It is resistant to the antibiotic resistance enzyme beta-lactamase, and has activity against Gram-positive and Gram-negative bacteria. E. coli strains resistant to ceftiofur have been reported.
^ Yancey RJ, Kinney ML, Roberts BJ, Goodenough KR, Hamel JC, Ford CW (1987). "Ceftiofur sodium, a broad-spectrum cephalosporin: evaluation in vitro and in vivo in mice". Am. J. Vet. Res.48 (7): 1050–3. PMID 3631686.
^ Pfizer Animal ealth Dairy Information on Products and Solutions. Retrieved on 2007-11-20.