Azithromycin failure in Mycoplasma genitalium urethritis.

We report significant failure rates (28%, 95% confidence interval 15%-45%) after administering 1 g azithromycin to men with Mycoplasma genitalium-positive nongonococcal urethritis. In vitro evidence supported reduced susceptibility of M. genitalium to macrolides. Moxifloxacin administration resulted in rapid symptom resolution and eradication of infection in all cases. These findings have implications for management of urethritis.