TABLE 2.
Antibiogram of Washington and Canadian S. pneumoniae isolates
| Isolate | MIC (μg/ml) of druga:
|
|||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pen | Ceftri | Ctax | Cefpro | Ceftaz | Lora | Eryth | Azith | Clin | Cipro | Grepa | Levo | Spar | Trova | Linez | HMR | |
| Related isolates | ||||||||||||||||
| WA1 | 2 | 2 | 2 | 16 | 16 | 128 | 4 | 2 | 0.03 | 16 | 0.25 | 1 | 0.5 | 0.125 | 1 | 0.002 |
| WA2 | 2 | 1 | 2 | 16 | 16 | 64 | 4 | 4 | 0.016 | 16 | 0.25 | 1 | 0.5 | 0.06 | 1 | 0.002 |
| WA3 | 2 | 2 | 2 | 16 | 16 | 128 | 8 | 2 | 0.03 | 16 | 0.25 | 1 | 0.5 | 0.06 | 1 | 0.016 |
| WA4 | 2 | 1 | 2 | 16 | 16 | 128 | 4 | 2 | 0.03 | 16 | 0.25 | 1 | 0.5 | 0.125 | 1 | 0.002 |
| WA5 | 2 | 1 | 2 | 16 | 16 | 64 | 4 | 2 | 0.03 | 16 | 0.25 | 1 | 0.25 | 0.125 | 1 | 0.002 |
| WA7 | 2 | 1 | 2 | 16 | 16 | 64 | 4 | 4 | 0.125 | 16 | 0.25 | 1 | 1 | 0.25 | 1 | 0.004 |
| WA8 | 1 | 1 | 1 | 16 | 32 | 64 | 4 | 2 | 0.03 | 8 | 0.25 | 1 | 0.5 | 0.125 | 1 | 0.002 |
| WA9 | 1 | 1 | 1 | 16 | 16 | 64 | 2b | 4b | 0.06b | 8 | 0.25 | 1 | 1 | 0.125 | 1 | 0.002 |
| WA10 | 2 | 1 | 1 | 16 | 16 | 64 | 4 | 4 | 0.03 | 8 | 0.125 | 1 | 0.5 | 0.25 | 0.25 | 0.016 |
| WA11 | 1 | 1 | 1 | 16 | 16 | 128 | 4 | 4 | 0.03 | 16 | 0.008 | 1 | 0.5 | 0.25 | 1 | 0.002 |
| WA12 | 1 | 1 | 1 | 16 | 16 | 64 | 2 | 2 | 0.03 | 8 | 0.125 | 1 | 0.5 | 0.25 | 1 | 0.016 |
| WA13 | 1 | 1 | 1 | 8 | 16 | 64 | 2 | 2 | 0.06 | 16 | 0.125 | 0.5 | 0.5 | 0.25 | 1 | 0.016 |
| WA14 | 1 | 0.5 | 1 | 16 | 16 | 64 | 4 | 2 | 0.03 | 8 | 0.125 | 1 | 0.5 | 0.25 | 1 | 0.002 |
| CN19 | 2 | 1 | 1 | 16 | 32 | 128 | 2 | 2 | 0.25 | 1 | 0.25 | 1 | 0.25 | 0.125 | 1 | 0.016 |
| CN20 | 2 | 1 | 1 | 8 | 32 | 64 | 1 | 1 | 0.25 | 0.5 | 0.25 | 0.5 | 0.125 | 0.125 | 1 | 0.016 |
| CN24 | 2 | 0.5 | 0.03 | 8 | 32 | 64 | 1 | 2 | 0.25 | 0.5 | 0.25 | 1 | 0.25 | 0.125 | 1 | 0.032 |
| Unrelated isolates | ||||||||||||||||
| WA6 | 1 | 1 | 1 | 0.25 | 0.25 | 0.5 | 1 | 0.25 | 0.016 | 0.125 | 0.062 | 0.5 | 0.125 | 4 | 0.25 | 0.002 |
| CN21 | 0.25 | 0.125 | 0.06 | 0.5 | 8 | 8 | 0.5 | 0.5 | 0.25 | 1 | 0.25 | 1 | 0.25 | 0.125 | 1 | 0.032 |
| CN22 | 0.5 | 0.25 | 0.12 | 1 | 16 | 128 | 1 | 2 | 0.25 | 0.5 | 0.25 | 0.5 | 0.25 | 0.125 | 1 | 0.016 |
| CN23 | 2 | 0.5 | 0.03 | 16 | 32 | 64 | 2 | 4 | 0.25 | 0.5 | 0.25 | 0.5 | 0.25 | 0.125 | 1 | 0.032 |
| CN25 | 0.12 | 0.25 | 0.03 | 0.5 | 16 | 32 | 0.5 | 0.5 | 0.25 | 0.5 | 0.25 | 0.5 | 0.25 | 0.125 | 1 | 0.032 |
| CN26 | 0.5 | 0.5 | 0.03 | 1 | 16 | 64 | 0.5 | 0.5 | 0.25 | 0.5 | 0.25 | 0.5 | 0.125 | 0.06 | 1 | 0.016 |
Pen, penicillin; Ceftri, ceftriaxone; Ctax, cefotaxime; Cefpro, cefprozil; Ceftaz, ceftazidime; Lora, loracarbef; Eryth, erythromycin; Azith, azithromycin; Clin, clindamycin; Cipro, ciprofloxacin; Grepa, grepafloxacin; Levo, levofloxacin; Spar, sparfloxacin; Trova, trovafloxacin; Linez, linezolid; HMR, HMR3647. Breakpoints (in micrograms per milliliter) per National Committee for Clinical Laboratory Standards guidelines (19), unless otherwise noted, are as follows. Penicillin: susceptible, ≤0.06; intermediate, ≥0.1; resistant, ≥2; ceftriaxone: susceptible, ≤0.5, intermediate, 1; resistant, ≥2; cefotaxime: susceptible, ≤0.5; intermediate, 1; resistant, ≥2; cefprozil: susceptible, ≤0.5; intermediate, 1; resistant, ≥2; ceftazidime: susceptible, ≤0.5; intermediate, 1; resistant, ≥2; erythromycin: susceptible, ≤0.25; intermediate, 0.5; resistant, ≥1; azithromycin: susceptible, ≤0.5; intermediate, 1; resistant, ≥2; clindamycin: susceptible, ≤0.25; intermediate, 0.5; resistant, ≥1; ciprofloxacin: susceptible, ≤2; intermediate, 4, resistant, ≥8; grepafloxacin: susceptible, ≤0.5; intermediate, 1; resistant, ≥2; levofloxacin: susceptible, ≤2; intermediate, 4; resistant, ≥8; sparfloxacin: susceptible, ≤0.5; intermediate, 1; resistant, ≥2; trovafloxacin: susceptible, ≤1; intermediate, 2; resistant, ≥4. Because loracarbef, linezolid, and HMR3647 do not have established breakpoints, they are not listed. The breakpoints for ceftazidime, ciprofloxacin, sparfloxacin, and trovafloxacin are based upon the breakpoints of similar antibiotics (ceftriaxone and levofloxacin). Antibiograms of the four Alaskan isolates (AK14 to AK18) were determined by alternate methods; however, the isolates were resistant to penicillin, the cephalosporins, the macrolides, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole (data not shown) and carried the mef gene.
Isolate WA9 contained both the mef and ermB genes. MICs were determined after the isolate was exposed to a low level of erythromycin (0.5 μg/ml), with corresponding MICs of erythromycin, azithromycin, and clindamycin being 128 μg/ml (17).