Table 2

MIC values and ranges by resistance mechanism of AMC-resistant E. coli isolates

Resistance mechanism (n)aMIC50 (μg/ml)MIC90 (μg/ml)MIC range (μg/ml)% of isolates with a MIC > 32/16 μg/ml
OXA-1 (54)32/1664/3216/8–128/6440.3
IRT (45)64/32128/6416/8–>128/6493.3
p-AmpC (43)64/32128/6432/16–>128/6492
c-AmpC (41)64/32128/6432/16–128/6483
P3/TEM-1 (27)64/3264/3216/8–>128/6466.7
Pdf3/TEM-1 (26)b64/32>128/6416/8–>128/6484.6
OXA-1+AmpC (13)64/3264/3232/16–64/3253.8
  • a n, number of isolates.

  • b Isolates with blaTEM-1 and with promoters other than P3.