Table 1.
In vitro antimicrobial resistance rates of E. coli bloodstream isolates to antimicrobials, 1998–2007
| Antimicrobial | 1998–99 | 2000–01 | 2002–03 | 2004–05 | 2006–07 | Overall | P value* |
|---|---|---|---|---|---|---|---|
| Ampicillin | 28/87 (32) | 27/80 (34) | 35/103 (34) | 36/98 (37) | 48/91 (53) | 174/459 (38) | 0.004 |
| Ampicillin/sulbactam | 20/87 (23) | 24/80 (30) | 30/103 (29) | 32/98 (33) | 41/91 (45) | 147/459 (32) | 0.002 |
| Cefazolin | 2/87 (2) | 1/80 (1) | 3/103 (3) | 3/98 (3) | 5/91 (5) | 14/459 (3) | 0.239 |
| Cefepime | 1/86 (1) | 0/75 (0) | 0/95 (0) | 1/89 (1) | 0/82 (0) | 2/427 (0) | 0.614 |
| Ceftazidime | 1/87 (1) | 1/80 (1) | 0/103 (0) | 1/98 (1) | 2/91 (2) | 5/459 (1) | 0.514 |
| Ciprofloxacin | 0/87 (0) | 4/80 (5) | 9/103 (9) | 7/98 (7) | 11/91 (12) | 31/459 (7) | 0.003 |
| Gentamicin | 1/87 (1) | 3/80 (4) | 4/103 (4) | 3/98 (3) | 4/91 (4) | 15/459 (3) | 0.241 |
| Imipenem | 0/86 (0) | 0/75 (0) | 0/95 (0) | 0/89 (0) | 0/82 (0) | 0/427 (0) | — |
| Levofloxacin | 0/86 (0) | 3/75 (4) | 9/95 (9) | 7/89 (8) | 9/82 (11) | 28/427 (7) | 0.004 |
| Meropenem | 0/86 (0) | 0/75 (0) | 0/95 (0) | 0/88 (0) | 0/82 (0) | 0/426 (0) | — |
| Piperacillin/tazobactam | 0/86 (0) | 0/75 (0) | 4/95 (4) | 0/89 (0) | 1/83 (1) | 5/428 (1) | 0.515 |
| Trimethoprim/sulfamethoxazole | 8/87 (9) | 17/80 (21) | 22/103 (21) | 15/98 (15) | 25/91 (27) | 87/459 (19) | 0.002 |
Data are shown as number of non-susceptible isolates/number of isolates tested (%).
In vitro antimicrobial susceptibility results were not available for two E. coli bloodstream isolates.
*P value denotes a one-degree of freedom test for linear trend using logistic regression.