非结构化摘要
Combining antibiotics with plant sterols that have antibacterial activity is a method of increasing the effectiveness of the antibiotics. In this study, we synthesized α-spinasterol from commercially available stigmasterol by a novel method in order to increase its yield, and tested the combination of the α-spinasterol with ceftiofur in vitro against four strains of pathogenic bacteria. The minimum inhibitory concentration (MIC) of stigmasterol, spinasterol and ceftiofur against Escherichia coli, Streptococcus pneumoniae CAU0070, Salmonella pullorum cvcc533 and Staphylococcus aureus were determined with a tube dilution method. Results showed that MICs of α-spinasterol against the four pathogenic microorganisms were the same for all (256 μg/ml), or one-half that of stigmasterol (512 μg/ml), and much greater than the MIC of ceftiofur (0.125 to 4 μg/ml). The combination of α-spinasterol and ceftiofur were strongly synergetic against the four bacterial strains; the fractional inhibitory concentrations on E. coli, S. pneumoniae CAU0070, S. pullorum cvcc533, and S. aureus were 0.375, 0.375, 0.533 and 0.5, respectively. In time-kill analyses, at concentrations above the MICs, ceftiofur exhibited only time-dependency against the four pathogenic microganisms, whereas ceftiofur in combination with α-spinasterol exhibited time-dependency and concentration-dependency. We conclude that ceftiofur combined with α-spinasterol, synthetized from stigmasterol by our method, is effective against four pathogenic bacterial strains in vitro. Effectiveness of this combination in vivo deserves investigation.
重写后的结构化摘要
Background/Aim. Combining antibiotics with plant sterols that have antibacterial activity is a method of increasing the effectiveness of the antibiotics. In this study, we synthesized α-spinasterol from commercially available stigmasterol by a novel method in order to increase its yield.
Methods. The minimum inhibitory concentration of stigmasterol, spinasterol and ceftiofur against Escherichia coli, Streptococcus pneumoniae CAU0070, Salmonella pullorum cvcc533 and Staphylococcus aureus were determined with a tube dilution method.
Results. Minimum inhibitory concentrations of α-spinasterol against the four pathogenic microorganisms were the same for all (256 μg/ml), or one-half that of stigmasterol (512 μg/ml), and much greater than the minimal inhibitory concentration of ceftiofur (0.125 to 4 μg/ml). The combination of α-spinasterol and ceftiofur were strongly synergetic against the four bacterial strains; the fractional inhibitory concentrations on E. coli, S. pneumoniae CAU0070, S. pullorum cvcc533, and S. aureus were 0.375, 0.375, 0.533 and 0.5, respectively. In time-kill analyses, at concentrations above the minimum inhibitory concentrations, ceftiofur exhibited only time-dependency against the four pathogenic microganisms, whereas ceftiofur in combination with α-spinasterol exhibited time-dependency and concentration-dependency.
Conclusions. Ceftiofur combined with α-spinasterol, synthetized from stigmasterol by our method, is effective against four pathogenic bacterial strains in vitro. Effectiveness of this combination in vivo deserves investigation.
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