Table 1

MICs for N152 CMY-2 variants and relative expression levels of N152 variants, as determined in Western blots probed with a polyclonal anti-CMY-2 antibody, relative to WT CMY-2 β-lactamase expression levels

VariantMIC (μg/ml)aRelative expression level (±10%)
ATMAMPPIPTZP 8:1CAZFOXCROCEFCTXFEP
DH10B≤0.06≤4≤2≤2/0.25≤0.25≤4≤0.015≤4≤2≤0.0150
WT212884/0.51632≤0.0151,0244≤0.015100
N152A≤0.06≤4≤2≤2/0.250.58≤0.015≤2≤0.01566
N152C≤0.0684≤2/0.2518≤0.015≤0.01539
N152D≤0.06≤4≤2≤2/0.250.58≤0.015≤0.01525
N152E≤0.068≤2≤2/0.25≤0.258≤0.015≤0.01533
N152F≤0.06≤4≤2≤2/0.25≤0.258≤0.015≤0.01535
N152G0.256416≤2/0.2548≤0.01564≤2≤0.01549
N152H≤0.06≤4≤2≤2/0.2518≤0.015≤0.01527
N152I≤0.0688≤2/0.250.58≤0.015≤4≤2≤0.01514
N152K≤0.06≤4≤2≤2/0.2518≤0.015≤4≤2≤0.01510
N152L≤0.06≤44≤2/0.250.5≤4≤0.015≤4≤2≤0.01565
N152M≤0.0684≤2/0.250.58≤0.015≤0.01525
N152P≤0.06≤4≤2≤2/0.25≤0.25≤4≤0.015≤4≤2≤0.01560
N152Q≤0.068≤2≤2/0.25≤0.25≤4≤0.015≤4≤2≤0.01545
N152R≤0.068≤2≤2/0.25≤0.258≤0.015≤0.01533
N152S0.253216≤2/0.258≤4≤0.015128≤2≤0.01551
N152T0.256432≤2/0.2548≤0.01564≤2≤0.01559
N152V≤0.06≤42≤2/0.25≤0.258≤0.015≤0.01532
N152W0.125≤42≤2/0.25≤0.258≤0.015≤4≤2≤0.01527
N152Y≤0.06≤42≤2/0.250.58≤0.015≤0.01545
  • a MICs are the mode of 3 to 5 determinations. ATM, aztreonam; AMP, ampicillin; PIP, piperacillin; TZP 8:1, piperacillin and tazobactam in a fixed ratio of 8:1; CAZ, ceftazidime; FOX, cefoxitin; CRO, ceftriaxone; CEF, cephalothin; CTX, cefotaxime; FEP, cefepime.