TABLE 1

Antimicrobial susceptibility profiles of bovine mastitis E. coli and Klebsiella pneumoniae subsp. pneumoniae isolates and selected transconjugantsa

AntimicrobialMIC (μg/ml)b
Parental isolatesConjugants
25(2053)26(2104A)27(2104B)28(2104C)32(2188)26C(2104A)28C(2104C)32C(2188)
AMP323232323232432
CFZ323232323232432
FEP24848828
CTX432321664320.1232
CTX-CLA0.250.060.50.50.2540.064
FOX1282128128212816128
CPD646464646464164
CAZ646425612864828
CAZ-CLA0.50.060.50.50.2520.252
CRO16646432128640.564
CEF323232323232NM32
CIP0.50.50.50.50.540.5NM
GEN323216163216216
IPM0.250.250.250.250.250.250.250.25
MEM0.50.50.50.50.50.50.50.5
PIP-TZB2212882222
  • a Abbreviations: AMP, ampicillin; CFZ, cefazolin; FEP, cefepime; CTX, cefotaxime; CTX-CLA, cefotaxime-clavulanic acid; FOX, cefoxitin; CPD, cefpodoxime; CAZ, ceftazidime; CAZ-CLA, ceftazidime-clavulanic acid; CRO, ceftriaxone; CEF, cephalothin; CIP, ciprofloxacin; GEN, gentamicin; IPM, imipenem; MEM, meropenem; PIP-TZB, piperacillin-tazobactam; NM, not measured.

  • b Bold represents resistance by CLSI interpretation rules.