New Ceftriaxone- and Multidrug-Resistant Neisseria gonorrhoeae Strain with a Novel Mosaic penA Gene Isolated in Japan

We have characterized in detail a new ceftriaxone- and multidrug-resistant Neisseria gonorrhoeae strain (FC428) isolated in Japan in 2015. FC428 differed from previous ceftriaxone-resistant strains and contained a novel mosaic penA allele encoding a new mosaic penicillin-binding protein 2 (PBP 2). However, the resistance-determining 3'-terminal region of penA was almost identical to the regions of two previously reported ceftriaxone-resistant strains from Australia and Japan, indicating that both ceftriaxone-resistant strains and conserved ceftriaxone resistance-determining PBP 2 regions might spread.