TABLE 2

Antimicrobial MICs for CTX-M-14- and CTX-M-140-producing P. mirabilis strains and their clones and variants

AntimicrobialMIC (μg/ml)
P. mirabilis strainsE. coli strains
GB03 (producing CTX-M-14)GB08 (producing CTX-M-14)GB11 (producing CTX-M-140)GB12 (producing CTX-M-140)J53 (pGB03)aJ53 (pGB08)aDH10B (pCTX-M-14)bDH10B (pCTX-M-140)bDH10B (pCTX-M-14 A109E)c,dDH10B (pCTX-M-14 A109D)c,dDH10B (pCTX-M-14 A109K)c,dDH10B (pCTX-M-14 A109R)c,dJ53DH10B [pBC-SK(−)]
Ampicillin>256>256>256>256>256>256>256>256328323288
Cefoxitin44448888888888
Cefotaxime32168412812812840.0630.0630.0630.0630.1250.063
Cefotaxime-clavulanic acid<0.032<0.032<0.032<0.0320.0630.0630.063<0.0320.0630.0630.0630.0630.0320.063
Ceftazidime2210.51681610.510.510.250.5
Ceftazidime-clavulanic acid0.1250.1250.1250.0630.250.250.50.50.50.50.50.50.1250.5
Ceftriaxone64324412864128320.1250.1250.1250.1250.1250.063
Aztreonam10.250.0630.063883240.250.250.250.250.0630.125
Cefepime44224220.250.0630.0630.0630.0630.016<0.032
  • a Transconjugant harboring a CTX-M-encoding plasmid from a clinical isolate.

  • b Transformant harboring a PCR-generated recombinant plasmid encoding CTX-M-14 or CTX-M-140.

  • c Transformant harboring a plasmid encoding a CTX-M-14 mutant construct.

  • d A, alanine; D, aspartic acid; E, glutamic acid; K, lysine; R, arginine.