In A and B, PCR primers targeting the junction sites of OC8 MbIN (A-C and B-D) and those targeting the corresponding region of USA300 FPR3757 (A-B and C-D) were designed based on the OC8 or USA300 FPR3757 complete genome sequence, respectively. The structures of the MbIN junction regions of OC8 and the corresponding regions of USA300 FPR3757 are from Fig 5. In C to E, PCR products with an asterisk were sequenced, and the sequences determined were consistent with the OC8 or USA300 FPR3757 genome sequence. ST8Kras is ST8/SCCmecIVc MRSA from Krasnoyarsk, Siberian Russia. The geographical location of MRSA isolated in European Russia: Mow, Moscow; St. P, St. Petersburg; Yar, Yaroslavl. Regarding Far Eastern Russia, MRSA was isolated in Vladivostok.