ABSTRACT
The antibacterial activity of pig and calf serum and its ability to interact with gentamicin and ciprofloxacin were studied in vitro using Escherichia coli K-12, Proteus rettgeri (Sanelli) and Klebsiella pneumoniae ATCC 10031. The antimicrobial activity of the above drugs, alone or in combination with serum, was investigated by the checkerboard method and expressed as the minimal inhibitory concentration (microg ml-1). Pig serum (25%) with gentamicin had a synergistic antibacterial effect against Escherichia coli K-12 and pig serum (25%) with ciprofloxacin against Proteus rettgeri (Sanelli) and Klebsiella pneumoniae ATCC 10031. Calf serum (25%) had a synergistic effect with gentamicin against Proteus rettgeri (Sanelli) and calf serum (25%) plus ciprofloxacin against Klebsiella pneumoniae ATCC 10031. The effects of these drugs may be enhanced by pig and calf sera.
