The First Report of Macrolide-Resistant Bordetella pertussis Isolation in Japan.

We report the first detection of a macrolide-resistant Bordetella pertussis strain in Japan. The isolate was highly resistant to the macrolides (minimum inhibitory concentrations for erythromycin and clarithromycin: > 256 µg/ml, for azithromycin: 32 µg/ml) and A2047G mutation was identified in the 23S rRNA. The Multilocus Sequence Typing and Multilocus Variable Number of Tandem Repeat Analysis genotypes of this isolate were MT195 and ptxP1/ptxA1/prn1/fim3A/fhaB3, respectively, suggesting a relationship with the macrolide-resistant B. pertussis lineage currently found in China. This raises the possibility that macrolide-resistant B. pertussis has already fully spread in Japan. For a better control of B. pertussis infections, the surveillance for macrolide-resistant B. pertussis is essential in not only Japan, but also other Asian countries.