Characteristics of Escherichia coli Isolated from Bovine Mastitis Exposed to Subminimum Inhibitory Concentrations of Cefalotin or Ceftazidime

Table 3

Antimicrobial susceptibility profiles of the Escherichia coli isolates recovered after induction with cefalotin.

	Resistant E. coli isolates
Antimicrobial	Derived from E4	Derived from E11	Derived from E21
Cefoxitin	CF-3/-4/-5/-6/-7/-8/-9	CF-5/-6/-7/-8/-9	CF-5/-6/-7/-8/-9
Ceftazidime	CF-5/-6/-7/-8/-9	CF-5/-6/-7/-8/-9	CF-7/-8/-9
Ampicillin	CF-4/-5/-6/-7/-8/-9	CF-3/-4/-5/-6/-7/-8/-9	CF-6/-7/-8/-9
Amoxicillin/clavulanic acid	CF-4/-5/-6/-7/-8/-9	CF-4/-5/-6/-7/-8/-9	CF-6/-7/-8/-9
Kanamycin	CF-4/-5/-6/-7/-8/-9	CF-7/-8/-9	CF-6/-7/-8/-9

All E. coli isolates had intermediate resistance to cefoxitin, ceftazidime, and kanamycin.