TABLE 1.
Comparative activity of 12 antimicrobials against Gram-negative clinical isolates from 10 medical centres
| Organism (number) | Antimicrobial agent | MIC (μg/mL)* | Resistant (%) | ||
|---|---|---|---|---|---|
| 50% | 90% | Range | |||
| Escherichia coli (373) | Cefotaxime | ≤0.06 | 0.12 | ≤0.06 – 1.0 | 0 |
| Ceftazidime | ≤0.50 | ≤0.50 | ≤0.50 – 1.0 | 1.1 | |
| Ceftriaxone | ≤0.50 | ≤0.50 | ≤0.50 – 1.0 | 0 | |
| Cefepime | ≤0.06 | ≤0.06 | ≤0.06 – 0.25 | 0 | |
| Piperacillin | 2.0 | >512.0 | ≤1.0 – >512.0 | 19.0 | |
| Piperacillin/tazobactam | 2.0 | 16.0 | ≤1.0 – >256.0 | 2.3 | |
| Ticarcillin/clavulanate | 2.0 | 64.0 | ≤1.0 – >256.0 | 5.8 | |
| Imipenem | 0.25 | 0.50 | ≤0.06 – 4.0 | 0 | |
| Gentamicin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 2.9 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 – 8.0 | 1.8 | |
| Ciprofloxacin | ≤0.06 | ≤0.06 | ≤0.06 – 8.0 | 1.1 | |
| TMP/SMX | ≤0.50 | >16.0 | ≤0.50 – >16.0 | 12.2 | |
| Klebsiella pneumoniae (247) | Cefotaxime | ≤0.06 | 0.12 | ≤0.06 – >64.0 | 1.1 |
| Ceftazidime | ≤0.50 | ≤0.50 | ≤0.50 – >128 | 2.9 | |
| Ceftriaxone | ≤0.50 | ≤0.50 | ≤0.50 – 128.0 | 0.4 | |
| Cefepime | ≤0.06 | 0.12 | ≤0.06 – 0.50 | 0 | |
| Piperacillin | 16.0 | 512.0 | ≤1.0 – >512.0 | 17.6 | |
| Piperacillin/tazobactam | 4.0 | 32.0 | ≤1.0 – >512.0 | 6.9 | |
| Ticarcillin/clavulanate | 2.0 | 16.0 | ≤1.0 – >256.0 | 2.7 | |
| Imipenem | 0.50 | 1.0 | ≤0.06 – 4.0 | 0 | |
| Gentamicin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 0.4 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 | 0 | |
| Ciprofloxacin | ≤0.06 | 0.12 | ≤0.06 – 0.50 | 0 | |
| TMP/SMX | 2.0 | 4.0 | ≤0.50 – >16.0 | 10.9 | |
| Citrobacter freundii (159) | Cefotaxime | 0.25 | 16.0 | ≤0.06 – >64.0 | 6.8 |
| Ceftazidime | ≤0.50 | 32.0 | ≤0.50 – >128.0 | 13.9 | |
| Ceftriaxone | ≤0.50 | 32.0 | ≤0.50 – >128.0 | 7.8 | |
| Cefepime | ≤0.06 | 0.25 | ≤0.06 – 2.0 | 0 | |
| Piperacillin | 8.0 | 512.0 | ≤1.0 – >512.0 | 18.4 | |
| Piperacillin/tazobactam | 4.0 | 64.0 | ≤1.0 – 256.0 | 5.1 | |
| Ticarcillin/clavulanate | 2.0 | 128.0 | ≤1.0 – >256.0 | 12.9 | |
| Imipenem | 1.0 | 4.0 | ≤0.06 – 4.0 | 0 | |
| Gentamicin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 2.6 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 1.7 | |
| Ciprofloxacin | ≤0.06 | ≤0.06 | ≤0.06 – 8.0 | 1.7 | |
| TMP/SMX | 1.0 | >16.0 | ≤0.50 – >16.0 | 21.6 | |
| Proteus vulgaris (23) | Cefotaxime | 0.50 | 2.0 | ≤0.06 – 8.0 | 0 |
| Ceftazidime | ≤0.50 | ≤0.50 | ≤0.50 – 2.0 | 0 | |
| Ceftriaxone | ≤0.50 | 64.0 | ≤0.50 – 64.0 | 12.7 | |
| Cefepime | 0.50 | 0.50 | ≤0.06 – 0.50 | 0 | |
| Piperacillin | 2.0 | 4.0 | ≤1.0 – 128.0 | 6.2 | |
| Piperacillin/tazobactam | 2.0 | 2.0 | ≤1.0 – 4.0 | 0 | |
| Ticarcillin/clavulanate | 2.0 | >256.0 | 2.0 – >256.0 | 6.4 | |
| Imipenem | 2.0 | 2.0 | 0.50 – 4.0 | 0 | |
| Gentamicin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 8.7 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 – 8.0 | 0 | |
| Ciprofloxacin | ≤0.06 | ≤0.06 | ≤0.06 – 0.12 | 0 | |
| TMP/SMX | 2.0 | 16.0 | ≤0.50 – >16.0 | 22.7 | |
| Proteus mirabilis (16) | Cefotaxime | 0.50 | 0.50 | ≤0.06 – >64.0 | 3.3 |
| Ceftazidime | ≤0.50 | ≤0.50 | ≤0.50 – 64.0 | 1.4 | |
| Ceftriaxone | ≤0.50 | ≤0.50 | ≤0.50 – 2.0 | 0 | |
| Cefepime | 0.50 | 0.50 | ≤0.06 – 1.0 | 0 | |
| Piperacillin | 2.0 | 8.0 | ≤1.0 – >512.0 | 18.8 | |
| Piperacillin/tazobactam | 2.0 | 2.0 | ≤1.0 – 2.0 | 0 | |
| Ticarcillin/clavulanate | 2.0 | 2.0 | 2.0 – >256.0 | 1.4 | |
| Imipenem | 1.0 | 4.0 | 0.50 – 8.0 | 6.2 | |
| Gentamicin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 8.7 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 – 8.0 | 0 | |
| Ciprofloxacin | ≤0.06 | ≤0.06 | ≤0.06 – 0.12 | 0 | |
| TMP/SMX | 2.0 | 16.0 | ≤0.50 – >16.0 | 22.7 | |
| Providencia species (10) | Cefotaxime | 1.0 | 4.0 | ≤0.50 – 4.0 | 0 |
| Ceftazidime | ≤0.50 | 1.0 | ≤0.50 – 16.0 | 0 | |
| Ceftriaxone | ≤0.50 | ≤0.50 | ≤0.50 – 4.0 | 0 | |
| Cefepime | ≤0.06 | 0.50 | ≤0.06 – 0.50 | 0 | |
| Piperacillin | 2.0 | 32.0 | <1.0 – 512.0 | 10.0 | |
| Piperacillin/tazobactam | ≤1.0 | 4.0 | ≤1.0 – 8.0 | 0 | |
| Ticarcillin/clavulanate | 2.0 | 16.0 | ≤1.0 – 16.0 | 0 | |
| Imipenem | 1.0 | 8.0 | ≤0.06 – 16.0 | 10.0 | |
| Gentamicin | 8.0 | >16 | ≤4.0 – >16.0 | 40.0 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 | 0 | |
| Ciprofloxacin | ≤0.06 | ≤0.06 | ≤0.06 | 0 | |
| TMP/SMX | 16.0 | >16.0 | ≤0.50 – >16.0 | 40.0 | |
| Enterobacter cloacae (550) | Cefotaxime | 1.0 | >64.0 | ≤0.06 – >64.0 | 16.8 |
| Ceftazidime | 8.0 | >128.0 | ≤0.50 – >128.0 | 28.9 | |
| Ceftriaxone | ≤0.5 | >128.0 | ≤0.5 – >128.0 | 18.5 | |
| Cefepime | 0.12 | 2.0 | ≤0.06 – 8.0 | 0.2 | |
| Piperacillin | 16.0 | 512.0 | ≤1.0 – >512.0 | 32.4 | |
| Piperacillin/tazobactam | 8.0 | 256.0 | ≤1.0 – >512.0 | 16.9 | |
| Ticarcillin/clavulanate | 32.0 | >256.0 | ≤1.0 – >256.0 | 43.6 | |
| Imipenem | 1.0 | 4.0 | ≤0.06 –>64.0 | 1.1 | |
| Gentamicin | ≤4.0 | 8.0 | ≤4.0 – >16.0 | 7.6 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 2.8 | |
| Ciprofloxacin | ≤0.06 | 0.12 | ≤0.06 – 8.0 | 0.9 | |
| TMP/SMX | 1.0 | 2.0 | ≤0.50 – >16.0 | 7.8 | |
| Enterobacter species† (132) | Cefotaxime | 0.25 | 32.0 | ≤0.06 – >64.0 | 7.7 |
| Ceftazidime | ≤0.50 | 128.0 | ≤0.50 – >128.0 | 18.9 | |
| Ceftriaxone | 0.50 | 64.0 | ≤0.50 – >128.0 | 10.3 | |
| Cefepime | ≤0.06 | 0.50 | ≤0.06 – 32.0 | 0.8 | |
| Piperacillin | 8.0 | 128.0 | <1.0 – >512.0 | 11.4 | |
| Piperacillin/tazobactam | 8.0 | 64.0 | ≤1.0 – 256.0 | 7.6 | |
| Ticarcillin/clavulanate | 4.0 | 256.0 | ≤1.0 – 256.0 | 22.2 | |
| Imipenem | 4.0 | 8.0 | ≤0.06 – 16.0 | 2.3 | |
| Gentamicin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 3.4 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 3.4 | |
| Ciprofloxacin | ≤0.06 | 1.0 | ≤0.06 – 8.0 | 5.1 | |
| TMP/SMX | ≤0.50 | 2.0 | ≤0.50 – >16.0 | 8.5 | |
| Serratia marcescens (189) | Cefotaxime | 0.25 | 2.0 | ≤0.06 – 64.0 | 0.7 |
| Ceftazidime | ≤0.50 | ≤0.50 | ≤0.50 – 32.0 | 0.5 | |
| Ceftriaxone | ≤0.50 | 1.0 | ≤0.50 – 32.0 | 0 | |
| Cefepime | ≤0.06 | 0.25 | ≤0.06 – 16.0 | 0 | |
| Piperacillin | 8.0 | >512.0 | ≤1.0 – >512.0 | 28.2 | |
| Piperacillin/tazobactam | 2.0 | 16.0 | ≤1.0 – >512.0 | 1.6 | |
| Ticarcillin/clavulanate | 8.0 | 128.0 | ≤1.0 – >256.0 | 14.0 | |
| Imipenem | 2.0 | 4.0 | ≤0.06 – 8.0 | 2.6 | |
| Gentamicin | ≤4.0 | 16.0 | ≤4.0 – >16.0 | 26.2 | |
| Tobramycin | ≤4.0 | 16.0 | ≤4.0 – >16.0 | 22.1 | |
| Ciprofloxacin | ≤0.06 | 0.50 | ≤0.06 – 8.0 | 2.7 | |
| TMP/SMX | 2.0 | 8.0 | ≤0.50 – >16.0 | 31.3 | |
| Morganella morganii (57) | Cefotaxime | 0.12 | 16.0 | ≤0.06 – 16.0 | 0 |
| Ceftazidime | ≤0.50 | 32.0 | ≤0.50 – >128.0 | 10.5 | |
| Ceftriaxone | 0.50 | 2.0 | ≤0.50 – 32.0 | 0 | |
| Cefepime | ≤0.06 | 0.12 | ≤0.06 – 0.25 | 0 | |
| Piperacillin | 4.0 | 256.0 | ≤1.0 – >512.0 | 17.5 | |
| Piperacillin/tazobactam | ≤1.0 | 32.0 | ≤1.0 – 256.0 | 3.5 | |
| Ticarcillin/clavulanate | 4.0 | 32.0 | ≤1.0 – 128.0 | 4.2 | |
| Imipenem | 8.0 | 16.0 | ≤0.06 – 16.0 | 28.0 | |
| Gentamicin | ≤4.0 | ≤4.0 | ≤4.0 – 8.0 | 0 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 – 16.0 | 2.1 | |
| Ciprofloxacin | ≤0.06 | 0.12 | ≤0.06 – 0.12 | 0 | |
| TMP/SMX | 2.0 | >16.0 | ≤0.50 – >16.0 | 14.6 | |
| Pseudomonas aeruginosa (228) | Cefotaxime | 32.0 | >64.0 | ≤0.06 – >64.0 | 43.2 |
| Ceftazidime | 4.0 | 32.0 | ≤0.50 – >128.0 | 11.7 | |
| Ceftriaxone | 32.0 | >128.0 | ≤0.50 – >128.0 | 32.2 | |
| Cefepime | 2.0 | 16.0 | ≤0.06 – 64.0 | 28.6 | |
| Piperacillin | 16.0 | 512.0 | ≤1.0 – >512.0 | 12.6 | |
| Piperacillin/tazobactam | 8.0 | 128.0 | ≤1.0 – >512.0 | 10.9 | |
| Ticarcillin/clavulanate | 32.0 | 128.0 | ≤1.0 – >256.0 | 10.3 | |
| Imipenem | 4.0 | 64.0 | ≤0.06 – 64.0 | 23.3 | |
| Gentamicin | ≤4.0 | 16.0 | ≤4.0 – >16.0 | 15.1 | |
| Tobramycin | ≤4.0 | ≤4.0 | ≤4.0 – >16.0 | 2.7 | |
| Ciprofloxacin | 0.25 | 2.0 | ≤0.06 – 32.0 | 4.8 | |
| TMP/SMX | >16.0 | >16.0 | >16.0 | 100 | |
*
Minimum inhibitory concentration (MIC) for 50 and 90% of isolates tested.
†
Includes 68 isolates of Enterobacter aerogenes, 27 isolates of Enterobacter agglomerans and 39 Enterobacter species.
TMP/SMX Trimethoprim-sulfamethoxazole