Table 1. Schematic representation of a microtitration plate for the determination of minimal inhibitory concentrations (MICs).

	mg/L	mg/L	mg/L	mg/L	mg/L	mg/L	mg/L	mg/L
Ampicillin	0.25	0.5	1	2	4	8	16	32
Ampicillin/sulbactam	0.25	0.5	1	2	4	8	16	32
Piperacillin/tazobactam	0.5/2	1	2	4	8	16	32	64
Cefuroxime	0.125	0.25	0.5	1	2	4	8	16
Cefotaxime	0.125	0.25	0.5	1	2	4	8	16
Imipenem	0.125	0.25	0.5	1	2	4	8	16
Gentamicin	0.125	0.25	0.5	1	2	4	8	16
Doxycyclin	0.125	0.25	0.5	1	2	4	8	GC
Cotrimoxazole	1	2	4	8	16	32	64	128
Ciprofloxacin	0.03	0.06	0.125	0.25	0.5	1	2	4
Levofloxacin	0.03	0.06	0.125	0.25	0.5	1	2	4
Moxifloxacin	0.03	0.06	0.125	0.25	0.5	1	2	4

The antibiotics and concentrations indicated are the ones that are usually selected. The results for a particular tested strain of E. coli are indicated by gray highlighting.

The MIC values for this strain and the sensitivity ratings that will be assigned to them henceforward by EUCAST are: ampicillin = 4 mg/L (i); ampicillin/sulbactam = 1 mg/L (i); piperacilin/tazobactam = 2 mg/L (s); cefuroxime = 4 mg/L (i); cefotaxime = 0.125 mg/L (s); imipenem = 0.5 mg/L (s); gentamicin = 0.25 mg/L (s); doxycycline = 8 mg/L (Ø); cotrimoxazole >128 mg/L (r); ciprofloxacin <0.03 mg/L (s); levofloxacin <0.03 mg/L (s); moxifloxacin = 0.06 mg/L (s); GC, growth control; Ø, no data, because the combination of organism and antibiotic is unsuitable; i, intermediate; s, susceptible; r, resistant.