Table 1: MICs and zone diameters for A. urinae isolates when tested by EUCAST standardized disk diffusion method, Etest, and broth microdilution (Sensititre).
A. urinae |
Disk diffusion (wildtype) |
Etest |
Broth microdilution * |
No. of isolates with MIC (mg/L) |
MIC (mg/L) |
MIC (mg/L) |
Antibiotic |
mm |
<0.002 |
0.004 |
0.008 |
0.016 |
0.032 |
0.064 |
0.125 |
0.25 |
0.5 |
1 |
2 |
MIC50
|
MIC90
|
Range |
MIC50
|
MIC90
|
Range |
Benzylpenicillin |
29-40 |
|
|
8 |
31 |
28 |
10 |
1 |
|
|
|
|
0.032 |
0.064 |
0.008-0.125 |
≤0.03 |
0.06 |
≤0.03-0.06 |
Cefotaxime |
24-38 |
|
|
|
1 |
5 |
20 |
22 |
18 |
8 |
3 |
1 |
0.125 |
0.5 |
0.016-2 |
0.25 |
1 |
≤0.125-2 |
Meropenem |
35-47 |
|
|
5 |
19 |
29 |
21 |
2 |
3 |
|
|
|
0.032 |
0.064 |
0.008-0.25 |
≤0.25 |
≤0.25 |
≤0.25 |
Vancomycin |
19-25 |
|
|
|
|
|
|
1 |
1 |
36 |
40 |
2 |
1 |
1 |
0.125-2 |
≤0.5 |
≤0.5 |
≤0.5 |
Linezolid |
27-35 |
|
|
|
|
|
|
|
5 |
10 |
35 |
28 |
1 |
2 |
0.25-2 |
1 |
1 |
≤0.25-2 |
Rifampicin |
34-46 |
5 |
11 |
27 |
26 |
5 |
1 |
1 |
|
|
|
|
0.008 |
0.016 |
<0.002-0.125 |
NR |
NR |
NR |
* Susceptibility recommendation method: Medium: Mueller-Hinton (MH) plates with 5% defibrinated horse blood and 20 mg/L β-NAD (MH-F). Inoculum: McFarland 0.5. Incubation: 5% CO2, 35±1 °C, 18±2h. Isolates with insufficient growth after 16-20 h incubation were re-incubated immediately and inhibition zones and MICs read after a total of 40-44 h incubation. Reading: Read zone edges as the point showing no growth viewed from the front of the plate with the lid removed and with reflected light.