TABLE 3.
Distribution of MICs for study isolates
| Antimicrobial agent | β-Lactamasea | No. of isolates with the following MIC (μg/ml)b:
|
||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.004 | 0.008 | 0.015 | 0.03 | 0.06 | 0.12 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | ≥ 64 | ||
| Cefazolin | None | 34 | 98 | 24 | 15 | 7 | 2 | 11 | ||||||||
| ESBL | 1 | 3 | 5 | 1 | 35 | |||||||||||
| pAmpC | 24 | |||||||||||||||
| ESBL + pAmpC | 4 | |||||||||||||||
| Ceftriaxone | None | 1 | 6 | 61 | 78 | 31 | 4 | 2 | 3 | 2 | 2 | 1 | ||||
| ESBL | 3 | 2 | 3 | 5 | 2 | 7 | 5 | 18 | ||||||||
| pAmpC | 3 | 2 | 7 | 7 | 5 | |||||||||||
| ESBL + pAmpC | 1 | 3 | ||||||||||||||
| Cefotaxime | None | 1 | 3 | 25 | 104 | 29 | 13 | 7 | 5 | 2 | 1 | 1 | ||||
| ESBL | 2 | 1 | 6 | 3 | 3 | 3 | 7 | 5 | 15 | |||||||
| pAmpC | 1 | 2 | 5 | 9 | 3 | 4 | ||||||||||
| ESBL + pAmpC | 1 | 1 | 2 | |||||||||||||
| Ceftazidime | None | 1 | 1 | 9 | 75 | 75 | 22 | 2 | 1 | 4 | 3 | 1 | 2 | |||
| ESBL | 2 | 1 | 2 | 2 | 3 | 7 | 2 | 26 | ||||||||
| pAmpC | 2 | 2 | 10 | 10 | ||||||||||||
| ESBL + pAmpC | 1 | 3 | ||||||||||||||
| Cefepime | None | 1 | 5 | 79 | 69 | 20 | 8 | 5 | 1 | 2 | 1 | |||||
| ESBL | 1 | 3 | 1 | 7 | 8 | 13 | 2 | 3 | 7 | |||||||
| pAmpC | 1 | 1 | 7 | 8 | 5 | 1 | 1 | |||||||||
| ESBL + pAmpC | 1 | 1 | 2 | |||||||||||||
| Aztreonam | None | 1 | 4 | 23 | 89 | 39 | 24 | 2 | 1 | 1 | 3 | 1 | 2 | 2 | ||
| ESBL | 1 | 3 | 2 | 5 | 2 | 7 | 25 | |||||||||
| pAmpC | 1 | 1 | 4 | 5 | 5 | 6 | 2 | |||||||||
| ESBL + pAmpC | 1 | 1 | 2 | |||||||||||||
a
The β-lactamase detected by ESBL- and/or pAmpC-directed PCR amplification.
b
Underlined numbers indicate susceptible category by current CLSI recommendations (≤8 μg/ml). Isolates for which cefpodoxime MICs were ≥8 μg/ml or the MICs of extended-spectrum cephalosporins were ≥1 μg/ml were subjected to PCR for detection of ESBL and pAmpC genes.