactamase; IPTW, inverse probability of treatment weights; IQR, interquartile range; WIC, weighted index of comorbidity

Supplementary Table 4. Acquisition sites and severity of infection in 232 patients with ESBL-B empirically treated with carbapenem or non-carbapenem, prior to definitive carbapenem therapy

Variables / Complete cohort / IPTW cohort*
Carbapenem
(n=183) / Non-carbapenem
(n=49) / P value / Carbapenem / Non-carbapenem / P value
Pathogen
E. coli / 121 (66.1%) / 38 (77.6%) / 0.13 / 125 (68.2%) / 34 (73.1%) / 0.46
K. pneumoniae / 62 (33.9%) / 11 (22.4%) / 0.13 / 59 (32.1%) / 12 (26.2%) / 0.46
Acquisition of infection
Community acquired / 27 (14.8%) / 12 (24.5%) / 0.11 / 31 (17.1%) / 7 (15.5%) / 0.81
Healthcare associated / 52 (28.4%) / 18 (36.7%) / 0.26 / 55 (30.3%) / 17 (36.2%) / 0.41
Hospital acquired / 104 (56.8%) / 19 (38.8%) / 0.02 / 97 (52.8%) / 22 (47.6%) / 0.56
Source of infection
Primary bacteremia / 45 (24.6%) / 11 (22.4%) / 0.76 / 42 (23.0%) / 14 (30.1%) / 0.29
Catheter-related BSI / 7 (3.8%) / 1 (2.0%) / 1.00 / 6 (3.3%) / 2 (4.0%) / 0.80
Urinary tract / 62 (33.9%) / 24 (49.0%) / 0.05 / 68 (37.3%) / 18 (38.2%) / 0.87
Intra-abdominal / 55 (30.1%) / 10 (20.4%) / 0.18 / 55 (30.0%) / 10 (21.4%) / 0.25
Others† / 14 (7.7%) / 3 (6%) / 0.74 / 12 (6.6%) / 3 (5.6%) / 0.80
Time interval from bacteremia, hr
(median, IQR)
To initial empirical antibiotics / 2 (1-5) / 2 (1-5) / 0.72 / 2 (1-5) / 2 (1-6) / 0.42
To appropriate antibiotics / 7 (1-24) / 4 (1-11) / 0.12 / 7 (2-24) / 4 (1-9) / 0.07
Laboratory tests (median, IQR)
WBC /mm3 / 9390 (1290-14900) / 11570 (5880-17700) / 0.07 / 9800 (2100-15110) / 9910 (2600-14290) / 0.96
Creatinine (mg/dL) / 0.97 (0.68-1.6) / 0.96 (0.73-1.7) / 0.89 / 0.95 (0.69-1.55) / 1 (0.78-1.9) / 0.23
CRP (mg/dL) / 9.74 (2.76-21.54) / 7.14 (3.02-18.53) / 0.61 / 10.34 (2.76-22.40) / 8.1 (5.08-19.07) / 0.58
Procalcitonin (ng/mL) / 4.16 (0.69-21.82) / 1.58 (0.46-6.69) / 0.11 / 4.03 (0.69-16.94) / 1.6 (0.42-12.24) / 0.05
ICU care
Bacteremia occurred in ICU / 20 (10.9%) / 2 (4.1%) / 0.18 / 18 (9.8%) / 4 (8.2%) / 0.75
Transfer to ICU within 48 hrs / 66 (36.1%) / 11 (22.4%) / 0.07 / 60 (32.9%) / 12 (26.2%) / 0.40
Severity scoring system
APACHE II (median, IQR) / 16 (12-22) / 13 (9-18) / < 0.01 / 15 (11-20) / 16 (10-21) / 0.50

Data are expressed as the No. (%) of patients, unless indicated otherwise

*Propensity score weighting variables: age, sex, acquisition of infection, urinary tract infection, procalcitonin, transfer to ICU within 48 hrs, APACHE II score, pulmonary disease, Charlson’s WIC score. †Others included respiratory tract, skin and soft tissue, and central nervous system infections.

Abbreviations: ESBL, extended-spectrum beta-lactamase; IPTW, inverse probability of treatment weights; IQR, interquartile range; BSI, bloodstream infection; WBC, white blood cell; CRP, C-reactive protein; ICU, intensive care unit; APACHE, acute physiology and chronic health evaluation

Supplementary Table 5. Outcomes of 232 patients with ESBL-B empirically treated with carbapenem or non-carbapenem, prior to definitive carbapenem therapy

Variables / Complete cohort / IPTW cohort*
Carbapenem
(n=183) / Non-carbapenem
(n=49) / P value / Carbapenem / Non-carbapenem / P value
Length of hospital stay, days (median, IQR) / 18.5 (12.5-32) / 15 (10-28) / 0.05 / 18 (13-32) / 19 (11-32) / 0.31
All-cause mortality
7-day / 4/181 (2.2%) / 1/49 (2.0%) / 1.00 / 3/182 (1.6%) / 1/47 (2.1%) / 0.79
14-day / 8/180 (4.4%) / 2/48 (4.2%) / 1.00 / 7/182 (3.8%) / 2/44 (4.5%) / 0.96
30-day / 20/175 (11.4%) / 3/48 (6.3%) / 0.42 / 18/176 (10.2%) / 3/44 (6.8%) / 0.55
Attributable mortality
7-day / 3/181 (1.7%) / 1/49 (2.0%) / 1.00 / 3/182 (1.6%) / 1/47 (2.1%) / 0.62
14-day / 5/180 (2.8%) / 2/48 (4.2%) / 0.64 / 4/182 (2.2%) / 2/44 (4.5%) / 0.59
30-day / 8/175 (4.6%) / 2/48 (4.2%) / 1.00 / 7/176 (4.0%) / 2/44 (4.5%) / 0.92
Bacteremia
Duration, hr (median, IQR) / 79.5 (54-136.5) / 69 (48-96) / 0.07 / 72 (51-96) / 73 (52-86) / 0.92
Persistent over 5 days / 22/160 (13.8%) / 5/43 (11.6%) / 0.72 / 22/160 (13.7%) / 4/35 (12.6%) / 0.63

Data are expressed as the No. (%) of patients, unless indicated otherwise

*Propensity score weighting variables: age, sex, acquisition of infection, urinary tract infection, procalcitonin, transfer to ICU within 48 hrs, APACHE II score, pulmonary disease, Charlson’s WIC score. †Others included respiratory tract, skin and soft tissue, and central nervous system infections.

Abbreviations: ESBL, extended-spectrum beta-lactamase; IPTW, inverse probability of treatment weights; IQR, interquartile range

Supplementary Table 6. Baseline characteristics of 224 patients with ESBL-B empirically treated with carbapenem PTZ, prior to definitive carbapenem therapy

Variables / Complete cohort / IPTW cohort*
Carbapenem
(n=183) / PTZ
(n=41) / P value / Carbapenem / PTZ / P value
Demographics
Age (median, IQR) / 61 (50-75) / 63 (54-73) / 0.14 / 61 (51-74) / 66 (53-78) / 0.63
Male / 102 (55.7%) / 20 (48.8%) / 0.42 / 99 (54.3%) / 18 (43.4%) / 0.22
Recent medical histories†
Recent operation history / 32 (17.5%) / 9 (22.0%) / 0.50 / 31 (16.9%) / 10 (23.1%) / 0.33
Recent admission history / 118 (64.5%) / 29 (70.7%) / 0.45 / 118 (64.6%) / 28 (66.3%) / 0.80
Recent antibiotics use / 110 (60.1%) / 23 (56.1%) / 0.64 / 109 (59.6%) / 24 (56.9%) / 0.78
Recent chemo/radio therapy / 51 (27.9%) / 9 (22.0%) / 0.44 / 50 (27.2%) / 9 (20.9%) / 0.41
Underlying diseases
Cardiovascular disease / 17 (9.3%) / 4 (9.8%) / 1.00 / 17 (9.2%) / 3 (6.8%) / 0.63
Pulmonary disease / 26 (14.2%) / 1 (2.4%) / 0.03 / 24 (13.3%) / 1 (2.6%) / 0.05
Liver disease / 32 (17.5%) / 5 (12.2%) / 0.41 / 34 (18.4%) / 4 (10.3%) / 0.21
Renal disease / 45 (24.6%) / 13 (31.7%) / 0.35 / 45 (24.4%) / 17 (40.8%) / 0.03
Neurologic disease / 34 (18.6%) / 6 (14.6%) / 0.55 / 34 (18.6%) / 9 (22.3%) / 0.57
Connective tissue disease / 6 (3.3%) / 2 (4.9%) / 0.64 / 6 (3.3%) / 1 (3.2%) / 0.97
Diabetes mellitus / 68 (37.2%) / 13 (31.7%) / 0.51 / 68 (37.4%) / 15 (35.3%) / 0.83
Solid cancer / 64 (35.0%) / 21 (51.2%) / 0.05 / 68 (37.4%) / 15 (36.8%) / 0.96
Curative setting / 33 (18.0%) / 8 (19.5%) / 0.82 / 32 (17.7%) / 8 (18.3%) / 0.91
Palliative setting / 31 (16.9%) / 13 (31.7%) / 0.03 / 36 (19.7%) / 8 (18.5%) / 0.87
Hematologic disease / 46 (25.1%) / 7 (17.1%) / 0.27 / 42 (23.1%) / 8 (20.0%) / 0.68
Leukemia / 27 (14.8%) / 4 (9.8%) / 0.40 / 25 (13.5%) / 4 (9.9%) / 0.54
Lymphoma / 20 (10.9%) / 3 (7.3%) / 0.78 / 18 (10.1%) / 4 (10.2%) / 0.98
Bone marrow transplantation / 10 (5.5%) / 1 (2.4%) / 0.69 / 9 (5.0%) / 1 (2.2%) / 0.44
Charlson’s WIC (median, IQR) / 2 (2-5) / 3 (2-6) / 0.71 / 3 (2-5) / 2 (2-4) / 0.80

Data are expressed as the No. (%) of patients, unless indicated otherwise

*Propensity score weighting variables: age, sex, acquisition of infection, urinary tract infection, CRP, procalcitonin, transfer to ICU within 48 hrs, APACHE II score, pulmonary disease, Charlson’s WIC score. †Within 3 months.

Abbreviations: ESBL, extended-spectrum beta-lactamase; PTZ, piperacillin-tazobactam; IPTW, inverse probability of treatment weights; IQR, interquartile range; WIC, weighted index of comorbidity

Supplementary Table 7. Acquisition and severity of infection in 224 patients with ESBL-B empirically treated with carbapenem PTZ, prior to definitive carbapenem therapy

Variables / Complete cohort / IPTW cohort*
Carbapenem
(n=183) / PTZ
(n=41) / P value / Carbapenem / PTZ / P value
Pathogen
E. coli / 121 (66.1%) / 31 (75.6%) / 0.24 / 124 (67.6%) / 34 (81.2%) / 0.07
K. pneumoniae / 62 (33.9%) / 10 (24.4%) / 0.24 / 59 (32.5%) / 8 (18.2%) / 0.07
Acquisition of infection
Community acquired / 27 (14.8%) / 8 (19.5%) / 0.45 / 29 (16.0%) / 7 (17.4%) / 0.81
Healthcare associated / 52 (28.4%) / 17 (41.5%) / 0.10 / 56 (30.6%) / 12 (27.9%) / 0.75
Hospital acquired / 104 (56.8%) / 16 (39.0%) / 0.04 / 98 (53.4%) / 23 (54.1%) / 0.91
Source of infection
Primary bacteremia / 45 (24.6%) / 10 (22.4%) / 0.98 / 42 (23.2%) / 11 (27.2%) / 0.56
Catheter-related BSI / 7 (3.8%) / 0 (0.0%) / 0.36 / 6 (3.5%) / 0 (0.0%) / 0.22
Urinary tract / 62 (33.9%) / 18 (43.9%) / 0.05 / 66 (36.1%) / 19 (44.5%) / 0.30
Intra-abdominal / 55 (30.1%) / 10 (24.4%) / 0.18 / 56 (30.4%) / 9 (22.4%) / 0.31
Others† / 14 (7.7%) / 3 (7.2%) / 0.63 / 13(6.8) / 2(5.1) / 0.70
Time interval from bacteremia
To initial empirical antibiotics / 2 (1, 5) / 2 (1, 5) / 0.54 / 2 (1, 5) / 3 (1, 6) / 0.80
To appropriate antibiotics / 7 (1, 24) / 4 (2, 15) / 0.69 / 7 (2, 24) / 4 (2, 13) / 0.19
Laboratory tests (median, IQR)
WBC /mm3 / 9390 (1290-14900) / 11100 (5200-18540) / 0.17 / 9800 (1800-15110) / 11570 (2700-20700) / 0.35
Creatinine (mg/dL) / 0.97 (0.68-1.6) / 0.96 (0.66-1.9) / 0.86 / 0.97 (0.69-1.56) / 1 (0.73-2.00) / 0.88
CRP (mg/dL) / 9.74 (2.76-21.54) / 7.62 (3.57-19.07) / 0.70 / 9.74 (2.76-22.40) / 9.23 (5.27-19.07) / 0.73
Procalcitonin (ng/mL) / 4.16 (0.69-21.82) / 1.35 (0.45-9.47) / 0.22 / 0.96 (0.42-3.08) / 0.96 (0.42-3.08) / 0.10
ICU care
Bacteremia occurred in ICU / 20 (10.9%) / 1 (2.4%) / 0.14 / 19 (10.3%) / 3 (6.8%) / 0.50
Transfer to ICU within 48 hrs / 66 (36.1%) / 11 (26.8%) / 0.26 / 63 (34.3%) / 16 (37.4%) / 0.68
Severity scoring system
APACHE II (median, IQR) / 16 (12-22) / 13 (9-19) / 0.02 / 15 (11-21) / 16 (11-20) / 0.54

Data are expressed as the No. (%) of patients, unless indicated otherwise

*Propensity score weighting variables: age, sex, acquisition of infection, urinary tract infection, CRP, procalcitonin, transfer to ICU within 48 hrs, APACHE II score, pulmonary disease, Charlson’s WIC score. †Others included respiratory tract, skin and soft tissue, and central nervous system infections.

Abbreviations: ESBL, extended-spectrum beta-lactamase; PTZ, piperacillin-tazobactam; IPTW, inverse probability of treatment weights; IQR, interquartile range; BSI, bloodstream infection; WBC, white blood cell; CPR, C-reactive protein; ICU, intensive care unit; APACHE, acute physiology and chronic health evaluation

Supplementary Table 8. Outcomes of 224 patients with ESBL-B empirically treated with carbapenem or PTZ, prior to definitive carbapenem therapy

Variables / Complete cohort / IPTW cohort*
Carbapenem
(n=183) / PTZ
(n=41) / P value / Carbapenem / PTZ / P value
Length of hospital stay, days (median, IQR) / 18.5 (12.5-32) / 15 (10-28) / 0.16 / 18 (13-32) / 19 (11-32) / 0.16
All-cause mortality
7-day / 4/181 (2.2%) / 1/41 (2.4%) / 1.00 / 4/182 (2.2%) / 1/39 (2.6%) / 1.00
14-day / 8/181 (4.4%) / 2/40 (5.0%) / 1.00 / 7/181 (3.9%) / 2/36 (5.6%) / 1.00
30-day / 20/176 (11.4%) / 3/40 (7.5%) / 0.58 / 19/176 (10.8%) / 4/36 (11.1%) / 1.00
Attributable mortality
7-day / 3/182 (1.6%) / 1/41 (2.4%) / 0.56 / 3/182 (1.6%) / 1/39 (2.6%) / 1.00
14-day / 5/181 (2.8%) / 2/40 (5.0%) / 0.62 / 5/181 (2.8%) / 2/36 (5.6%) / 0.74
30-day / 8/176 (4.5%) / 2/40 (5.0%) / 1.00 / 7/176 (4.0%) / 2/36 (5.6%) / 1.000
Bacteremia
Duration, hr (median, IQR) / 79.5 (54-136.5) / 69 (48-96) / 0.39 / 72 (49-96) / 70 (50-80) / 0.66
Persistent over 5 days / 22/160 (13.8%) / 3/37 (8.1%) / 0.43 / 22/160 (13.9%) / 2/30 (5.6%) / 0.21

Data are expressed as the No. (%) of patients, unless indicated otherwise

*Propensity score weighting variables: age, sex, acquisition of infection, urinary tract infection, procalcitonin, transfer to ICU within 48 hrs, APACHE II score, pulmonary disease, Charlson’s WIC score. †Others included respiratory tract, skin and soft tissue, and central nervous system infections.

Abbreviations: ESBL, extended-spectrum beta-lactamase; PTZ, piperacillin-tazobactam; IPTW, inverse probability of treatment weights; IQR, interquartile range

Supplementary Table 9. 30-day mortality for 224 patients with ESBL-B empirically treated with carbapenem or PTZ, in a propensity score weighted cohort

Variables / Univariate analysis / Multivariate analysis
HR (95% CI) / P value / HR (95% CI) / P value
Empirical PTZ use / 0.94 (0.30-2.93) / 0.91 / 1.21 (0.37-4.00) / 0.75
Age / 1.02 (0.99-1.05) / 0.20 / 1.03 (1.00-1.06) / 0.09
K. pneumoniae infection* / 1.43 (0.54-3.76) / 0.47 / 2.90 (0.89-9.47) / 0.08
Antibiotic administration interval† / 1.00 (0.97-1.03) / 0.93 / 1.02 (0.99-1.05) / 0.31
Source of infection
Primary bacteremia / 1 / 1
Catheter-related BSI / 3.25 (0.58-18.08) / 0.18 / 3.12 (0.45-21.84) / 0.25
Urinary tract / 0.17 (0.03-1.09) / 0.06 / 0.06 (0.01-0.44) / 0.01
Intra-abdominal / 1.92 (0.70-5.25) / 0.20 / 1.20 (0.39-3.73) / 0.75
Others‡ / 1.21 (0.21-6.81) / 0.83 / 0.61 (0.09-4.01) / 0.61
Transfer to ICU within 48 hrs / 3.92 (1.66-9.28) / < 0.01 / 4.55 (1.67-12.44) / < 0.01
APACHE II / 1.05 (1.00-1.11) / 0.08 / 1.03 (0.96-1.10) / 0.42
Charlson’s WIC / 1.03 (0.87-1.20) / 0.75 / 0.99 (0.84-1.16) / 0.85

*Compared to E. coli infection. †Time interval from the diagnosis of bacteremia to administration of appropriate antibiotics. ‡Others included respiratory tract, skin and soft tissue, and central nervous system infections.

Abbreviations: ESBL, extended-spectrum beta-lactamase; PTZ, piperacillin-tazobactam; BSI, bloodstream infection; ICU, intensive care unit; APACHE, acute physiology and chronic health evaluation; WIC, weighted index of comorbidity