Fig. 1.
In vitro antimicrobial activity against Pseudomonas aeruginosa isolates including total and multidrug-resistant strains_
| Organism/antimicrobial | MIC50 (mg/l) | MIC90 (mg/l) | MIC range (mg/l) | % S |
|---|---|---|---|---|
| P. aeruginosa (n = 100) | ||||
| Amikacin | ≤ 2 | 16 | ≤ 2 to ≥ 64 | 93 |
| Gentamicin | ≤ 1 | 8 | ≤ 1 to ≥ 16 | 87 |
| Aztreonam | 8 | ≥ 64 | ≤ 1 to ≥ 64 | 82 |
| Ciprofloxacin | ≤ 0.25 | ≥ 4 | ≤ 0.25 to ≥ 4 | 68 |
| Ceftazidime-avibactam | 4 | 8 | ≤ 1 to ≥ 128 | 95 |
| Ceftazidime | 4 | 32 | ≤ 1 to ≥ 128 | 76 |
| Cefepime | 2 | 32 | ≤ 1 to ≥ 64 | 82 |
| Imipenem | 2 | ≥ 16 | ≤ 0.25 to ≥ 16 | 76 |
| Meropenem | 0.5 | ≥ 16 | ≤ 0.25 to ≥ 16 | 75 |
| Piperacillin-tazobactam | 8 | ≥ 128 | ≤ 4 to ≥ 128 | 72 |
| Colistin | 1 | 2 | ≤ 0.5 to ≥ 128 | 91 |
| MDR P. aeruginosa (n = 37) | ||||
| Amikacin | 4 | ≥ 64 | ≤ 2 to ≥ 64 | 81.1 |
| Gentamicin | 4 | ≥ 16 | < 1 to ≥ 16 | 37.6 |
| Aztreonam | 16 | ≥ 64 | ≤ 1 to ≥ 64 | 21.6 |
| Ciprofloxacin | ≥ 4 | ≥ 4 | ≤ 0.25 to ≥ 4 | 24.3 |
| Ceftazidime-avibactam | 4 | 16 | ≤ 1 to ≥ 128 | 86.5 |
| Ceftazidime | 16 | 128 | 2 to ≥ 128 | 45.9 |
| Cefepime | 8 | ≥ 64 | ≤ 1 to ≥ 64 | 51.4 |
| Imipenem | ≥ 16 | ≥ 16 | 1 to ≥ 16 | 43.2 |
| Meropenem | 8 | ≥ 16 | ≤ 0.25 to ≥ 16 | 37.8 |
| Piperacillin-tazobactam | 64 | ≥ 128 | ≤ 4 to ≥ 128 | 27.0 |
| Colistin | 1 | 4 | ≤ 0.5 to ≥ 128 | 89.2 |
Characteristics and antimicrobial susceptibility profiles of carbapenemase-producing Pseudomonas aeruginosa isolates_
| Characteristics | PA-57 | PA-16 | PA-28 | PA-40 |
|---|---|---|---|---|
| Carbapenemase | IMP | IMP + KPC | KPC | KPC |
| Clinical specimen | Genitourinary | Genitourinary | Genitourinary | Respiratory |
| MIC Values (mg/l) | ||||
| Amikacin | ≥ 64 | ≥ 64 | 4 | ≤ 2 |
| Gentamicin | ≥ 16 | ≥ 16 | 4 | 2 |
| Aztreonam | 32 | 32 | ≥ 64 | ≥ 64 |
| Ciprofloxacin | ≥ 4 | ≥ 4 | ≥ 4 | ≥ 4 |
| Ceftazidime-avibactam | ≥ 128 | ≥ 128 | 8 | 16 |
| Ceftazidime | ≥ 128 | ≥ 128 | 16 | 64 |
| Cefepime | ≥ 64 | 32 | ≥ 64 | 16 |
| Imipenem | ≥ 16 | ≥ 16 | ≥ 16 | ≥ 16 |
| Meropenem | ≥ 16 | ≥ 16 | ≥ 16 | ≥ 16 |
| Piperacillin-tazobactam | ≥ 128 | ≥ 128 | ≥ 128 | ≥ 128 |
| Colistin | ≤ 0.5 | 1 | 2 | 8 |
In vitro antimicrobial activity against Pseudomonas aeruginosa isolates including carbapenem-resistant and difficult-to-treat strains_
| Organism/antimicrobial | MIC50 (mg/l) | MIC90 (mg/l) | MIC range (mg/l) | % S |
|---|---|---|---|---|
| CR P. aeruginosa (n = 27) | ||||
| Amikacin | 4 | ≥ 64 | ≤ 2 to ≥ 64 | 74.1 |
| Gentamicin | 2 | ≥ 16 | ≤ 1 to ≥ 16 | 66.7 |
| Aztreonam | 16 | ≥ 64 | ≤ 1 to ≥ 64 | 25.9 |
| Ciprofloxacin | ≥ 4 | ≥ 4 | ≤ 0.25 to ≥ 4 | 29.6 |
| Ceftazidime-avibactam | 4 | 16 | ≤ 1 to ≥ 128 | 85.2 |
| Ceftazidime | 8 | 64 | 2 to ≥ 128 | 51.9 |
| Cefepime | 8 | ≥ 64 | ≤ 1 to ≥ 64 | 51.9 |
| Imipenem | ≥ 16 | ≥ 16 | 2 to ≥ 16 | 11.1 |
| Meropenem | ≥ 16 | ≥ 16 | 0.5 to ≥ 16 | 7.4 |
| Piperacillin-tazobactam | 32 | ≥ 128 | ≤ 4 to ≥ 128 | 44.4 |
| Colistin | 1 | 4 | ≤ 0.5 to ≥ 128 | 88.9 |
| DTR P. aeruginosa (n = 9) | ||||
| Amikacin | ≥ 64 | ≥ 64 | ≤ 2 to ≥ 64 | 33.3 |
| Gentamicin | ≥ 16 | ≥ 16 | 2 to ≥ 16 | 33.3 |
| Aztreonam | 32 | ≥ 64 | 16 to ≥ 64 | 0 |
| Ciprofloxacin | ≥ 4 | ≥ 4 | ≥ 4 to ≥ 4 | 0 |
| Ceftazidime-avibactam | 4 | ≥ 128 | ≤ 1 to ≥ 128 | 66.7 |
| Ceftazidime | 64 | ≥ 128 | 16 to ≥ 128 | 0 |
| Cefepime | 32 | ≥ 64 | 16 to ≥ 64 | 0 |
| Imipenem | ≥ 16 | ≥ 16 | 8 to ≥ 16 | 0 |
| Meropenem | ≥ 16 | ≥ 16 | 8 to ≥ 16 | 0 |
| Piperacillin-tazobactam | ≥ 128 | ≥ 128 | 32 to ≥ 128 | 0 |
| Colistin | 1 | 8 | ≤ 0.5 to 8 | 77.8 |
Culture source and clinical characteristics of patients infected with multidrug-resistant and non-multidrug-resistant Pseudomonas aeruginosa_
| Demographic parameter | No. of isolates (%) | p-value | |
|---|---|---|---|
| Non-multidrug-resistant P. aeruginosa (n = 63) | Multidrug-resistant P. aeruginosa* (n = 37) | ||
| Male gender | 44 (69.8) | 27 (73.0) | 0.916 |
| Age groups (years) | 0.291 | ||
| < 18 | 7 (11.1) | 1 (2.7) | |
| 18–64 | 23 (36.5) | 13 (35.1) | |
| ≥ 65 | 33 (52.4) | 23 (62.2) | |
| ICU admission | 9 (14.3) | 8 (21.6) | 0.505 |
| Surgical department† | 25 (39.7) | 13 (35.1) | 0.811 |
| Clinical specimen | 1.000 | ||
| Respiratory | 31 (49.2) | 22 (59.5) | |
| Genitourinary | 16 (25.3) | 9 (24.3) | |
| Skin and soft tissue | 10 (15.9) | 6 (16.2) | |
| Gastrointestinal | 3 (4.8) | 0 (0) | |
| Blood | 1 (1.6) | 0 (0) | |
| Bone and joint | 2 (3.2) | 0 (0) | |
| Treatment characteristic | |||
| ≥ 1 active agentx‡ | 45 (71.4) | 21 (56.8) | 0.202 |
| Use of carbapenem | 11 (17.5) | 18 (48.6) | 0.002 |
| Use of colistin | 3 (4.8) | 10 (27.0) | 0.004 |
| Clinical success | 54 (85.7) | 24 (64.9) | 0.029 |
| Death attributable to P. aeruginosa | 6 (9.5) | 10 (27.0) | 0.043 |