Differential intracellular efficacies of ciprofloxacin and cefixime against Neisseria gonorrhoeae in human fallopian tube organ culture

This study compared the abilities of ciprofluxaein and cefixime to kill intracellular Neisseria gonorrhoeae in a human fallopian tube organ culture assay. When invasion was inhibited by cytochalasin D, 0.996% of the tissue- associated gonococci survived ciprofloxacin exposure compared to 1.70% of gonococci exposed to cefixime (95% confidence interval fur the ratio of the means, 0.267 to 1.30), indicating that the two antibiotics did nut significantly differ in the ability to kill extracellular attached organisms. In the absence of cytochalasin D. 1.63% survived ciprofloxacin exposure while 9.76% survived cefixime treatment (95% confidence interval for the ratio of the means, 0.067 to 0.418). These results suggest that ciprofloxacin penetrated epithelial cells and killed intracellular gonococci better than did cefixime. Thus, at concentrations achievable in serum, ciprofloxacin was more effective in total gonococcal killing than cefixime in this human fallopian tube organ culture model.