TABLE 2.

β-Lactam resistance phenotypes for 59 E. coli isolates for which the MIC of cefpodoxime is ≥2 and that of ceftazidime is ≤1 μg/mla

MIC (μg/ml)
Major phenotypesMinor phenotypes
ABCDE
n strains (%)32 (54.2%)18 (30.5%)7 (11.9%)1 (1.7%)1 (1.7%)
β-Lactamase pI5.4≥8.57.25.4, 5.7, 6.8
AMX>6432->64>644>64
AMX-CLAV16-3216-3232->64432
TIC>1288-32>1288>128
PIP>128<4-8>12816>128
PIP-TZ8->128<4-8≥1281616
CFZ16->2564-6416-32216
CFZ-CLAV2-42-164-812
CXM16-328-3232-12816128
CPD2-42-44-842
FOX16->328-328-321616
CAZ0.5-10.5-10.25-10.51
CAZ-CLAV0.50.5-10.12-0.50.50.5
CTX0.50.25-1110.5
CTX-CLAV0.25-0.50.12-0.50.250.50.5
FEP0.12-0.50.06-0.252-40.250.5
FEP-CLAV0.120.06-0.120.12-0.50.120.12
  • a NCCLS breakpoints (S/I/R): AMX, CAZ, CXM, CFZ, FEP, FOX, ≤8/16/≥32; CPD, ≤2/4/≥8; CTX, ≤8/16-32/≥64; PIP, TIC, ≤16/32-64/≥128