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.