Background
Methods
Study population
Strain identification and antimicrobial susceptibility test
Molecular characterization of β-lactamases
Capsular genotype
Pulsed-field gel electrophoresis (PFGE)
Data collection
Statistical analyses
Results
Microbiological characteristics
Antimicrobial agent | MICarange (μg/mL) | MIC50
b(μg/mL) | MIC90
c(μg/mL) | No. (%) of isolates susceptible |
---|---|---|---|---|
Tigecycline | 3-32 | 6 | 8 | |
Ciprofloxacin | <0.25 to >4 | 2 | >4 | 15 (42) |
Levofloxacin | 0.5 to >8 | >8 | >8 | 14 (39) |
Ampicillin-sulbactam | 8 to >32 | >32 | >32 | 2 (6) |
Piperacillin-tazobactam*
| 8 to >128 | 32 | >128 | 12 (48) |
Cefazolin | <1 to >64 | >64 | >64 | 13 (36) |
Ceftriaxone | <1 to >64 | <1 | >64 | 21 (58) |
Ceftazidime | <1 to >64 | 16 | >64 | 16 (44) |
Cefepime | <1 to >64 | <1 | >64 | 23 (64) |
Amikacin | <2 to >64 | <2 | 16 | 33 (92) |
Gentamicin | <1 to >16 | <1 | >16 | 22 (61) |
Ertapenem | <0.5 to >8 | <0.5 | 4 | 28 (78) |
Imipenem | <0.25 to 4 | <1 | <1 | 34 (94) |
Isolate | Tigecycline MIC | Ertapenem MIC | TEM | SHV | CTX-M | DHA-1 |
---|---|---|---|---|---|---|
1 | 3 | <0.5 | — | SHV-1 | — | + |
2 | 3 | <0.5 | — | SHV-12 | — | + |
3 | 3 | 8 | — | -a
| — | — |
4 | 3 | <0.5 | TEM-1 | SHV-11 | — | — |
5 | 4 | <0.5 | TEM-1 | SHV-11 | CTXM-15 | + |
6 | 4 | 2 | — | SHV-1 | CTXM-15 | + |
7 | 4 | <0.5 | — | SHV-12 | — | + |
8 | 4 | <0.5 | — | SHV-31 | — | + |
9 | 4 | <0.5 | TEM-1 | SHV-2 | — | — |
10 | 4 | 1 | TEM-1 | SHV-1 | CTXM-15 | + |
11 | 6 | 8 | — | SHV-2 | — | + |
12 | 6 | 4 | — | SHV-1 | — | + |
13 | 6 | <0.5 | TEM-1 | SHV-1 | CTXM-15 | + |
14 | 6 | <0.5 | TEM-1 | SHV-1 | CTXM-15 | + |
15 | 6 | <0.5 | TEM-1 | SHV-11 | — | + |
16 | 6 | 1 | TEM-1 | SHV-11 | — | + |
17 | 8 | 1 | TEM-1 | SHV-11 | CTXM-14 | + |
18 | 8 | <0.5 | — | SHV-12 | — | + |
19 | 8 | <0.5 | — | —a
| — | + |
20 | 8 | 8 | — | SHV-31 | — | — |
21 | 16 | <0.5 | — | SHV-11 | — | + |
22 | 32 | <0.5 | TEM-1 | SHV-11 | — | + |
Clinical characteristics
Characteristic | n (%) |
---|---|
Age (years, median, IQR) | 75.5, 63.5–81.7 |
Male sex | 27 (75) |
Underlying disease | |
Immunosuppressiona
| 9 (25) |
Diabetes mellitus | 18 (50) |
Chronic obstructive lung disease | 5 (13.9) |
Cerebral vascular disease | 10 (27.8) |
Chronic kidney disease, stage = 4 or 5 | 13 (36.1) |
Hemodialysis | 11 (30.6) |
Malignancy | 14 (38.9) |
Hematological malignancy | 3 ( 8.3) |
Solid tumor | 11 (30.6) |
Liver cirrhosis | 3 (8.3) |
Charlson comorbidity score (median, IQR) | 3, 2–6 |
Community-acquired infections
| 3 ( 8.3) |
Healthcare-associated infectionsb
| 6 (16.7) |
Nosocomial infectionsb
| 27 (75) |
ICU | 14 (38.9) |
Medical ward | 8 (22.2) |
Surgical ward | 5 (13.9) |
Polymicrobial infection | 2 (5.6) |
Antibiotic exposure in the past 30 days, ≥3 days | |
Any | 29 (80.6) |
Tigecycline | 13 (36.1) |
Glycopeptides | 11 (30.6) |
β-lactams plus β-lactamase inhibitors | 12 (33.3) |
First- and second-generation cephalosporins | 11 (30.6) |
Third- or fourth-generation cephalosporins | 10 (27.8) |
Carbapenem | 9 (25) |
Fluoroquinolones | 8 (22.2) |
Metronidazole | 9 (25) |
Ward, duration of stay and devices at the time of bacteremia | |
Acquired after ICU >48 h | 14 (38.9) |
Days of hospitalization before bacteremia (median, IQR) | 48, 18–82 |
Urinary catheter | 17 (47.2) |
Central venous catheter | 23 (63.9) |
Mechanical ventilation | 18 (50) |
Pitt bacteremia score (mean ± SD) | 4 ± 4 |
APACHE II score (mean ± SD) | 23 ± 10 |
Infection sources and clinical syndrome | |
Pneumonia | 10 (27.8) |
Intra-abdominal infection other than biliary-tract infection | 5 (13.9) |
Biliary-tract infection | 7 (19.4) |
Skin and soft-tissue infection | 2 (5.6) |
Catheter infection | 1 (2.8) |
Urinary-tract infection | 1 (2.8) |
Unknown primary focus | 10 (27.8) |
Appropriate antibiotic treatment | 17 (47.2) |
Outcome | |
Presentation with septic shock | 19 (52.8) |
Requiring admission to ICU after bacteremia | 19 (52.8) |
In-hospital death | 17 (47.2) |
28-day mortality | 14 (38.9) |
Survivors (n = 22), n (%) | Non-survivors (n = 14), n (%) | p | Adjustedpa
| |
---|---|---|---|---|
Age (years, median, IQR) | 76.5, 69.3–84.3 | 71, 60.3–79 | 0.175 | |
Male sex | 17 (77.3) | 10 (71.4) | 0.988 | |
Underlying disease | ||||
Immunosuppressionb
| 5 (22.7) | 4 (28.6) | 0.988 | |
Diabetes mellitus | 9 (40.9) | 9 (64.3) | 0.305 | |
Chronic obstructive lung disease | 2 (9.1) | 3 (21.4) | 0.574 | |
Hemodialysis | 5 (22.7) | 6 (42.9) | 0.364 | |
Malignancy | 7 (31.8) | 7 (50) | 0.458 | |
Liver cirrhosis | 2 ( 9.1) | 1 (7.1) | 1.000 | |
Cerebral vascular disease | 6 (27.3) | 4 (28.6) | 1.000 | |
Charlson comorbidity score (median, IQR) | 3, 2–5 | 4, 3–8.3 | 0.171 | |
Pitt bacteremia score (mean ± SD) | 3.3 ± 3.1 | 5.9 ± 3.7 | 0.037 | 0.847 |
APACHE II score (mean ± SD) | 20.1 ± 0.6 | 27.6 ± 11.0 | 0.016 | 0.958 |
Acquired after ICU >48 h | 3 (13.6) | 11 (78.6) | <0.001 | 0.021 |
Infection sources and clinical syndrome | ||||
Pneumonia | 3 (13.6) | 7 (50) | 0.047 | 0.569 |
Intra-abdominal infection other than biliary-tract infection | 2 (9.1) | 3 (21.4) | 0.574 | |
Biliary-tract infection | 7 (31.8) | 0 (0) | ||
Unknown primary focus | 8 (36.4) | 2 (14.3) | 0.289 | |
Presentation with septic shock | 9 (40.9) | 10 (71.4) | 0.147 | |
Appropriate antibiotic treatment | 12 (54.6) | 6 (42.9) | 0.733 | |
Ertapenem non-susceptibility | 6 (27.3) | 2 (14.3) | 0.628 | |
Tigecycline MIC >4 μg/mL | 10 (45.5) | 8 (57.1) | 0.733 | |
Tigecycline MIC >6 μg/mL | 4 (18.2) | 6 (42.9) | 0.220 | |
ESBL-producing strain | 10 (45.5) | 8 (57.1) | 0.733 |