Date of Original Version
Ciprofloxacin and enoxacin were two- to fourfold less active against Pseudomonas aeruginosa in calcium- and magnesium-supplemented broth compared with unsupplemented broth regardless of inoculum size, presence of serum, or use of inhibitory or bactericidal endpoints (P < 0.01). The effect of cation supplementation was less pronounced and less consistent for Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus.
Blaser, J., Dudley, M. N., Gilbert, D., & Zinner, S. H. (1986). Influence of Medium and Method on the In Vitro Susceptibility of Pseudomonas aeruginosa and Other Bacteria to Ciprofloxacin and Enoxacin. Antimicrob. Agents Chemother., 29(5), 927-929. doi: 10.1128/AAC.29.5.92.
Available at: http://dx.doi.org/10.1128/AAC.29.5.927